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Sample records for reservoir quality-frio sandstone

  1. Revitalizing a mature oil play: Strategies for finding and producing unrecovered oil in frio fluvial-deltaic sandstone reservoirs at South Texas. Annual report, October 1994--October 1995

    Energy Technology Data Exchange (ETDEWEB)

    Holtz, M.; Knox, P.; McRae, L. [and others

    1996-02-01

    The Frio Fluvial-Deltaic Sandstone oil play of South Texas has produced nearly 1 billion barrels of oil, yet it still contains about 1.6 billion barrels of unrecovered mobile oil and nearly the same amount of residual oil resources. Interwell-scale geologic facise models of Frio Fluvial-deltaic reservoirs are being combined with engineering assessments and geophysical evaluations in order to determine the controls that these characteristics exert on the location and volume or unrecovered mobile and residual oil. Progress in the third year centered on technology transfer. An overview of project tasks is presented.

  2. Sedimentological reservoir characteristics of the Paleocene fluvial/lacustrine Yabus Sandstone, Melut Basin, Sudan

    Science.gov (United States)

    Mahgoub, M. I.; Padmanabhan, E.; Abdullatif, O. M.

    2016-11-01

    Melut Basin in Sudan is regionally linked to the Mesozoic-Cenozoic Central and Western African Rift System (CWARS). The Paleocene Yabus Formation is the main oil producing reservoir in the basin. It is dominated by channel sandstone and shales deposited in fluvial/lacustrine environment during the third phase of rifting in the basin. Different scales of sedimentological heterogeneities influenced reservoir quality and architecture. The cores and well logs analyses revealed seven lithofacies representing fluvial, deltaic and lacustrine depositional environments. The sandstone is medium to coarse-grained, poorly to moderately-sorted and sub-angular to sub-rounded, arkosic-subarkosic to sublitharenite. On the basin scale, the Yabus Formation showed variation in sandstone bodies, thickness, geometry and architecture. On macro-scale, reservoir quality varies vertically and laterally within Yabus Sandstone where it shows progressive fining upward tendencies with different degrees of connectivity. The lower part of the reservoir showed well-connected and amalgamated sandstone bodies, the middle to the upper parts, however, have moderate to low sandstone bodies' connectivity and amalgamation. On micro-scale, sandstone reservoir quality is directly affected by textures and diagenetic changes such as compaction, cementation, alteration, dissolution and kaolinite clays pore fill and coat all have significantly reduced the reservoir porosity and permeability. The estimated porosity in Yabus Formation ranges from 2 to 20% with an average of 12%; while permeability varies from 200 to 500 mD and up to 1 Darcy. The understanding of different scales of sedimentological reservoir heterogeneities might contribute to better reservoir quality prediction, architecture, consequently enhancing development and productivity.

  3. Diagenesis and reservoir quality of the Lower Cretaceous Quantou Formation tight sandstones in the southern Songliao Basin, China

    Science.gov (United States)

    Xi, Kelai; Cao, Yingchang; Jahren, Jens; Zhu, Rukai; Bjørlykke, Knut; Haile, Beyene Girma; Zheng, Lijing; Hellevang, Helge

    2015-12-01

    The Lower Cretaceous Quantou Formation in the southern Songliao Basin is the typical tight oil sandstone in China. For effective exploration, appraisal and production from such a tight oil sandstone, the diagenesis and reservoir quality must be thoroughly studied first. The tight oil sandstone has been examined by a variety of methods, including core and thin section observation, XRD, SEM, CL, fluorescence, electron probing analysis, fluid inclusion and isotope testing and quantitative determination of reservoir properties. The sandstones are mostly lithic arkoses and feldspathic litharenites with fine to medium grain size and moderate to good sorting. The sandstones are dominated by feldspar, quartz, and volcanic rock fragments showing various stages of disintegration. The reservoir properties are quite poor, with low porosity (average 8.54%) and permeability (average 0.493 mD), small pore-throat radius (average 0.206 μm) and high displacement pressure (mostly higher than 1 MPa). The tight sandstone reservoirs have undergone significant diagenetic alterations such as compaction, feldspar dissolution, quartz cementation, carbonate cementation (mainly ferrocalcite and ankerite) and clay mineral alteration. As to the onset time, the oil emplacement was prior to the carbonate cementation but posterior to the quartz cementation and feldspar dissolution. The smectite to illite reaction and pressure solution at stylolites provide a most important silica sources for quartz cementation. Carbonate cements increase towards interbedded mudstones. Mechanical compaction has played a more important role than cementation in destroying the reservoir quality of the K1q4 sandstone reservoirs. Mixed-layer illite/smectite and illite reduced the porosity and permeability significantly, while chlorite preserved the porosity and permeability since it tends to be oil wet so that later carbonate cementation can be inhibited to some extent. It is likely that the oil emplacement occurred

  4. Salinity variations and chemical compositions of waters in the Frio Formation, Texas Gulf Coast. Annual report

    Energy Technology Data Exchange (ETDEWEB)

    Morton, R.A.; Garrett, C.M. Jr.; Posey, J.S.; Han, J.H.; Jirik, L.A.

    1981-11-01

    Waters produced from sandstone reservoirs of the deep Frio Formation exhibit spatial variations in chemical composition that roughly coincide with the major tectonic elements (Houston and Rio Grande Embayments, San Marcos Arch) and corresponding depositional systems (Houston and Norias deltas, Greta-Carancahua barrier/strandplain system) that were respectively active along the upper, lower, and middle Texas Coast during Frio deposition. Within an area, salinities are usually depth dependent, and primary trends closely correspond to pore pressure gradients and thermal gradients. Where data are available (mainly in Brazoria County) the increases in TDS and calcium with depth coincide with the zone of albitization, smectite-illite transition, and calcite decrease in shales. Waters have fairly uniform salinities when produced from the same sandstone reservoir within a fault block or adjacent fault blocks with minor displacement. In contrast, stratigraphically equivalent sandstones separated by faults with large displacement usually yield waters with substantially different salinities owing to the markedly different thermal and pressure gradients across the faults that act as barriers to fluid movement.

  5. Diagenesis and reservoir quality of Bhuban sandstones (Neogene), Titas Gas Field, Bengal Basin, Bangladesh

    Science.gov (United States)

    Aminul Islam, M.

    2009-06-01

    This study deals with the diagenesis and reservoir quality of sandstones of the Bhuban Formation located at the Titas Gas Field of Bengal Basin. Petrographic study including XRD, CL, SEM and BSE image analysis and quantitative determination of reservoir properties were carried out for this study. The sandstones are fine to medium-grained, moderately well to well sorted subfeldspathic arenites with subordinate feldspathic and lithic arenites. The diagenetic processes include clay infiltration, compaction and cementation (quartz overgrowth, chlorite, kaolinite, calcite and minor amount of pyrite, dolomite and K-feldspar overgrowth). Quartz is the dominant pore occluding cement and generally occurred as small euhedral crystals, locally as large pyramidal crystals in the primary pores. Pressure solution derived from grain contact is the main contributor of quartz overgrowths. Chlorite occurs as pore-lining and pore filling cement. In some cases, chlorite helps to retain porosity by preventing quartz overgrowth. In some restricted depth interval, pore-occlusion by calcite cement is very much intense. Kaolinite locally developed as vermiform and accelerated the minor porosity loss due to pore-occlusion. Kaolinite/chlorite enhances ineffective microporosity. Kaolinite is a by-product of feldspar leaching in the presence of acidic fluid produced during the maturation of organic matter in the adjacent Miocene or deeper Oligocene source rocks. The relation between diagenesis and reservoir quality is as follows: the initial porosity was decreased by compaction and cementation and then increased by leaching of the metastable grains and dissolution of cement. Good quality reservoir rocks were deposited in fluvial environment and hence quality of reservoir rocks is also environment selective. Porosity and permeability data exhibit good inverse correlation with cement. However, some data points indicate multiple controls on permeability. Reservoir quality is thus controlled by

  6. Reservoir characterization of Pennsylvanian sandstone reservoirs. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kelkar, M.

    1995-02-01

    This final report summarizes the progress during the three years of a project on Reservoir Characterization of Pennsylvanian Sandstone Reservoirs. The report is divided into three sections: (i) reservoir description; (ii) scale-up procedures; (iii) outcrop investigation. The first section describes the methods by which a reservoir can be described in three dimensions. The next step in reservoir description is to scale up reservoir properties for flow simulation. The second section addresses the issue of scale-up of reservoir properties once the spatial descriptions of properties are created. The last section describes the investigation of an outcrop.

  7. Micropore Structure Representation of Sandstone in Petroleum Reservoirs Using an Atomic Force Microscope

    International Nuclear Information System (INIS)

    Bai Yong-Qiang; Zhu Xing; Wu Jun-Zheng; Bai Wen-Guang

    2011-01-01

    The pore structure of sandstone in an oil reservoir is investigated using atomic force microscopy (AFM). At nanoscale resolution, AFM images of sandstone show us the fine structure. The real height data of images display the three-dimensional space structure of sandstone effectively. The three-dimensional analysis results show that the AFM images of sandstone have unique characteristics that, like fingerprints, can identify different structural properties of sandstones. The results demonstrate that AFM is an effective method used to represent original sandstone in petroleum reservoirs, and may help geologists to appreciate the sandstone in oil reservoirs fully. (general)

  8. Diagenetic effect on permeabilities of geothermal sandstone reservoirs

    DEFF Research Database (Denmark)

    Weibel, Rikke; Olivarius, Mette; Kristensen, Lars

    The Danish subsurface contains abundant sedimentary deposits, which can be utilized for geothermal heating. The Upper Triassic – Lower Jurassic continental-marine sandstones of the Gassum Formation has been utilised as a geothermal reservoir for the Thisted Geothermal Plant since 1984 extracting...... and permeability is caused by increased diagenetic changes of the sandstones due to increased burial depth and temperatures. Therefore, the highest water temperatures typically correspond with the lowest porosities and permeabilities. Especially the permeability is crucial for the performance of the geothermal......-line fractures. Continuous thin chlorite coatings results in less porosity- and permeability-reduction with burial than the general reduction with burial, unless carbonate cemented. Therefore, localities of sandstones characterized by these continuous chlorite coatings may represent fine geothermal reservoirs...

  9. Controls on the quality of Miocene reservoirs, southern Gulf of Mexico

    Science.gov (United States)

    Gutiérrez Paredes, Hilda Clarisa; Catuneanu, Octavian; Hernández Romano, Ulises

    2018-01-01

    An investigation was conducted to determine the main controls on the reservoir quality of the middle and upper Miocene sandstones in the southern Gulf of Mexico based on core descriptions, thin section petrography and petrophysical data; as well as to explore the possible link between the sequence stratigraphic framework, depositional facies and diagenetic alterations. The Miocene deep marine sandstones are attributed to the falling-stage, lowstand, and transgressive systems tracts. The middle Miocene falling-stage systems tract includes medium-to very fine-grained, and structureless sandstones deposited in channels and frontal splays, and muddy sandstones, deposited in lobes of debrites. The lowstand and transgressive systems tracts consist of medium-to very fine-grained massive and normally graded sandstones deposited in channel systems within frontal splay complexes. The upper Miocene falling-stage systems tract includes medium-to coarse-grained, structureless sandstones deposited in channel systems and frontal splay, as well as lobes of debrites formed by grain flows and hybrid-flow deposits. The lowstand and transgressive systems tracts include fine-grained sandstones deposited in overbank deposits. The results reveal that the depositional elements with the best reservoir quality are the frontal splays deposited during the falling-stage system tracts. The reservoir quality of the Miocene sandstones was controlled by a combination of depositional facies, sand composition and diagenetic factors (mainly compaction and calcite cementation). Sandstone texture, controlled primarily by depositional facies appears more important than sandstone composition in determining reservoir quality; and compaction was more important than cementation in porosity destruction. Compaction was stopped, when complete calcite cementation occurred.

  10. Provenance, diagenesis, tectonic setting and reservoir quality of the sandstones of the Kareem Formation, Gulf of Suez, Egypt

    Science.gov (United States)

    Zaid, Samir M.

    2013-09-01

    The Middle Miocene Kareem sandstones are important oil reservoirs in the southwestern part of the Gulf of Suez basin, Egypt. However, their diagenesis and provenance and their impact on reservoir quality, are virtually unknown. Samples from the Zeit Bay Oil Field, and the East Zeit Oil Field represent the Lower Kareem (Rahmi Member) and the Upper Kareem (Shagar Member), were studied using a combination of petrographic, mineralogical and geochemical techniques. The Lower Rahmi sandstones have an average framework composition of Q95F3.4R1.6, and 90% of the quartz grains are monocrystalline. By contrast, the Upper Shagar sandstones are only slightly less quartzose with an average framework composition of Q76F21R3 and 82% of the quartz grains are monocrystalline. The Kareem sandstones are mostly quartzarenite with subordinate subarkose and arkose. Petrographical and geochemical data of sandstones indicate that they were derived from granitic and metamorphic terrains as the main source rock with a subordinate quartzose recycled sedimentary rocks and deposited in a passive continental margin of a syn rift basin. The sandstones of the Kareem Formation show upward decrease in maturity. Petrographic study revealed that dolomite is the dominant cement and generally occurs as fine to medium rhombs pore occluding phase and locally as a grain replacive phase. Authigenic quartz occurs as small euhedral crystals, locally as large pyramidal crystals in the primary pores. Authigenic anhydrites typically occur as poikilotopic rhombs or elongate laths infilling pores but also as vein filling cement. The kaolinite is a by-product of feldspar leaching in the presence of acidic fluid produced during the maturation of organic matter in the adjacent Miocene rocks. Diagenetic features include compaction; dolomite, silica and anhydrite cementation with minor iron-oxide, illite, kaolinite and pyrite cements; dissolution of feldspars, rock fragments. Silica dissolution, grain replacement and

  11. Reservoir heterogeneity in carboniferous sandstone of the Black Warrior basin. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kugler, R.L.; Pashin, J.C.; Carroll, R.E.; Irvin, G.D.; Moore, H.E.

    1994-06-01

    Although oil production in the Black Warrior basin of Alabama is declining, additional oil may be produced through improved recovery strategies, such as waterflooding, chemical injection, strategic well placement, and infill drilling. High-quality characterization of reservoirs in the Black Warrior basin is necessary to utilize advanced technology to recover additional oil and to avoid premature abandonment of fields. This report documents controls on the distribution and producibility of oil from heterogeneous Carboniferous reservoirs in the Black Warrior basin of Alabama. The first part of the report summarizes the structural and depositional evolution of the Black Warrior basin and establishes the geochemical characteristics of hydrocarbon source rocks and oil in the basin. This second part characterizes facies heterogeneity and petrologic and petrophysical properties of Carter and Millerella sandstone reservoirs. This is followed by a summary of oil production in the Black Warrior basin and an evaluation of seven improved-recovery projects in Alabama. In the final part, controls on the producibility of oil from sandstone reservoirs are discussed in terms of a scale-dependent heterogeneity classification.

  12. Reservoir heterogeneity in Carboniferous sandstone of the Black Warrior basin. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kugler, R.L.; Pashin, J.C.; Carroll, R.E.; Irvin, G.D.; Moore, H.E.

    1994-04-01

    Although oil production in the Black Warrior basin of Alabama is declining, additional oil may be produced through improved recovery strategies, such as waterflooding, chemical injection, strategic well placement, and infill drilling. High-quality characterization of reservoirs in the Black Warrior basin is necessary to utilize advanced technology to recover additional oil and to avoid premature abandonment of fields. This report documents controls on the distribution and producibility of oil from heterogeneous Carboniferous reservoirs in the Black Warrior basin of Alabama. The first part of the report summarizes the structural and depositional evolution of the Black Warrior basin and establishes the geochemical characteristics of hydrocarbon source rocks and oil in the basin. This second part characterizes facies heterogeneity and petrologic and petrophysical properties of Carter and Millerella sandstone reservoirs. This is followed by a summary of oil production in the Black Warrior basin and an evaluation of seven improved-recovery projects in Alabama. In the final part, controls on the producibility of oil from sandstone reservoirs are discussed in terms of a scale-dependent heterogeneity classification.

  13. Diagenetic controls on porosity variations within an aeolian sandstone reservoir, borehole Kudu 9A-3

    International Nuclear Information System (INIS)

    Marot, J.E.B.

    1990-01-01

    Three boreholes, Kudu 9A-1, 9A-2 and 9A-3, were drilled approximately 125 km west of the Orange River mouth to test a gas-bearing structure of Barremian age. The reservoir interval comprises an upper unit of interbedded shallow marine sandstones, limestones and volcaniclastic mass flow deposits, and a lower non-marine unit of interbedded aeolian sandstones, basaltic lavas and volcaniclastic deposits. Despite the overall good poroperm characteristics of the aeolian sandstone and its apparent mineralogical homogeneity, as implied by a gamma ray trace, the core analysis results show an extreme variation in porosity and permeability values. In order to assist in reservoir quality prediction and to assess the regional prospectivity of the sandstone, it was necessary to explain these variations. The resuls of the study indicate that compositionally and texturally the sandstones are extremely homogeneous. It is concluded that the marked variation in the poroperm characteristics of the aeolian sandstones is a result of a relatively complex diagenesis. A fluctuating water table resulted in the formation of a pattern of calcite, anhydrite and quartz cements within an aeolian dune sandstone. 7 refs., 1 fig

  14. Diagenetic Evolution and Reservoir Quality of Sandstones in the North Alpine Foreland Basin: A Microscale Approach.

    Science.gov (United States)

    Gross, Doris; Grundtner, Marie-Louise; Misch, David; Riedl, Martin; Sachsenhofer, Reinhard F; Scheucher, Lorenz

    2015-10-01

    Siliciclastic reservoir rocks of the North Alpine Foreland Basin were studied focusing on investigations of pore fillings. Conventional oil and gas production requires certain thresholds of porosity and permeability. These parameters are controlled by the size and shape of grains and diagenetic processes like compaction, dissolution, and precipitation of mineral phases. In an attempt to estimate the impact of these factors, conventional microscopy, high resolution scanning electron microscopy, and wavelength dispersive element mapping were applied. Rock types were established accordingly, considering Poro/Perm data. Reservoir properties in shallow marine Cenomanian sandstones are mainly controlled by the degree of diagenetic calcite precipitation, Turonian rocks are characterized by reduced permeability, even for weakly cemented layers, due to higher matrix content as a result of lower depositional energy. Eocene subarkoses tend to be coarse-grained with minor matrix content as a result of their fluvio-deltaic and coastal deposition. Reservoir quality is therefore controlled by diagenetic clay and minor calcite cementation.Although Eocene rocks are often matrix free, occasionally a clay mineral matrix may be present and influence cementation of pores during early diagenesis. Oligo-/Miocene deep marine rocks exhibit excellent quality in cases when early cement is dissolved and not replaced by secondary calcite, mainly bound to the gas-water contact within hydrocarbon reservoirs.

  15. Architecture of an Upper Jurassic barrier island sandstone reservoir, Danish Central Graben:

    DEFF Research Database (Denmark)

    Johannessen, Peter N.; Nielsen, Lars H.; Nielsen, Lars

    2010-01-01

    An unusually thick (c. 88 m), transgressive barrier island and shoreface sandstone succession characterizes the Upper Jurassic Heno Formation reservoir of the Freja oil field situated on the boundary of Denmark and Norway. The development and preservation of such thick transgressive barrier island...... sands is puzzling since a barrier island typically migrates landwards during transgression and only a thin succession of back-barrier and shoreface sands is preserved. Investigation of the development and geometry of the Freja reservoir sandstones is problematic since the reservoir is buried c. 5 km...... and seismic resolution is inadequate for architectural analysis. Description of the reservoir sandstone bodies is thus based on sedimentological interpretation and correlation of seven wells, of which five were cored. Palaeotopography played a major role in the position and preservation of the thick reservoir...

  16. On the water saturation calculation in hydrocarbon sandstone reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Stalheim, Stein Ottar

    2002-07-01

    The main goal of this work was to identify the most important uncertainty sources in water saturation calculation and examine the possibility for developing new S{sub w} - equations or possibility to develop methods to remove weaknesses and uncertainties in existing S{sub w} - equations. Due to the need for industrial applicability of the equations we aimed for results with the following properties: The accuracy in S{sub w} should increase compared with existing S{sub w} - equations. The equations should be simple to use in petrophysical evaluations. The equations should be based on conventional logs and use as few as possible input parameters. The equations should be numerical stable. This thesis includes an uncertainty and sensitivity analysis of the most common S{sub w} equations. The results are addressed in chapter 3 and were intended to find the most important uncertainty sources in water saturation calculation. To increase the knowledge of the relationship between R{sub t} and S{sub w} in hydrocarbon sandstone reservoirs and to understand how the pore geometry affects the conductivity (n and m) of the rock a theoretical study was done. It was also an aim to examine the possibility for developing new S{sub w} - equations (or investigation an effective medium model) valid inhydrocarbon sandstone reservoirs. The results are presented in paper 1. A new equation for water saturation calculation in clean sandstone oil reservoirs is addressed in paper 2. A recommendation for best practice of water saturation calculation in non water wet formation is addressed in paper 3. Finally a new equation for water saturation calculation in thinly interbedded sandstone/mudstone reservoirs is presented in paper 4. The papers are titled: 1) Is the saturation exponent n a constant. 2) A New Model for Calculating Water Saturation In 3) Influence of wettability on water saturation modeling. 4) Water Saturation Calculations in Thinly Interbedded Sandstone/mudstone Reservoirs. A

  17. Muddy and dolomitic rip-up clasts in Triassic fluvial sandstones: Origin and impact on potential reservoir properties (Argana Basin, Morocco)

    Science.gov (United States)

    Henares, Saturnina; Arribas, Jose; Cultrone, Giuseppe; Viseras, Cesar

    2016-06-01

    The significance of rip-up clasts as sandstone framework grains is frequently neglected in the literature being considered as accessory components in bulk sandstone composition. However, this study highlights the great value of muddy and dolomitic rip-up clast occurrence as: (a) information source about low preservation potential from floodplain deposits and (b) key element controlling host sandstone diagenetic evolution and thus ultimate reservoir quality. High-resolution petrographic analysis on Triassic fluvial sandstones from Argana Basin (T6 and T7/T8 units) highlights the significance of different types of rip-up clasts as intrabasinal framework components of continental sediments from arid climates. On the basis of their composition and ductility, three main types are distinguished: (a) muddy rip-up clasts, (b) dolomitic muddy rip-up clasts and (c) dolomite crystalline rip-up clasts. Spatial distribution of different types is strongly facies-related according to grain size. Origin of rip-up clasts is related to erosion of coeval phreatic dolocretes, in different development stages, and associated muddy floodplain sediments. Cloudy cores with abundant inclusions and clear outer rims of dolomite crystals suggest a first replacive and a subsequent displacive growth, respectively. Dolomite crystals are almost stoichiometric. This composition is very similar to that of early sandstone dolomite cement, supporting phreatic dolocretes as dolomite origin in both situations. Sandstone diagenesis is dominated by mechanical compaction and dolomite cementation. A direct correlation exists between: (1) muddy rip-up clast abundance and early reduction of primary porosity by compaction with irreversible loss of intergranular volume (IGV); and (2) occurrence of dolomitic rip-up clasts and dolomite cement nucleation in host sandstone, occluding adjacent pores but preserving IGV. Both processes affect reservoir quality by generation of vertical and 3D fluid flow baffles and

  18. Diagenesis and reservoir quality evolution of palaeocene deep-water, marine sandstones, the Shetland-Faroes Basin, British continental shelf

    Energy Technology Data Exchange (ETDEWEB)

    Mansurbeg, H. [Department of Earth Sciences, Uppsala University, Villavaegen 16, SE 752 36 Uppsala (Sweden); Morad, S. [Department of Earth Sciences, Uppsala University, Villavaegen 16, SE 752 36 Uppsala (Sweden); Department of Petroleum Geosciences, The Petroleum Institute, P.O. Box 2533, Abu Dhabi (United Arab Emirates); Salem, A. [Faculty of Education at Kafr El-Sheikh, Tanta University, Kafr El-Sheikh (Egypt); Marfil, R.; Caja, M.A. [Departmento Petrologia y Geoquimica, Facultad de Geologia, UCM, 28040 Madrid (Spain); El-ghali, M.A.K. (Geology Department, Al-Fateh University, P.O. Box 13696, Libya); Nystuen, J.P. [Department of Geosciences, University of Oslo, P.O. Box 1047 Blindern, NO-0316 Oslo (Norway); Amorosi, A. [Department of Earth Sciences, University of Bologna, Via Zamboni 67, 40127 Bologna (Italy); Garcia, D. [Centre SPIN, Department GENERIC, Ecole Nationale Superieure des Mines de Saint Etienne 158, Cours Fauriel 42023, Saint-Etienne (France); La Iglesia, A. [Instituto de Geologia Economica (CSIC-UCM), Facultad de Geologia, UCM, 28040 Madrid (Spain)

    2008-06-15

    The Palaeocene, deep-water marine sandstones recovered from six wells in the Shetland-Faroes Basin represent lowstand, transgressive and highstand systems tract turbiditic sediments. Mineralogic, petrographic, and geochemical analyses of these siliciclastics are used to decipher and discuss the diagenetic alterations and subsequent reservoir quality evolution. The Middle-Upper Palaeocene sandstones (subarkoses to arkoses) from the Shetland-Faroes Basin, British continental shelf are submarine turbiditic deposits that are cemented predominantly by carbonates, quartz and clay minerals. Carbonate cements (intergranular and grain replacive calcite, siderite, ferroan dolomite and ankerite) are of eogenetic and mesogenetic origins. The eogenetic alterations have been mediated by marine, meteoric and mixed marine/meteoric porewaters and resulted mainly in the precipitation of calcite ({delta}{sup 18}O{sub V-PDB}=-10.9 permille and -3.8 permille), trace amounts of non-ferroan dolomite, siderite ({delta}{sup 18}O{sub V-PDB}=-14.4 permille to -0.6 permille), as well as smectite and kaolinite in the lowstand systems tract (LST) and highstand systems tract (HST) turbiditic sandstone below the sequence boundary. Minor eogenetic siderite has precipitated between expanded and kaolinitized micas, primarily biotite. The mesogenetic alterations are interpreted to have been mediated by evolved marine porewaters and resulted in the precipitation of calcite ({delta}{sup 18}O{sub V-PDB}=-12.9 permille to -7.8 permille) and Fe-dolomite/ankerite ({delta}{sup 18}O{sub V-PDB}=-12.1 permille to -6.3 permille) at temperatures of 50-140 and 60-140 C, respectively. Quartz overgrowths and outgrowth, which post- and pre-date the mesogenetic carbonate cements is more common in the LST and TST of distal turbiditic sandstone. Discrete quartz cement, which is closely associated with illite and chlorite, is the final diagenetic phase. The clay minerals include intergranular and grain replacive

  19. Electrofacies vs. lithofacies sandstone reservoir characterization Campanian sequence, Arshad gas/oil field, Central Sirt Basin, Libya

    Science.gov (United States)

    Burki, Milad; Darwish, Mohamed

    2017-06-01

    The present study focuses on the vertically stacked sandstones of the Arshad Sandstone in Arshad gas/oil field, Central Sirt Basin, Libya, and is based on the conventional cores analysis and wireline log interpretation. Six lithofacies types (F1 to F6) were identified based on the lithology, sedimentary structures and biogenic features, and are supported by wireline log calibration. From which four types (F1-F4) represent the main Campanian sandstone reservoirs in the Arshad gas/oil field. Lithofacies F5 is the basal conglomerates at the lower part of the Arshad sandstones. The Paleozoic Gargaf Formation is represented by lithofacies F6 which is the source provenance for the above lithofacies types. Arshad sediments are interpreted to be deposited in shallow marginal and nearshore marine environment influenced by waves and storms representing interactive shelf to fluvio-marine conditions. The main seal rocks are the Campanian Sirte shale deposited in a major flooding events during sea level rise. It is contended that the syn-depositional tectonics controlled the distribution of the reservoir facies in time and space. In addition, the post-depositional changes controlled the reservoir quality and performance. Petrophysical interpretation from the porosity log values were confirmed by the conventional core measurements of the different sandstone lithofacies types. Porosity ranges from 5 to 20% and permeability is between 0 and 20 mD. Petrophysical cut-off summary of the lower part of the clastic dominated sequence (i. e. Arshad Sandstone) calculated from six wells includes net pay sand ranging from 19.5‧ to 202.05‧, average porosity from 7.7 to 15% and water saturation from 19 to 58%.

  20. CHARACTERIZATION OF SANDSTONE RESERVOIRS FOR ENHANCED OIL RECOVERY: THE PERMIAN UPPER MINNELUSA FORMATION, POWDER RIVER BASIN, WYOMING.

    Science.gov (United States)

    Schenk, C.J.; Schmoker, J.W.; Scheffler, J.M.

    1986-01-01

    Upper Minnelusa sandstones form a complex group of reservoirs because of variations in regional setting, sedimentology, and diagenetic alteration. Structural lineaments separate the reservoirs into northern and southern zones. Production in the north is from a single pay sand, and in the south from multi-pay sands due to differential erosion on top of the Upper Minnelusa. The intercalation of eolian dune, interdune, and sabkha sandstones with marine sandstones, carbonates, and anhydrites results in significant reservoir heterogeneity. Diagenetic alterations further enhance heterogeneity, because the degree of cementation and dissolution is partly facies-related.

  1. Implications of heterogeneous fracture distribution on reservoir quality; an analogue from the Torridon Group sandstone, Moine Thrust Belt, NW Scotland

    Science.gov (United States)

    Watkins, Hannah; Healy, David; Bond, Clare E.; Butler, Robert W. H.

    2018-03-01

    Understanding fracture network variation is fundamental in characterising fractured reservoirs. Simple relationships between fractures, stress and strain are commonly assumed in fold-thrust structures, inferring relatively homogeneous fracture patterns. In reality fractures are more complex, commonly appearing as heterogeneous networks at outcrop. We use the Achnashellach Culmination (NW Scotland) as an outcrop analogue to a folded tight sandstone reservoir in a thrust belt. We present fracture data is collected from four fold-thrust structures to determine how fracture connectivity, orientation, permeability anisotropy and fill vary at different structural positions. We use a 3D model of the field area, constructed using field observations and bedding data, and geomechanically restored using Move software, to determine how factors such as fold curvature and strain influence fracture variation. Fracture patterns in the Torridon Group are consistent and predictable in high strain forelimbs, however in low strain backlimbs fracture patterns are inconsistent. Heterogeneities in fracture connectivity and orientation in low strain regions do not correspond to fluctuations in strain or fold curvature. We infer that where strain is low, other factors such as lithology have a greater control on fracture formation. Despite unpredictable fracture attributes in low strain regions, fractured reservoir quality would be highest here because fractures in high strain forelimbs are infilled with quartz. Heterogeneities in fracture attribute data on fold backlimbs mean that fractured reservoir quality and reservoir potential is difficult to predict.

  2. Effect of pore structure on the seepage characteristics of tight sandstone reservoirs: A case study of Upper Jurassic Penglaizhen Fm reservoirs in the western Sichuan Basin

    Directory of Open Access Journals (Sweden)

    Liqiang Sima

    2017-01-01

    Full Text Available Tight sandstone reservoirs are characterized by complex pore structures and strong heterogeneity, and their seepage characteristics are much different from those of conventional sandstone reservoirs. In this paper, the tight sandstone reservoirs of Upper Jurassic Penglaizhen Fm in western Sichuan Basin were analyzed in terms of their pore structures by using the data about physical property, mercury injection and nuclear magnetic resonance (NMR tests. Then, the seepage characteristics and the gas–water two-phase migration mechanisms and distribution of tight sandstone reservoirs with different types of pore structures in the process of hydrocarbon accumulation and development were simulated by combining the relative permeability experiment with the visual microscopic displacement model. It is shown that crotch-like viscous fingering occurs in the process of gas front advancing in reservoirs with different pore structures. The better the pore structure is, the lower the irreducible water saturation is; the higher the gas-phase relative permeability of irreducible water is, the more easily the gas reservoir can be developed. At the late stage of development, the residual gas is sealed in reservoirs in the forms of bypass, cutoff and dead end. In various reservoirs, the interference between gas and water is stronger, so gas and water tends to be produced simultaneously. The sealed gas may reduce the production rate of gas wells significantly, and the existence of water phase may reduce the gas permeability greatly; consequently, the water-bearing low-permeability tight sandstone gas reservoirs reveal serious water production, highly-difficult development and low-recovery percentage at the late stage, which have adverse impacts on the effective production and development of gas wells.

  3. A New Multichelating Acid System for High-Temperature Sandstone Reservoirs

    Directory of Open Access Journals (Sweden)

    Nianyin Li

    2015-01-01

    Full Text Available Sandstone reservoir acidizing is a complex and heterogeneous acid-rock reaction process. If improper acid treatment is implemented, further damage can be induced instead of removing the initial plug, particularly in high-temperature sandstone reservoirs. An efficient acid system is the key to successful acid treatment. High-temperature sandstone treatment with conventional mud acid system faces problems including high acid-rock reaction rate, short acid effective distance, susceptibility to secondary damage, and serious corrosion to pipelines. In this paper, a new multichelating acid system has been developed to overcome these shortcomings. The acid system is composed of ternary weak acid, organic phosphonic chelating agent, anionic polycarboxylic acid chelating dispersant, fluoride, and other assisted additives. Hydrogen ion slowly released by multistage ionization in ternary weak acid and organic phosphonic within the system decreases the concentration of HF to achieve retardation. Chelating agent and chelating dispersant within the system inhibited anodic and cathodic reaction, respectively, to protect the metal from corrosion, while chelating dispersant has great chelating ability on iron ions, restricting the depolarization reaction of ferric ion and metal. The synergic effect of chelating agent and chelating dispersant removes sulfate scale precipitation and inhibits or decreases potential precipitation such as CaF2, silica gel, and fluosilicate. Mechanisms of retardation, corrosion-inhibition, and scale-removing features have been discussed and evaluated with laboratory tests. Test results indicate that this novel acid system has good overall performance, addressing the technical problems and improving the acidizing effect as well for high-temperature sandstone.

  4. A new biostratigraphical tool for reservoir characterisation and well correlation in permo-carboniferous sandstones

    NARCIS (Netherlands)

    Garming, J.F.L.; Cremer, H.; Verreussel, R.M.C.H.; Guasti, E.; Abbink, O.A.

    2010-01-01

    Permo-Carboniferous sandstones are important reservoir rocks for natural gas in the Southern North Sea basin. This is a mature area which makes tools for reservoir characterization and well to well correlation important for field optimalisation and ongoing exploration activities. Within the

  5. Geological and Petrophysical Characterization of the Ferron Sandstone for 3-D Simulation of a Fluvial-Deltaic Reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Chidsey, Jr, Thomas C.

    2001-10-31

    The objective of the Ferron Sandstone project was to develop a comprehensive, interdisciplinary, quantitative characterization f fluvial-deltaic reservoir to allow realistic interwell and reservoir-scale models to be developed for improved oil-field development in similar reservoirs world-wide. Quantitative geological and petrophysical information on the Cretaceous Ferron Sandstone in east-central Utah was collected. Both new and existing data was integrated into a three-dimensional model of spatial variations in porosity, storativity, and tensorial rock permeability at a scale appropriate for inter-well to regional-scale reservoir simulation. Simulation results could improve reservoir management through proper infill and extension drilling strategies, reduction of economic risks, increased recovery from existing oil fields, and more reliable reserve calculations.

  6. Facies architecture of the Bluejacket Sandstone in the Eufaula Lake area, Oklahoma: Implications for the reservoir characterization of the Bartlesville Sandstone

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Liangmiao; Yang, Kexian [Univ. of Tulsa, OK (United States)

    1997-08-01

    Outcrop studies of the Bluejacket Sandstone (Middle Pennsylvanian) provide significant insights to reservoir architecture of the subsurface equivalent Bartlesville Sandstone. Quarry walls and road cuts in the Lake Eufaula area offer excellent exposures for detailed facies architectural investigations using high-precision surveying, photo mosaics. Directional minipermeameter measurements are being conducted. Subsurface studies include conventional logs, borehole image log, and core data. Reservoir architectures are reconstructed in four hierarchical levels: multi-storey sandstone, i.e. discrete genetic intervals; individual discrete genetic interval; facies within a discrete genetic interval; and lateral accretion bar deposits. In both outcrop and subsurface, the Bluejacket (Bartlesville) Sandstone comprises two distinctive architectures: a lower braided fluvial and an upper meandering fluvial. Braided fluvial deposits are typically 30 to 80 ft thick, and are laterally persistent filling an incised valley wider than the largest producing fields. The lower contact is irregular with local relief of 50 ft. The braided-fluvial deposits consist of 100-400-ft wide, 5-15-ft thick channel-fill elements. Each channel-fill interval is limited laterally by an erosional contact or overbank deposits, and is separated vertically by discontinuous mudstones or highly concentrated mudstone interclast lag conglomerates. Low-angle parallel-stratified or trough cross-stratified medium- to coarse-grained sandstones volumetrically dominate. This section has a blocky well log profile. Meandering fluvial deposits are typically 100 to 150 ft thick and comprise multiple discrete genetic intervals.

  7. Improving recovery efficiency of water-drive channel sandstone reservoir by drilling wells laterally

    Energy Technology Data Exchange (ETDEWEB)

    Zhiguo, F.; Quinglong, D.; Pingshi, Z.; Bingyu, J.; Weigang, L. [Research Institute of Exploration and Development, Daqing (China)

    1998-12-31

    Example of drilling a horizontal well in reservoir rock of only four meter thick by using existing casing pipe of low efficiency vertical wells to induce production in the top remaining reservoir is described. The experience shows that drilling horizontal wells laterally in thin bodies of sandstone reservoirs and improve their productivity is a feasible proposition. Productivity will still be low, but it can be improved by well stimulation. 3 refs., 3 figs.

  8. Prediction of calcite Cement Distribution in Shallow Marine Sandstone Reservoirs using Seismic Data

    Energy Technology Data Exchange (ETDEWEB)

    Bakke, N.E.

    1996-12-31

    This doctoral thesis investigates how calcite cemented layers can be detected by reflection seismic data and how seismic data combined with other methods can be used to predict lateral variation in calcite cementation in shallow marine sandstone reservoirs. Focus is on the geophysical aspects. Sequence stratigraphy and stochastic modelling aspects are only covered superficially. Possible sources of calcite in shallow marine sandstone are grouped into internal and external sources depending on their location relative to the presently cemented rock. Well data and seismic data from the Troll Field in the Norwegian North Sea have been analysed. Tuning amplitudes from stacks of thin calcite cemented layers are analysed. Tuning effects are constructive or destructive interference of pulses resulting from two or more closely spaced reflectors. The zero-offset tuning amplitude is shown to depend on calcite content in the stack and vertical stack size. The relationship is found by regression analysis based on extensive seismic modelling. The results are used to predict calcite distribution in a synthetic and a real data example. It is found that describing calcite cemented beds in shallow marine sandstone reservoirs is not a deterministic problem. Hence seismic inversion and sequence stratigraphy interpretation of well data have been combined in a probabilistic approach to produce models of calcite cemented barriers constrained by a maximum amount of information. It is concluded that seismic data can provide valuable information on distribution of calcite cemented beds in reservoirs where the background sandstones are relatively homogeneous. 63 refs., 78 figs., 10 tabs.

  9. Characterization and 3D reservoir modelling of fluvial sandstones of the Williams Fork Formation, Rulison Field, Piceance Basin, Colorado, USA

    International Nuclear Information System (INIS)

    Pranter, Matthew J; Vargas, Marielis F; Davis, Thomas L

    2008-01-01

    This study describes the stratigraphic characteristics and distribution of fluvial deposits of the Upper Cretaceous Williams Fork Formation in a portion of Rulison Field and addresses 3D geologic modelling of reservoir sand bodies and their associated connectivity. Fluvial deposits include isolated and stacked point-bar deposits, crevasse splays and overbank (floodplain) mudrock. Within the Williams Fork Formation, the distribution and connectivity of fluvial sandstones significantly impact reservoir productivity and ultimate recovery. The reservoir sandstones are primarily fluvial point-bar deposits interbedded with shales and coals. Because of the lenticular geometry and limited lateral extent of the reservoir sandstones (common apparent widths of ∼500–1000 ft; ∼150–300 m), relatively high well densities (e.g. 10 acre (660 ft; 200 m) spacing) are often required to deplete the reservoir. Heterogeneity of these fluvial deposits includes larger scale stratigraphic variability associated with vertical stacking patterns and structural heterogeneities associated with faults that exhibit lateral and reverse offsets. The discontinuous character of the fluvial sandstones and lack of distinct marker beds in the middle and upper parts of the Williams Fork Formation make correlation between wells tenuous, even at a 10 acre well spacing. Some intervals of thicker and amalgamated sandstones within the middle and upper Williams Fork Formation can be correlated across greater distances. To aid correlation and for 3D reservoir modelling, vertical lithology proportion curves were used to estimate stratigraphic trends and define the stratigraphic zonation within the reservoir interval. Object-based and indicator-based modelling methods have been applied to the same data and results from the models were compared. Results from the 3D modelling indicate that sandstone connectivity increases with net-to-gross ratio and, at lower net-to-gross ratios (<30%), differences exist in

  10. Hydrocarbon Potential in Sandstone Reservoir Isolated inside Low Permeability Shale Rock (Case Study: Beruk Field, Central Sumatra Basin)

    Science.gov (United States)

    Diria, Shidqi A.; Musu, Junita T.; Hasan, Meutia F.; Permono, Widyo; Anwari, Jakson; Purba, Humbang; Rahmi, Shafa; Sadjati, Ory; Sopandi, Iyep; Ruzi, Fadli

    2018-03-01

    Upper Red Bed, Menggala Formation, Bangko Formation, Bekasap Formation and Duri Formationare considered as the major reservoirs in Central Sumatra Basin (CSB). However, Telisa Formation which is well-known as seal within CSB also has potential as reservoir rock. Field study discovered that lenses and layers which has low to high permeability sandstone enclosed inside low permeability shale of Telisa Formation. This matter is very distinctive and giving a new perspective and information related to the invention of hydrocarbon potential in reservoir sandstone that isolated inside low permeability shale. This study has been conducted by integrating seismic data, well logs, and petrophysical data throughly. Facies and static model are constructed to estimate hydrocarbon potential resource. Facies model shows that Telisa Formation was deposited in deltaic system while the potential reservoir was deposited in distributary mouth bar sandstone but would be discontinued bedding among shale mud-flat. Besides, well log data shows crossover between RHOB and NPHI, indicated that distributary mouth bar sandstone is potentially saturated by hydrocarbon. Target area has permeability ranging from 0.01-1000 mD, whereas porosity varies from 1-30% and water saturation varies from 30-70%. The hydrocarbon resource calculation approximates 36.723 MSTB.

  11. STRUCTURAL HETEROGENEITIES AND PALEO FLUID FLOW IN AN ANALOG SANDSTONE RESERVOIR 2001-2004

    International Nuclear Information System (INIS)

    Pollard, David; Aydin, Atilla

    2005-01-01

    Fractures and faults are brittle structural heterogeneities that can act both as conduits and barriers with respect to fluid flow in rock. This range in the hydraulic effects of fractures and faults greatly complicates the challenges faced by geoscientists working on important problems: from groundwater aquifer and hydrocarbon reservoir management, to subsurface contaminant fate and transport, to underground nuclear waste isolation, to the subsurface sequestration of CO2 produced during fossil-fuel combustion. The research performed under DOE grant DE-FG03-94ER14462 aimed to address these challenges by laying a solid foundation, based on detailed geological mapping, laboratory experiments, and physical process modeling, on which to build our interpretive and predictive capabilities regarding the structure, patterns, and fluid flow properties of fractures and faults in sandstone reservoirs. The material in this final technical report focuses on the period of the investigation from July 1, 2001 to October 31, 2004. The Aztec Sandstone at the Valley of Fire, Nevada, provides an unusually rich natural laboratory in which exposures of joints, shear deformation bands, compaction bands and faults at scales ranging from centimeters to kilometers can be studied in an analog for sandstone aquifers and reservoirs. The suite of structures there has been documented and studied in detail using a combination of low-altitude aerial photography, outcrop-scale mapping and advanced computational analysis. In addition, chemical alteration patterns indicative of multiple paleo fluid flow events have been mapped at outcrop, local and regional scales. The Valley of Fire region has experienced multiple episodes of fluid flow and this is readily evident in the vibrant patterns of chemical alteration from which the Valley of Fire derives its name. We have successfully integrated detailed field and petrographic observation and analysis, process-based mechanical modeling, and numerical

  12. ANALYSIS OF OIL-BEARING CRETACEOUS SANDSTONE HYDROCARBON RESERVOIRS, EXCLUSIVE OF THE DAKOTA SANDSTONE, ON THE JICARILLA APACHE INDIAN RESERVATION, NEW MEXICO

    International Nuclear Information System (INIS)

    Jennie Ridgley

    2000-01-01

    A goal of the Mesaverde project was to better define the depositional system of the Mesaverde in hopes that it would provide insight to new or by-passed targets for oil exploration. The new, detailed studies of the Mesaverde give us a better understanding of the lateral variability in depositional environments and facies. Recognition of this lateral variability and establishment of the criteria for separating deltaic, strandplain-barrier, and estuarine deposits from each other permit development of better hydrocarbon exploration models, because the sandstone geometry differs in each depositional system. Although these insights will provide better exploration models for gas exploration, it does not appear that they will be instrumental in finding more oil. Oil in the Mesaverde Group is produced from isolated fields on the Chaco slope; only a few wells define each field. Production is from sandstone beds in the upper part of the Point Lookout Sandstone or from individual fluvial channel sandstones in the Menefee. Stratigraphic traps rather than structural traps are more important. Source of the oil in the Menefee and Point Lookout may be from interbedded organic-rich mudstones or coals rather than from the Lewis Shale. The Lewis Shale appears to contain more type III organic matter and, hence, should produce mainly gas. Outcrop studies have not documented oil staining that might point to past oil migration through the sandstones of the Mesaverde. The lack of oil production may be related to the following: (1) lack of abundant organic matter of the type I or II variety in the Lewis Shale needed to produce oil, (2) ineffective migration pathways due to discontinuities in sandstone reservoir geometries, (3) cementation or early formation of gas prior to oil generation that reduced effective permeabilities and served as barriers to updip migration of oil, or (4) erosion of oilbearing reservoirs from the southern part of the basin. Any new production should mimic that of

  13. The effects of impure CO2 on reservoir sandstones: results from mineralogical and geomechanical experiments

    Science.gov (United States)

    Marbler, H.; Erickson, K. P.; Schmidt, M.; Lempp, Ch.; Pöllmann, H.

    2012-04-01

    An experimental study of the behaviour of reservoir sandstones from deep saline aquifers during the injection and geological storage of CO2 with the inherent impurities SOX and NOX is part of the German national project COORAL*. Sample materials were taken from outcrops of possible reservoir formations of Rotliegend and Bunter Sandstones from the North German Basin. A combination of mineralogical alteration experiments and geomechanical tests was carried out on these rocks to study the potential effects of the impurities within the CO2 pore fluid. Altered rock samples after the treatment with CO2 + SOX/NOX in an autoclave system were loaded in a triaxial cell under in-situ pressure and temperature conditions in order to estimate the modifications of the geomechanical rock properties. Mineralogical alterations were observed within the sandstones after the exposure to impure supercritical (sc)CO2 and brine, mainly of the carbonatic, but also of the silicatic cements, as well as of single minerals. Besides the partial solution effects also secondary carbonate and minor silicate mineral precipitates were observed within the pore space of the treated sandstones. These alterations affect the grain structure of the reservoir rock. Results of geomechanical experiments with unaltered sandstones show that the rock strength is influenced by the degree of rock saturation before the experiment and the chemical composition of the pore fluid (scCO2 + SOX + NOX). After long-term autoclave treatment with impure scCO2, the sandstone samples exhibit modified strength parameters and elastic deformation behaviour as well as changes in porosity compared to untreated samples. Furthermore, the injected fluid volume into the pore space of sandstones from the same lithotype varies during triaxial loading depending on the chemistry of the pore fluid. CO2 with NOX and SOX bearing fluid fills a significantly larger proportion of the sandstone pore space than brine with pure scCO2. * The

  14. Petroacoustic Modelling of Heterolithic Sandstone Reservoirs: A Novel Approach to Gassmann Modelling Incorporating Sedimentological Constraints and NMR Porosity data

    Science.gov (United States)

    Matthews, S.; Lovell, M.; Davies, S. J.; Pritchard, T.; Sirju, C.; Abdelkarim, A.

    2012-12-01

    Heterolithic or 'shaly' sandstone reservoirs constitute a significant proportion of hydrocarbon resources. Petroacoustic models (a combination of petrophysics and rock physics) enhance the ability to extract reservoir properties from seismic data, providing a connection between seismic and fine-scale rock properties. By incorporating sedimentological observations these models can be better constrained and improved. Petroacoustic modelling is complicated by the unpredictable effects of clay minerals and clay-sized particles on geophysical properties. Such effects are responsible for erroneous results when models developed for "clean" reservoirs - such as Gassmann's equation (Gassmann, 1951) - are applied to heterolithic sandstone reservoirs. Gassmann's equation is arguably the most popular petroacoustic modelling technique in the hydrocarbon industry and is used to model elastic effects of changing reservoir fluid saturations. Successful implementation of Gassmann's equation requires well-constrained drained rock frame properties, which in heterolithic sandstones are heavily influenced by reservoir sedimentology, particularly clay distribution. The prevalent approach to categorising clay distribution is based on the Thomas - Stieber model (Thomas & Stieber, 1975), this approach is inconsistent with current understanding of 'shaly sand' sedimentology and omits properties such as sorting and grain size. The novel approach presented here demonstrates that characterising reservoir sedimentology constitutes an important modelling phase. As well as incorporating sedimentological constraints, this novel approach also aims to improve drained frame moduli estimates through more careful consideration of Gassmann's model assumptions and limitations. A key assumption of Gassmann's equation is a pore space in total communication with movable fluids. This assumption is often violated by conventional applications in heterolithic sandstone reservoirs where effective porosity, which

  15. Topological representation of the porous structure and its evolution of reservoir sandstone under excavation-induced loads

    Directory of Open Access Journals (Sweden)

    Ju Yang

    2017-01-01

    Full Text Available The porous structure of a reservoir rock greatly influences its evolutive deformation and fracture behavior during excavation of natural resources reservoirs. Most numerical models for porous structures have been used to predict the quasi-static mechanical properties, but few are available to accurately characterize the evolution process of the porous structure and its influence on the macroscopic properties of reservoir rocks. This study reports a novel method to characterize the porous structure of sandstone using its topological parameters and to determine the laws that govern the evolutive deformation and failure of the topological structure under various uniaxial compressive loads. A numerical model of the porous sandstone was established based on the pore characteristics that were acquired using computed tomography imaging techniques. The analytical method that integrates the grassfire algorithm and the maximum inscribed sphere algorithm was proposed to create the 3-D topological model of the deformed porous structure, through which the topological parameters of the structure were measured and identified. The evolution processes of the porous structure under various loads were characterized using its equivalent topological model and parameters. This study opens a new way to characterize the dynamic evolution of the pore structure of reservoir sandstone under excavation disturbance.

  16. Potential environmental issues of CO2 storage in deep saline aquifers: Geochemical results from the Frio-I Brine Pilot test, Texas, USA

    Science.gov (United States)

    Kharaka, Yousif K.; Thordsen, James J.; Hovorka, Susan D.; Nance, H. Seay; Cole, David R.; Phelps, Tommy J.; Knauss, Kevin G.

    2009-01-01

    Sedimentary basins in general, and deep saline aquifers in particular, are being investigated as possible repositories for large volumes of anthropogenic CO2 that must be sequestered to mitigate global warming and related climate changes. To investigate the potential for the long-term storage of CO2 in such aquifers, 1600 t of CO2 were injected at 1500 m depth into a 24-m-thick "C" sandstone unit of the Frio Formation, a regional aquifer in the US Gulf Coast. Fluid samples obtained before CO2 injection from the injection well and an observation well 30 m updip showed a Na–Ca–Cl type brine with ∼93,000 mg/L TDS at saturation with CH4 at reservoir conditions; gas analyses showed that CH4 comprised ∼95% of dissolved gas, but CO2 was low at 0.3%. Following CO2 breakthrough, 51 h after injection, samples showed sharp drops in pH (6.5–5.7), pronounced increases in alkalinity (100–3000 mg/L as HCO3) and in Fe (30–1100 mg/L), a slug of very high DOC values, and significant shifts in the isotopic compositions of H2O, DIC, and CH4. These data, coupled with geochemical modeling, indicate corrosion of pipe and well casing as well as rapid dissolution of minerals, especially calcite and iron oxyhydroxides, both caused by lowered pH (initially ∼3.0 at subsurface conditions) of the brine in contact with supercritical CO2.These geochemical parameters, together with perfluorocarbon tracer gases (PFTs), were used to monitor migration of the injected CO2 into the overlying Frio “B”, composed of a 4-m-thick sandstone and separated from the “C” by ∼15 m of shale and siltstone beds. Results obtained from the Frio “B” 6 months after injection gave chemical and isotopic markers that show significant CO2 (2.9% compared with 0.3% CO2 in dissolved gas) migration into the “B” sandstone. Results of samples collected 15 months after injection, however, are ambiguous, and can be interpreted to show no additional injected CO2 in the “B” sandstone

  17. Seismic spectral decomposition and analysis based on Wigner–Ville distribution for sandstone reservoir characterization in West Sichuan depression

    International Nuclear Information System (INIS)

    Wu, Xiaoyang; Liu, Tianyou

    2010-01-01

    Reflections from a hydrocarbon-saturated zone are generally expected to have a tendency to be low frequency. Previous work has shown the application of seismic spectral decomposition for low-frequency shadow detection. In this paper, we further analyse the characteristics of spectral amplitude in fractured sandstone reservoirs with different fluid saturations using the Wigner–Ville distribution (WVD)-based method. We give a description of the geometric structure of cross-terms due to the bilinear nature of WVD and eliminate cross-terms using smoothed pseudo-WVD (SPWVD) with time- and frequency-independent Gaussian kernels as smoothing windows. SPWVD is finally applied to seismic data from West Sichuan depression. We focus our study on the comparison of SPWVD spectral amplitudes resulting from different fluid contents. It shows that prolific gas reservoirs feature higher peak spectral amplitude at higher peak frequency, which attenuate faster than low-quality gas reservoirs and dry or wet reservoirs. This can be regarded as a spectral attenuation signature for future exploration in the study area

  18. Permeability model of tight reservoir sandstones combining core-plug and miniperm analysis of drillcore; longyearbyen co2lab, Svalbard

    NARCIS (Netherlands)

    Magnabosco, Cara; Braathen, Alvar; Ogata, Kei

    2014-01-01

    Permeability measurements in Mesozoic, low-permeability sandstone units within the strata cored in seven drillholes near Longyearbyen, Svalbard, have been analysed to assess the presence of aquifers and their potentials as reservoirs for the storage of carbon dioxide. These targeted sandstones are

  19. Study of the Effect of Clay Particles on Low Salinity Water Injection in Sandstone Reservoirs

    Directory of Open Access Journals (Sweden)

    Sina Rezaei Gomari

    2017-03-01

    Full Text Available The need for optimal recovery of crude oil from sandstone and carbonate reservoirs around the world has never been greater for the petroleum industry. Water-flooding has been applied to the supplement primary depletion process or as a separate secondary recovery method. Low salinity water injection is a relatively new method that involves injecting low salinity brines at high pressure similar to conventional water-flooding techniques, in order to recover crude oil. The effectiveness of low salinity water injection in sandstone reservoirs depends on a number of parameters such as reservoir temperature, pressure, type of clay particle and salinity of injected brine. Clay particles present on reservoir rock surfaces adsorb polar components of oil and modify wettability of sandstone rocks to the oil-wet state, which is accountable for the reduced recovery rates by conventional water-flooding. The extent of wettability alteration caused by three low salinity brines on oil-wet sandstone samples containing varying clay content (15% or 30% and type of clay (kaolinite/montmorillonite were analyzed in the laboratory experiment. Contact angles of mica powder and clay mixture (kaolinite/montmorillonite modified with crude oil were measured before and after injection with three low salinity sodium chloride brines. The effect of temperature was also analyzed for each sample. The results of the experiment indicate that samples with kaolinite clay tend to produce higher contact angles than samples with montmorillonite clay when modified with crude oil. The highest degree or extent of wettability alteration from oil-wet to intermediate-wet state upon injection with low salinity brines was observed for samples injected with brine having salinity concentration of 2000 ppm. The increase in temperature tends to produce contact angles values lying in the higher end of the intermediate-wet range (75°–115° for samples treated at 50 °C, while their corresponding

  20. Assessing Uncertainty and Repeatability in Time-Lapse VSP Monitoring of CO2 Injection in a Brine Aquifer, Frio Formation, Texas (A Case Study)

    Energy Technology Data Exchange (ETDEWEB)

    Nazari, Siamak [Univ. of California, Berkeley, CA (United States). Dept. of Civil and Environmental Engineering; Daley, Thomas M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Division

    2013-02-07

    This study was done to assess the repeatability and uncertainty of time-lapse VSP response to CO2 injection in the Frio formation near Houston Texas. A work flow was built to assess the effect of time-lapse injected CO2 into two Frio brine reservoir intervals, the ‘C’ sand (Frio1) and the ‘Blue sand’ (Frio2). The time-lapse seismic amplitude variations with sensor depth for both reservoirs Frio1 and Frio2 were computed by subtracting the seismic response of the base survey from each of the two monitor seismic surveys. Source site 1 has been considered as one of the best sites for evaluating the time-lapse response after injection. For site 1, the computed timelapse NRMS levels after processing had been compared to the estimated time-lapse NRMS level before processing for different control reflectors, and for brine aquifers Frio1, and Frio2 to quantify detectability of amplitude difference. As the main interest is to analyze the time-lapse amplitude variations, different scenarios have been considered. Three different survey scenarios were considered: the base survey which was performed before injection, monitor1 performed after the first injection operation, and monitor2 which was after the second injection. The first scenario was base-monitor1, the second was basemonitor2, and the third was monitor1-monitor2. We considered three ‘control’ reflections above the Frio to assist removal of overburden changes, and concluded that third control reflector (CR3) is the most favorable for the first scenario in terms of NRMS response, and first control reflector (CR1) is the most favorable for the second and third scenarios in terms of NRMS response. The NRMS parameter is shown to be a useful measure to assess the effect of processing on time-lapse data. The overall NRMS for the Frio VSP data set was found to be in the range of 30% to 80% following basic processing. This could be considered as an estimated baseline in assessing the utility

  1. Measuring permanence of CO2 storage in saline formations: The Frio experiment

    Science.gov (United States)

    Hovorka, Susan D.; Benson, Sally M.; Doughty, Christine; Freifeild, Barry M.; Sakurai, Shinichi; Daley, Thomas M.; Kharaka, Yousif K.; Holtz, Mark H.; Trautz, Robert C.; Nance, H. Seay; Myer, Larry R.; Knauss, Kevin G.

    2006-01-01

    If CO2 released from fossil fuel during energy production is returned to the subsurface, will it be retained for periods of time significant enough to benefit the atmosphere? Can trapping be assured in saline formations where there is no history of hydrocarbon accumulation? The Frio experiment in Texas was undertaken to provide answers to these questions.One thousand six hundred metric tons of CO2 were injected into the Frio Formation, which underlies large areas of the United States Gulf Coast. Reservoir characterization and numerical modeling were used to design the experiment, as well as to interpret the results through history matching. Closely spaced measurements in space and time were collected to observe the evolution of immiscible and dissolved CO2 during and after injection. The high-permeability, steeply dipping sandstone allowed updip flow of supercritical CO2 as a result of the density contrast with formation brine and absence of a local structural trap.The front of the CO2 plume moved more quickly than had been modeled. By the end of the 10-day injection, however, the plume geometry in the plane of the observation and injection wells had thickened to a distribution similar to the modeled distribution. As expected, CO2 dissolved rapidly into brine, causing pH to fall and calcite and metals to be dissolved.Postinjection measurements, including time-lapse vertical seismic profiling transects along selected azimuths, cross-well seismic topography, and saturation logs, show that CO2 migration under gravity slowed greatly 2 months after injection, matching model predictions that significant CO2 is trapped as relative permeability decreases.

  2. USGS assessment of undiscovered oil and gas resources for the Oligocene Frio and Anahuac formations, U.S. Gulf of Mexico coastal plain and state waters: Review of assessment units

    Science.gov (United States)

    Swanson, Sharon M.; Karlsen, Alexander W.; Warwick, Peter D.; Kennan, Lorcan; Pindell, James; Rosen, Norman C.

    2007-01-01

    The Oligocene Frio and Anahuac formations were examined by the U.S. Geological Survey (USGS) as part of an assessment of technically recoverable undiscovered conventional and unconventional hydrocarbon resources in Paleogene and Neogene strata underlying the U.S. Gulf of Mexico Coastal Plain and state waters. Work included the identification of structural, stratigraphic, and tectonic relations between petroleum source rocks and migration pathways to Frio and Anahuac reservoirs; preliminary evaluation of the potential for shallow (less than 3,000 ft) biogenic gas accumulations; and evaluation of the potential for deep, undiscovered gas and oil accumulations in slope and basin floor areas. All assessments were conducted using USGS methodology (http://energy.cr.usgs.gov/oilgas/noga/methodology.html). Final products from the USGS assessment of the Paleogene and Neogene were reported in USGS fact sheets (Dubiel et al., 2007; Warwick et al., 2007).Five assessment units for the Frio Formation were defined, and three of these were based on the character of the reservoirs in relation to growth faults and other related factors: (1) the Frio stable shelf oil and gas assessment unit, which contains thin (average thickness of 34 ft) and shallow reservoirs (average depth of 4,834 ft); (2) the Frio expanded fault zone oil and gas assessment unit, which contains thick (average thickness of 56 ft) and deep reservoirs (average depth of 9,050 ft) in over-pressured intervals; and (3) the Frio slope and basin floor gas assessment unit, which has potential for deep gas (greater than 15,000 ft) and extends from the downdip boundary of the expanded fault zone to the offshore State/Federal water boundary. The fourth Frio assessment unit is the Hackberry oil and gas assessment unit. The Hackberry embayment of southeast Texas and southwest Louisiana consists of a slope facies in the middle part of the Frio Formation. The fifth unit, the Frio basin margin assessment unit, extends from the

  3. Reservoir Characterization of Bridgeport and Cypress Sandstones in Lawrence Field Illinois to Improve Petroleum Recovery by Alkaline-Surfactant-Polymer Flood

    Energy Technology Data Exchange (ETDEWEB)

    Seyler, Beverly; Grube, John; Huff, Bryan; Webb, Nathan; Damico, James; Blakley, Curt; Madhavan, Vineeth; Johanek, Philip; Frailey, Scott

    2012-12-21

    Within the Illinois Basin, most of the oilfields are mature and have been extensively waterflooded with water cuts that range up to 99% in many of the larger fields. In order to maximize production of significant remaining mobile oil from these fields, new recovery techniques need to be researched and applied. The purpose of this project was to conduct reservoir characterization studies supporting Alkaline-Surfactant-Polymer Floods in two distinct sandstone reservoirs in Lawrence Field, Lawrence County, Illinois. A project using alkaline-surfactantpolymer (ASP) has been established in the century old Lawrence Field in southeastern Illinois where original oil in place (OOIP) is estimated at over a billion barrels and 400 million barrels have been recovered leaving more than 600 million barrels as an EOR target. Radial core flood analysis using core from the field demonstrated recoveries greater than 20% of OOIP. While the lab results are likely optimistic to actual field performance, the ASP tests indicate that substantial reserves could be recovered even if the field results are 5 to 10% of OOIP. Reservoir characterization is a key factor in the success of any EOR application. Reservoirs within the Illinois Basin are frequently characterized as being highly compartmentalized resulting in multiple flow unit configurations. The research conducted on Lawrence Field focused on characteristics that define reservoir compartmentalization in order to delineate preferred target areas so that the chemical flood can be designed and implemented for the greatest recovery potential. Along with traditional facies mapping, core analyses and petrographic analyses, conceptual geological models were constructed and used to develop 3D geocellular models, a valuable tool for visualizing reservoir architecture and also a prerequisite for reservoir simulation modeling. Cores were described and potential permeability barriers were correlated using geophysical logs. Petrographic analyses

  4. Estimation of porosity of Khewra sandstone of cambrian age by using helium porosimeter and its application in reservoir evaluation

    International Nuclear Information System (INIS)

    Khan, M.S.; Bhatti, A.A.; Gillani, S.T.A.; Raza, A.

    2012-01-01

    Estimation of petrophysical properties of the rock formations played decisive role in all the processes of petroleum exploration. The Cambrian sequence is well established as reservoir rocks in the various parts of the world from where petroleum is being tapped. The Cambrian sequence has been encountered in the Potwar area and limited petroleum is being produced from the Adhi Oil Field. The Khewra Sandstone of the Cambrian sequence is outcropped in the Khewra Gorge, Salt Range Pakistan below an unconformity qf the Tobra Formation. For the assessment of porosity and reservoir characterization Helium Porosimeter has been used, six samples Qf the upper horizon were collected from various locations of the Khewra Gorge and the Khewra Choha Sadden Shah road side section; cores were prepared from these samples according to the instrument standard. The results of this study revealed that the upper horizon Qf the Khewra Sandstone Formation has good porosity ranging from 18.76% to 21.07%, porosity varied in different parts of the formation. These results are in good agreement with the internationally reported values for petroleum reservoir of the Cambrian sandstone. (author)

  5. Outcrop analogue study of Permocarboniferous geothermal sandstone reservoir formations (northern Upper Rhine Graben, Germany): impact of mineral content, depositional environment and diagenesis on petrophysical properties

    Science.gov (United States)

    Aretz, Achim; Bär, Kristian; Götz, Annette E.; Sass, Ingo

    2016-07-01

    oil and acidic waters led to the dissolution of haematite cements in the lower Permocarboniferous formations. During the Eocene, subsidence of the Upper Rhine Graben porosities and permeabilities of the sandstones of these formations were strongly reduced to 2.5 % and 3.2 × 10-18 m2. The second important influence on reservoir quality is the distinct depositional environment and its influence on early diagenetic processes. In early stage diagenesis, the best influence on reservoir properties exhibits a haematite cementation. It typically occurs in eolian sandstones of the Kreuznach Formation (Upper Permocarboniferous) and is characterized by grain covering haematite coatings, which are interpreted to inhibit cementation, compaction and illitization of pore space during burial. Eolian sandstones taken from outcrops and reservoir depths exhibit the highest porosities (16.4; 12.3 %) and permeabilities (2.0 × 10-15; 8.4 × 10-16 m2). A third important influence on reservoir quality is the general mineral composition and the quartz content which is the highest in the Kreuznach Formation with 73.8 %. Based on the integrated study of depositional environments and diagenetic processes, reservoir properties of the different Permocarboniferous formations within the northern Upper Rhine Graben and their changes with burial depth can be predicted with satisfactory accuracy. This leads to a better understanding of the reservoir quality and enables an appropriate well design for exploration and exploitation of these geothermal resources.

  6. Flow units classification for geostatisitical three-dimensional modeling of a non-marine sandstone reservoir: A case study from the Paleocene Funing Formation of the Gaoji Oilfield, east China

    Science.gov (United States)

    Zhang, Penghui; Zhang, Jinliang; Wang, Jinkai; Li, Ming; Liang, Jie; Wu, Yingli

    2018-05-01

    Flow units classification can be used in reservoir characterization. In addition, characterizing the reservoir interval into flow units is an effective way to simulate the reservoir. Paraflow units (PFUs), the second level of flow units, are used to estimate the spatial distribution of continental clastic reservoirs at the detailed reservoir description stage. In this study, we investigate a nonroutine methodology to predict the external and internal distribution of PFUs. The methodology outlined enables the classification of PFUs using sandstone core samples and log data. The relationships obtained between porosity, permeability and pore throat aperture radii (r35) values were established for core and log data obtained from 26 wells from the Funing Formation, Gaoji Oilfield, Subei Basin, China. The present study refines predicted PFUs at logged (0.125-m) intervals, whose scale is much smaller than routine methods. Meanwhile, three-dimensional models are built using sequential indicator simulation to characterize PFUs in wells. Four distinct PFUs are classified and located based on the statistical methodology of cluster analysis, and each PFU has different seepage ability. The results of this study demonstrate the obtained models are able to quantify reservoir heterogeneity. Due to different petrophysical characteristics and seepage ability, PFUs have a significant impact on the distribution of the remaining oil. Considering these allows a more accurate understanding of reservoir quality, especially within non-marine sandstone reservoirs.

  7. Experimental evaluation on the damages of different drilling modes to tight sandstone reservoirs

    Directory of Open Access Journals (Sweden)

    Gao Li

    2017-07-01

    Full Text Available The damages of different drilling modes to reservoirs are different in types and degrees. In this paper, the geologic characteristics and types of such damages were analyzed. Then, based on the relationship between reservoir pressure and bottom hole flowing pressure corresponding to different drilling modes, the experimental procedures on reservoir damages in three drilling modes (e.g. gas drilling, liquid-based underbalanced drilling and overbalanced drilling were designed. Finally, damage simulation experiments were conducted on the tight sandstone reservoir cores of the Jurassic Ahe Fm in the Tarim Basin and Triassic Xujiahe Fm in the central Sichuan Basin. It is shown that the underbalanced drilling is beneficial to reservoir protection because of its less damage on reservoir permeability, but it is, to some extent, sensitive to the stress and the empirical formula of stress sensitivity coefficient is obtained; and that the overbalanced drilling has more reservoir damages due to the invasion of solid and liquid phases. After the water saturation of cores rises to the irreducible water saturation, the decline of gas logging permeability speeds up and the damage degree of water lock increases. It is concluded that the laboratory experiment results of reservoir damage are accordant with the reservoir damage characteristics in actual drilling conditions. Therefore, this method reflects accurately the reservoir damage characteristics and can be used as a new experimental evaluation method on reservoir damage in different drilling modes.

  8. Characterization of the Qishn sandstone reservoir, Masila Basin-Yemen, using an integrated petrophysical and seismic structural approach

    Science.gov (United States)

    Lashin, Aref; Marta, Ebrahim Bin; Khamis, Mohamed

    2016-03-01

    This study presents an integrated petrophysical and seismic structural analysis that is carried out to evaluate the reservoir properties of Qishn sandstone as well as the entrapment style of the hydrocarbons at Sharyoof field, Sayun-Masila Basin that is located at the east central of Yemen. The reservoir rocks are dominated by clean porous and permeable sandstones zones usually intercalated with some clay stone interbeds. As identified from well logs, Qishn sandstone is classified into subunits (S1A, S1B, S1C and S2) with different reservoir characteristics and hydrocarbon potentiality. A number of qualitative and quantitative well logging analyses are used to characterize the different subunits of the Qishn reservoir and identify its hydrocarbon potentiality. Dia-porosity, M-N, Pickett, Buckles plots, petrophysical analogs and lateral distribution maps are used in the analysis. Shale volume, lithology, porosity, and fluid saturation are among the most important deduced parameters. The analysis revealed that S1A and S1C are the main hydrocarbon-bearing units. More specifically, S1A unit is the best, as it attains the most prolific hydrocarbon saturations (oil saturation "SH″ up to 65) and reservoir characteristics. An average petrophysical ranges of 4-21%, 16-23%, 11-19%, 0-65%, are detected for S1A unit, regarding shale volume, total and effective porosity, and hydrocarbon saturation, respectively. Meanwhile, S1B unit exhibits less reservoir characteristics (Vsh>30%, ϕEff<15% and SH< 15%). The lateral distribution maps revealed that most of the hydrocarbons (for S1A and S1C units) are indicated at the middle of the study area as NE-SW oriented closures. The analysis and interpretation of seismic data had clarified that the structure of study area is represented by a big middle horst bounded by a group of step-like normal faults at the extreme boundaries (faulted anticlinal-structure). In conclusion, the entrapment of the encountered hydrocarbon at Sharyoof oil

  9. Understanding creep in sandstone reservoirs - theoretical deformation mechanism maps for pressure solution in granular materials

    Science.gov (United States)

    Hangx, Suzanne; Spiers, Christopher

    2014-05-01

    Subsurface exploitation of the Earth's natural resources removes the natural system from its chemical and physical equilibrium. As such, groundwater extraction and hydrocarbon production from subsurface reservoirs frequently causes surface subsidence and induces (micro)seismicity. These effects are not only a problem in onshore (e.g. Groningen, the Netherlands) and offshore hydrocarbon fields (e.g. Ekofisk, Norway), but also in urban areas with extensive groundwater pumping (e.g. Venice, Italy). It is known that fluid extraction inevitably leads to (poro)elastic compaction of reservoirs, hence subsidence and occasional fault reactivation, and causes significant technical, economic and ecological impact. However, such effects often exceed what is expected from purely elastic reservoir behaviour and may continue long after exploitation has ceased. This is most likely due to time-dependent compaction, or 'creep deformation', of such reservoirs, driven by the reduction in pore fluid pressure compared with the rock overburden. Given the societal and ecological impact of surface subsidence, as well as the current interest in developing geothermal energy and unconventional gas resources in densely populated areas, there is much need for obtaining better quantitative understanding of creep in sediments to improve the predictability of the impact of geo-energy and groundwater production. The key problem in developing a reliable, quantitative description of the creep behaviour of sediments, such as sands and sandstones, is that the operative deformation mechanisms are poorly known and poorly quantified. While grain-scale brittle fracturing plus intergranular sliding play an important role in the early stages of compaction, these time-independent, brittle-frictional processes give way to compaction creep on longer time-scales. Thermally-activated mass transfer processes, like pressure solution, can cause creep via dissolution of material at stressed grain contacts, grain

  10. Geothermal characteristics of Buntsandstein sandstone reservoir of Alsace

    International Nuclear Information System (INIS)

    Haffen, Sebastien

    2012-01-01

    The Buntsandstein, located in the Upper Rhine Graben, appears to be an easy target for geothermal exploitation, linking sandstone and clay with the regional thermal anomaly. This study aims at characterizing petrophysical characteristics of these sandstones as well as the fracturing affecting them, with the intention of providing a conceptual model of the formation which will act as guide for future exploitation. The sedimentary facies are composed by five petrographical facies (clean sandstones, sandstones with clayey coating, clay matrix sandstones, silicified sandstones and carbonated matrix sandstones) which split with variable proportions and control a part of petrophysical properties measured at matrix scale. The comparison between petrophysical data, macroscopic data from temperature gradient analysis, modelling data and fracturing, allows the building of a Buntsandstein Sandstones fluids circulation conceptual model. This analysis points the role of the damage zone of fault zones for fluids transfer at large scale, but also that of two sedimentary facies: marginal erg and Playa Lake. The analysis of different outcrops shows that the fracturing evolves according to the situation in the sedimentary pile and according to the situation in comparison with major tectonic accidents. (author) [fr

  11. Production Characteristics and Reservoir Quality at the Ivanić Oil Field (Croatia) Predicted by Machine Learning System

    OpenAIRE

    Hernitz, Zvonimir; Đureković, Miro; Crnički, Josip

    1996-01-01

    At the Ivanić oil field, hydrocarbons are accumulated in fine tomedium grained litharenits of the Ivanić-Grad Formation (Iva-sandstones member) of Upper Miocene age. Reservoir rocks are dividedinlo eight depositional (production) units (i1- i8). Deposits of eachunit are characterized by their own reservoir quality parameters(porosity, horizontal permeability, net pay ... ). Production characteristicsof 30 wells have been studied by a simple slatistical method. Twomajor production well ca...

  12. Reservoir characterization of the Mt. Simon Sandstone, Illinois Basin, USA

    Science.gov (United States)

    Frailey, S.M.; Damico, J.; Leetaru, H.E.

    2011-01-01

    The integration of open hole well log analyses, core analyses and pressure transient analyses was used for reservoir characterization of the Mt. Simon sandstone. Characterization of the injection interval provides the basis for a geologic model to support the baseline MVA model, specify pressure design requirements of surface equipment, develop completion strategies, estimate injection rates, and project the CO2 plume distribution.The Cambrian-age Mt. Simon Sandstone overlies the Precambrian granite basement of the Illinois Basin. The Mt. Simon is relatively thick formation exceeding 800 meters in some areas of the Illinois Basin. In the deeper part of the basin where sequestration is likely to occur at depths exceeding 1000 m, horizontal core permeability ranges from less than 1 ?? 10-12 cm 2 to greater than 1 ?? 10-8 cm2. Well log and core porosity can be up to 30% in the basal Mt. Simon reservoir. For modeling purposes, reservoir characterization includes absolute horizontal and vertical permeability, effective porosity, net and gross thickness, and depth. For horizontal permeability, log porosity was correlated with core. The core porosity-permeability correlation was improved by using grain size as an indication of pore throat size. After numerous attempts to identify an appropriate log signature, the calculated cementation exponent from Archie's porosity and resistivity relationships was used to identify which porosity-permeability correlation to apply and a permeability log was made. Due to the relatively large thickness of the Mt. Simon, vertical permeability is an important attribute to understand the distribution of CO2 when the injection interval is in the lower part of the unit. Only core analyses and specifically designed pressure transient tests can yield vertical permeability. Many reservoir flow models show that 500-800 m from the injection well most of the CO2 migrates upward depending on the magnitude of the vertical permeability and CO2 injection

  13. Architecture and reservoir quality of low-permeable Eocene lacustrine turbidite sandstone from the Dongying Depression, East China

    Science.gov (United States)

    Munawar, Muhammad Jawad; Lin, Chengyan; Chunmei, Dong; Zhang, Xianguo; Zhao, Haiyan; Xiao, Shuming; Azeem, Tahir; Zahid, Muhammad Aleem; Ma, Cunfei

    2018-05-01

    The architecture and quality of lacustrine turbidites that act as petroleum reservoirs are less well documented. Reservoir architecture and multiscale heterogeneity in turbidites represent serious challenges to production performance. Additionally, establishing a hierarchy profile to delineate heterogeneity is a challenging task in lacustrine turbidite deposits. Here, we report on the turbidites in the middle third member of the Eocene Shahejie Formation (Es3), which was deposited during extensive Middle to Late Eocene rifting in the Dongying Depression. Seismic records, wireline log responses, and core observations were integrated to describe the reservoir heterogeneity by delineating the architectural elements, sequence stratigraphic framework and lithofacies assemblage. A petrographic approach was adopted to constrain microscopic heterogeneity using an optical microscope, routine core analyses and X-ray diffraction (XRD) analyses. The Es3m member is interpreted as a sequence set composed of four composite sequences: CS1, CS2, CS3 and CS4. A total of forty-five sequences were identified within these four composite sequences. Sand bodies were mainly deposited as channels, levees, overbank splays, lobes and lobe fringes. The combination of fining-upward and coarsening-upward lithofacies patterns in the architectural elements produces highly complex composite flow units. Microscopic heterogeneity is produced by diagenetic alteration processes (i.e., feldspar dissolution, authigenic clay formation and quartz cementation). The widespread kaolinization of feldspar and mobilization of materials enhanced the quality of the reservoir by producing secondary enlarged pores. In contrast, the formation of pore-filling authigenic illite and illite/smectite clays reduced its permeability. Recovery rates are higher in the axial areas and smaller in the marginal areas of architectural elements. This study represents a significant insight into the reservoir architecture and

  14. Geological and petrophysical characterization of the Ferron Sandstone for 3-D simulation of a fluvial-deltaic reservoir. Deliverable 2.5.4, Ferron Sandstone lithologic strip logs, Emergy & Sevier Counties, Utah: Volume I

    Energy Technology Data Exchange (ETDEWEB)

    Allison, M.L.

    1995-12-08

    Strip logs for 491 wells were produced from a digital subsurface database of lithologic descriptions of the Ferron Sandstone Member of the Mancos Shale. This subsurface database covers wells from the parts of Emery and Sevier Counties in central Utah that occur between Ferron Creek on the north and Last Chance Creek on the south. The lithologic descriptions were imported into a logging software application designed for the display of stratigraphic data. Strip logs were produced at a scale of one inch equals 20 feet. The strip logs were created as part of a study by the Utah Geological Survey to develop a comprehensive, interdisciplinary, and qualitative characterization of a fluvial-deltaic reservoir using the Ferron Sandstone as a surface analogue. The study was funded by the U.S. Department of Energy (DOE) under the Geoscience/Engineering Reservoir Characterization Program.

  15. Study on fine geological modelling of the fluvial sandstone reservoir in Daqing oilfield

    Energy Technology Data Exchange (ETDEWEB)

    Zhoa Han-Qing [Daqing Research Institute, Helongjiang (China)

    1997-08-01

    These paper aims at developing a method for fine reservoir description in maturing oilfields by using close spaced well logging data. The main productive reservoirs in Daqing oilfield is a set of large fluvial-deltaic deposits in the Songliao Lake Basin, characterized by multi-layers and serious heterogeneities. Various fluvial channel sandstone reservoirs cover a fairly important proportion of reserves. After a long period of water flooding, most of them have turned into high water cut layers, but there are considerable residual reserves within them, which are difficult to find and tap. Making fine reservoir description and developing sound a geological model is essential for tapping residual oil and enhancing oil recovery. The principal reason for relative lower precision of predicting model developed by using geostatistics is incomplete recognition of complex distribution of fluvial reservoirs and their internal architecture`s. Tasking advantage of limited outcrop data from other regions (suppose no outcrop data available in oilfield) can only provide the knowledge of subtle changing of reservoir parameters and internal architecture. For the specific geometry distribution and internal architecture of subsurface reservoirs (such as in produced regions) can be gained only from continuous infilling logging well data available from studied areas. For developing a geological model, we think the first important thing is to characterize sandbodies geometries and their general architecture`s, which are the framework of models, and then the slight changing of interwell parameters and internal architecture`s, which are the contents and cells of the model. An excellent model should possess both of them, but the geometry is the key to model, because it controls the contents and cells distribution within a model.

  16. Predictive modeling of CO2 sequestration in deep saline sandstone reservoirs: Impacts of geochemical kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Balashov, Victor N.; Guthrie, George D.; Hakala, J. Alexandra; Lopano, Christina L.; Rimstidt, J. Donald; Brantley, Susan L.

    2013-03-01

    One idea for mitigating the increase in fossil-fuel generated CO{sub 2} in the atmosphere is to inject CO{sub 2} into subsurface saline sandstone reservoirs. To decide whether to try such sequestration at a globally significant scale will require the ability to predict the fate of injected CO{sub 2}. Thus, models are needed to predict the rates and extents of subsurface rock-water-gas interactions. Several reactive transport models for CO{sub 2} sequestration created in the last decade predicted sequestration in sandstone reservoirs of ~17 to ~90 kg CO{sub 2} m{sup -3|. To build confidence in such models, a baseline problem including rock + water chemistry is proposed as the basis for future modeling so that both the models and the parameterizations can be compared systematically. In addition, a reactive diffusion model is used to investigate the fate of injected supercritical CO{sub 2} fluid in the proposed baseline reservoir + brine system. In the baseline problem, injected CO{sub 2} is redistributed from the supercritical (SC) free phase by dissolution into pore brine and by formation of carbonates in the sandstone. The numerical transport model incorporates a full kinetic description of mineral-water reactions under the assumption that transport is by diffusion only. Sensitivity tests were also run to understand which mineral kinetics reactions are important for CO{sub 2} trapping. The diffusion transport model shows that for the first ~20 years after CO{sub 2} diffusion initiates, CO{sub 2} is mostly consumed by dissolution into the brine to form CO{sub 2,aq} (solubility trapping). From 20-200 years, both solubility and mineral trapping are important as calcite precipitation is driven by dissolution of oligoclase. From 200 to 1000 years, mineral trapping is the most important sequestration mechanism, as smectite dissolves and calcite precipitates. Beyond 2000 years, most trapping is due to formation of aqueous HCO{sub 3}{sup -}. Ninety-seven percent of the

  17. Performance of Surfactant Methyl Ester Sulphonate solution for Oil Well Stimulation in reservoir sandstone TJ Field

    Science.gov (United States)

    Eris, F. R.; Hambali, E.; Suryani, A.; Permadi, P.

    2017-05-01

    Asphaltene, paraffin, wax and sludge deposition, emulsion and water blocking are kinds ofprocess that results in a reduction of the fluid flow from the reservoir into formation which causes a decrease of oil wells productivity. Oil well Stimulation can be used as an alternative to solve oil well problems. Oil well stimulation technique requires applying of surfactant. Sodium Methyl Ester Sulphonate (SMES) of palm oil is an anionic surfactant derived from renewable natural resource that environmental friendly is one of potential surfactant types that can be used in oil well stimulation. This study was aimed at formulation SMES as well stimulation agent that can identify phase transitions to phase behavior in a brine-surfactant-oil system and altered the wettability of rock sandstone and limestone. Performance of SMES solution tested by thermal stability test, phase behavioral examination and rocks wettability test. The results showed that SMES solution (SMES 5% + xylene 5% in the diesel with addition of 1% NaCl at TJformation water and SMES 5% + xylene 5% in methyl ester with the addition of NaCl 1% in the TJ formation water) are surfactant that can maintain thermal stability, can mostly altered the wettability toward water-wet in sandstone reservoir, TJ Field.

  18. Digital Rock Physics Aplications: Visualisation Complex Pore and Porosity-Permeability Estimations of the Porous Sandstone Reservoir

    Science.gov (United States)

    Handoyo; Fatkhan; Del, Fourier

    2018-03-01

    Reservoir rock containing oil and gas generally has high porosity and permeability. High porosity is expected to accommodate hydrocarbon fluid in large quantities and high permeability is associated with the rock’s ability to let hydrocarbon fluid flow optimally. Porosity and permeability measurement of a rock sample is usually performed in the laboratory. We estimate the porosity and permeability of sandstones digitally by using digital images from μCT-Scan. Advantages of the method are non-destructive and can be applied for small rock pieces also easily to construct the model. The porosity values are calculated by comparing the digital image of the pore volume to the total volume of the sandstones; while the permeability values are calculated using the Lattice Boltzmann calculations utilizing the nature of the law of conservation of mass and conservation of momentum of a particle. To determine variations of the porosity and permeability, the main sandstone samples with a dimension of 300 × 300 × 300 pixels are made into eight sub-cubes with a size of 150 × 150 × 150 pixels. Results of digital image modeling fluid flow velocity are visualized as normal velocity (streamline). Variations in value sandstone porosity vary between 0.30 to 0.38 and permeability variations in the range of 4000 mD to 6200 mD. The results of calculations show that the sandstone sample in this research is highly porous and permeable. The method combined with rock physics can be powerful tools for determining rock properties from small rock fragments.

  19. Quantification of a maximum injection volume of CO2 to avert geomechanical perturbations using a compositional fluid flow reservoir simulator

    Science.gov (United States)

    Jung, Hojung; Singh, Gurpreet; Espinoza, D. Nicolas; Wheeler, Mary F.

    2018-02-01

    Subsurface CO2 injection and storage alters formation pressure. Changes of pore pressure may result in fault reactivation and hydraulic fracturing if the pressure exceeds the corresponding thresholds. Most simulation models predict such thresholds utilizing relatively homogeneous reservoir rock models and do not account for CO2 dissolution in the brine phase to calculate pore pressure evolution. This study presents an estimation of reservoir capacity in terms of allowable injection volume and rate utilizing the Frio CO2 injection site in the coast of the Gulf of Mexico as a case study. The work includes laboratory core testing, well-logging data analyses, and reservoir numerical simulation. We built a fine-scale reservoir model of the Frio pilot test in our in-house reservoir simulator IPARS (Integrated Parallel Accurate Reservoir Simulator). We first performed history matching of the pressure transient data of the Frio pilot test, and then used this history-matched reservoir model to investigate the effect of the CO2 dissolution into brine and predict the implications of larger CO2 injection volumes. Our simulation results -including CO2 dissolution- exhibited 33% lower pressure build-up relative to the simulation excluding dissolution. Capillary heterogeneity helps spread the CO2 plume and facilitate early breakthrough. Formation expansivity helps alleviate pore pressure build-up. Simulation results suggest that the injection schedule adopted during the actual pilot test very likely did not affect the mechanical integrity of the storage complex. Fault reactivation requires injection volumes of at least about sixty times larger than the actual injected volume at the same injection rate. Hydraulic fracturing necessitates much larger injection rates than the ones used in the Frio pilot test. Tested rock samples exhibit ductile deformation at in-situ effective stresses. Hence, we do not expect an increase of fault permeability in the Frio sand even in the presence of

  20. Sedimentology and Reservoir Characteristics of Early Cretaceous Fluvio-Deltaic and Lacustrine Deposits, Upper Abu Gabra Formation, Sufyan Sub-basin, Muglad Rift Basin, Sudan

    Science.gov (United States)

    Yassin, Mohamed; Abdullatif, Osman; Hariri, Mustafa

    2017-04-01

    Sufyan Sub-basin is an East-West trending Sub-basin located in the northwestern part of the Muglad Basin (Sudan), in the eastern extension of the West and Central Africa Rift System (WCARS). The Early Cretaceous Abu Gabra Formation considered as the main source rock in the Muglad Basin. In Sufyan Sub-basin the Early Cretaceous Upper Abu Gabra Formation is the main oil-producing reservoir. It is dominated by sandstone and shales deposited in fluvio-deltaic and lacustrine environment during the first rift cycle in the basin. Depositional and post-depositional processes highly influenced the reservoir quality and architecture. This study investigates different scales of reservoir heterogeneities from macro to micro scale. Subsurface facies analysis was analyzed based on the description of six conventional cores from two wells. Approaches include well log analysis, thin sections and scanning electron microscope (SEM) investigations, grain-size, and X-ray diffraction (XRD) analysis of the Abu Gabra sandstone. The cores and well logs analyses revealed six lithofacies representing fluvio-deltaic and lacustrine depositional environment. The sandstone is medium to coarse-grained, poorly to moderately sorted and sub-angular to subrounded, Sub-feldspathic arenite to quartz arenite. On macro-scale, reservoir quality varies within Abu Gabra reservoir where it shows progressive coarsening upward tendencies with different degrees of connectivity. The upper part of the reservoir showed well connected and amalgamated sandstone bodies, the middle to lower parts, however, have moderate to low sandstone bodies' connectivity and amalgamation. On micro-scale, sandstone reservoir quality is directly affected by textures and diagenesis.The XRD and SEM analyses show that kaolinite and chlorite clay are the common clay minerals in the studied samples. Clay matrix and quartz overgrowth have significantly reduced the reservoir porosity and permeability, while the dissolution of feldspars

  1. ) Sediment petrographic characterisation and diagenetic pathways of the Miocene Agbada sandstone, Niger delta

    International Nuclear Information System (INIS)

    Akaegbobi, I. M; Gaupp, R.; Fischer, C.

    2003-01-01

    Combined petrophysical and petrographic investigations of he Agbada sandstone interbeds has been undertaken in order to determine the controlling factors on the reservoir quality of he paralic sandstone facies. Well logs, petrophysical data and a set of core samples from two wells located in the eastern onshore of he Niger delta spanning a depth interval of 3200 to 330m, formed the basic material for the present study. Four sandstone and siltstone facies units ranging form coastal bar sands through transgressive sands to marine claystones were identified based on petrophysical log signatures. Thin section analysis of a selected set of sandstone samples revealed essentially a unimodal, homogeneous grain size distribution of the detrital mineral components. Quantitative assessment of the mineralogical composition using point count method (300 points) revealed the predominance of dring. etrital quartz (85%) over feldspar minerals (9%) and lithic fragments (6%). A database generated from the point counting of the sandstones provided a broad perspective to the relative variations of the intergranular porosities (28%), cementation and matrix. These are remarkable indicators for low compaction. Authigenic kaoline and illite were identified. The partial leaching of detrital feldspars are responsible for the low percentages of intragranular volume (secondary porosity). The main controlling factor on the high porosity can be traced to either low compactional effects (overpressure?) or total leaching of unknown early cements. We suggest that the excellent reservoir properties of the Agbada sandstones are due to under compaction, caused by continuous long-term over pressuring

  2. Rate type isotach compaction of consolidated sandstone

    NARCIS (Netherlands)

    Waal, J.A. de; Thienen-Visser, K. van; Pruiksma, J.P.

    2015-01-01

    Laboratory experiments on samples from a consolidated sandstone reservoir are presented that demonstrate rate type compaction behaviour similar to that observed on unconsolidated sands and soils. Such rate type behaviour can have large consequences for reservoir compaction, surface subsidence and

  3. Sandstone-filled normal faults: A case study from central California

    Science.gov (United States)

    Palladino, Giuseppe; Alsop, G. Ian; Grippa, Antonio; Zvirtes, Gustavo; Phillip, Ruy Paulo; Hurst, Andrew

    2018-05-01

    Despite the potential of sandstone-filled normal faults to significantly influence fluid transmissivity within reservoirs and the shallow crust, they have to date been largely overlooked. Fluidized sand, forcefully intruded along normal fault zones, markedly enhances the transmissivity of faults and, in general, the connectivity between otherwise unconnected reservoirs. Here, we provide a detailed outcrop description and interpretation of sandstone-filled normal faults from different stratigraphic units in central California. Such faults commonly show limited fault throw, cm to dm wide apertures, poorly-developed fault zones and full or partial sand infill. Based on these features and inferences regarding their origin, we propose a general classification that defines two main types of sandstone-filled normal faults. Type 1 form as a consequence of the hydraulic failure of the host strata above a poorly-consolidated sandstone following a significant, rapid increase of pore fluid over-pressure. Type 2 sandstone-filled normal faults form as a result of regional tectonic deformation. These structures may play a significant role in the connectivity of siliciclastic reservoirs, and may therefore be crucial not just for investigation of basin evolution but also in hydrocarbon exploration.

  4. Anomalies of natural gas compositions and carbon isotope ratios caused by gas diffusion - A case from the Donghe Sandstone reservoir in the Hadexun Oilfield, Tarim Basin, northwest China

    Science.gov (United States)

    Wang, Yangyang; Chen, Jianfa; Pang, Xiongqi; Zhang, Baoshou; Wang, Yifan; He, Liwen; Chen, Zeya; Zhang, Guoqiang

    2018-05-01

    Natural gases in the Carboniferous Donghe Sandstone reservoir within the Block HD4 of the Hadexun Oilfield, Tarim Basin are characterized by abnormally low total hydrocarbon gas contents ( δ13C ethane (C2) gas has never been reported previously in the Tarim Basin and such large variations in δ13C have rarely been observed in other basins globally. Based on a comprehensive analysis of gas geochemical data and the geological setting of the Carboniferous reservoirs in the Hadexun Oilfield, we reveal that the anomalies of the gas compositions and carbon isotope ratios in the Donghe Sandstone reservoir are caused by gas diffusion through the poorly-sealed caprock rather than by pathways such as gas mixing, microorganism degradation, different kerogen types or thermal maturity degrees of source rocks. The documentation of an in-reservoir gas diffusion during the post entrapment process as a major cause for gas geochemical anomalies may offer important insight into exploring natural gas resources in deeply buried sedimentary basins.

  5. Greybull Sandstone Petroleum Potential on the Crow Indian Reservation, South-Central Montana

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, David A.

    2002-05-13

    The focus of this project was to explore for stratigraphic traps that may be present in valley-fill sandstone at the top of the Lower Cretaceous Kootenai Formation. This sandstone interval, generally known as the Greybull Sandstone, has been identified along the western edge of the reservation and is a known oil and gas reservoir in the surrounding region. The Greybull Sandstone was chosen as the focus of this research because it is an excellent, well-documented, productive reservoir in adjacent areas, such as Elk Basin; Mosser Dome field, a few miles northwest of the reservation; and several other oil and gas fields in the northern portion of the Bighorn Basin.

  6. Effective Wettability Measurements of CO2-Brine-Sandstone System at Different Reservoir Conditions

    Science.gov (United States)

    Al-Menhali, Ali; Krevor, Samuel

    2014-05-01

    , core-scale effective contact angle can be determined. In addition to providing a quantitative measure of the core-averaged wetting properties, the technique allows for the observation of shifts in contact angle with changing conditions. We examine the wettability changes of the CO2-brine system in Berea sandstone with variations in reservoir conditions including supercritical, gaseous and liquid CO2injection. We evaluate wettability variation within a single rock with temperature, pressure, and salinity across a range of conditions relevant to subsurface CO2 storage. This study will include results of measurements in a Berea sandstone sample across a wide range of conditions representative of subsurface reservoirs suitable for CO2 storage (5-20 MPa, 25-90 oC, 0-5 mol kg-1). The measurement uses X-ray CT imaging in a state of the art core flooding laboratory designed to operate at high temperature, pressure, and concentrated brines.

  7. An interpretation of core and wireline logs for the Petrophysical evaluation of Upper Shallow Marine sandstone reservoirs of the Bredasdorp Basin, offshore South Africa

    Science.gov (United States)

    Magoba, Moses; Opuwari, Mimonitu

    2017-04-01

    This paper embodies a study carried out to assess the Petrophysical evaluation of upper shallow marine sandstone reservoir of 10 selected wells in the Bredasdorp basin, offshore, South Africa. The studied wells were selected randomly across the upper shallow marine formation with the purpose of conducting a regional study to assess the difference in reservoir properties across the formation. The data sets used in this study were geophysical wireline logs, Conventional core analysis and geological well completion report. The physical rock properties, for example, lithology, fluid type, and hydrocarbon bearing zone were qualitatively characterized while different parameters such as volume of clay, porosity, permeability, water saturation ,hydrocarbon saturation, storage and flow capacity were quantitatively estimated. The quantitative results were calibrated with the core data. The upper shallow marine reservoirs were penetrated at different depth ranging from shallow depth of about 2442m to 3715m. The average volume of clay, average effective porosity, average water saturation, hydrocarbon saturation and permeability range from 8.6%- 43%, 9%- 16%, 12%- 68% , 32%- 87.8% and 0.093mD -151.8mD respectively. The estimated rock properties indicate a good reservoir quality. Storage and flow capacity results presented a fair to good distribution of hydrocarbon flow.

  8. Imaging fluid/solid interactions in hydrocarbon reservoir rocks.

    Science.gov (United States)

    Uwins, P J; Baker, J C; Mackinnon, I D

    1993-08-01

    The environmental scanning electron microscope (ESEM) has been used to image liquid hydrocarbons in sandstones and oil shales. Additionally, the fluid sensitivity of selected clay minerals in hydrocarbon reservoirs was assessed via three case studies: HCl acid sensitivity of authigenic chlorite in sandstone reservoirs, freshwater sensitivity of authigenic illite/smectite in sandstone reservoirs, and bleach sensitivity of a volcanic reservoir containing abundant secondary chlorite/corrensite. The results showed the suitability of using ESEM for imaging liquid hydrocarbon films in hydrocarbon reservoirs and the importance of simulating in situ fluid-rock interactions for hydrocarbon production programmes. In each case, results of the ESEM studies greatly enhanced prediction of reservoir/borehole reactions and, in some cases, contradicted conventional wisdom regarding the outcome of potential engineering solutions.

  9. Origin, conditions and processes of sandstone reservoir diagenetic silicification in the North Sea; Origine, conditions et processus de la silicification diagenetique de reservoir greseux en Mer du Nord

    Energy Technology Data Exchange (ETDEWEB)

    Blanchet, A.

    2002-02-01

    The petroleum reservoir qualities of sandstones are partially reduce by the presence of diagenetic quartz which occlude the cement porosity. Two sandstones reservoirs have been studied to understand the process and origin of silicification. The Brent sandstones have been sampled in the Alwyn north and Dunbar fields (North Sea) and the Franklin sandstones in the Elgin and Glenelg fields (North Sea). Fluid inclusions are often used to constrain quartz precipitation temperature. However their possible stretching with burial is still a problem. Fluid inclusion (FI) petrographic and micro-thermometric study does not show any evidence of stretching: no correlation between size, shape and homogenization temperature (Th) has been observed. Large Th range, even for FI in a single detrital grain overgrowth boundary, cannot been explained by temperature reset. The fluorescence of hydrocarbon inclusions has been analysed by micro-spectro-fluorimeter (MSF) and interpreted as density after calibration using known crude oils. Hydrocarbon inclusions show large density range for FI trapped along a single detrital grain overgrowth boundary. Raman spectroscopy reveals that aqueous inclusions are not saturated with methane. Moreover, a linear relation between methane content and Th implies pressure corrections reducing the range of trapping temperatures. The similarity of Th and MSF data between FI located along detrital grain-overgrowth boundary and within the overgrowth of a single grain indicates that FI located along the boundary are trapped after the precipitation of the first overgrowth zone. These inclusions cannot then be used to represent the beginning of the silicification. The diagenetic sequence and aluminium content in the quartz overgrowth allow to establish the origin of silica for each overgrowth zone defined in cathodoluminescence. High aluminium contents (up to 1375 ppm) are linked to feldspar dissolution which can be induced by acid meteoric water or organic acids

  10. Determination of residual oil saturation from time-lapse pulsed neutron capture logs in a large sandstone reservoir

    International Nuclear Information System (INIS)

    Syed, E.V.; Salaita, G.N.; McCaffery, F.G.

    1991-01-01

    Cased hole logging with pulsed neutron tools finds extensive use for identifying zones of water breakthrough and monitoring oil-water contacts in oil reservoirs being depleted by waterflooding or natural water drive. Results of such surveys then find direct use for planning recompletions and water shutoff treatments. Pulsed neutron capture (PNC) logs are useful for estimating water saturation changes behind casing in the presence of a constant, high-salinity environment. PNC log surveys run at different times, i.e., in a time-lapse mode, are particularly amenable to quantitative analysis. The combined use of the original open hole and PNC time-lapse log information can then provide information on remaining or residual oil saturations in a reservoir. This paper reports analyses of historical pulsed neutron capture log data to assess residual oil saturation in naturally water-swept zones for selected wells from a large sandstone reservoir in the Middle East. Quantitative determination of oil saturations was aided by PNC log information obtained from a series of tests conducted in a new well in the same field

  11. Wettability Alteration of Sandstone and Carbonate Rocks by Using ZnO Nanoparticles in Heavy Oil Reservoirs

    Directory of Open Access Journals (Sweden)

    Masoumeh Tajmiri

    2015-10-01

    Full Text Available Efforts to enhance oil recovery through wettability alteration by nanoparticles have been attracted in recent years. However, many basic questions have been ambiguous up until now. Nanoparticles penetrate into pore volume of porous media, stick on the core surface, and by creating homogeneous water-wet area, cause to alter wettability. This work introduces the new concept of adding ZnO nanoparticles by an experimental work on wettability alteration and oil recovery through spontaneous imbibition mechanism. Laboratory tests were conducted in two experimental steps on four cylindrical core samples (three sandstones and one carbonate taken from a real Iranian heavy oil reservoir in Amott cell. In the first step, the core samples were saturated by crude oil. Next, the core samples were flooded with nanoparticles and saturated by crude oil for about two weeks. Then, the core samples were immersed in distilled water and the amount of recovery was monitored during 30 days for both steps. The experimental results showed that oil recovery for three sandstone cores changed from 20.74, 4.3, and 3.5% of original oil in place (OOIP in the absence of nanoparticles to 36.2, 17.57, and 20.68% of OOIP when nanoparticles were added respectively. Moreover, for the carbonate core, the recovery changed from zero to 8.89% of OOIP by adding nanoparticles. By the investigation of relative permeability curves, it was found that by adding ZnO nanoparticles, the crossover-point of curves shifted to the right for both sandstone and carbonate cores, which meant wettability was altered to water- wet. This study, for the first time, illustrated the remarkable role of ZnO nanoparticles in wettability alteration toward more water-wet for both sandstone and carbonate cores and enhancing oil recovery.

  12. Long-Term CO2 Exposure Experiments - Geochemical Effects on Brine-Saturated Reservoir Sandstone

    Science.gov (United States)

    Fischer, Sebastian; Zemke, Kornelia; Liebscher, Axel; Wandrey, Maren

    2010-05-01

    The injection of CO2 into deep saline aquifers is the most promising strategy for the reduction of CO2 emissions to the atmosphere via long-term geological storage. The study is part of the CO2SINK project conducted at Ketzin, situated 40 km west of Berlin. There, food grade CO2 has been pumped into the Upper Triassic Stuttgart Formation since June 2008. The main objective of the experimental program is to investigate the effects of long-term CO2 exposure on the physico-chemical properties of the reservoir rock. To achieve this goal, core samples from observation well Ktzi 202 have been saturated with synthetic brine and exposed to CO2 in high quality steel autoclaves at simulated reservoir P-T-conditions of 5.5 MPa and 40 ° C. The synthetic brine had a composition representative of the formation fluid (Förster et al., 2006) of 172.8 g/l NaCl, 8.0 g/l MgCl2×2H2O, 4.8 g/l CaCl2×2H2O and 0.6 g/l KCl. After 15 months, the first set of CO2-exposed samples was removed from the pressure vessels. Thin sections, XRD, SEM as well as EMP data were used to determine the mineralogical features of the reservoir rocks before and after the experiments. Additionally, NMR relaxation and MP was performed to measure poroperm and pore size distribution values of the twin samples. The analyzed samples are fine- to medium grained, moderately well- to well sorted and weakly consolidated sandstones. Quartz and plagioclase are the major components, while K-feldspar, hematite, white & dark mica, chlorite and illite are present in minor and varying amounts. Cements are composed of analcime, dolomite and anhydrite. Some samples show mm- to cm-scale cross-beddings. The laminae comprise lighter, quartz- and feldspar-dominated layers and dark-brownish layers with notably less quartz and feldspars. The results are consistent with those of Blaschke et al. (2008). The plagioclase composition indicates preferred dissolution of the Ca-component and a trend toward albite-rich phases or even pure

  13. Mechanical changes caused by CO2-driven cement dissolution in the Morrow B Sandstone at reservoir conditions: Experimental observations

    Science.gov (United States)

    Wu, Z.; Luhmann, A. J.; Rinehart, A. J.; Mozley, P.; Dewers, T. A.

    2017-12-01

    Carbon Capture, Utilization and Storage (CCUS) in transmissive reservoirs is a proposed mechanism in reducing CO2 emissions. Injection of CO2 perturbs reservoir chemistry, and can modify porosity and permeability and alter mineralogy. However, little work has been done on the coupling of rock alteration by CO2 injection and the mechanical integrity of the reservoir. In this study, we perform flow-through experiments on calcite- and dolomite-cemented Pennsylvanian Morrow B Sandstone (West Texas, USA) cores. We hypothesize that poikilotopic calcite cement has a larger impact on chemo-mechanical alteration than disseminated dolomite cement given similar CO2 exposure. With one control brine flow-through experiment and two CO2-plus-brine flow-through experiments for each cement composition, flow rates of 0.1 and 0.01 ml/min were applied under 4200 psi pore fluid pressure and 5000 psi confining pressure at 71 °C. Fluid chemistry and permeability data enable monitoring of mineral dissolution. Ultrasonic velocities were measured pre-test using 1.2 MHz source-receiver pairs at 0.5 MPa axial load and show calcite-cemented samples with higher dynamic elastic moduli than dolomite-cemented samples. Velocities measured post-experiment will identify changes from fluid-rock interaction. We plan to conduct cylinder-splitting destructive mechanical test (Brazil test) to measure the pristine and altered tensile strength of different cemented sandstones. The experiments will identify extents to which cement composition and texture control chemo-mechanical degradation of CCUS reservoirs. Funding for this project is provided by the U.S. Department of Energy's (DOE) National Energy Technology Laboratory (NETL) through the Southwest Regional Partnership on Carbon Sequestration (SWP) under Award No. DE-FC26-05NT42591. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of

  14. Application of Advanced Reservoir Characterization, Simulation, and Production Optimization Strategies to Maximize Recovery in Slope and Basin Clastic Reservoirs, West Texas (Delaware Basin)

    Energy Technology Data Exchange (ETDEWEB)

    Andrew G. Cole; George B. Asquith; Jose I. Guzman; Mark D. Barton; Mohammad A. Malik; Shirley P. Dutton; Sigrid J. Clift

    1998-04-01

    The objective of this Class III project is to demonstrate that detailed reservoir characterization of clastic reservoirs in basinal sandstones of the Delaware Mountain Group in the Delaware Basin of West Texas and New Mexico is a cost-effective way to recover more of the original oil in place by strategic infill-well placement and geologically based enhanced oil recovery. The study focused on the Ford Geraldine unit, which produces from the upper Bell Canyon Formation (Ramsey sandstone). Reservoirs in this and other Delaware Mountain Group fields have low producibility (average recovery <14 percent of the original oil in place) because of a high degree of vertical and lateral heterogeneity caused by depositional processes and post-depositional diagenetic modification. Outcrop analogs were studied to better interpret the depositional processes that formed the reservoirs at the Ford Geraldine unit and to determine the dimensions of reservoir sandstone bodies. Facies relationships and bedding architecture within a single genetic unit exposed in outcrop in Culberson County, Texas, suggest that the sandstones were deposited in a system of channels and levees with attached lobes that initially prograded basinward, aggraded, and then turned around and stepped back toward the shelf. Channel sandstones are 10 to 60 ft thick and 300 to 3,000 ft wide. The flanking levees have a wedge-shaped geometry and are composed of interbedded sandstone and siltstone; thickness varies from 3 to 20 ft and length from several hundred to several thousands of feet. The lobe sandstones are broad lens-shaped bodies; thicknesses range up to 30 ft with aspect ratios (width/thickness) of 100 to 10,000. Lobe sandstones may be interstratified with laminated siltstones.

  15. High-resolution 3D X-ray microtomography as tool to investigate size distribution of grain phase and pore space in sandstones

    Science.gov (United States)

    Kahl, Wolf-Achim; Holzheid, Astrid

    2013-04-01

    The geometry and internal structures of sandstone reservoirs, like grain size, sorting, degree of bioturbation, and the history of the diagenetic alterations determine the quantity, flow rates, and recovery of hydrocarbons present in the pore space. In this respect, processes influencing the deep reservoir quality in sandstones are either of depositional, shallow diagenetic, or deep-burial origin. To assess the effect of compaction and cementation on the pore space during diagenesis, we investigated a set of sandstone samples using high-resolution microtomography (µ-CT). By high-resolution µ-CT, size distributions (in 2D and 3D), surface areas and volume fractions of the grain skeleton and pore space of sandstones and - in addition - of mineral powders have been determined. For this study, we analysed aliquots of sandstones that exhibit either complete, partial or no cemententation of the pore space, and sets of mineral powders (quartz, feldspar, calcite). As the resolution of the µ-CT scans is in the µm-range, the surface areas determined for sandstones and powders do detect the geometric surface of the material (Kahl & Holzheid, 2010). Since there are differing approaches to "size" parameters like e.g., long/short particle axes, area equivalent radius, Feret-diameter (2D), and structural thickness (3D), we decided to illustrate the effect of various size determinations for (a) single grains, (b) grain skeletons, and (c) pore space. Therefor, the computer-aided morphometric analysis of the segmented 3D models of the reconstructed scan images comprises versatile calculation algorithms. For example, size distribution of the pore space of partially cemented sandstones can be used to infer the timing of the formation of the cement in respect to tectonic/diagenetic activities. In the case of a late-stage partial cementation of a Bunter sandstone, both pore space and cement phase show identical size distributions. On the contrary, the anhydrite cement of a

  16. UNIDADES DE FRIO PARA MACIEIRAS NA REGIÃO DE VACARIA – RS, BRASIL

    Directory of Open Access Journals (Sweden)

    LOANA SILVEIRA CARDOSO

    2015-06-01

    Full Text Available As macieiras necessitam de um período de acumulação de frio para a quebra da dormência das gemas. Neste estudo, as unidades de frioforam quantificadas por diferentes métodos de cálculo para a região de Vacaria-RS, Brasil, a fim de compará-las com as necessidades de macieiras ‘Gala’ e ‘Fuji’. As unidades de frio foram calculadas para o período de2000/2009, através dos seguintes métodos: Horas de Frio Ponderadas, Utah, Carolina do Norte, Utah Modificado e Carolina do Norte Modificado. Na região estudada, o número de unidades de frio apresenta altavariabilidade entre os anos, independentemente dos métodos de cálculo. Mesmo em anos com alta disponibilidade de horas de frio, o número de unidades de frio necessárias para a quebra de dormência em macieiras ‘Gala’ e ‘Fuji’ não é alcançado, naturalmente. Maio, junho e julho é o principal trimestre para acumular unidades de frio, durante o período de dormência de gemas de macieira.

  17. Effect of temperature on sandstone permeability

    DEFF Research Database (Denmark)

    Rosenbrand, Esther; Kjøller, Claus

    Hot water injection in geothermal sandstone aquifers is considered for seasonal energy storage in Denmark. However, an increase in the aquifer temperature might reduce permeability, and thereby increase production costs. An understanding of the factors that control permeability is required in order...... and the Klinkenberg procedure showed the expected correlation between the two measures, however, differences could be around one order of magnitude. In tight gas sandstones, permeability is often sensitive to net stress, which might change due to the pore pressure change in the Klinkenberg procedure. Besides...... affecting the Klinkenberg procedure, the combined effect of slip and changes in permeability would affect production during pressure depletion in tight gas sandstone reservoirs; therefore effects of gas slip and net stress on permeability were combined in a model based on the Klinkenberg equation. A lower...

  18. The Bentheim Sandstone: Geology, petrophysics, varieties and it's use as dimension stone

    NARCIS (Netherlands)

    Dubelaar, C.W.; Nijland, T.G.

    2014-01-01

    The shallow-marine Bentheim Sandstone was deposited in one of the NW-SE trending basins north of the London-Brabant and Rhenish massifs during the Valanginian (Early Cretaceous). The Bentheim Sandstone forms an important reservoir rock for petroleum, but has also proven itself as a very durable

  19. Improved prediction of reservoir behavior through integration of quantitative geological and petrophysical data

    Energy Technology Data Exchange (ETDEWEB)

    Auman, J. B.; Davies, D. K.; Vessell, R. K.

    1997-08-01

    Methodology that promises improved reservoir characterization and prediction of permeability, production and injection behavior during primary and enhanced recovery operations was demonstrated. The method is based on identifying intervals of unique pore geometry by a combination of image analysis techniques and traditional petrophysical measurements to calculate rock type and estimate permeability and saturation. Results from a complex carbonate and sandstone reservoir were presented as illustrative examples of the versatility and high level of accuracy of this method in predicting reservoir quality. 16 refs., 5 tabs., 14 figs.

  20. The experimental modeling of gas percolation mechanisms in a coal-measure tight sandstone reservoir: A case study on the coal-measure tight sandstone gas in the Upper Triassic Xujiahe Formation, Sichuan Basin, China

    Directory of Open Access Journals (Sweden)

    Shizhen Tao

    2016-12-01

    Full Text Available Tight sandstone gas from coal-measure source rock is widespread in China, and it is represented by the Xujiahe Formation of the Sichuan Basin and the Upper Paleozoic of the Ordos Basin. It is affected by planar evaporative hydrocarbon expulsion of coal-measure source rock and the gentle structural background; hydrodynamics and buoyancy play a limited role in the gas migration-accumulation in tight sandstone. Under the conditions of low permeability and speed, non-Darcy flow is quite apparent, it gives rise to gas-water mixed gas zone. In the gas displacing water experiment, the shape of percolation flow curve is mainly influenced by core permeability. The lower the permeability, the higher the starting pressure gradient as well as the more evident the non-Darcy phenomenon will be. In the gas displacing water experiment of tight sandstone, the maximum gas saturation of the core is generally less than 50% (ranging from 30% to 40% and averaging at 38%; it is similar to the actual gas saturation of the gas zone in the subsurface core. The gas saturation and permeability of the core have a logarithm correlation with a correlation coefficient of 0.8915. In the single-phase flow of tight sandstone gas, low-velocity non-Darcy percolation is apparent; the initial flow velocity (Vd exists due to the slippage effect of gas flow. The shape of percolation flow curve of a single-phase gas is primarily controlled by core permeability and confining pressure; the lower the permeability or the higher the confining pressure, the higher the starting pressure (0.02–0.08 MPa/cm, whereas, the higher the quasi-initial flow speed, the longer the nonlinear section and the more obvious the non-Darcy flow will be. The tight sandstone gas seepage mechanism study shows that the lower the reservoir permeability, the higher the starting pressure and the slower the flow velocity will be, this results in the low efficiency of natural gas migration and accumulation as well as

  1. Reservoir compartmentalization and management strategies: Lessons learned in the Illinois basin

    Energy Technology Data Exchange (ETDEWEB)

    Grube, J.P.; Crockett, J.E.; Huff, B.G. [and others

    1997-08-01

    A research project jointly sponsored by the US Department of Energy and the Illinois State Geological Survey focused on the Cypress and Aux Vases Formations (Mississippian), major clastic reservoirs in the Illinois Basin. Results from the research showed that understanding the nature and distribution of reservoir compartments, and using effective reservoir management strategies, can significantly improve recovery efficiencies from oil fields in this mature basin. Compartments can be most effectively drained where they are geologically well defined and reservoir management practices are coordinated through unified, compartment-wide, development programs. Our studies showed that the Cypress and Aux Vases reservoirs contain lateral and vertical permeability barriers forming compartments that range in size from isolated, interlaminated sandstone and shale beds to sandstone bodies tens of feet in thickness and more than a mile in length. Stacked or shingled, genetically similar sandstone bodies are commonly separated by thin impermeable intervals that can be difficult to distinguish on logs and can, therefore, cause correlation problems, even between wells drilled on spacing of less than ten acres. Lateral separation of sandstone bodies causes similar problems. Reservoir compartmentalization reduces primary and particularly secondary recovery by trapping pockets of by-passed or banked oil. Compartments can be detected by comparing recovery factors of genetically similar sandstone bodies within a field; using packers to separate commingled intervals and analyzing fluid recoveries and pressures; making detailed core-to-log calibrations that identify compartment boundaries; and analyzing pressure data from waterflood programs.

  2. Occurrence of gas hydrate in Oligocene Frio sand: Alaminos Canyon Block 818: Northern Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Boswell, R.D.; Shelander, D.; Lee, M.; Latham, T.; Collett, T.; Guerin, G.; Moridis, G.; Reagan, M.; Goldberg, D.

    2009-07-15

    A unique set of high-quality downhole shallow subsurface well log data combined with industry standard 3D seismic data from the Alaminos Canyon area has enabled the first detailed description of a concentrated gas hydrate accumulation within sand in the Gulf of Mexico. The gas hydrate occurs within very fine grained, immature volcaniclastic sands of the Oligocene Frio sand. Analysis of well data acquired from the Alaminos Canyon Block 818 No.1 ('Tigershark') well shows a total gas hydrate occurrence 13 m thick, with inferred gas hydrate saturation as high as 80% of sediment pore space. Average porosity in the reservoir is estimated from log data at approximately 42%. Permeability in the absence of gas hydrates, as revealed from the analysis of core samples retrieved from the well, ranges from 600 to 1500 millidarcies. The 3-D seismic data reveals a strong reflector consistent with significant increase in acoustic velocities that correlates with the top of the gas-hydrate-bearing sand. This reflector extends across an area of approximately 0.8 km{sup 2} and delineates the minimal probable extent of the gas hydrate accumulation. The base of the inferred gas-hydrate zone also correlates well with a very strong seismic reflector that indicates transition into units of significantly reduced acoustic velocity. Seismic inversion analyses indicate uniformly high gas-hydrate saturations throughout the region where the Frio sand exists within the gas hydrate stability zone. Numerical modeling of the potential production of natural gas from the interpreted accumulation indicates serious challenges for depressurization-based production in settings with strong potential pressure support from extensive underlying aquifers.

  3. Structural-Diagenetic Controls on Fracture Opening in Tight Gas Sandstone Reservoirs, Alberta Foothills

    Science.gov (United States)

    Ukar, Estibalitz; Eichhubl, Peter; Fall, Andras; Hooker, John

    2013-04-01

    relatively undeformed backlimb strata. Fracture apertures locally increase adjacent to reverse faults without an overall increase in fracture frequency. Fluid inclusion analyses of crack-seal quartz cement indicate both aqueous and methane-rich inclusions are present. Homogenization temperatures of two-phase inclusions indicate synkinematic fracture cement precipitation and fracture opening under conditions at or near maximum burial of 190-210°C in core samples, and 120-160°C in outcrop samples. In comparison with the fracture evolution in other, less deformed tight-gas sandstone reservoirs such as the Piceance and East Texas basins where fracture opening is primarily controlled by gas generation, gas charge, and pore fluid pressure, these results suggest a strong control of regional tectonic processes on fracture generation. In conjunction with timing and rate of gas charge, rates of fracture cement growth, and stratigraphic-lithological controls, these processes determine the overall distribution of open fractures in these reservoirs.

  4. Characterizing gas shaly sandstone reservoirs using the magnetic resonance technology in the Anaco area, East Venezuela

    Energy Technology Data Exchange (ETDEWEB)

    Fam, Maged; August, Howard [Halliburton, Houston, TX (United States); Zambrano, Carlos; Rivero, Fidel [PDVSA Gas (Venezuela)

    2008-07-01

    With demand for natural gas on the rise every day, accounting for and booking every cubic foot of gas is becoming very important to operators exploiting natural gas reservoirs. The initial estimates of gas reserves are usually established through the use of petrophysical parameters normally based on wireline and/or LWD logs. Conventional logs, such as gamma ray, density, neutron, resistivity and sonic, are traditionally used to calculate these parameters. Sometimes, however, the use of such conventional logs may not be enough to provide a high degree of accuracy in determining these petrophysical parameters, which are critical to reserve estimates. Insufficient accuracy can be due to high complexities in the rock properties and/or a formation fluid distribution within the reservoir layers that is very difficult to characterize with conventional logs alone. The high degree of heterogeneity in the shaly sandstone rock properties of the Anaco area, East Venezuela, can be characterized by clean, high porosity, high permeability sands to very shaly, highly laminated, and low porosity rock. This wide variation in the reservoir properties may pose difficulties in identifying gas bearing zones which may affect the final gas reserves estimates in the area. The application of the magnetic resonance imaging (MRI) logging technology in the area, combined with the application of its latest acquisition and interpretation methods, has proven to be very adequate in detecting and quantifying gas zones as well as providing more realistic petrophysical parameters for better reserve estimates. This article demonstrates the effectiveness of applying the MRI logging technology to obtain improved petrophysical parameters that will help better characterize the shaly-sands of Anaco area gas reservoirs. This article also demonstrates the value of MRI in determining fluid types, including distinguishing between bound water and free water, as well as differentiating between gas and liquid

  5. Diagenesis and reservoir properties of Cretaceous-Lower Tertiary sandstones: the GANT-1 well, western Nuussuaq, central West Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Kierkegaard, Thomas

    1998-08-01

    The main purpose of this study is to describe the diagenetic alterations occurring in the Cretaceous to Lower Paleocene sedimentary succession of the GANT-1 well, and to determine the diagenetic and detrital factors which control present porosity and permeability. The GANT-1 well is located on north-western Nuussuaq, central West Greenland. The West Greenland margin is a continental margin subdivided into linked basins where Cretaceous to Lower Tertiary and probably older sediments have been deposited. In the Nuussuaq area these sediments are overlain by a succession of Early Tertiary basaltic volcanic rocks which reaches a combined thickness of around 2-2.5 km. Although the reservoir properties of the sandstone intervals in the GANT-1 and GANE-1 wells are generally relatively poor, it is suggested that moderate to good properties may be found in certain intervals within the Maastrichtian-Paleocene succession. However, the reason for the locally enhanced reservoir properties in GANT-1 was not clarified by this study due to the lack of regional petrographical data. (EG) EFP-96. 41 refs., 3 maps

  6. Thermophysical behavior of St. Peter sandstone: application to compressed air energy storage in an aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Erikson, R.L.

    1983-12-01

    The long-term stability of a sandstone reservoir is of primary importance to the success of compressed air energy storage (CAES) in aquifers. The purpose of this study was to: develop experimental techniques for the operation of the CAES Porous Media Flow Loop (PMFL), an apparatus designed to study the stability of porous media in subsurface geologic environments, conduct experiments in the PMFL designed to determine the effects of temperature, stress, and humidity on the stability of candidate CAES reservoir materials, provide support for the CAES field demonstration project in Pittsfield, Illinois, by characterizing the thermophysical stability of Pittsfield reservoir sandstone under simulated field conditions.

  7. Depositional and diagenetic variability within the Cambrian Mount Simon Sandstone: Implications for carbon dioxide sequestration

    Science.gov (United States)

    Bowen, B.B.; Ochoa, R.I.; Wilkens, N.D.; Brophy, J.; Lovell, T.R.; Fischietto, N.; Medina, C.R.; Rupp, J.A.

    2011-01-01

    The Cambrian Mount Simon Sandstone is the major target reservoir for ongoing geologic carbon dioxide (CO2) sequestration demonstrations throughout the midwest United States. The potential CO2 reservoir capacity, reactivity, and ultimate fate of injected CO2 depend on textural and compositional properties determined by depositional and diagenetic histories that vary vertically and laterally across the formation. Effective and efficient prediction and use of the available pore space requires detailed knowledge of the depositional and diagenetic textures and mineralogy, how these variables control the petrophysical character of the reservoir, and how they vary spatially. Here, we summarize the reservoir characteristics of the Mount Simon Sandstone based on examination of geophysical logs, cores, cuttings, and analysis of more than 150 thin sections. These samples represent different parts of the formation and depth ranges of more than 9000 ft (>2743 m) across the Illinois Basin and surrounding areas. This work demonstrates that overall reservoir quality and, specifically, porosity do not exhibit a simple relationship with depth, but vary both laterally and with depth because of changes in the primary depositional facies, framework composition (i.e., feldspar concentration), and diverse diagenetic modifications. Diagenetic processes that have been significant in modifying the reservoir include formation of iron oxide grain coatings, chemical compaction, feldspar precipitation and dissolution, multiple generations of quartz overgrowth cementation, clay mineral precipitation, and iron oxide cementation. These variables provide important inputs for calculating CO2 capacity potential, modeling reactivity, and are also an important baseline for comparisons after CO2 injection. Copyright ??2011. The American Association of Petroleum Geologists/Division of Environmental Geosciences. All rights reserved.

  8. Layers of 'Cabo Frio' in 'Victoria Crater'

    Science.gov (United States)

    2006-01-01

    This view of 'Victoria crater' is looking southeast from 'Duck Bay' towards the dramatic promontory called 'Cabo Frio.' The small crater in the right foreground, informally known as 'Sputnik,' is about 20 meters (about 65 feet) away from the rover, the tip of the spectacular, layered, Cabo Frio promontory itself is about 200 meters (about 650 feet) away from the rover, and the exposed rock layers are about 15 meters (about 50 feet) tall. This is an approximately true color rendering of images taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity during the rover's 952nd sol, or Martian day, (Sept. 28, 2006) using the camera's 750-nanometer, 530-nanometer and 430-nanometer filters.

  9. Diagenetic history of the Surma Group sandstones (Miocene) in the Surma Basin, Bangladesh

    Science.gov (United States)

    Rahman, M. Julleh Jalalur; McCann, Tom

    2012-02-01

    This study examines the various diagenetic controls of the Miocene Surma Group sandstones encountered in petroleum exploration wells from the Surma Basin, which is situated in the northeastern part of the Bengal Basin, Bangladesh. The principal diagenetic minerals/cements in the Surma Group sandstones are Fe-carbonates (with Fe-calcite dominating), quartz overgrowths and authigenic clays (predominantly chlorite, illite-smectite and minor kaolin). The isotopic composition of the carbonate cement revealed a narrow range of δ 18O values (-10.3‰ to -12.4‰) and a wide range of δ 13C value (+1.4‰ to -23.1‰). The δ 13C VPDB and δ 18O VPDB values of the carbonate cements reveal that carbon was most likely derived from the thermal maturation of organic matter during burial, as well as from the dissolution of isolated carbonate clasts and precipitated from mixed marine-meteoric pore waters. The relationship between the intergranular volume (IGV) versus cement volume indicates that compaction played a more significant role than cementation in destroying the primary porosity. However, cementation also played a major role in drastically reducing porosity and permeability in sandstones with poikilotopic, pore-filling blocky cements formed in early to intermediate and deep burial areas. In addition to Fe-carbonate cements, various clay minerals including illite-smectite and chlorite occur as pore-filling and pore-lining authigenic phases. Significant secondary porosity has been generated at depths from 2500 m to 4728 m. The best reservoir rocks found at depths of 2500-3300 m are well sorted, relatively coarse grained; more loosely packed and better rounded sandstones having good porosities (20-30%) and high permeabilities (12-6000 mD). These good quality reservoir rocks are, however, not uniformly distributed and can be considered to be compartmentalized as a result of interbedding with sandstone layers of low to moderate porosities, low permeabilities owing to poor

  10. Interpreting Fracture Patterns in Sandstones Interbedded with Ductile Strata at the Salt Valley Anticline, Arches National Park, Utah; TOPICAL

    International Nuclear Information System (INIS)

    LORENZ, JOHN C.; COOPER, SCOTT P.

    2001-01-01

    Sandstones that overlie or that are interbedded with evaporitic or other ductile strata commonly contain numerous localized domains of fractures, each covering an area of a few square miles. Fractures within the Entrada Sandstone at the Salt Valley Anticline are associated with salt mobility within the underlying Paradox Formation. The fracture relationships observed at Salt Valley (along with examples from Paleozoic strata at the southern edge of the Holbrook basin in northeastern Arizona, and sandstones of the Frontier Formation along the western edge of the Green River basin in southwestern Wyoming), show that although each fracture domain may contain consistently oriented fractures, the orientations and patterns of the fractures vary considerably from domain to domain. Most of the fracture patterns in the brittle sandstones are related to local stresses created by subtle, irregular flexures resulting from mobility of the associated, interbedded ductile strata (halite or shale). Sequential episodes of evaporite dissolution and/or mobility in different directions can result in multiple, superimposed fracture sets in the associated sandstones. Multiple sets of superimposed fractures create reservoir-quality fracture interconnectivity within restricted localities of a formation. However, it is difficult to predict the orientations and characteristics of this type of fracturing in the subsurface. This is primarily because the orientations and characteristics of these fractures typically have little relationship to the regional tectonic stresses that might be used to predict fracture characteristics prior to drilling. Nevertheless, the high probability of numerous, intersecting fractures in such settings attests to the importance of determining fracture orientations in these types of fractured reservoirs

  11. Experimental Study of Cement - Sandstone/Shale - Brine - CO2 Interactions.

    Science.gov (United States)

    Carroll, Susan A; McNab, Walt W; Torres, Sharon C

    2011-11-11

    Reactive-transport simulation is a tool that is being used to estimate long-term trapping of CO2, and wellbore and cap rock integrity for geologic CO2 storage. We reacted end member components of a heterolithic sandstone and shale unit that forms the upper section of the In Salah Gas Project carbon storage reservoir in Krechba, Algeria with supercritical CO2, brine, and with/without cement at reservoir conditions to develop experimentally constrained geochemical models for use in reactive transport simulations. We observe marked changes in solution composition when CO2 reacted with cement, sandstone, and shale components at reservoir conditions. The geochemical model for the reaction of sandstone and shale with CO2 and brine is a simple one in which albite, chlorite, illite and carbonate minerals partially dissolve and boehmite, smectite, and amorphous silica precipitate. The geochemical model for the wellbore environment is also fairly simple, in which alkaline cements and rock react with CO2-rich brines to form an Fe containing calcite, amorphous silica, smectite and boehmite or amorphous Al(OH)3. Our research shows that relatively simple geochemical models can describe the dominant reactions that are likely to occur when CO2 is stored in deep saline aquifers sealed with overlying shale cap rocks, as well as the dominant reactions for cement carbonation at the wellbore interface.

  12. Application of advanced reservoir characterization, simulation, and production optimization strategies to maximize recovery in slope and basin clastic reservoirs, west Texas (Delaware Basin). Annual progress report, March 31, 1995--March 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Dutton, S.P.; Hovorka, S.D.; Cole, A.G.

    1996-08-01

    The objective of this Class III project is to demonstrate that detailed reservoir characterization of clastic reservoirs in basinal sandstones of the Delaware Mountain Group in the Delaware Basin of West Texas and New Mexico is a cost-effective way to recover more of the original oil in place by strategic infill-well placement and geologically based field development. Reservoirs in the Delaware Mountain Group have low producibility (average recovery <14 percent of the original oil in place) because of a high degree of vertical and lateral heterogeneity caused by depositional processes and post-depositional diagenetic modification. Detailed correlations of the Ramsey sandstone reservoirs in Geraldine Ford field suggest that lateral sandstone continuity is less than interpreted by previous studies. The degree of lateral heterogeneity in the reservoir sandstones suggests that they were deposited by eolian-derived turbidites. According to the eolian-derived turbidite model, sand dunes migrated across the exposed shelf to the shelf break during sea-level lowstands and provided well sorted sand for turbidity currents or grain flows into the deep basin.

  13. Geothermal resources: Frio Formation, Upper Texas Gulf Coast. Geological circular 76-3

    Energy Technology Data Exchange (ETDEWEB)

    Bebout, D.G.; Loucks, R.G.; Bosch, S.C.; Dorfman, M.H.

    1976-01-01

    Major sand trends were identified in the Frio Formation, Upper Texas Gulf Coast as part of the evaluation of its potential for producing geothermal energy. Electrical logs from 465 wells spaced 5 to 10 miles apart were used in the study. Maps illustrating total net sand and total sand percentage of the Frio Formation are included. It was found that subsurface fluid temperatures of greater than 250/sup 0/F occur in the Frio sand bodies up to 100 ft thick downdip of the high-sand trends. LA broad band in Brazoria and Galveston Counties was delineated as having geothermal potential. (JGB)

  14. Consolidation of geologic studies of geopressured geothermal resources in Texas. 1982 annual report

    Energy Technology Data Exchange (ETDEWEB)

    Morton, R.A.; Ewing, T.E.; Kaiser, W.R.; Finley, R.J.

    1983-03-01

    Detailed structural mapping at several horizons in selected study areas within the Frio growth-fault trend demonstrates a pronounced variability in structural style. At Sarita in South Texas, shale mobilization produced one or more shale ridges, one of which localized a low-angle growth fault trapping a wedge of deltaic sediments. At Corpus Christi, shale mobilization produced a series of large growth faults, shale-cored domed anticlines, and shale-withdrawal basins, which become progressively younger basinward. At Blessing, major growth faults trapped sands of the Greta/Carancahua barrier system with little progradation. At Pleasant Bayou, a major early growth-fault pattern was overprinted by later salt tectonics - the intrusion of Danbury Dome and the development of a salt-withdrawal basin. At Port Arthur, low-displacement, long-lived faults formed on a sand-poor shelf margin contemporaneously with broad salt uplifts and basins. Variability in styles is related to the nature and extent of Frio sedimentation and shelf-margin progradation and to the presence or absence of salt. Structural styles that are conducive to the development of large geothermal reservoirs include blocks between widely spaced growth faults having dip reversal, salt-withdrawal basins, and shale-withdrawal basins. These styles are widespread on the Texas Gulf Coast. However, actually finding a large reservoir depends on demonstrating the existence of sufficient sandstone with adequate quality to support geopressured geothermal energy production.

  15. Different effects of temperature and salinity on permeability reduction by fines migration in Berea sandstone

    DEFF Research Database (Denmark)

    Rosenbrand, Esther; Kjøller, Claus; Riis, Jacob Fabricius

    2015-01-01

    Hot water injection into geothermal aquifers is considered in order to store energy seasonally. Berea sandstone is often used as a reference formation to study mechanisms that affect permeability in reservoir sandstones. Both heating of the pore fluid and reduction of the pore fluid salinity can...

  16. Genesis and distribution pattern of carbonate cements in lacustrine deep-water gravity-flow sandstone reservoirs in the third member of the Shahejie Formation in the Dongying Sag, Jiyang Depression, Eastern China

    DEFF Research Database (Denmark)

    Yang, Tian; Cao, Yingchang; Friis, Henrik

    2018-01-01

    The lacustrine deep-water gravity-flow sandstone reservoirs in the third member of the Shahejie Formation are the main exploration target for hydrocarbons in the Dongying Sag, Eastern China. Carbonate cementation is responsible for much of the porosity and permeability reduction in the lacustrine...

  17. Geologic framework for the assessment of undiscovered oil and gas resources in sandstone reservoirs of the Upper Jurassic-Lower Cretaceous Cotton Valley Group, U.S. Gulf of Mexico region

    Science.gov (United States)

    Eoff, Jennifer D.; Dubiel, Russell F.; Pearson, Ofori N.; Whidden, Katherine J.

    2015-01-01

    The U.S. Geological Survey (USGS) is assessing the undiscovered oil and gas resources in sandstone reservoirs of the Upper Jurassic–Lower Cretaceous Cotton Valley Group in onshore areas and State waters of the U.S. Gulf of Mexico region. The assessment is based on geologic elements of a total petroleum system. Four assessment units (AUs) are defined based on characterization of hydrocarbon source and reservoir rocks, seals, traps, and the geohistory of the hydrocarbon products. Strata in each AU share similar stratigraphic, structural, and hydrocarbon-charge histories.

  18. Influence of fluvial sandstone architecture on geothermal energy production

    NARCIS (Netherlands)

    Willems, C.J.L.; Maghami Nick, Hamidreza M.; Weltje, G.J.; Donselaar, M.E.; Bruhn, D.F.

    2015-01-01

    Fluvial sandstone reservoirs composed of stacked meander belts are considered as potential geothermal resources in the Netherlands. Net-to-gross, orientation and stacking pattern of the channel belts is of major importance for the connectivity between the injection and production well in such

  19. Water in chalk reservoirs: 'friend or foe?'

    International Nuclear Information System (INIS)

    Hjuler, Morten Leth

    2004-01-01

    Most of the petroleum fields in the Norwegian sector of the North Sea are sandstone reservoirs; the oil and gas are trapped in different species of sandstone. But the Ekofisk Field is a chalk reservoir, which really challenges the operator companies. When oil is produced from chalk reservoirs, water usually gets in and the reservoir subsides. The subsidence may be expensive for the oil companies or be used to advantage by increasing the recovery rate. Since 60 per cent of the world's petroleum reserves are located in carbonate reservoirs, it is important to understand what happens as oil and gas are pumped out. Comprehensive studies at the Department of Petroleum Technology and Applied Geophysics at Stavanger University College in Norway show that the mechanical properties of chalk are considerably altered when the pores in the rock become saturated with oil/gas or water under different stress conditions. The processes are extremely complex. The article also maintains that the effects of injecting carbon dioxide from gas power plants into petroleum reservoirs should be carefully studied before this is done extensively

  20. On the origin of calcite-cemented sandstones in the clearwater formation oil-sands, Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Colquhoun, I.M.

    1999-01-01

    This thesis examined the formation of calcite-cemented sandstones in the Clearwater Formation within the Cold Lake and southern Primrose areas of the Alberta oil sands. Three stages of diagenesis have been recognized, both in the calcite-cemented sandstones and reservoir sands. Diagenesis of the Clearwater Formation in the Cold Lake and southern Primrose areas ended once the reservoir filled with hydrocarbons, but in the Cold Lake area, diagenesis of water-saturated sands likely continued after hydrocarbon emplacement. The reservoir sands in the formation contain a diverse clay mineral assemblage. In general, 0.7 nm clays dominate the diagenetic clay mineralogy of the Clearwater sands. Reservoir sands that contain large amounts of detrital clays and early diagenetic, grain-coating chlorite/smectite have significantly reduced bitumen-saturation. The presence of detrital and diagenetic smectitic clays complicates the removal of bitumen from the Clearwater formation using cyclic steam stimulation techniques because they swell during steam stimulation and reduce porosity and permeability of reservoir sands. Reservoir sands that contain kaolinite, feldspar and calcite react to form smectitic clays, which swell upon cyclic steam stimulation and further reduce porosity and permeability of reservoir sands. However, in the Cold Lake and Primrose areas, the dominant clay mineral is berthierine, which is associated with high calcite, which help to preserve porosity, permeability and bitumen saturation. The porous nature of bitumen-saturated, calcite-cemented sandstones that are laterally extensive could possibly provide a preferential path for steam to initiate calcite dissolution and produce significant concentrations of dissolved carbon dioxide in injected fluids. It was noted that this may then precipitate as carbonate scale within the reservoir and could cause formation damage or affect production equipment. 207 refs., 9 tabs., 58 figs., 3 appendices.

  1. Characterization of dynamic change of Fan-delta reservoir properties in water-drive development

    Energy Technology Data Exchange (ETDEWEB)

    Wu Shenghe; Xiong Qihua; Liu Yuhong [Univ. of Petroleum Changping, Beijing (China)

    1997-08-01

    Fan-delta reservoir in Huzhuangji oil field of east China, is a typical highly heterogeneous reservoir. The oil field has been developed by water-drive for 10 years, but the oil recovery is less than 12%, and water cut is over 90%, resulting from high heterogeneity and serious dynamic change of reservoir properties. This paper aims at the study of dynamic change of reservoir properties in water-drive development. Through quantitative imaging analysis and mercury injection analysis of cores from inspection wells, the dynamic change of reservoir pore structure in water-drive development was studied. The results show that the {open_quotes}large pore channels{close_quotes} develop in distributary channel sandstone and become larger in water-drive development, resulting in more serious pore heterogeneity. Through reservoir sensitivity experiments, the rock-fluid reaction in water-drive development is studied. The results show the permeability of some distal bar sandstone and deserted channel sandstone becomes lower due to swelling of I/S clay minerals in pore throats. OD the other hand, the permeability of distributary channel and mouth bar sandstone become larger because the authigenic Koalinites in pore throats are flushed away with the increase of flow rate of injection water. Well-logging analysis of flooded reservoirs are used to study the dynamic change of reservoir properties in various flow units. The distribution of remaining oil is closely related to the types and distribution of flow units.

  2. ANALYSIS OF OIL-BEARING CRETACEOUS SANDSTONE HYDROCARBON RESERVOIRS, EXCLUSIVE OF THE DAKOTA SANDSTONE, ON THE JICARILLA APACHE INDIAN RESERVATION, NEW MEXICO

    International Nuclear Information System (INIS)

    Jennie Ridgley

    2000-01-01

    An additional 450 wells were added to the structural database; there are now 2550 wells in the database with corrected tops on the Juana Lopez, base of the Bridge Creek Limestone, and datum. This completes the structural data base compilation. Fifteen oil and five gas fields from the Mancos-ElVado interval were evaluated with respect to the newly defined sequence stratigraphic model for this interval. The five gas fields are located away from the structural margins of the deep part of the San Juan Basin. All the fields have characteristics of basin-centered gas and can be considered as continuous gas accumulations as recently defined by the U.S. Geological Survey. Oil production occurs in thinly interbedded sandstone and shale or in discrete sandstone bodies. Production is both from transgressive and regressive strata as redefined in this study. Oil production is both stratigraphically and structurally controlled with production occurring along the Chaco slope or in steeply west-dipping rocks along the east margin of the basin. The ElVado Sandstone of subsurface usage is redefined to encompass a narrower interval; it appears to be more time correlative with the Dalton Sandstone. Thus, it was deposited as part of a regressive sequence, in contrast to the underlying rock units which were deposited during transgression

  3. Layers of 'Cabo Frio' in 'Victoria Crater' (Stereo)

    Science.gov (United States)

    2006-01-01

    This view of 'Victoria crater' is looking southeast from 'Duck Bay' towards the dramatic promontory called 'Cabo Frio.' The small crater in the right foreground, informally known as 'Sputnik,' is about 20 meters (about 65 feet) away from the rover, the tip of the spectacular, layered, Cabo Frio promontory itself is about 200 meters (about 650 feet) away from the rover, and the exposed rock layers are about 15 meters (about 50 feet) tall. This is a red-blue stereo anaglyph generated from images taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity during the rover's 952nd sol, or Martian day, (Sept. 28, 2006) using the camera's 430-nanometer filters.

  4. Fluvial-deltaic sedimentation and stratigraphy of the ferron sandstone

    Science.gov (United States)

    Anderson, P.B.; Chidsey, T.C.; Ryer, T.A.

    1997-01-01

    East-central Utah has world-class outcrops of dominantly fluvial-deltaic Turonian to Coniacian aged strata deposited in the Cretaceous foreland basin. The Ferron Sandstone Member of the Mancos Shale records the influences of both tidal and wave energy on fluvial-dominated deltas on the western margin of the Cretaceous western interior seaway. Revisions of the stratigraphy are proposed for the Ferron Sandstone. Facies representing a variety of environments of deposition are well exposed, including delta-front, strandline, marginal marine, and coastal-plain. Some of these facies are described in detail for use in petroleum reservoir characterization and include permeability structure.

  5. Phytoplankton and water quality in a Mediterranean drinking-water reservoir (Marathonas Reservoir, Greece).

    Science.gov (United States)

    Katsiapi, Matina; Moustaka-Gouni, Maria; Michaloudi, Evangelia; Kormas, Konstantinos Ar

    2011-10-01

    Phytoplankton and water quality of Marathonas drinking-water Reservoir were examined for the first time. During the study period (July-September 2007), phytoplankton composition was indicative of eutrophic conditions although phytoplankton biovolume was low (max. 2.7 mm³ l⁻¹). Phytoplankton was dominated by cyanobacteria and diatoms, whereas desmids and dinoflagellates contributed with lower biovolume values. Changing flushing rate in the reservoir (up to 0.7% of reservoir's water volume per day) driven by water withdrawal and occurring in pulses for a period of 15-25 days was associated with phytoplankton dynamics. Under flushing pulses: (1) biovolume was low and (2) both 'good' quality species and the tolerant to flushing 'nuisance' cyanobacterium Microcystis aeruginosa dominated. According to the Water Framework Directive, the metrics of phytoplankton biovolume and cyanobacterial percentage (%) contribution indicated a moderate ecological water quality. In addition, the total biovolume of cyanobacteria as well as the dominance of the known toxin-producing M. aeruginosa in the reservoir's phytoplankton indicated a potential hazard for human health according to the World Health Organization.

  6. Damage evaluation on oil-based drill-in fluids for ultra-deep fractured tight sandstone gas reservoirs

    Directory of Open Access Journals (Sweden)

    Jinzhi Zhu

    2017-07-01

    Full Text Available In order to explore the damage mechanisms and improve the method to evaluate and optimize the performance of formation damage control of oil-based drill-in fluids, this paper took an ultra-deep fractured tight gas reservoir in piedmont configuration, located in the Cretaceous Bashijiqike Fm of the Tarim Basin, as an example. First, evaluation experiments were conducted on the filtrate invasion, the dynamic damage of oil-based drill-in fluids and the loading capacity of filter cakes. Meanwhile, the evaluating methods were optimized for the formation damage control effect of oil-based drill-in fluids in laboratory: pre-processing drill-in fluids before grading analysis; using the dynamic damage method to simulate the damage process for evaluating the percentage of regained permeability; and evaluating the loading capacity of filter cakes. The experimental results show that (1 oil phase trapping damage and solid phase invasion are the main formation damage types; (2 the damage degree of filtrate is the strongest on the matrix; and (3 the dynamic damage degree of oil-based drill-in fluids reaches medium strong to strong on fractures and filter cakes show a good sealing capacity for the fractures less than 100 μm. In conclusion, the filter cakes' loading capacity should be first guaranteed, and both percentage of regained permeability and liquid trapping damage degree should be both considered in the oil-based drill-in fluids prepared for those ultra-deep fractured tight sandstone gas reservoirs.

  7. Low finding costs calculated in Mississippi's Tuscaloosa, Frio

    International Nuclear Information System (INIS)

    Dowty, S.G.; Moody, J.S.

    1992-01-01

    This paper reports on a recent study conducted by the Mississippi Office of Geology which examined oil and gas finding costs in southwestern Mississippi for the period from 1986 through 1990. The formations of interest were the Upper Cretaceous Lower Tuscaloosa formation and the Oligocene Frio formation. The model incorporated the following financial considerations for exploratory activity: seismic data acquisition, geologic expenses, leasing and legal fees, and drilling costs. Average drilling and completion costs were also assigned to the development wells. The finding cost formula divided the total exploration and development costs by the recoverable reserves. Reserves were multiplied by a 75% net revenue for the Tuscaloosa and 80% for the Frio leases to account for royalty interests and severance taxes. No field operating expenses were included

  8. Application of Advanced Reservoir Characterization, Simulation, and Production Optimization Strategies to Maximize Recovery in Slope and Basin Clastic Reservoirs, West Texas (Delaware Basin), Class III

    Energy Technology Data Exchange (ETDEWEB)

    Dutton, Shirley P.; Flanders, William A.

    2001-11-04

    The objective of this Class III project was demonstrate that reservoir characterization and enhanced oil recovery (EOR) by CO2 flood can increase production from slope and basin clastic reservoirs in sandstones of the Delaware Mountain Group in the Delaware Basin of West Texas and New Mexico. Phase 1 of the project, reservoir characterization, focused on Geraldine Ford and East Ford fields, which are Delaware Mountain Group fields that produce from the upper Bell Canyon Formation (Ramsey sandstone). The demonstration phase of the project was a CO2 flood conducted in East Ford field, which is operated by Orla Petco, Inc., as the East Ford unit.

  9. Structural diagenesis in Upper Carboniferous tight gas sandstones. Lessons learned from the Piesberg analog study

    Energy Technology Data Exchange (ETDEWEB)

    Steindorf, P.; Hoehne, M.; Becker, S.; Hilgers, C. [RWTH Aachen Univ. (Germany). Energy and Mineral Resources Group (EMR); Koehrer, B. [Wintershall Holding GmbH, Barnstorf (Germany)

    2013-08-01

    Upper Carboniferous tight gas sandstone reservoirs in NW-Germany consist of thick successions of cyclothems. Our focus is the Westphalian D of the Piesberg quarry near Osnabrueck, which exposes cemented, faulted and jointed third-order coarse- to fine-grained sandstone cycles separated by anthracite coal seams. We characterize the rocks and the lateral variation of rock properties such as porosity to better constrain input data for reservoir modelling. Three cycles are exposed, each approximately 50 m thick. Rock types can be clearly distinguished by spectral gamma ray in the quarry. Sandstones are intensely compacted and cemented with quartz and generally characterized by low porosities < 8 % (Hepycnometry on plugs and cuttings). Porosities are secondary and mainly related to detrital carbonate dissolution. Around faults dissolution is higher and the porosities can increase to up to 25%. The normal faults show different throws in the quarry and bands of shale and coal have smeared into the fault at juxtaposed beds, which may result in compartments. They dominantly strike W-E and NNW-SSE, but subordinate NE-SW striking fault patterns are also present. Joints were analyzed in a 50 x 50 m section of the quarry wall using Lidar (Light detection and ranging) laser scanning, which allows the characterization of the lithology and quantitative measurement of bedding and fracture orientation data in inaccessible areas. NNE-SSW and W-E joint sets are accompanied by northeasterly and northwesterly striking sets. Around faults, fault planes and fractures are cemented with quartz veins, showing localized mass transport. Due to the intense cementation, the sandstones can reach uniaxial strengths of more than 100 MPa normal to bedding, and approximately 50 MPa parallel to bedding. Sandstone beds within and close to faults are leached by fluids, and their uniaxial strength is reduced by a factor of more than two. Our high resolution field data enables a better understanding of

  10. Temperature Effects on Stiffness Moduli of Reservoir Sandstone from the Deep North Sea

    DEFF Research Database (Denmark)

    Orlander, Tobias; Andreassen, Katrine Alling; Fabricius, Ida Lykke

    We investigate effect of testing temperature on the dynamic frame stiffness of quartz-bearing North Sea sandstone from depths of 5 km. We show that at low stress levels, the rock frame stiffens with increasing temperature and we propose an explanation for the controlling mechanisms. While...... temperature. This is unfortunate and hence, we designed a testing program with the intension of separating and quantifying effects of temperature and stress, specifically for the sandstone material subject to this study....

  11. New Acid Combination for a Successful Sandstone Acidizing

    Science.gov (United States)

    Shafiq, M. U.; Mahmud, H. K. B.; Rezaee, R.

    2017-05-01

    With the development of new enhanced oil recovery techniques, sandstone acidizing has been introduced and played a pivotal role in the petroleum industry. Different acid combinations have been applied, which react with the formation, dissolve the soluble particles; thus increase the production of hydrocarbons. To solve the problems which occurred using current preflush sandstone acidizing technology (hydrochloric acid); a new acid combination has been developed. Core flooding experiments on sandstone core samples with dimensions 1.5 in. × 3 in. were conducted at a flow rate of 2 cm3/min. A series of hydrochloric-acetic acid mixtures with different ratios were tested under 150°F temperature. The core flooding experiments performed are aimed to dissolve carbonate, sodium, potassium and calcium particles from the core samples. These experiments are followed by few important tests which include, porosity-permeability, pH value, Inductively Coupled Plasma (ICP) analysis and Nuclear Magnetic Resonance (NMR measurements). All the results are compared with the results of conventional hydrochloric acid technology. NMR and porosity analysis concluded that the new acid combination is more effective in creating fresh pore spaces and thus increasing the reservoir permeability. It can be seen from the pore distribution before and after the acidizing. Prior applying acid; the large size of pores appears most frequently in the pore distribution while with the applied acid, it was found that the small pore size is most the predominant of the pore distribution. These results are validated using ICP analysis which shows the effective removal of calcium and other positive ions from the core sample. This study concludes that the combination of acetic-hydrochloric acid can be a potential candidate for the preflush stage of sandstone acidizing at high temperature reservoirs.

  12. Paragenetic evolution of reservoir facies, Middle Triassic Halfway Formation, PeeJay Field, northeastern British Columbia: controls on reservoir quality

    Energy Technology Data Exchange (ETDEWEB)

    Caplan, M. L. [Alberta Univ., Dept. of Earth and Atmospheric Sciences, Edmonton, AB (Canada); Moslow, T. F. [Ulster Petroleum Ltd., Calgary, AB (Canada)

    1998-09-01

    Because of the obvious importance of reservoir quality to reservoir performance, diagenetic controls on reservoir quality of Middle Triassic reservoir facies are investigated by comparing two reservoir lithofacies. The implications of porosity structure on the efficiency of primary and secondary hydrocarbon recovery are also assessed. Halfway reservoir facies are composed of bioclastic grainstones (lithofacies G) and litharenites/sublitharenites (lithofacies H), both of which are interpreted as tidal inlet fills. Although paragenetic evolution was similar for the two reservoir facies, subtle differences in reservoir quality are discernible. These are controlled by sedimentary structures, porosity type, grain constituents, and degree of cementation. Reservoir quality in lithofacies G is a function of connectivity of the pore network. In lithofacies H, secondary granular porosity creates a more homogeneous interconnected pore system, wide pore throats and low aspect ratios. The high porosity and low permeability values of the bioclastic grainstones are suspected to cause inefficient flushing of hydrocarbons during waterflooding. However, it is suggested that recovery may be enhanced by induced hydraulic fracturing and acidization of lower permeability calcareous cemented zones. 52 refs., 15 figs.

  13. Reactive transport modeling to study changes in water chemistry induced by CO2 injection at the Frio-I brine pilot

    Energy Technology Data Exchange (ETDEWEB)

    Kharaka, Y.K; Doughty, C.; Freifeld, B.M.; Daley, T.M.; Xu, T.

    2009-11-01

    To demonstrate the potential for geologic storage of CO{sub 2} in saline aquifers, the Frio-I Brine Pilot was conducted, during which 1600 tons of CO{sub 2} were injected into a high-permeability sandstone and the resulting subsurface plume of CO{sub 2} was monitored using a variety of hydrogeological, geophysical, and geochemical techniques. Fluid samples were obtained before CO{sub 2} injection for baseline geochemical characterization, during the CO{sub 2} injection to track its breakthrough at a nearby observation well, and after injection to investigate changes in fluid composition and potential leakage into an overlying zone. Following CO{sub 2} breakthrough at the observation well, brine samples showed sharp drops in pH, pronounced increases in HCO{sub 3}{sup -} and aqueous Fe, and significant shifts in the isotopic compositions of H{sub 2}O and dissolved inorganic carbon. Based on a calibrated 1-D radial flow model, reactive transport modeling was performed for the Frio-I Brine Pilot. A simple kinetic model of Fe release from the solid to aqueous phase was developed, which can reproduce the observed increases in aqueous Fe concentration. Brine samples collected after half a year had lower Fe concentrations due to carbonate precipitation, and this trend can be also captured by our modeling. The paper provides a method for estimating potential mobile Fe inventory, and its bounding concentration in the storage formation from limited observation data. Long-term simulations show that the CO{sub 2} plume gradually spreads outward due to capillary forces, and the gas saturation gradually decreases due to its dissolution and precipitation of carbonates. The gas phase is predicted to disappear after 500 years. Elevated aqueous CO{sub 2} concentrations remain for a longer time, but eventually decrease due to carbonate precipitation. For the Frio-I Brine Pilot, all injected CO{sub 2} could ultimately be sequestered as carbonate minerals.

  14. Layers of 'Cabo Frio' in 'Victoria Crater' (False Color)

    Science.gov (United States)

    2006-01-01

    This view of 'Victoria crater' is looking southeast from 'Duck Bay' towards the dramatic promontory called 'Cabo Frio.' The small crater in the right foreground, informally known as 'Sputnik,' is about 20 meters (about 65 feet) away from the rover, the tip of the spectacular, layered, Cabo Frio promontory itself is about 200 meters (about 650 feet) away from the rover, and the exposed rock layers are about 15 meters (about 50 feet) tall. This is an enhanced false color rendering of images taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity during the rover's 952nd sol, or Martian day, (Sept. 28, 2006) using the camera's 750-nanometer, 530-nanometer and 430-nanometer filters.

  15. CO2 Storage Potential of the Eocene Tay Sandstone, Central North Sea, UK

    Science.gov (United States)

    Gent, Christopher; Williams, John

    2017-04-01

    Carbon Capture and Storage (CCS) is crucial for low-carbon industry, climate mitigation and a sustainable energy future. The offshore capacity of the UK is substantial and has been estimated at 78 Gt of CO2 in saline aquifers and hydrocarbon fields. The early-mid Eocene Tay Sandstone Member of the Central North Sea (CNS) is a submarine-fan system and potential storage reservoir with a theoretical capacity of 123 Mt of CO2. The Tay Sandstone comprises of 4 sequences, amalgamating into a fan complex 125km long and 40 km at a minimum of 1500 m depth striking NW-SE, hosting several hydrocarbon fields including Gannett A, B, D and Pict. In order to better understand the storage potential and characteristics, the Tay Sandstone over Quadrant 21 has been interpreted using log correlation and 3D seismic. Understanding the internal and external geometry of the sandstone as well as the lateral extent of the unit is essential when considering CO2 vertical and horizontal fluid flow pathways and storage security. 3D seismic mapping of a clear mounded feature has revealed the youngest sequence of the Tay complex; a homogenous sand-rich channel 12 km long, 1.5 km wide and on average 100 m thick. The sandstone has porosity >35%, permeability >5 D and a net to gross of 0.8, giving a total pore volume of 927x106 m3. The remaining three sequences are a series of stacked channels and interbedded mudstones which are more quiescent on the seismic, however, well logs indicate each subsequent sequence reduce in net to gross with age as mud has a greater influence in the early fan system. Nevertheless, the sandstone properties remain relatively consistent and are far more laterally extensive than the youngest sequence. The Tay Sandstone spatially overlaps several other potential storage sites including the older Tertiary sandstones of the Cromarty, Forties and Mey Members and deeper Jurassic reservoirs. This favours the Tay Sandstone to be considered in a secondary or multiple stacked

  16. Depositional history of the reservoir sandstones, Akpor and Apara oilfields, eastern Niger Delta, Nigeria

    Energy Technology Data Exchange (ETDEWEB)

    Amajor, L.C.; Agbaire, D.W. (Port Harcourt Univ. (NG). Dept. of Geology)

    1989-10-01

    A subsurface study of the Agbada Formation in the Akpor and Apara oilfields in the eastern Niger Delta was undertaken in order to determine the depositional development of the reservoir sand-bodies. The study area comprises a maximum of 29 relatively thick sandstones, cyclically interbedded with shales of varying thicknesses. The lowest two sand units, separated by a shale unit and located near the base, produce petroleum from ten wells in both fields. Each sand-body exhibits a coarsening-upward textural gradient. The lower sand-body which is oval-shaped, moderately- to poorly-sorted, fine- to very coarse-grained, carbonaceous, with clay and lignite horizons, is interpreted as a deltaic sand. The unit appears to have migrated landwards, probably as a result of localized transgression, and developed maximum thickness between the two fields. The upper sand is fine-to-pebbly in grain size, well-sorted and glauconitic. Maximum development occurred slightly east of the delta. As the unit prograded in a predominantly southerly direction, genetic currents simultaneously caused it to be channelized. This sand-body is interpreted as an offshore marine bar. The intervening carbonaceous shale is thought to be of lagoonal origin. The pinch-out edges of these sand bodies may constitute prolific stratigraphic traps. (author).

  17. Spatially pooled depth-dependent reservoir storage, elevation, and water-quality data for selected reservoirs in Texas, January 1965-January 2010

    Science.gov (United States)

    Burley, Thomas E.; Asquith, William H.; Brooks, Donald L.

    2011-01-01

    The U.S. Geological Survey (USGS), in cooperation with Texas Tech University, constructed a dataset of selected reservoir storage (daily and instantaneous values), reservoir elevation (daily and instantaneous values), and water-quality data from 59 reservoirs throughout Texas. The period of record for the data is as large as January 1965-January 2010. Data were acquired from existing databases, spreadsheets, delimited text files, and hard-copy reports. The goal was to obtain as much data as possible; therefore, no data acquisition restrictions specifying a particular time window were used. Primary data sources include the USGS National Water Information System, the Texas Commission on Environmental Quality Surface Water-Quality Management Information System, and the Texas Water Development Board monthly Texas Water Condition Reports. Additional water-quality data for six reservoirs were obtained from USGS Texas Annual Water Data Reports. Data were combined from the multiple sources to create as complete a set of properties and constituents as the disparate databases allowed. By devising a unique per-reservoir short name to represent all sites on a reservoir regardless of their source, all sampling sites at a reservoir were spatially pooled by reservoir and temporally combined by date. Reservoir selection was based on various criteria including the availability of water-quality properties and constituents that might affect the trophic status of the reservoir and could also be important for understanding possible effects of climate change in the future. Other considerations in the selection of reservoirs included the general reservoir-specific period of record, the availability of concurrent reservoir storage or elevation data to match with water-quality data, and the availability of sample depth measurements. Additional separate selection criteria included historic information pertaining to blooms of golden algae. Physical properties and constituents were water

  18. Upper Hiwassee River Basin reservoirs 1989 water quality assessment

    International Nuclear Information System (INIS)

    Fehring, J.P.

    1991-08-01

    The water in the Upper Hiwassee River Basin is slightly acidic and low in conductivity. The four major reservoirs in the Upper Hiwassee River Basin (Apalachia, Hiwassee, Chatuge, and Nottely) are not threatened by acidity, although Nottely Reservoir has more sulfates than the other reservoirs. Nottely also has the highest organic and nutrient concentrations of the four reservoirs. This results in Nottely having the poorest water clarity and the most algal productivity, although clarity as measured by color and secchi depths does not indicate any problem with most water use. However, chlorophyll concentrations indicate taste and odor problems would be likely if the upstream end of Nottely Reservoir were used for domestic water supply. Hiwassee Reservoir is clearer and has less organic and nutrient loading than either of the two upstream reservoirs. All four reservoirs have sufficient algal activity to produce supersaturated dissolved oxygen conditions and relatively high pH values at the surface. All four reservoirs are thermally stratified during the summer, and all but Apalachia have bottom waters depleted in oxygen. The very short residence time of Apalachia Reservoir, less than ten days as compared to over 100 days for the other three reservoirs, results in it being more riverine than the other three reservoirs. Hiwassee Reservoir actually develops three distinct water temperature strata due to the location of the turbine intake. The water quality of all of the reservoirs supports designated uses, but water quality complaints are being received regarding both Chatuge and Nottely Reservoirs and their tailwaters

  19. Conservação de maracujá-doce pelo uso de cera e choque a frio

    Directory of Open Access Journals (Sweden)

    Silva Alessandra Pereira da

    1999-01-01

    Full Text Available Estudou-se o efeito do choque a frio e da cera, na conservação pós-colheita do maracujá-doce (Passiflora alata Dryander, verificando as principais alterações físicas e químicas durante o armazenamento. Os frutos, colhidos no estádio pré-climatérico, foram desinfetados com hipoclorito de sódio e em seguida, submetidos aos tratamentos: testemunha; cera Sta fresh (1:2; choque frio (-2°C por 2 horas + cera Sta fresh (1:2; choque frio (-2°C por 2 horas. Os frutos foram avaliados a cada 6 dias quanto a perda de peso, textura, rendimento de suco, sólidos solúveis totais e acidez total titulável. Após 30 dias a 9°C e 85-90% UR, pode-se concluir que o tratamento mais adequado à conservação do maracujá-doce foi o que utilizou a cera Sta Fresh. Os tratamentos com choque a frio e com choque a frio + cera não foram eficientes para manutenção da qualidade pós-colheita do maracujá-doce.

  20. Heavy mineral sorting in downwards injected Palaeocene sandstone, Siri Canyon, Danish North Sea

    DEFF Research Database (Denmark)

    Kazerouni, Afsoon Moatari; Friis, Henrik; Svendsen, Johan Byskov

    2011-01-01

    Post-depositional remobilization and injection of sand are often seen in deep-water clastic systems and has been recently recognised as a significant modifier of deep-water sandstone geometry. Large-scale injectite complexes have been interpreted from borehole data in the Palaeocene Siri Canyon...... of depositional structures in deep-water sandstones, the distinction between "in situ" and injected or remobilised sandstones is often ambiguous. Large scale heavy mineral sorting (in 10 m thick units) is observed in several reservoir units in the Siri Canyon and has been interpreted to represent the depositional...... sorting. In this study we describe an example of effective shear-zone sorting of heavy minerals in a thin downward injected sandstone dyke which was encountered in one of the cores in the Cecilie Field, Siri Canyon. Differences in sorting pattern of heavy minerals are suggested as a tool for petrographic...

  1. Multinomial Logistic Regression & Bootstrapping for Bayesian Estimation of Vertical Facies Prediction in Heterogeneous Sandstone Reservoirs

    Science.gov (United States)

    Al-Mudhafar, W. J.

    2013-12-01

    Precisely prediction of rock facies leads to adequate reservoir characterization by improving the porosity-permeability relationships to estimate the properties in non-cored intervals. It also helps to accurately identify the spatial facies distribution to perform an accurate reservoir model for optimal future reservoir performance. In this paper, the facies estimation has been done through Multinomial logistic regression (MLR) with respect to the well logs and core data in a well in upper sandstone formation of South Rumaila oil field. The entire independent variables are gamma rays, formation density, water saturation, shale volume, log porosity, core porosity, and core permeability. Firstly, Robust Sequential Imputation Algorithm has been considered to impute the missing data. This algorithm starts from a complete subset of the dataset and estimates sequentially the missing values in an incomplete observation by minimizing the determinant of the covariance of the augmented data matrix. Then, the observation is added to the complete data matrix and the algorithm continues with the next observation with missing values. The MLR has been chosen to estimate the maximum likelihood and minimize the standard error for the nonlinear relationships between facies & core and log data. The MLR is used to predict the probabilities of the different possible facies given each independent variable by constructing a linear predictor function having a set of weights that are linearly combined with the independent variables by using a dot product. Beta distribution of facies has been considered as prior knowledge and the resulted predicted probability (posterior) has been estimated from MLR based on Baye's theorem that represents the relationship between predicted probability (posterior) with the conditional probability and the prior knowledge. To assess the statistical accuracy of the model, the bootstrap should be carried out to estimate extra-sample prediction error by randomly

  2. Evaluation of input output efficiency of oil field considering undesirable output —A case study of sandstone reservoir in Xinjiang oilfield

    Science.gov (United States)

    Zhang, Shuying; Wu, Xuquan; Li, Deshan; Xu, Yadong; Song, Shulin

    2017-06-01

    Based on the input and output data of sandstone reservoir in Xinjiang oilfield, the SBM-Undesirable model is used to study the technical efficiency of each block. Results show that: the model of SBM-undesirable to evaluate its efficiency and to avoid defects caused by traditional DEA model radial angle, improve the accuracy of the efficiency evaluation. by analyzing the projection of the oil blocks, we find that each block is in the negative external effects of input redundancy and output deficiency benefit and undesirable output, and there are greater differences in the production efficiency of each block; the way to improve the input-output efficiency of oilfield is to optimize the allocation of resources, reduce the undesirable output and increase the expected output.

  3. Sequence Stratigraphy of the Dakota Sandstone, Eastern San Juan Basin, New Mexico, and its Relationship to Reservoir Compartmentalization

    Energy Technology Data Exchange (ETDEWEB)

    Varney, Peter J.

    2002-04-23

    This research established the Dakota-outcrop sequence stratigraphy in part of the eastern San Juan Basin, New Mexico, and relates reservoir quality lithologies in depositional sequences to structure and reservoir compartmentalization in the South Lindrith Field area. The result was a predictive tool that will help guide further exploration and development.

  4. Low permeability Neogene lithofacies in Northern Croatia as potential unconventional hydrocarbon reservoirs

    Science.gov (United States)

    Malvić, Tomislav; Sučić, Antonija; Cvetković, Marko; Resanović, Filip; Velić, Josipa

    2014-06-01

    We present two examples of describing low permeability Neogene clastic lithofacies to outline unconventional hydrocarbon lithofacies. Both examples were selected from the Drava Depression, the largest macrostructure of the Pannonian Basin System located in Croatia. The first example is the Beničanci Field, the largest Croatian hydrocarbon reservoir discovered in Badenian coarse-grained clastics that consists mostly of breccia. The definition of low permeability lithofacies is related to the margins of the existing reservoir, where the reservoir lithology changed into a transitional one, which is mainly depicted by the marlitic sandstones. However, calculation of the POS (probability of success of new hydrocarbons) shows critical geological categories where probabilities are lower than those in the viable reservoir with proven reserves. Potential new hydrocarbon volumes are located in the structural margins, along the oil-water contact, with a POS of 9.375%. These potential reserves in those areas can be classified as probable. A second example was the Cremušina Structure, where a hydrocarbon reservoir was not proven, but where the entire structure has been transferred onto regional migration pathways. The Lower Pontian lithology is described from well logs as fine-grained sandstones with large sections of silty or marly clastics. As a result, the average porosity is low for conventional reservoir classification (10.57%). However, it is still an interesting case for consideration as a potentially unconventional reservoir, such as the "tight" sandstones.

  5. Experimental Investigation of Crack Extension Patterns in Hydraulic Fracturing with Shale, Sandstone and Granite Cores

    Directory of Open Access Journals (Sweden)

    Jianming He

    2016-12-01

    Full Text Available Hydraulic fracturing is an important method of reservoir stimulation in the exploitation of geothermal resources, and conventional and unconventional oil and gas resources. In this article, hydraulic fracturing experiments with shale, sandstone cores (from southern Sichuan Basin, and granite cores (from Inner Mongolia were conducted to investigate the different hydraulic fracture extension patterns in these three reservoir rocks. The different reactions between reservoir lithology and pump pressure can be reflected by the pump pressure monitoring curves of hydraulic fracture experiments. An X-ray computer tomography (CT scanner was employed to obtain the spatial distribution of hydraulic fractures in fractured shale, sandstone, and granite cores. From the microscopic and macroscopic observation of hydraulic fractures, different extension patterns of the hydraulic fracture can be analyzed. In fractured sandstone, symmetrical hydraulic fracture morphology could be formed, while some micro cracks were also induced near the injection hole. Although the macroscopic cracks in fractured granite cores are barely observed by naked eye, the results of X-ray CT scanning obviously show the morphology of hydraulic fractures. It is indicated that the typical bedding planes well developed in shale formation play an important role in the propagation of hydraulic fractures in shale cores. The results also demonstrated that heterogeneity influenced the pathway of the hydraulic fracture in granite cores.

  6. Identification and assessment of potential water quality impact factors for drinking-water reservoirs.

    Science.gov (United States)

    Gu, Qing; Deng, Jinsong; Wang, Ke; Lin, Yi; Li, Jun; Gan, Muye; Ma, Ligang; Hong, Yang

    2014-06-10

    Various reservoirs have been serving as the most important drinking water sources in Zhejiang Province, China, due to the uneven distribution of precipitation and severe river pollution. Unfortunately, rapid urbanization and industrialization have been continuously challenging the water quality of the drinking-water reservoirs. The identification and assessment of potential impacts is indispensable in water resource management and protection. This study investigates the drinking water reservoirs in Zhejiang Province to better understand the potential impact on water quality. Altogether seventy-three typical drinking reservoirs in Zhejiang Province encompassing various water storage levels were selected and evaluated. Using fifty-two reservoirs as training samples, the classification and regression tree (CART) method and sixteen comprehensive variables, including six sub-sets (land use, population, socio-economy, geographical features, inherent characteristics, and climate), were adopted to establish a decision-making model for identifying and assessing their potential impacts on drinking-water quality. The water quality class of the remaining twenty-one reservoirs was then predicted and tested based on the decision-making model, resulting in a water quality class attribution accuracy of 81.0%. Based on the decision rules and quantitative importance of the independent variables, industrial emissions was identified as the most important factor influencing the water quality of reservoirs; land use and human habitation also had a substantial impact on water quality. The results of this study provide insights into the factors impacting the water quality of reservoirs as well as basic information for protecting reservoir water resources.

  7. The impact of hydraulic flow unit & reservoir quality index on pressure profile and productivity index in multi-segments reservoirs

    Directory of Open Access Journals (Sweden)

    Salam Al-Rbeawi

    2017-12-01

    Full Text Available The objective of this paper is studying the impact of the hydraulic flow unit and reservoir quality index (RQI on pressure profile and productivity index of horizontal wells acting in finite reservoirs. Several mathematical models have been developed to investigate this impact. These models have been built based on the pressure distribution in porous media, depleted by a horizontal well, consist of multi hydraulic flow units and different reservoir quality index. The porous media are assumed to be finite rectangular reservoirs having different configurations and the wellbores may have different lengths. Several analytical models describing flow regimes have been derived wherein hydraulic flow units and reservoir quality index have been included in addition to rock and fluid properties. The impact of these two parameters on reservoir performance has also been studied using steady state productivity index.It has been found that both pressure responses and flow regimes are highly affected by the existence of multiple hydraulic flow units in the porous media and the change in reservoir quality index for these units. Positive change in the RQI could lead to positive change in both pressure drop required for reservoir fluids to move towards the wellbore and hence the productivity index.

  8. INTRODUCTION Sandstone beds within Auchi locality are the ...

    African Journals Online (AJOL)

    The major framework composition is Q F L which classifies the sandstone as Quartz ... The grains are texturally immature as depicted by their subangular edges but mineralogically ..... Fig 6 : Vertical Section of Bioturbated Sandstone Lithofacies Showing Trace Fossils ..... on Water Quality and Planktonic Production in an.

  9. Economic evaluation on tight sandstone gas development projects in China and recommendation on fiscal and taxation support policies

    OpenAIRE

    Zhen Yang; Lingfeng Kong; Min Du; Chenhui Zhao

    2016-01-01

    China is rich in tight sandstone gas resources (“tight gas” for short). For example, the Sulige Gasfield in the Ordos Basin and the Upper Triassic Xujiahe Fm gas reservoir in the Sichuan Basin are typical tight gas reservoirs. In the past decade, tight gas reserve and production both have increased rapidly in China, but tight gas reservoirs are always managed as conventional gas reservoirs without effective fiscal, taxation and policy supports. The potential of sustainable tight gas productio...

  10. Water Quality Assessment of Danjiangkou Reservoir and its Tributaries in China

    Science.gov (United States)

    Liu, Linghua; Peng, Wenqi; Wu, Leixiang; Liu, Laisheng

    2018-01-01

    Danjiangkou Reservoir is an important water source for the middle route of the South to North Water Diversion Project in China, and water quality of Danjiangkou Reservoir and its tributaries is crucial for the project. The purpose of this study is to evaluate the water quality of Daniiangkou Reservoir and its tributaries based on Canadian Council of Ministers of the Environment Water Quality Index (CCMEWQI). 22 water quality parameters from 25 sampling sites were analyzed to calculate WQI. The results indicate that water quality in Danjiangkou Reservoir area, Hanjiang River and Danjiang River is excellent. And the seriously polluted tributary rivers were Shending River, Jianghe River, Sihe River, Tianhe River, Jianhe River and Jiangjun River. Water quality parameters that cannot meet the standard limit for drinking water source were fecal coliform bacteria, CODcr, CODMn, BOD5, NH3-N, TP, DO, anionic surfactant and petroleum. Fecal coliform bacteria, TP, ammonia nitrogen, CODMn were the most common parameters to fail.

  11. Permeability in Rotliegend gas sandstones to gas and brine as predicted from NMR, mercury injection and image analysis

    DEFF Research Database (Denmark)

    Rosenbrand, Esther; Fabricius, Ida Lykke; Fisher, Quentin

    2015-01-01

    Permeability characterisation of low permeability, clay-rich gas sandstones is part of production forecasting and reservoir management. The physically based Kozeny (1927) equation linking permeability with porosity and pore size is derived for a porous medium with a homogeneous pore size, whereas...... the pore sizes in tight sandstones can range from nm to μm. Nuclear magnetic resonance (NMR) transverse relaxation was used to estimate a pore size distribution for 63 samples of Rotliegend sandstone. The surface relaxation parameter required to relate NMR to pore size is estimated by combination of NMR...

  12. Sequence Stratigraphy of the Dakota Sandstone, Eastern San Juan Basin, New Mexico, and its Relationship to Reservoir Compartmentalization; FINAL

    International Nuclear Information System (INIS)

    Varney, Peter J.

    2002-01-01

    This research established the Dakota-outcrop sequence stratigraphy in part of the eastern San Juan Basin, New Mexico, and relates reservoir quality lithologies in depositional sequences to structure and reservoir compartmentalization in the South Lindrith Field area. The result was a predictive tool that will help guide further exploration and development

  13. Application of advanced reservoir characterization, simulation, and production optimization strategies to maximize recovery in slope and basin clastic reservoirs, West Texas (Delaware Basin), Class III

    Energy Technology Data Exchange (ETDEWEB)

    Dutton, Shirley P.; Flanders, William A.; Zirczy, Helena H.

    2000-05-24

    The objective of this Class 3 project was to demonstrate that detailed reservoir characterization of slope and basin clastic reservoirs in sandstones of the Delaware Mountain Group in the Delaware Basin of West Texas and New Mexico is a cost effective way to recover a higher percentage of the original oil in place through strategic placement of infill wells and geologically based field development. Phase 1 of the project, reservoir characterization, was completed this year, and Phase 2 began. The project is focused on East Ford field, a representative Delaware Mountain Group field that produces from the upper Bell Canyon Formation (Ramsey sandstone). The field, discovered in 1960, is operated by Oral Petco, Inc., as the East Ford unit. A CO{sub 2} flood is being conducted in the unit, and this flood is the Phase 2 demonstration for the project.

  14. SUSCETIBILIDADE VARIETAL DE FRUTOS DE BANANEIRA AO FRIO COLD DAMAGE IN BANANAS

    Directory of Open Access Journals (Sweden)

    LUIZ ALBERTO LICHTEMBERG

    2001-12-01

    Full Text Available No Sul do Brasil, os danos causados pelo frio depreciam a qualidade da banana que permanece no campo durante o outono e inverno, dificultando a sua comercialização. Visando a verificar diferenças entre cultivares quanto à resistência ao frio no campo e em pós-colheita, foram realizados três experimentos em Itajaí-SC. No primeiro, foram avaliados os danos de frio em 13 cultivares do grupo AAA, 7 cultivares do grupo AAB, 6 híbridos do grupo AAAB e 1 cultivar do grupo ABB, em cachos colhidos em outubro de 1997. No segundo experimento, foram avaliados danos de frio em cultivares dos grupos AAA, AAB, ABB e AAAB, em cachos colhidos de 07-05-99 a 27-08-99. No terceiro experimento, foram avaliados danos de frio em bananas de quatro cultivares, armazenadas a 10°C, durante 5, 10 e 20 dias. O genoma B conferiu maior resistência da fruta às baixas temperaturas, tanto a campo quanto na armazenagem. Verificaram-se diferenças quanto a danos de frio tanto entre grupos genômicos, quanto entre cultivares do mesmo grupo. A maior resistência às baixas temperaturas pode permitir o transporte de bananas dos grupos AAB, ABB e AAAB a longas distâncias, em temperaturas inferiores a 12°C.In Southern Brazil, banana bunches that remain in the field during the Fall and Winter are subject to cold damage. Three experiments were carried out in Itajaí, SC, Brazil, with the purpose of investigating the differences among banana cultivars as to their resistance to cold damage. In the first experiment, 13 AAA group cultivars, 7 AAB group cultivars, 6 AAAB hybrids and 1 ABB group cultivar were evaluated as to the level of cold damage. The second experiment evaluated banana bunches of cultivars of AAA, AAB, ABB, and AAAB groups, harvested from May 07/99 to August 27/99. The third experiment examined cold damage to banana clusters stored at 10°C during 5, 10 and 20 days. The B genome appeared to confer the greatest cold resistance to banana fruits, both in the

  15. Evolution of pores and fractures in an unconventional Upper Carboniferous reservoir analogue, Westphalian D, W-Germany

    Energy Technology Data Exchange (ETDEWEB)

    Hoehne, M.; Schurk, K.; Hilgers, C. [RWTH Aachen Univ. (Germany). Reservoir-Petrology, Energy and Mineral Resources Group (EMR); Koehrer, B. [Wintershall Holding GmbH, Barnstorf (Germany); Bertier, P. [RWTH Aachen Univ. (Germany). Inst. of Clay and Interface Mineralogy

    2013-08-01

    Uncertainties in reservoir characterization of tight gas sandstones can be significantly reduced by using quantitative data from outcrops. The active Piesberg quarry near Osnabrueck exposes Upper Carboniferous strata and therefore provides a reservoir outcrop analog to the gas-bearing tight gas fields in NW-Germany. This study focused on variations of sedimentary facies, porosity, diagenesis and structural inventory in the quarry. The Westphalian D strata at Piesberg consist of siliciclastic, coarse- to fine-grained sandstones with a strong cementation, intercalated with coal seams, siltstones and mudstones. Petrography shows shale-, mudstone and clay rip-up fragments squeezed into primary porosity during eodiagenesis. Sandstone types commonly show low porosities (<10 %) and very low permeabilities (<0.01 mD) mainly due to intense quartz cementation. Scarce authigenic carbonates are euhedral ankerites formed during burial. Secondary porosity resulted mostly from detrital carbonate leaching and limited dissolution of feldspars. Within a zone of up to several meters around faults, porosity is much higher. Feldspars are almost completely altered to illite and locally to kaolinite. Partly dissolved detrital carbonates show Fe-oxide margins around intragranular pores, indicative of Fe-rich compositions formed during telo-diagenesis. Both joints and faults were mapped throughout the quarry and strike, slip and throw of the latter were documented. Cemented fractures prevail around faults and may thus be associated with the structural and diagenetic evolution of the Upper Carboniferous of the Piesberg area. This study is embedded into a larger outcrop analog study of RWTH Aachen in cooperation with Wintershall. Its aim is to unravel the impact of structural diagenesis on the alteration and evolution of pore space and thus reservoir quality. Results can be used to develop datadriven exploration strategies and improved development options for analogous subsurface tight gas

  16. Fe-oxide grain coatings support bacterial Fe-reducing metabolisms in 1.7-2.0 km-deep subsurface quartz arenite sandstone reservoirs of the Illinois Basin (USA

    Directory of Open Access Journals (Sweden)

    Yiran eDong

    2014-09-01

    Full Text Available The Cambrian-age Mt. Simon Sandstone, deeply buried within the Illinois Basin of the midcontinent of North America, contains quartz sand grains ubiquitously encrusted with iron-oxide cements and dissolved ferrous iron in pore-water. Although microbial iron reduction has previously been documented in the deep terrestrial subsurface, the potential for diagenetic mineral cementation to drive microbial activity has not been well studied. In this study, two subsurface formation water samples were collected at 1.72 and 2.02 km, respectively, from the Mt. Simon Sandstone in Decatur, Illinois. Low-diversity microbial communities were detected from both horizons and were dominated by Halanaerobiales of Phylum Firmicutes. Iron-reducing enrichment cultures fed with ferric citrate were successfully established using the formation water. Phylogenetic classification identified the enriched species to be related to Vulcanibacillus from the 1.72 km depth sample, while Orenia dominated the communities at 2.02 km of burial depth. Species-specific quantitative analyses of the enriched organisms in the microbial communities suggest that they are indigenous to the Mt. Simon Sandstone. Optimal iron reduction by the 1.72 km enrichment culture occurred at a temperature of 40oC (range 20 to 60oC and a salinity of 25 parts per thousand (range 25-75 ppt. This culture also mediated fermentation and nitrate reduction. In contrast, the 2.02 km enrichment culture exclusively utilized hydrogen and pyruvate as the electron donors for iron reduction, tolerated a wider range of salinities (25-200 ppt, and exhibited only minimal nitrate- and sulfate-reduction. In addition, the 2.02 km depth community actively reduces the more crystalline ferric iron minerals goethite and hematite. The results suggest evolutionary adaptation of the autochthonous microbial communities to the Mt. Simon Sandstone and carries potentially important implications for future utilization of this reservoir

  17. Changes in the composition and properties of Ashalchinskoye bitumen-saturated sandstones when exposed to water vapor

    Science.gov (United States)

    Korolev, E.; Eskin, A.; Kolchugin, A.; Morozov, V.; Khramchenkov, M.; Gabdelvalieva, R.

    2018-05-01

    Ashalchinskoye bitumen deposit is an experimental platform for testing technology of high-viscosity oil extraction from reservoir rocks. Last time for enhanced of oil recovery in reservoir used pressurization a water vapor with a temperature of ∼ 180 ° C (SAGD technology). However, what happens in sandstone reservoir is little known. We did a study of the effects of water vapor on the structural components of bitumen saturated sandstone. In paper were studied the rock samples at base condition and after one week exposure by water vapour. The thermal analysis showed that steaming helps to removes light and middle oil fractions with a boiling point up to 360 ° C from oil saturated sandstones. Content of heavy oil fractions virtually unchanged. Studying the composition of water extractions of samples showed that the process of aquathermolysis of oil is accompanied by a lowering of the pH of the pore solution from 7.4 to 6.5 and rise content in several times of mobile cations Ca2+, Mg2+ and HCO3 -, SO4 2- anions. Follows from this that the thermal steam effect by bitumen saturated sandstones leads to partial oxidation of hydrocarbons with to form a carbon dioxide. The source of sulfate ions were oxidized pyrite aggregates. Due to the increasing acidity of condensed water, which fills the pore space of samples, pore fluid becomes aggressive to calcite and dolomite cement of bitumen saturated sandstones. As a result of the dissolution of carbonate cement the pore fluid enriched by calcium and magnesium cations. Clearly, that the process is accompanied by reduction of contact strength between fragments of minerals and rocks. Resulting part of compounds is separated from the outer side of samples and falls to bottom of water vapor container. Decreasing the amount of calcite and dolomite anions in samples in a steam-treated influence is confirmed by X-Ray analysis. X-Ray analysis data of study adscititious component of rocks showed that when influenced of water vapor to

  18. Lessons learned from IOR steamflooding in a bitumen-light oil heterogeneous reservoir

    NARCIS (Netherlands)

    Al Mudhafar, W.J.M.; Hosseini Nasab, S.M.

    2015-01-01

    The Steamflooding was considered in this research to extract the discontinuous bitumen layers that are located at the oil-water contact for the heterogeneous light oil sandstone reservoir of South Rumaila Field. The reservoir heterogeneity and the bitumen layers impede water aquifer approaching into

  19. Integrated geomechanical, petrographical and petrophysical study of the sandstones of the Wajid Group, SW Saudi Arabia

    Science.gov (United States)

    Benaafi, Mohammed; Hariri, Mustafa; Al-Shaibani, Abdulaziz; Abdullatif, Osman; Makkawi, Mohammed

    2018-07-01

    The Cambro-Permian siliciclastic succession in southwestern Saudi Arabia is represented by the Wajid Group, which consists mainly of fluvial, shallow marine, aeolian, and glacial sandstones. The Wajid Group comprises the Dibsiyah, Sanamah, Qalibah, Khusayyayn, and Juwayl Formations. It is exposed in the Wadi Al-Dawasir area and extends to Najran City. The sandstones of the Wajid Group serve as groundwater aquifers in the Wadi Al-Dawasir and Najran areas and host hydrocarbon (mainly gas) reservoirs in the Rub' Al-Khali Basin. This study aims to characterize the geomechanical properties (rock strength and Young's modulus) of the sandstones of the Wajid Group using field and experimental techniques. A further objective is to investigate the relationships between the geomechanical properties and the petrographical and petrophysical properties of the studied sandstones. The geomechanical properties of the studied sandstones vary from glacial to non-glacial sandstones, as the glacial sandstones display high values of the geomechanical properties with high variability indices. Four geological factors including grain size, cement content, porosity and permeability were observed as the main controls on the geomechanical behaviour of the studied sandstones except for the Khusayyayn sandstone, where the mineral composition was also important. Significant correlations were observed between the petrographical and petrophysical properties and the geomechanical properties of the glacial sandstones. Predictive models of the geomechanical properties (RN, UCS, and E) were generated using regression analysis to account for the glacial sandstones.

  20. Application of Advanced Reservoir Characterization, Simulation, and Production Optimization Strategies to Maximize Recovery in Slope and Basin Clastic Reservoirs, West Texas (Delaware Basin), Class III

    Energy Technology Data Exchange (ETDEWEB)

    Dutton, Shirley P.; Flanders, William A.; Mendez, Daniel L.

    2001-05-08

    The objective of this Class 3 project was demonstrate that detailed reservoir characterization of slope and basin clastic reservoirs in sandstone's of the Delaware Mountain Group in the Delaware Basin of West Texas and New Mexico is a cost effective way to recover oil more economically through geologically based field development. This project was focused on East Ford field, a Delaware Mountain Group field that produced from the upper Bell Canyon Formation (Ramsey sandstone). The field, discovered in 9160, is operated by Oral Petco, Inc., as the East Ford unit. A CO2 flood was being conducted in the unit, and this flood is the Phase 2 demonstration for the project.

  1. The effect of rock electrical parameters on the calculation of reservoir saturation

    International Nuclear Information System (INIS)

    Li, Xiongyan; Qin, Ruibao; Liu, Chuncheng; Mao, Zhiqiang

    2013-01-01

    The error in calculating a reservoir saturation caused by the error in the cementation exponent, m, and the saturation exponent, n, should be analysed. In addition, the influence of m and n on the reservoir saturation should be discussed. Based on the Archie formula, the effect of variables m and n on the reservoir saturation is analysed, while the formula for the error in calculating the reservoir saturation, caused by the error in m and n, is deduced, and the main factors affecting the error in reservoir saturation are illustrated. According to the physical meaning of m and n, it can be interpreted that they are two independent parameters, i.e., there is no connection between m and n. When m and n have the same error, the impact of the variables on the calculation of the reservoir saturation should be compared. Therefore, when the errors of m and n are respectively equal to 0.2, 0.4 and 0.6, the distribution range of the errors in calculating the reservoir saturation is analysed. However, in most cases, the error of m and n is about 0.2. When the error of m is 0.2, the error in calculating the reservoir saturation ranges from 0% to 35%. Meanwhile, when the error in n is 0.2, the error in calculating the reservoir saturation is almost always below 5%. On the basis of loose sandstone, medium sandstone, tight sandstone, conglomerate, tuff, breccia, basalt, andesite, dacite and rhyolite, this paper first analyses the distribution range and change amplitude of m and n. Second, the impact of m and n on the calculation of reservoir saturation is elaborated upon. With regard to each lithology, the distribution range and change amplitude of m are greater than those of n. Therefore, compared with n, the effect of m on the reservoir saturation is stronger. The influence of m and n on the reservoir saturation is determined, and the error in calculating the reservoir saturation caused by the error of m and n is calculated. This is theoretically and practically significant for

  2. Uranium favorability of late Eocene through Pliocene rocks of the South Texas Coastal Plain

    Energy Technology Data Exchange (ETDEWEB)

    Quick, J.V.; Thomas, N.G.; Brogdon, L.D.; Jones, C.A.; Martin, T.S.

    1977-02-01

    The results of a subsurface uranium favorability study of Tertiary rocks (late Eocene through Pliocene) in the Coastal Plain of South Texas are given. In ascending order, these rock units include the Yegua Formation, Jackson Group, Frio Clay, Catahoula Tuff, Oakville Sandstone, and Goliad Sand. The Vicksburg Group, Anahuac Formation, and Fleming Formation were not considered because they have unfavorable lithologies. The Yegua Formation, Jackson Group, Frio Clay, Catahoula Tuff, Oakville Sandstone, and Goliad Sand contain sandstones that may be favorable uranium hosts under certain environmental and structural conditions. All except the Yegua are known to contain ore-grade uranium deposits. Yegua and Jackson sandstones are found in strand plain-barrier bar systems that are aligned parallel to depositional and structural strike. These sands grade into shelf muds on the east, and lagoonal sediments updip toward the west. The lagoonal sediments in the Jackson are interrupted by dip-aligned fluvial systems. In both units, favorable areas are found in the lagoonal sands and in sands on the updip side of the strand-plain system. Favorable areas are also found along the margins of fluvial systems in the Jackson. The Frio and Catahoula consist of extensive alluvial-plain deposits. Favorable areas for uranium deposits are found along the margins of the paleo-channels where favorable structural features and numerous optimum sands are present. The Oakville and Goliad Formations consist of extensive continental deposits of fluvial sandstones. In large areas, these fluvial sandstones are multistoried channel sandstones that form very thick sandstone sequences. Favorable areas are found along the margins of the channel sequences. In the Goliad, favorable areas are also found on the updip margin of strand-plain sandstones where there are several sandstones of optimum thickness.

  3. Uranium favorability of late Eocene through Pliocene rocks of the South Texas Coastal Plain

    International Nuclear Information System (INIS)

    Quick, J.V.; Thomas, N.G.; Brogdon, L.D.; Jones, C.A.; Martin, T.S.

    1977-02-01

    The results of a subsurface uranium favorability study of Tertiary rocks (late Eocene through Pliocene) in the Coastal Plain of South Texas are given. In ascending order, these rock units include the Yegua Formation, Jackson Group, Frio Clay, Catahoula Tuff, Oakville Sandstone, and Goliad Sand. The Vicksburg Group, Anahuac Formation, and Fleming Formation were not considered because they have unfavorable lithologies. The Yegua Formation, Jackson Group, Frio Clay, Catahoula Tuff, Oakville Sandstone, and Goliad Sand contain sandstones that may be favorable uranium hosts under certain environmental and structural conditions. All except the Yegua are known to contain ore-grade uranium deposits. Yegua and Jackson sandstones are found in strand plain-barrier bar systems that are aligned parallel to depositional and structural strike. These sands grade into shelf muds on the east, and lagoonal sediments updip toward the west. The lagoonal sediments in the Jackson are interrupted by dip-aligned fluvial systems. In both units, favorable areas are found in the lagoonal sands and in sands on the updip side of the strand-plain system. Favorable areas are also found along the margins of fluvial systems in the Jackson. The Frio and Catahoula consist of extensive alluvial-plain deposits. Favorable areas for uranium deposits are found along the margins of the paleo-channels where favorable structural features and numerous optimum sands are present. The Oakville and Goliad Formations consist of extensive continental deposits of fluvial sandstones. In large areas, these fluvial sandstones are multistoried channel sandstones that form very thick sandstone sequences. Favorable areas are found along the margins of the channel sequences. In the Goliad, favorable areas are also found on the updip margin of strand-plain sandstones where there are several sandstones of optimum thickness

  4. Reservoir architecture modeling: Nonstationary models for quantitative geological characterization. Final report, April 30, 1998

    Energy Technology Data Exchange (ETDEWEB)

    Kerr, D.; Epili, D.; Kelkar, M.; Redner, R.; Reynolds, A.

    1998-12-01

    The study was comprised of four investigations: facies architecture; seismic modeling and interpretation; Markov random field and Boolean models for geologic modeling of facies distribution; and estimation of geological architecture using the Bayesian/maximum entropy approach. This report discusses results from all four investigations. Investigations were performed using data from the E and F units of the Middle Frio Formation, Stratton Field, one of the major reservoir intervals in the Gulf Coast Basin.

  5. Analysis of the pre-rift/rifte transition interval (Serraria and Barra de Itiuba formations) from the Sergipe-Alagoas basin; Analise da secao de transicao pre-rifte/rifte (formacoes Serraria e Barra de Itiuba) da Bacia Sergipe-Alagoas

    Energy Technology Data Exchange (ETDEWEB)

    Barreiro, C.B.; Mizusaki, A.M.P. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil)]. E-mail: camilita@terra.com.br; ana.misuzaki@ufrgs.br; Garcia, A.J.V. [Universidade do Vale do Rio dos Sinos (UNISINOS), Sao Leopoldo, RS (Brazil)]. E-mail: garcia@euler.unisinos.br

    2003-07-01

    The pre-rift/rift transition is represented by the Serraria and Barra de Itiuba formations. This interval was analyzed through qualitative and quantitative descriptions of cores, electric log analysis and studies of outcropping sections. The integration of surface and subsurface data allowed the stratigraphic characterization of sandstone bodies in the pre-rift/rift. These sandstones bodies were deposited by fluvial braided, lacustrine and deltaic systems (delta plain, delta front and pro delta). The sedimentary deposits characterized in the Serraria Formation are of channel, flooding of the fluvial system and eolic. The upper interval of this formation is characterized by to coarse medium-grained sandstones identified as the Caioba Sandstone. The Barra de Itiuba Formation contains lake, pro delta, frontal bar, distributary mouth, crevasse and distributary channel deposits. The sandstone units were specifically characterized in terms of their potential reservoir quality, and they were characterized the reservoirs R1 (good to medium quality) and Caioba (good quality) from the pre-rift phase, and reservoirs R2 (medium quality) and R3 (medium to good quality) from the rift phase. The reservoirs from pre-rift phase phase show the better reservoirs quality potential of the pre-rift/rift transition in the Sergipe-Alagoas Basin. (author)

  6. Cyclicity and reservoir properties of Lower-Middle Miocene sediments of South Kirinsk oil and gas field

    Science.gov (United States)

    Kurdina, Nadezhda

    2017-04-01

    Exploration and additional exploration of oil and gas fields, connected with lithological traps, include the spreading forecast of sedimentary bodies with reservoir and seal properties. Genetic identification and forecast of geological bodies are possible in case of large-scale studies, based on the study of cyclicity, structural and textural features of rocks, their composition, lithofacies and depositional environments. Porosity and permeability evaluation of different reservoir groups is also an important part. Such studies have been successfully completed for productive terrigenous Dagi sediments (Lower-Middle Miocene) of the north-eastern shelf of Sakhalin. In order to identify distribution of Dagi reservoirs with different properties in section, core material of the one well of South Kirinsk field has been studied (depth interval from 2902,4 to 2810,5 m). Productive Dagi deposits are represented by gray-colored sandstones with subordinate siltstones and claystones (total thickness 90,5 m). Analysis of cyclicity is based on the concepts of Vassoevich (1977), who considered cycles as geological body, which is the physical result of processes that took place during the sedimentation cycle. Well section was divided into I-X units with different composition and set of genetic features due to layered core description and elementary cyclites identification. According to description of thin sections and results of cylindrical samples porosity and permeability studies five groups of reservoirs were determined. There are coarse-grained and fine-coarse-grained sandstones, fine-grained sandstones, fine-grained silty sandstones, sandy siltstones and siltstones. It was found, in Dagi section there is interval of fine-coarse-grained and coarse-grained sandstones with high petrophysical properties: permeability 3000 mD, porosity more than 25%, but rocks with such properties spread locally and their total thickness is 6 meters only. This interval was described in the IV unit

  7. Magmatism and cenozoic tectonism in the Cabo Frio region, RJ, Brazil

    International Nuclear Information System (INIS)

    Mohriak, W.U.; Barros, A.Z.N. de; Fujita, A.

    1990-01-01

    The western portion of the Campos Basin is limited by a hinge line that bounds the deposition of pre-Aptian sediments in the offshore region. The Cabo Frio arch corresponds to a platform with smaller relative subsidence, where Tertiary sediments are deposited directly on shallow basement rocks. Towards the continental slope of the Cabo Frio region, tectonic activity is also observed in the post-Aptian sequence, particularly in the region between the Santos and Campos basins, where a very large graben trends parallel to the pre-Aptian limit of the basin, and is controlled by faults that-affect Upper Miocene rocks. Eastwards of this region, an array of antithetic faults trends in a NE direction. These faults, apparently detaching an the Aptian salt, show unique geometric patterns. The rupturing of Pangea in the Lower Cretaceous is marked by widespread outpouring of mafic magmas in Campos and Santos basins. Radiometric age determinations for this volcanism show a mean of about 139 M.a. After the rift phase, another volcanic episode is observed in the Cabo Frio region, with K/Ar radiometric dating of about 50 M.a. Volcanic mounds are observed within the Eocene sedimentary sequence. An Eocene volcanic episode is characterized by the presence of volcaniclassic rocks, including autoclastic, hydroclastic, epiclastic and pyroclastic sediments. This tectonic episode is also identified within other stratigraphic intervals in the sedimentary column. (author)

  8. Differences in microbial community composition between injection and production water samples of water flooding petroleum reservoirs

    Directory of Open Access Journals (Sweden)

    P. K. Gao

    2015-06-01

    Full Text Available Microbial communities in injected water are expected to have significant influence on those of reservoir strata in long-term water flooding petroleum reservoirs. To investigate the similarities and differences in microbial communities in injected water and reservoir strata, high-throughput sequencing of microbial partial 16S rRNA of the water samples collected from the wellhead and downhole of injection wells, and from production wells in a homogeneous sandstone reservoir and a heterogeneous conglomerate reservoir were performed. The results indicate that a small number of microbial populations are shared between the water samples from the injection and production wells in the sandstone reservoir, whereas a large number of microbial populations are shared in the conglomerate reservoir. The bacterial and archaeal communities in the reservoir strata have high concentrations, which are similar to those in the injected water. However, microbial population abundance exhibited large differences between the water samples from the injection and production wells. The number of shared populations reflects the influence of microbial communities in injected water on those in reservoir strata to some extent, and show strong association with the unique variation of reservoir environments.

  9. PRELIMINARY RESULTS OF QUALITY STUDY OF WATER FROM SMALL MICHALICE RESERVOIR ON WIDAWA RIVER

    Directory of Open Access Journals (Sweden)

    Mirosław Wiatkowski

    2014-10-01

    Full Text Available The paper presents an analysis of water quality of the small Michalice reservoir. A preliminary assessment of the reservoir water quality and its usability was made. The quality of water in the reservoir is particularly important as the main functions of the reservoir are agricultural irrigation, recreation and flood protection . The following physico-chemical parameters of the Widawa River were analyzed: NO3 -, NO2 -, NH4 +, PO4 3-, COD, water temperature, pH and electrolytic conductivity. Main descriptive statistical data were presented for the analyzed water quality indicators. The research results indicate that the reservoir contributed to the reduced concentrations of the following water quality indicators: nitrates, nitrites, phosphates, electrolytic conductivity and COD (in the outflowing water – St.3 in comparison to the water flowing into the reservoir – St.1. In the water flowing out of the Psurów reservoir higher values of the remaining indicators were observed if compared with the inflowing water. It was stated, as well, that analised waters are not vulnerable to nitrogen compounds pollution coming from the agricultural sources and are eutrophic. For purpose obtaining of the précised information about condition of Michalice reservoir water purity as well as river Widawa it becomes to continue the hydrological monitoring and water quality studies.

  10. A numerical investigation of the atmosphere-ocean thermal contrast over the coastal upwelling region of Cabo Frio, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Dourado, M. [Departamento de Meteorologia, Universidade Federal de Pelotas, Pelotas RS (Brazil)]. E-mail: marcelo_dourado@ufpel.edu.br; Pereira de Oliveira, A. [Departamento de Ciencias Atmosfericas, Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo, (Brazil)

    2008-01-15

    An one-dimensional atmospheric second order closure model, coupled to an oceanic mixed layer model, is used to investigate the short term variation of the atmospheric and oceanic boundary layers in the coastal upwelling area of Cabo Frio, Brazil (23 degrees Celsius S, 42 degrees Celsius 08' W). The numerical simulations were carried out to evaluate the impact caused by the thermal contrast between atmosphere and ocean on the vertical extent and other properties of both atmospheric and oceanic boundary layers. The numerical simulations were designed taking as reference the observations carried out during the passage of a cold front that disrupted the upwelling regime in Cabo Frio in July of 1992. The simulations indicated that in 10 hours the mechanical mixing, sustained by a constant background flow of 10 m s-1, increases the atmospheric boundary layer in 214 m when the atmosphere is initially 2 K warmer than the ocean (positive thermal contrast observed during upwelling regime). For an atmosphere initially -2 K colder than the ocean (negative thermal contrast observed during passage of the cold front), the incipient thermal convection intensifies the mechanical mixing increasing the vertical extent of the atmospheric boundary layer in 360 m. The vertical evolution of the atmospheric boundary layer is consistent with the observations carried out in Cabo Frio during upwelling condition. When the upwelling is disrupted, the discrepancy between the simulated and observed atmospheric boundary layer heights in Cabo Frio during July of 1992 increases considerably. During the period of 10 hours, the simulated oceanic mixed layer deepens 2 m and 5.4 m for positive and negative thermal contrasts of 2 K and -2 K, respectively. In the latter case, the larger vertical extent of the oceanic mixed layer is due to the presence of thermal convection in the atmospheric boundary layer, which in turn is associated to the absence of upwelling caused by the passage of cold fronts

  11. Evaluation, prediction, and protection of water quality in Danjiangkou Reservoir, China

    Directory of Open Access Journals (Sweden)

    Xiao-kang Xin

    2015-01-01

    Full Text Available The water quality in the Danjiangkou Reservoir has attracted considerable attention from the Chinese public and government since the announcement of the Middle Route of the South to North Water Diversion Project (SNWDP, which commenced transferring water in 2014. Integrated research on the evaluation, prediction, and protection of water quality in the Danjiangkou Reservoir was carried out in this study in order to improve environmental management. Based on 120 water samples, wherein 17 water quality indices were measured at 20 monitoring sites, a single factor evaluation method was used to evaluate the current status of water quality. The results show that the main indices influencing the water quality in the Danjiangkou Reservoir are total phosphorus (TP, permanganate index (CODMn, dissolved oxygen (DO, and five-day biochemical oxygen demand (BOD5, and the concentrations of TP, BOD5, ammonia nitrogen (NH3–N, CODMn, DO, and anionic surfactant (Surfa do not reach the specified standard levels in the tributaries. Seasonal Mann–Kendall tests indicated that the CODMn concentration shows a highly significant increasing trend, and the TP concentration shows a significant increasing trend in the Danjiangkou Reservoir. The distribution of the main water quality indices in the Danjiangkou Reservoir was predicted using a two-dimensional water quality numerical model, and showed that the sphere of influence from the tributaries can spread across half of the Han Reservoir if the pollutants are not controlled. Cluster analysis (CA results suggest that the Shending River is heavily polluted, that the Jianghe, Sihe, and Jianhe rivers are moderately polluted, and that they should be the focus of environmental remediation.

  12. Comparative water quality assessment between a young and a stabilized hydroelectric reservoir in Aliakmon River, Greece.

    Science.gov (United States)

    Samiotis, Georgios; Trikoilidou, Eleni; Tsikritzis, Lazaros; Amanatidou, Elisavet

    2018-03-20

    In this work, a comparative study on the water quality characteristics of two in-line water reservoirs (artificial lakes) in Aliakmon River (Western Macedonia, Greece) is performed. Polyfytos Reservoir and Ilarion Reservoir were created in 1975 and 2012 respectively, in order to serve the homonymous hydroelectric stations. In young artificial lakes, severe deterioration of water quality may occur; thus, the monitoring and assessment of their water quality characteristics and their statistical interpretation are of great importance. In order to evaluate any temporal or spatial variations and to characterize water quality of these two in-line water reservoirs, water quality data from measurements conducted from 2012 to 2015 were statistically processed and interpreted by using a modified National Sanitation Foundation water quality index (WQI). The water physicochemical characteristics of the two reservoirs were found to be generally within the legislation limits, with relatively small temporal and spatial variations. Although Polyfytos Reservoir showed no significant deviations of its water quality, Ilarion Reservoir exhibited deviations in total Kjeldahl nitrogen, nitrite nitrogen, total suspended solids, and turbidity due to the inundated vegetation decomposition. The conducted measurements and the use of the modified NSFWQI revealed that during the inundation period of Ilarion Reservoir, its water quality was "moderate" and that the deviations were softened through time, leading to "good" water quality during its maturation period. Three years since the creation of Ilarion Reservoir, water quality does not match that of Aliakmon River (feeding water) or that of the stabilized reservoir (Polyfytos Reservoir), whose quality is characterized as "high." The use of a WQI, such as the proposed modified NSFWQI, for evaluating water quality of each sampling site and of an entire water system proved to be a rapid and relatively accurate assessment tool.

  13. Architecture and quantitative assessment of channeled clastic deposits, Shihezi sandstone (Lower Permian, Ordos Basin, China

    Directory of Open Access Journals (Sweden)

    Chengye Jia

    2017-02-01

    Full Text Available Lower Permian Shihezi sandstone in Ordos Basin is the largest gas reservoir in China. Architecture elements of channel, overbank and floodplain facies of braided channel deposits were identified through an outcrops survey, and their proportion of channel facies have been quantitatively estimated from well logging. Characteristics of architecture elements, such as sand thickness, bounding surfaces and lithofacies were investigated through outcrops and core. Petrology of Shihezi sandstone has also been studied in detail. Analysis on sandstone components shows that monocrystalline quartz with approximately 76% bulk volume, and lithic up to 5%–45% bulk volume, are the two main components. Litharenite and lithic quartz sandstone are the main rock types. Compaction is concluded by former researchers as the control factor of low permeability. Examination through thin section reveals that secondary pores developed well in coarse sand. Inter-granular dissolution is included as the positive effect to increasing porosity, and is concluded as the control factor to the generation of net pay. Scale of coarse grained channel fills and channel bar sandstone bodies are quantitatively estimated. Strike-oriented, dip-oriented, and vertical distribution of channel fills and channel bar sandstone bodies have been investigated. The geometry of sand bodies can be depicted as an elongated lens. Subsurface mapping reveals that channel sandstone bodies distribute widely from both lateral and longitudinal cross section profiles, and are poorly connected.

  14. Research and performance evaluation on an HA integrated acid system for sandstone acidizing

    Directory of Open Access Journals (Sweden)

    Liqiang Zhao

    2018-03-01

    Full Text Available When the conventional sandstone acidizing technologies are adopted, many slugs are needed in the injection of prepad fluid, treatment fluid and postpad fluid, and consequently the production and operation suffers inconveniences and difficulties. In view of this, a kind of HA integrated acid system which is mainly composed of organic polybasic acids (HA+HCl + HF and an efficient organic solvent was developed in this paper based on the idea of integrated acid replacing ''multiple steps'' and high efficiency and intensification. Via this HA integrated acid system, the complicated blockage in sandstone reservoirs can be removed effectively. Then, experiments were carried out on this system to evaluate its performance in terms of its retardance, organic blockage dissolution, chelating and precipitation inhibition. It is indicated that this new system can not only realize the acidizing of conventional integrated acid, but also present a good retarding performance by controlling H+ multi-stage ionization step by step and by forming silica acid-aluminum phosphonate film on the surface of clay minerals; that via this new HA integrated acid system, the organic blockage can be removed efficiently; and that it is wider in pH solution range than conventional APCs (aminopolycarboxyliates chelants, stronger in chelating capacity of Ca2+, Mg2+ and Fe3+ than conventional chelants (e.g. EDTA, NTA and DTPA, and better in precipitation inhibition on metal fluoride, fluosilicic acid alkali metal, fluoaluminic acid alkali metal and hydroxide than multi-hydrogen acid, fluoboric acid and mud acid systems. These research results provide a technical support for the plugging removal in high-temperature deep oil and gas reservoirs. Keywords: Organic polybasic acid, Integrated acid, Retardance, Chelating, Precipitation, Acidizing, Sandstone, Reservoir

  15. Micro- and macro-scale petrophysical characterization of potential reservoir units from the Northern Israel

    Science.gov (United States)

    Haruzi, Peleg; Halisch, Matthias; Katsman, Regina; Waldmann, Nicolas

    2016-04-01

    Lower Cretaceous sandstone serves as hydrocarbon reservoir in some places over the world, and potentially in Hatira formation in the Golan Heights, northern Israel. The purpose of the current research is to characterize the petrophysical properties of these sandstone units. The study is carried out by two alternative methods: using conventional macroscopic lab measurements, and using CT-scanning, image processing and subsequent fluid mechanics simulations at a microscale, followed by upscaling to the conventional macroscopic rock parameters (porosity and permeability). Comparison between the upscaled and measured in the lab properties will be conducted. The best way to upscale the microscopic rock characteristics will be analyzed based the models suggested in the literature. Proper characterization of the potential reservoir will provide necessary analytical parameters for the future experimenting and modeling of the macroscopic fluid flow behavior in the Lower Cretaceous sandstone.

  16. Lack of inhibiting effect of oil emplacement on quartz cementation: Evidence from Cambrian reservoir sandstones, Paleozoic Baltic Basin

    DEFF Research Database (Denmark)

    Molenaar, Nicolaas; Cyziene, Jolanta; Sliaupa, Saulius

    2008-01-01

    Currently, the question of whether or not the presence of oil in sandstone inhibits quartz cementation and preserves porosity is still debated. Data from a number of Cambrian sandstone oil fields and dry fields have been studied to determine the effects of oil emplacement on quartz cementation. T...

  17. Spatial and Temporal Variations of Water Quality and Trophic Status in Xili Reservoir: a Subtropics Drinking Water Reservoir of Southeast China

    Science.gov (United States)

    Yunlong, Song; Zhang, Jinsong; Zhu, Jia; Li, Wang; Chang, Aimin; Yi, Tao

    2017-12-01

    Controlling of water quality pollution and eutrophication of reservoirs has become a very important research topic in urban drinking water field. Xili reservoir is an important water source of drinking water in Shenzhen. And its water quality has played an important role to the city’s drinking water security. A fifteen-month’s field observation was conducted from April 2013 to June 2014 in Xili reservoir, in order to analyze the temporal and spatial distribution of water quality factors and seasonal variation of trophic states. Xili reservoir was seriously polluted by nitrogen. Judged by TN most of the samples were no better than grade VI. Other water quality factor including WT, SD, pH, DO, COD, TOC, TP, Fe, silicate, turbidity, chlorophyll-a were pretty good. One-way ANOVA showed that significant difference was found in water quality factors on month (p Latter rainy period > High temperature and rain free period > Temperature jump period > Winter drought period. Two-way ANOVA showed that months rather than locations were the key influencing factors of water quality factors succession.TLI (Σ) were about 35~52, suggesting Xili reservoir was in mycotrophic trophic states. As a result of runoff pollution, water quality at sampling sites 1 and 10 was poor. In the rainy season, near sampling sites 1 and 10, water appeared to be Light-eutrophic. The phytoplankton biomass of Xili reservoir was low. Water temperature was the main driving factor of phytoplankton succession.The 14 water quality factors were divided into five groups by factor analysis. The total interpretation rate was about 70.82%. F1 represents the climatic change represented by water temperature and organic pollution. F2 represents the concentration of nitrogen. F3 represents the phytoplankton biomass. F4 represents the sensory indexes of water body, such as turbidity, transparency.

  18. Geological Carbon Sequestration Storage Resource Estimates for the Ordovician St. Peter Sandstone, Illinois and Michigan Basins, USA

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, David; Ellett, Kevin; Leetaru, Hannes

    2014-09-30

    The Cambro-Ordovician strata of the Midwest of the United States is a primary target for potential geological storage of CO2 in deep saline formations. The objective of this project is to develop a comprehensive evaluation of the Cambro-Ordovician strata in the Illinois and Michigan Basins above the basal Mount Simon Sandstone since the Mount Simon is the subject of other investigations including a demonstration-scale injection at the Illinois Basin Decatur Project. The primary reservoir targets investigated in this study are the middle Ordovician St Peter Sandstone and the late Cambrian to early Ordovician Knox Group carbonates. The topic of this report is a regional-scale evaluation of the geologic storage resource potential of the St Peter Sandstone in both the Illinois and Michigan Basins. Multiple deterministic-based approaches were used in conjunction with the probabilistic-based storage efficiency factors published in the DOE methodology to estimate the carbon storage resource of the formation. Extensive data sets of core analyses and wireline logs were compiled to develop the necessary inputs for volumetric calculations. Results demonstrate how the range in uncertainty of storage resource estimates varies as a function of data availability and quality, and the underlying assumptions used in the different approaches. In the simplest approach, storage resource estimates were calculated from mapping the gross thickness of the formation and applying a single estimate of the effective mean porosity of the formation. Results from this approach led to storage resource estimates ranging from 3.3 to 35.1 Gt in the Michigan Basin, and 1.0 to 11.0 Gt in the Illinois Basin at the P10 and P90 probability level, respectively. The second approach involved consideration of the diagenetic history of the formation throughout the two basins and used depth-dependent functions of porosity to derive a more realistic spatially variable model of porosity rather than applying a

  19. Impacts of water quality variation and rainfall runoff on Jinpen Reservoir, in Northwest China

    Directory of Open Access Journals (Sweden)

    Zi-zhen Zhou

    2015-10-01

    Full Text Available The seasonal variation characteristics of the water quality of the Jinpen Reservoir and the impacts of rainfall runoff on the reservoir were investigated. Water quality monitoring results indicated that, during the stable stratification period, the maximum concentrations of total nitrogen, total phosphorus, ammonia nitrogen, total organic carbon, iron ion, and manganese ion in the water at the reservoir bottom on September 6 reached 2.5 mg/L, 0.12 mg/L, 0.58 mg/L, 3.2 mg/L, 0.97 mg/L, and 0.32 mg/L, respectively. Only heavy storm runoff can affect the main reservoir and cause the water quality to seriously deteriorate. During heavy storms, the stratification of the reservoir was destroyed, and the reservoir water quality consequently deteriorated due to the high-turbidity particulate phosphorus and organic matter in runoff. The turbidity and concentrations of total phosphorus and total organic carbon in the main reservoir increased to 265 NTU, 0.224 mg/L, and 3.9 mg/L, respectively. Potential methods of dealing with the water problems in the Jinpen Reservoir are proposed. Both in stratification and in storm periods, the use of measures such as adjusting intake height, storing clean water, and releasing turbid flow can be helpful to safeguarding the quality of water supplied to the water treatment plants.

  20. Climate-water quality relationships in Texas reservoirs

    Science.gov (United States)

    Gelca, Rodica; Hayhoe, Katharine; Scott-Fleming, Ian; Crow, Caleb; Dawson, D.; Patino, Reynaldo

    2015-01-01

    Water temperature, dissolved oxygen, and concentrations of salts in surface water bodies can be affected by the natural environment, local human activities such as surface and ground water withdrawals, land use, and energy extraction, and variability and long-term trends in atmospheric conditions including temperature and precipitation. Here, we quantify the relationship between 121 indicators of mean and extreme temperature and precipitation and 24 water quality parameters in 57 Texas reservoirs using observational data records covering the period 1960 to 2010. We find that water temperature, dissolved oxygen, pH, specific conductance, chloride, sulfate, and phosphorus all show consistent correlations with atmospheric predictors, including high and low temperature extremes, dry days, heavy precipitation events, and mean temperature and precipitation over time scales ranging from one week to two years. Based on this analysis and published future projections for this region, we expect climate change to increase water temperatures, decrease dissolved oxygen levels, decrease pH, increase specific conductance, and increase levels of sulfate, chloride in Texas reservoirs. Over decadal time scales, this may affect aquatic ecosystems in the reservoirs, including altering the risk of conditions conducive to algae occurrence, as well as affecting the quality of water available for human consumption and recreation.

  1. Geological Characterisation of Depleted Oil and Gas Reservoirs for ...

    African Journals Online (AJOL)

    Dr Tse

    The reservoir formation consists of multilayered alternating beds of sandstone and shale cap rocks ... In the oil sector, Nigeria is one of the highest emitters ... Industrial emission and flaring .... integration of the 3D seismic data and wireline logs.

  2. Uma contribuição ao estudo do forjamento a frio de engrenagens helicoidais

    OpenAIRE

    Daniel Villas Boas

    2009-01-01

    Resumo: Os processos de forjamento se caracterizam por forjamento a quente, a morno e a frio e são processos que geralmente necessitam de algumas operações de usinagem para que se obtenha o produto final na qualidade especificada. O forjamento a frio merece uma atenção especial na fabricação de peças com geometrias complexas, pois existem limitações no grau de deformação da matéria prima trabalhada, bem como limitações da própria ferramenta, quando solicitada mecanicamente. Nessas ferramentas...

  3. Opportunity on 'Cabo Frio' (Simulated)

    Science.gov (United States)

    2006-01-01

    This image superimposes an artist's concept of the Mars Exploration Rover Opportunity atop the 'Cabo Frio' promontory on the rim of 'Victoria Crater' in the Meridiani Planum region of Mars. It is done to give a sense of scale. The underlying image was taken by Opportunity's panoramic camera during the rover's 952nd Martian day, or sol (Sept. 28, 2006). This synthetic image of NASA's Opportunity Mars Exploration Rover at Victoria Crater was produced using 'Virtual Presence in Space' technology. Developed at NASA's Jet Propulsion Laboratory, Pasadena, Calif., this technology combines visualization and image processing tools with Hollywood-style special effects. The image was created using a photorealistic model of the rover and an approximately full-color mosaic.

  4. Performance of Different Acids on Sandstone Formations

    Directory of Open Access Journals (Sweden)

    M. A. Zaman

    2013-12-01

    Full Text Available Stimulation of sandstone formations is a challenging task, which involves several chemicals and physical interactions of the acid with the formation. Some of these reactions may result in formation damage. Mud acid has been successfully used to stimulate sandstone reservoirs for a number of years. It is a mixture of hydrofluoric (HF and hydrochloric (HCl acids designed to dissolve clays and siliceous fines accumulated in the near-wellbore region. Matrix acidizing may also be used to increase formation permeability in undamaged wells. The change may be up to 50% to 100% with the mud acid. For any acidizing process, the selection of acid (Formulation and Concentration and the design (Pre-flush, Main Acid, After-flush is very important. Different researchers are using different combinations of acids with different concentrations to get the best results for acidization. Mainly the common practice is combination of Hydrochloric Acid – Hydrofluoric with Concentration (3% HF – 12% HCl. This paper presents the results of a laboratory investigation of Orthophosphoric acid instead of hydrochloric acid in one combination and the second combination is Fluoboric and formic acid and the third one is formic and hydrofluoric acid. The results are compared with the mud acid and the results calculated are porosity, permeability, and FESEM Analysis and Strength tests. All of these new combinations shows that these have the potential to be used as acidizing acids on sandstone formations.

  5. Application of Reservoir Characterization and Advanced Technology to Improve Recovery and Economics in a Lower Quality Shallow Shelf Carbonate Reservoir

    International Nuclear Information System (INIS)

    Hickman, Scott T.; Justice James L.; Taylor, Archie R.

    1999-01-01

    The Class 2 Project at West Welch was designed to demonstrate the use of advanced technologies to enhance the economics of improved oil recovery (IOR) projects in lower quality Shallow Shelf Carbonate (SSC) reservoirs, resulting in recovery of additional oil that would otherwise be left in the reservoir at project abandonment. Accurate reservoir description is critical to the effective evaluation and efficient design of IOR projects in the heterogeneous SSC reservoirs

  6. Stratigraphic and structural compartmentalization observed within a model turbidite reservoir, Pennsylvanian Upper Jackfork Formation, Hollywood Quarry, Arkansas

    Energy Technology Data Exchange (ETDEWEB)

    Slatt, R. [Colorado School of Mines, Golden, CO (United States); Jordan, D. [Arco International Oil and Gas Co., Plano, TX (United States); Stone, C. [Arkansas Geological Commission, Little Rock, AR (United States)] [and others

    1995-08-01

    Hollywood Quarry is a 600 x 375 x 150 ft. (200 x 125 x 50m) excavation which provides a window into lower Pennsylvanian Jackfork Formation turbidite stratal architecture along the crest of a faulted anticlinal fold. A variety of turbidite facies are present, including: (a) lenticular, channelized sandstones, pebbly sandstones, and conglomerates within shale, (b) laterally continuous, interbedded thin sandstones and shales, and (c) thicker, laterally continuous shales. The sandstone and shale layers we broken by several strike-slip and reverse faults, with vertical displacements of up to several feet. This combination of facies and structural elements has resulted in a highly compartmentalized stratigraphic interval, both horizontally and vertically, along the anticlinal flexure. The quarry can be considered analogous to a scaled-down turbidite reservoir. Outcrop gamma-ray logs, measured sections, a fault map, and cross sections provide a database which is analogous to what would be available for a subsurface reservoir. Thus, the quarry provides an ideal outdoor geologic and engineering {open_quote}workshop{close_quote} venue for visualizing the potential complexities of a combination structural-stratigraphic (turbidite) reservoir. Since all forms of compartmentalization are readily visible in the quarry, problems related to management of compartmentalized reservoirs can be discussed and analyzed first-hand while standing in the quarry, within this {open_quote}model reservoir{close_quotes}. These problems include: (a) the high degree of stratigraphic and structural complexity that may be encountered, even at close well spacings, (b) uncertainty in well log correlations and log-shape interpretations, (c) variations in volumetric calculations as a function of amount of data available, and (d) potential production problems associated with specific {open_quote}field{close_quote} development plans.

  7. Characterization of oil and gas reservoir heterogeneity

    Energy Technology Data Exchange (ETDEWEB)

    Tyler, N.; Barton, M.D.; Bebout, D.G.; Fisher, R.S.; Grigsby, J.D.; Guevara, E.; Holtz, M.; Kerans, C.; Nance, H.S.; Levey, R.A.

    1992-10-01

    Research described In this report addresses the internal architecture of two specific reservoir types: restricted-platform carbonates and fluvial-deltaic sandstones. Together, these two reservoir types contain more than two-thirds of the unrecovered mobile oil remaining ill Texas. The approach followed in this study was to develop a strong understanding of the styles of heterogeneity of these reservoir types based on a detailed outcrop description and a translation of these findings into optimized recovery strategies in select subsurface analogs. Research targeted Grayburg Formation restricted-platform carbonate outcrops along the Algerita Escarpment and In Stone Canyon In southeastern New Mexico and Ferron deltaic sandstones in central Utah as analogs for the North Foster (Grayburg) and Lake Creek (Wilcox) units, respectively. In both settings, sequence-stratigraphic style profoundly influenced between-well architectural fabric and permeability structure. It is concluded that reservoirs of different depositional origins can therefore be categorized Into a heterogeneity matrix'' based on varying intensity of vertical and lateral heterogeneity. The utility of the matrix is that it allows prediction of the nature and location of remaining mobile oil. Highly stratified reservoirs such as the Grayburg, for example, will contain a large proportion of vertically bypassed oil; thus, an appropriate recovery strategy will be waterflood optimization and profile modification. Laterally heterogeneous reservoirs such as deltaic distributary systems would benefit from targeted infill drilling (possibly with horizontal wells) and improved areal sweep efficiency. Potential for advanced recovery of remaining mobile oil through heterogeneity-based advanced secondary recovery strategies In Texas is projected to be an Incremental 16 Bbbl. In the Lower 48 States this target may be as much as 45 Bbbl at low to moderate oil prices over the near- to mid-term.

  8. Influence of Extreme Strength in Water Quality of the Jucazinho Reservoir, Northeastern Brazil, PE

    Directory of Open Access Journals (Sweden)

    Rafael Roney Camara de Melo

    2017-12-01

    Full Text Available The Jucazinho reservoir was built in the State of Pernambuco, Northeastern Brazil, to water supply in a great part of the population that live in the semi-arid of Pernambuco. This reservoir controls the high part of Capibaribe river basin, area affected several actions that can compromise the reservoir water quality such as disposal of domestic sewage, industrial wastewater and agriculture with use of fertilizers. This study aimed to identify the factors that lead to water quality of the Jucazinho reservoir using a database containing information of nine years of reservoir water quality monitoring in line with a multivariate statistical technique known as Principal Component Analysis (PCA. To use this technique, it was selected two components which determine the quality of the reservoir water. The first principal component, ranging from an annual basis, explained the relationship between the development of cyanobacteria, the concentration of dissolved solids and electrical conductivity, comparing it with the variation in the dam volume, total phosphorus levels and turbidity. The second principal component, ranging from a mensal basis, explained the photosynthetic activity performed by cyanobacteria confronting with the variation in the dam volume. It observed the relationship between water quality parameters with rainfall, featuring an annual and seasonal pattern that can be used as reference to behaviour studies of this reservoir.

  9. Petrographic study of core plugs from lower goru sandstones

    International Nuclear Information System (INIS)

    Memon, M.K.; Tunio, A.; Leghari, A.

    2008-01-01

    Petrographic rock type description is a fundamental component in the reservoir description processes and typically included measurement to identify sediment source, texture, composition and mineralogy. Petroleum workers have long used the Petrographic microscope as an in put device to aid in the study of pore systems. Standard Petrographic thin sections are typically 30 micrometers thick and are usually illuminated by transmitted light. Experienced examiners have trained themselves to see information such as pore size, mineralogy, compaction, etc by disregarding artifacts produced by passing light through a section. This method is adequate for qualitative interpretation of data from thin sections. Rocks in thin section under a microscope display great complexity in pore sizes and shapes. Petrographic study provides measurement on rock texture. Texture deals with the size, shape and arrangement of the component minerals of a rock. It is essentially the micro geometry of the rock. Permeability of collected core plugs of lower Goru sandstones was measured. From this Petrographic study we have identified as the sandstone of Lower Goru constitute almost entirely of quartz. The grains range in size from very fine to medium, moderately well sorted to well sorted and rounded to sub rounded in shape. Particularly attention was paid to mineral content present in Lower Goru Sandstone. The mineral composition from these core plugs of Lower Goru Sandstone as identified contain about 70-80% Quartz with traces of feldspar, muscovite, biotite, Epidote and hornblende. Calcite was present as cementing material and it was about 15 -30% of the total rock. (author)

  10. Geohydrology of the Navajo sandstone in western Kane, southwestern Garfield, and southeastern Iron counties, Utah

    Science.gov (United States)

    Freethey, G.W.

    1988-01-01

    The upper Navajo and Lamb Point aquifers in the Navajo Sandstone are the principal source of water for the city of Kanab, irrigation, stock, and for rural homes in the study area. Well logs and outcrop descriptions indicate the Navajo Sandstone consists of the Lamb Point Tongue and an unnamed upper member that are separated by the Tenney Canyon Tongue of the Kayenta Formation. The main Kayenta Formation underlies the Lamb Point Tongue. The Lamb Point Tongue and the upper member of the Navajo Sandstone are saturated and hydraulically connected through the Tenney Canyon Tongue. Available data indicate that precipitation percolates to the groundwater reservoir where the Navajo Sandstone crops out. Estimates of the rate of recharge at the outcrop range from 0.1 to as much as 2.8 in/yr. Water level data indicate that water moves from the upper member of the Navajo Sandstone, through the Tenney Canyon Tongue, and into the Lamb Point Tongue. Lateral flow is generally from the outcrop areas toward the incised canyons formed by tributaries of Kanab Creek and Johnson Wash. Direction and rate of groundwater movement and the location and character of the natural hydrologic boundaries in the northern part of the area where the Navajo Sandstone is buried cannot be determined conclusively without additional water level data. (Author 's abstract)

  11. Combined rock-physical modelling and seismic inversion techniques for characterisation of stacked sandstone reservoir

    NARCIS (Netherlands)

    Justiniano, A.; Jaya, Y.; Diephuis, G.; Veenhof, R.; Pringle, T.

    2015-01-01

    The objective of the study is to characterise the Triassic massive stacked sandstone deposits of the Main Buntsandstein Subgroup at Block Q16 located in the West Netherlands Basin. The characterisation was carried out through combining rock-physics modelling and seismic inversion techniques. The

  12. Application of Advanced Reservoir Characterization, Simulation, and Production Optimization Strategies to Maximize Recovery in Slope and Basin Clastic Reservoirs, West Texas (Delaware Basin)

    Energy Technology Data Exchange (ETDEWEB)

    Dutton, S.P.; Flanders, W.A.; Guzman, J.I.; Zirczy, H.

    1999-06-08

    The objective of this Class III project is to demonstrate that detailed reservoir characterization of slope and basin clastic reservoirs in sandstones of the Delaware Mountain Group in the Delaware Basin of West Texas and New Mexico is a cost-effective way to recover a higher percentage of the original oil in place through geologically based field development. This year the project focused on reservoir characterization of the East Ford unit, a representative Delaware Mountain Group field that produces from the upper Bell Canyon Formation (Ramsey Sandstone). The field, discovered in 1960, is operated by Orla Petco, Inc., as the East Ford unit; it contained an estimated 19.8 million barrels (MMbbl) of original oil in place. Petrophysical characterization of the East Ford unit was accomplished by integrating core and log data and quantifying petrophysical properties from wireline logs. Most methods of petrophysical analysis that had been developed during an earlier study of the Ford Geraldine unit were successfully transferred to the East Ford unit. The approach that was used to interpret water saturation from resistivity logs, however, had to be modified because in some East Ford wells the log-calculated water saturation was too high and inconsistent with observations made during the actual production. Log-porosity to core-porosity transforms and core-porosity to core-permeability transforms were derived from the East Ford reservoir. The petrophysical data were used to map porosity, permeability, net pay, water saturation, mobil-oil saturation, and other reservoir properties.

  13. Trap architecture of the Early Cretaceous Sarir Sandstone in the eastern Sirt Basin, Libya

    Energy Technology Data Exchange (ETDEWEB)

    Gras, R. [Schlumberger GeoQuest, Cedex (France); Thusu, B. [Arabian Gulf Oil Company, Benghazi (Libyan Arab Jamahiriya)

    1998-12-31

    The Sarir Sandstone is the principal reservoir for oil accumulations in the eastern Sirt Basin in Libya. The main phase of the rifting in this area took place in the Late Jurassic-Early Cretaceous, during which time the Sarir Sandstone was deposited as a non-marine, intra-continental clastic syn-rift sequence. Although successfully explored from 1959 onwards, the prolific eastern Sirt Basin is in a relatively immature stage of exploration regarding wildcat drilling and 3D seismic data acquisition. The most recent phase of exploration, utilizing 3D seismic techniques, revealed a complex structural development. The trap geometries are often related to E-W trending, basement-controlled fault systems, oblique to the NNW-SSE Sirt Basin trend. The fault systems were active during the Sarir Sandstone deposition, giving rise to structural as well as combined structural-traps. An increased understanding of trap architecture has led to both re-evaluation of older fields and new discoveries. (author)

  14. Spatial and Temporal Variations of Water Quality and Trophic Status in Sembrong Reservoir, Johor

    Science.gov (United States)

    Intan Najla Syed Hashim, Syarifah; Hidayah Abu Talib, Siti; Salleh Abustan, Muhammad

    2018-03-01

    A study of spatial and temporal variations on water quality and trophic status was conducted to determine the temporal (average reading by month) and spatial variations of water quality in Sembrong reservoir and to evaluate the trophic status of the reservoir. Water samples were collected once a month from November 2016 to June 2017 in seventeen (17) sampling stations at Sembrong Reservoir. Results obtained on the concentration of dissolved oxygen (DO), water temperature, pH and secchi depth had no significant differences compared to Total Phosphorus (TP) and chlorophyll-a. The water level has significantly decreased the value of the water temperature, pH and TP. The water quality of Sembrong reservoir is classified in Class II which is suitable for recreational uses and required conventional treatment while TSI indicates that sembrong reservoir was in lower boundary of classical eutrophic (TSI > 50).

  15. Sintomas da injúria por frio em Heliconia spp

    Directory of Open Access Journals (Sweden)

    GUSTAVO JONNAS S. M. BEZERRA

    2008-07-01

    Full Text Available As helicônias, entre as flores tropicais, têm se destacado no mercado internacional (Europa e Estados Unidos devido à beleza, diversidade de cores e formas e durabilidade. No entanto, para a comercialização a longas distâncias é necessário adotar formas de transporte que inibam o processo de senescência das flores e conservem a qualidade pós-colheita. O transporte de flores em temperaturas baixas é o mais utilizado, no entanto, em “flores tropicais” podem causar danos de injúria por frio. O objetivo deste trabalho foi descrever os sintomas causados pela injúria por frio em hastes florais de três genótipos de helicônia (H. bihai, H. wagneriana e H. caribaea x H. bihai cv. Carib Flame. As hastes florais de helicônia foram submetidas, por 72 horas, a três condições de temperatura: refrigerador expositor (2 ºC em caixa de papelão (embalagem padrão para transporte; refrigerador expositor (2 ºC sem caixa de papelão; e laboratório a 25 ºC e U.R. 60% (testemunha. O delineamento experimental utilizado foi o inteiramente casualizado, com três tratamentos e sete repetições na primeira avaliação e cinco repetições na segunda avaliação. Os sintomas da injúria por frio foram descritos a partir da comparação do aspecto visual das hastes florais submetidas a 2 °C com as testemunhas. A temperatura de 2 ºC, com ou sem a embalagem de transporte, provocou sintomas como: aspecto de queimadura no centro das brácteas, manchas escurecidas na área de inserção das brácteas na ráquis e murchamento das extremidades dos pecíolos das folhas e da base das inflorescências.

  16. Geothermal resources: Frio Formation, Middle Texas Gulf Coast. Geological circular 75-8

    Energy Technology Data Exchange (ETDEWEB)

    Bebout, D.G.; Agagu, O.K.; Dorfman, M.H.

    1975-01-01

    Regional sand distribution of the Frio Formation is determined; depositional environments are identified; and the geopressured zone and its relationship to sand/shale distribution, growth faults, and fluid temperatures in the Middle Texas Gulf Coast are delineated. (MHR)

  17. Rock Physics and Petrographic Parameters Relationship Within Siliciclastic Rocks: Quartz Sandstone Outcrop Study Case

    Science.gov (United States)

    Syafriyono, S.; Caesario, D.; Swastika, A.; Adlan, Q.; Syafri, I.; Abdurrokhim, A.; Mardiana, U.; Mohamad, F.; Alfadli, M. K.; Sari, V. M.

    2018-03-01

    Rock physical parameters value (Vp and Vs) is one of fundamental aspects in reservoir characterization as a tool to detect rock heterogenity. Its response is depend on several reservoir conditions such as lithology, pressure and reservoir fluids. The value of Vp and Vs is controlled by grain contact and contact stiffness, a function of clay mineral content and porosity also affected by mineral composition. The study about Vp and Vs response within sandstone and its relationship with petrographic parameters has become important to define anisotrophy of reservoir characteristics distribution and could give a better understanding about local diagenesis that influence clastic reservoir properties. Petrographic analysis and Vp-Vs calculation was carried out to 12 core sample which is obtained by hand-drilling of the outcrop in Sukabumi area, West Java as a part of Bayah Formation. Data processing and interpretation of sedimentary vertical succession showing that this outcrop comprises of 3 major sandstone layers indicating fluvial depositional environment. As stated before, there are 4 petrographic parameters (sorting, roundness, clay mineral content, and grain contact) which are responsible to the differences of shear wave and compressional wave value in this outcrop. Lithology with poor-sorted and well- roundness has Vp value lower than well-sorted and poor-roundness (sub-angular) grain. For the sample with high clay content, Vp value is ranging from 1681 to 2000 m/s and could be getting high until 2190 to 2714 m/s in low clay content sample even though the presence of clay minerals cannot be defined neither as matrix nor cement. The whole sample have suture grain contact indicating telogenesis regime whereas facies has no relationship with Vp and Vs value because of the different type of facies show similar petrographic parameters after diagenesis.

  18. Biological and oceanographic upwelling indicators at Cabo Frio (RJ

    Directory of Open Access Journals (Sweden)

    Gleyci A. O. Moser

    1997-01-01

    Full Text Available Phytoplankton biomass, chemical parameters and hydrology were studied in a transect 101.6 km long off Cabo Frio (RJ, Southeast Brazil, during summer (December 29 to 31, 1991 and winter (June 27 to 30, 1992. Wind induced upwelling events are frequently observed in the area during summer, becoming rare during winter. By the summer cruise a bloom of phytoplankton was observed in surface, close to the coast, with chlorophyll concentrations reaching 25.55 mg Chl-a m-3, uncoupled from the cold, nutrient rich waters of South Atlantic Central Water (SACW, found below 40 m depth. During the winter cruise, the SACW raised at the surface waters in front of Cabo Frio depicting an upwelling event. However, in spite of high surface nitrate concentrations (up to 7.7 f.1M chlorophyll-a were lower than 2 mg Chl-a m-3. The phytoplankton biomass, meteorological and hydrological data suggest a probable upwelling event immediately before the summer cruise, and an ongoing one during winter time. Cluster analyses and principal component analyses (PCA were applied to summer and winter data, pointing out multidimensional fronts in the area during both seasons.A biomassa fitoplanctônica, parâmetros químicos e hidrologia foram estudadas em um transecto de 101,6 Km ao largo de Cabo Frio, (RJ Brasil, durante o verão (Dezembro 29 a 31, 1991 e inverno (Junho 27 a 30, 1992. Nesta área, eventos de ressurgência induzidos pelo vento são comuns durante o verão, tornando-se mais raros durante o inverno. Durante o período de verão uma floração de fitoplâncton foi observada na superfície próximo ao continente, apresentando um máximo de clorofila-a igual a 25,55 mg Cl-a m'3 desacoplado das águas frias e ricas em nutrientes da Água Central do Atlântico Sul (ACAS, presente abaixo de 40 m. Durante o inverno, a ACAS alcançou a superflcie em frente a Cabo Frio, caracterizando um evento de ressurgência. Entretanto, apesar das altas concentrações de nitrato na superf

  19. Quality of water and bottom material in Breckenridge Reservoir, Virginia, September 2008 through August 2009

    Science.gov (United States)

    Lotspeich, Russell

    2012-01-01

    Breckenridge Reservoir is located within the U.S. Marine Corps Base in Quantico, which is in the Potomac River basin and the Piedmont Physiographic Province of northern Virginia. Because it serves as the principal water supply for the U.S. Marine Corps Base in Quantico, an assessment of the water-quality of Breckenridge Reservoir was initiated. Water samples were collected and physical properties were measured by the U.S. Geological Survey at three sites in Breckenridge Reservoir, and physical properties were measured at six additional reservoir sites from September 2008 through August 2009. Water samples were also collected and physical properties were measured in each of the three major tributaries to Breckenridge Reservoir: North Branch Chopawamsic Creek, Middle Branch Chopawamsic Creek, and South Branch Chopawamsic Creek. One site on each tributary was sampled at least five times during the study. Monthly profiles were conducted for water temperature, dissolved-oxygen concentrations, specific conductance, pH, and turbidity measured at 2-foot intervals throughout the water column of the reservoir. These profiles were conducted at nine sites in the reservoir, and data values were measured at these sites from the water surface to the bottom of the reservoir. These profiles were conducted along three cross sections and were used to define the characteristics of the entire water column of the reservoir. The analytical results of reservoir and tributary samples collected and physical properties measured during this study were compared to ambient water-quality standards of the Virginia Department of Environmental Quality and Virginia State Water Control Board. Water temperature, dissolved-oxygen concentration, specific conductance, pH, and turbidity measured in Breckenridge Reservoir generally indicated a lack of stratification in the water column of the reservoir throughout the study period. This is unlike most other reservoirs in the region and may be influenced by

  20. Monitoring CO2 penetration and storage in the brine-saturated low permeable sandstone by the geophysical exploration technologies

    Science.gov (United States)

    Honda, H.; Mitani, Y.; Kitamura, K.; Ikemi, H.; Imasato, M.

    2017-12-01

    (Capillary trapping) capacity. There is a positive possibility to conduct CCS in the low-quality reservoir (low permeable sandstone).

  1. Avaliação da necessidade de frio em pessegueiro Avaliation of chilling requirement in peach

    Directory of Open Access Journals (Sweden)

    Idemir Citadin

    2002-12-01

    Full Text Available A necessidade de frio de seis cultivares de pessegueiro [Prunus persica (L. Batsch] foi estudada em plantas de um e dois anos, em vasos, submetidas a 150; 300; 450 e 600 horas a 2ºC, e em ramos coletados periodicamente em plantas sob condições de frio natural, a campo. Considerando os resultados obtidos nos dois experimentos, estima-se que a necessidade de frio de 'Precocinho' é em torno de 300 horas a 2ºC, equivalente a 150 unidades de frio (UF pelo modelo de Utah, ou próxima a 200 horas abaixo de 12ºC; para 'Eldorado' e 'Rio grandense', em 450 horas a 2ºC (225 UF ou 365 horas abaixo de 12ºC; para 'BR-1', em 450 horas a 2ºC (225 UF ou 418 horas abaixo de 12ºC; e para 'Planalto' e 'Della Nona', acima de 600 horas a 2ºC (>300 UF. Não foi possível estabelecer a necessidade de frio abaixo de 12ºC para 'Della Nona'.Chilling requirement was investigated in six peach [Prunus persica (L. Batsch] cultivars observing plants in containers, with one or two years, artificially chilled by 150, 300, 450, and 600 hours at 2ºC, and in excised shoots that were periodically taken from the orchard during the rest period. Chilling requirement of 'Precocinho' is 300 hours at 2ºC (around 150 chilling units - CU - using Utah Model or around 200 hours under 12ºC; 'Riograndense' and 'Eldorado' have 450 chilling hours at 2ºC (225 CU or 365 chilling hours under 12ºC; 'BR-1' is 450 chilling requirement at 2ºC (225 CU or 418 chilling hours under 12 ºC; and 'Planalto' and 'Della Nona' are over 600 chilling hours at 2ºC (>300 CU. It was not possible to estimate chilling requirement in 'Della Nona' using temperatures under 12 ºC.

  2. Spatial and Temporal Variations of Water Quality and Trophic Status in Sembrong Reservoir, Johor

    Directory of Open Access Journals (Sweden)

    Hashim Syarifah Intan Najla Syed

    2018-01-01

    Full Text Available A study of spatial and temporal variations on water quality and trophic status was conducted to determine the temporal (average reading by month and spatial variations of water quality in Sembrong reservoir and to evaluate the trophic status of the reservoir. Water samples were collected once a month from November 2016 to June 2017 in seventeen (17 sampling stations at Sembrong Reservoir. Results obtained on the concentration of dissolved oxygen (DO, water temperature, pH and secchi depth had no significant differences compared to Total Phosphorus (TP and chlorophyll-a. The water level has significantly decreased the value of the water temperature, pH and TP. The water quality of Sembrong reservoir is classified in Class II which is suitable for recreational uses and required conventional treatment while TSI indicates that sembrong reservoir was in lower boundary of classical eutrophic (TSI > 50.

  3. Simulation of the mulltizones clastic reservoir: A case study of Upper Qishn Clastic Member, Masila Basin-Yemen

    Science.gov (United States)

    Khamis, Mohamed; Marta, Ebrahim Bin; Al Natifi, Ali; Fattah, Khaled Abdel; Lashin, Aref

    2017-06-01

    The Upper Qishn Clastic Member is one of the main oil-bearing reservoirs that are located at Masila Basin-Yemen. It produces oil from many zones with different reservoir properties. The aim of this study is to simulate and model the Qishn sandstone reservoir to provide more understanding of its properties. The available, core plugs, petrophysical, PVT, pressure and production datasets, as well as the seismic structural and geologic information, are all integrated and used in the simulation process. Eclipse simulator was used as a powerful tool for reservoir modeling. A simplified approach based on a pseudo steady-state productivity index and a material balance relationship between the aquifer pressure and the cumulative influx, is applied. The petrophysical properties of the Qishn sandstone reservoir are mainly investigated based on the well logging and core plug analyses. Three reservoir zones of good hydrocarbon potentiality are indicated and named from above to below as S1A, S1C and S2. Among of these zones, the S1A zone attains the best petrophysical and reservoir quality properties. It has an average hydrocarbon saturation of more than 65%, high effective porosity up to 20% and good permeability record (66 mD). The reservoir structure is represented by faulted anticline at the middle of the study with a down going decrease in geometry from S1A zone to S2 zone. It is limited by NE-SW and E-W bounding faults, with a weak aquifer connection from the east. The analysis of pressure and PVT data has revealed that the reservoir fluid type is dead oil with very low gas liquid ratio (GLR). The simulation results indicate heterogeneous reservoir associated with weak aquifer, supported by high initial water saturation and high water cut. Initial oil in place is estimated to be around 628 MM BBL, however, the oil recovery during the period of production is very low (<10%) because of the high water cut due to the fractures associated with many faults. Hence, secondary and

  4. Application of Reservoir Characterization and Advanced Technology to Improve Recovery and Economics in a Lower Quality Shallow Shelf Carbonate Reservoir

    International Nuclear Information System (INIS)

    Taylor, Archie R.

    1996-01-01

    The Class 2 Project at West Welch was designed to demonstrate the use of advanced technologies to enhance the economics of improved oil recovery (IOR) projects in lower quality Shallow Shelf Carbonate (SSC) reservoirs, resulting in recovery of additional oil that would otherwise be left in the reservoir at project abandonment. Accurate reservoir description is critical to the effective evaluation and efficient design of IOR projects in the heterogeneous SSC reservoirs. Therefore, the majority of Budget Period 1 was devoted to reservoir characterization. Technologies being demonstrated include: (1) Advanced petrophysics; (2) Three dimensional (3-D) seismic; (3) Cross-well bore tomography; (4) Advanced reservoir simulation; (5) Carbon dioxide (CO 2 ) stimulation treatments; (6) Hydraulic fracturing design and monitoring; and (7) Mobility control agents

  5. Research on the calculation method of shale and tuff content: taking tuffaceous reservoirs of X depression in the Hailar–Tamtsag Basin as an example

    International Nuclear Information System (INIS)

    Liu, Sihui; Huang, Buzhou; Pan, Baozhi; Guo, Yuhang; Fang, Chunhui; Wang, Guiping; Sun, Fengxian; Qiu, Haibo; Jiang, Bici

    2015-01-01

    Shale content is known in reservoir evaluation as an important parameter in well logging. However, the log response characteristics are simultaneously affected by shale and tuff existing in tuffaceous sandstone reservoirs. Due to the fact that tuff content exerts an influence on the calculation of shale content, the former is equally important as the latter. Owing to the differences in the source and composition between shale and tuff, the calculation of tuff content using the same methods for shale content cannot meet the accuracy requirements of logging evaluation. The present study takes the tuffaceous reservoirs in the X depression of the Hailar–Tamtsag Basin as an example. The differences in the log response characteristics between shale and tuff are theoretically analyzed and verified using core analysis data. The tuff is then divided into fine- and coarse-grained fractions, according to the differences in the distribution of the radioactive elements, uranium, thorium and potassium. Next, a volume model suitable for tuffaceous sandstone reservoirs is established to include a sandstone matrix, shale, fine-grained tuff, coarse-grained tuff and pore. A comparison of three optimization algorithms shows that the particle swarm optimization (PSO) yields better calculation results with small mean errors. The resistivity differences among shale, fine-grained tuff and coarse-grained tuff are considered in the calculation of saturation. The water saturation of tuffaceous reservoirs is computed using the improved Poupon’s equation, which is suitable for tuffaceous sandstone reservoirs with low water salinity. The method is used in well Y, and is shown to have a good application effect. (paper)

  6. THE OHIO RIVER VALLEY CO2 STORAGE PROJECT - PRELIMINARY ASSESSMENT OF DEEP SALINE RESERVOIRS AND COAL SEAMS

    Energy Technology Data Exchange (ETDEWEB)

    Michael J. Mudd; Howard Johnson; Charles Christopher; T.S. Ramakrishnan, Ph.D.

    2003-08-01

    This report describes the geologic setting for the Deep Saline Reservoirs and Coal Seams in the Ohio River Valley CO{sub 2} Storage Project area. The object of the current project is to site and design a CO{sub 2} injection facility. A location near New Haven, WV, has been selected for the project. To assess geologic storage reservoirs at the site, regional and site-specific geology were reviewed. Geologic reports, deep well logs, hydraulic tests, and geologic maps were reviewed for the area. Only one well within 25 miles of the site penetrates the deeper sedimentary rocks, so there is a large amount of uncertainty regarding the deep geology at the site. New Haven is located along the Ohio River on the border of West Virginia and Ohio. Topography in the area is flat in the river valley but rugged away from the Ohio River floodplain. The Ohio River Valley incises 50-100 ft into bedrock in the area. The area of interest lies within the Appalachian Plateau, on the western edge of the Appalachian Mountain chain. Within the Appalachian Basin, sedimentary rocks are 3,000 to 20,000 ft deep and slope toward the southeast. The rock formations consist of alternating layers of shale, limestone, dolomite, and sandstone overlying dense metamorphic continental shield rocks. The Rome Trough is the major structural feature in the area, and there may be some faults associated with the trough in the Ohio-West Virginia Hinge Zone. The area has a low earthquake hazard with few historical earthquakes. Target injection reservoirs include the basal sandstone/Lower Maryville and the Rose Run Sandstone. The basal sandstone is an informal name for sandstones that overlie metamorphic shield rock. Regional geology indicates that the unit is at a depth of approximately 9,100 ft below the surface at the project site and associated with the Maryville Formation. Overall thickness appears to be 50-100 ft. The Rose Run Sandstone is another potential reservoir. The unit is located approximately 1

  7. Qualitative and quantitative changes in detrital reservoir rocks caused by CO2-brine-rock interactions during first injection phases (Utrillas sandstones, northern Spain)

    Science.gov (United States)

    Berrezueta, E.; Ordóñez-Casado, B.; Quintana, L.

    2016-01-01

    The aim of this article is to describe and interpret qualitative and quantitative changes at rock matrix scale of lower-upper Cretaceous sandstones exposed to supercritical (SC) CO2 and brine. The effects of experimental injection of CO2-rich brine during the first injection phases were studied at rock matrix scale, in a potential deep sedimentary reservoir in northern Spain (Utrillas unit, at the base of the Cenozoic Duero Basin).Experimental CO2-rich brine was exposed to sandstone in a reactor chamber under realistic conditions of deep saline formations (P ≈ 7.8 MPa, T ≈ 38 °C and 24 h exposure time). After the experiment, exposed and non-exposed equivalent sample sets were compared with the aim of assessing possible changes due to the effect of the CO2-rich brine exposure. Optical microscopy (OpM) and scanning electron microscopy (SEM) aided by optical image analysis (OIA) were used to compare the rock samples and get qualitative and quantitative information about mineralogy, texture and pore network distribution. Complementary chemical analyses were performed to refine the mineralogical information and to obtain whole rock geochemical data. Brine composition was also analyzed before and after the experiment.The petrographic study of contiguous sandstone samples (more external area of sample blocks) before and after CO2-rich brine injection indicates an evolution of the pore network (porosity increase ≈ 2 %). It is probable that these measured pore changes could be due to intergranular quartz matrix detachment and partial removal from the rock sample, considering them as the early features produced by the CO2-rich brine. Nevertheless, the whole rock and brine chemical analyses after interaction with CO2-rich brine do not present important changes in the mineralogical and chemical configuration of the rock with respect to initial conditions, ruling out relevant precipitation or dissolution at these early stages to rock-block scale. These results

  8. Sequence stratigraphic and sedimentologic significance of biogenic structures from a late Paleozoic marginal- to open-marine reservoir, Morrow Sandstone, subsurface of southwest Kansas, USA

    Science.gov (United States)

    Buatois, L.A.; Mangano, M.G.; Alissa, A.; Carr, T.R.

    2002-01-01

    Integrated ichnologic, sedimentologic, and stratigraphic studies of cores and well logs from Lower Pennsylvanian oil and gas reservoirs (lower Morrow Sandstone, southwest Kansas) allow distinction between fluvio-estuarine and open marine deposits in the Gentzler and Arroyo fields. The fluvio-estuarine facies assemblage is composed of both interfluve and valley-fill deposits, encompassing a variety of depositional environments such as fluvial channel, interfluve paleosol, bay head delta, estuary bay, restricted tidal flat, intertidal channel, and estuary mouth. Deposition in a brackish-water estuarine valley is supported by the presence of a low diversity, opportunistic, impoverished marine ichnofaunal assemblage dominated by infaunal structures, representing an example of a mixed, depauperate Cruziana and Skolithos ichnofacies. Overall distribution of ichnofossils along the estuarine valley was mainly controlled by the salinity gradient, with other parameters, such as oxygenation, substrate and energy, acting at a more local scale. The lower Morrow estuarine system displays the classical tripartite division of wave-dominated estuaries (i.e. seaward-marine sand plug, fine-grained central bay, and sandy landward zone), but tidal action is also recorded. The estuarine valley displays a northwest-southeast trend, draining to the open sea in the southeast. Recognition of valley-fill sandstones in the lower Morrow has implications for reservoir characterization. While the open marine model predicts a "layer-cake" style of facies distribution as a consequence of strandline shoreline progradation, identification of valley-fill sequences points to more compartmentalized reservoirs, due to the heterogeneity created by valley incision and subsequent infill. The open-marine facies assemblage comprises upper, middle, and lower shoreface; offshore transition; offshore; and shelf deposits. In contrast to the estuarine assemblage, open marine ichnofaunas are characterized by a

  9. Effect of a reservoir in the water quality of the Reconquista River, Buenos Aires, Argentina.

    Science.gov (United States)

    Rigacci, Laura N; Giorgi, Adonis D N; Vilches, Carolina S; Ossana, Natalia Alejandra; Salibián, Alfredo

    2013-11-01

    The lower portion of the Reconquista River is highly polluted. However, little is known about the state of the high and middle basins. The aims of this work were to assess the water quality on the high and middle Reconquista River basins and to determinate if the presence of a reservoir in the river has a positive effect on the water quality. We conducted a seasonal study between August 2009 and November 2010 at the mouth of La Choza, Durazno, and La Horqueta streams at the Roggero reservoir--which receives the water from the former streams--at the origin of the Reconquista River and 17 km downstream from the reservoir. We measured 25 physical and chemical parameters, including six heavy metal concentrations, and performed a multivariate statistical analysis to summarize the information and allow the interpretation of the whole data set. We found that the Durazno and La Horqueta streams had better water quality than La Choza, and the presence of the reservoir contributed to the improvement of the water quality, allowing oxygenation of the water body and processing of organic matter and ammonia. The water quality of the Reconquista River at its origin is good and similar to the reservoir, but a few kilometers downstream, the water quality declines as a consequence of the presence of industries and human settlements. Therefore, the Roggero reservoir produces a significant improvement of water quality of the river, but the discharge of contaminants downstream quickly reverses this effect.

  10. Upwelling regime off the Cabo Frio region in Brazil and impact on acoustic propagation.

    Science.gov (United States)

    Calado, Leandro; Camargo Rodríguez, Orlando; Codato, Gabriel; Contrera Xavier, Fabio

    2018-03-01

    This work introduces a description of the complex upwelling regime off the Cabo Frio region in Brazil and shows that ocean modeling, based on the feature-oriented regional modeling system (FORMS) technique, can produce reliable predictions of sound speed fields for the corresponding shallow water environment. This work also shows, through the development of simulations, that the upwelling regime can be responsible for the creation of shadow coastal zones, in which the detection probability is too low for an acoustic source to be detected. The development of the FORMS technique and its validation with real data, for the particular region of coastal upwelling off Cabo Frio, reveals the possibility of a sustainable and reliable forecast system for the corresponding (variable in space and time) underwater acoustic environment.

  11. Bathymetric maps and water-quality profiles of Table Rock and North Saluda Reservoirs, Greenville County, South Carolina

    Science.gov (United States)

    Clark, Jimmy M.; Journey, Celeste A.; Nagle, Doug D.; Lanier, Timothy H.

    2014-01-01

    Lakes and reservoirs are the water-supply source for many communities. As such, water-resource managers that oversee these water supplies require monitoring of the quantity and quality of the resource. Monitoring information can be used to assess the basic conditions within the reservoir and to establish a reliable estimate of storage capacity. In April and May 2013, a global navigation satellite system receiver and fathometer were used to collect bathymetric data, and an autonomous underwater vehicle was used to collect water-quality and bathymetric data at Table Rock Reservoir and North Saluda Reservoir in Greenville County, South Carolina. These bathymetric data were used to create a bathymetric contour map and stage-area and stage-volume relation tables for each reservoir. Additionally, statistical summaries of the water-quality data were used to provide a general description of water-quality conditions in the reservoirs.

  12. Assessment of managed aquifer recharge at Sand Hollow Reservoir, Washington County, Utah, updated to conditions through 2014

    Science.gov (United States)

    Marston, Thomas M.; Heilweil, Victor M.

    2016-09-08

    Sand Hollow Reservoir in Washington County, Utah, was completed in March 2002 and is operated primarily for managed aquifer recharge by the Washington County Water Conservancy District. From 2002 through 2014, diversions of about 216,000 acre-feet from the Virgin River to Sand Hollow Reservoir have allowed the reservoir to remain nearly full since 2006. Groundwater levels in monitoring wells near the reservoir rose through 2006 and have fluctuated more recently because of variations in reservoir stage and nearby pumping from production wells. Between 2004 and 2014, about 29,000 acre-feet of groundwater was withdrawn by these wells for municipal supply. In addition, about 31,000 acre-feet of shallow seepage was captured by French drains adjacent to the North and West Dams and used for municipal supply, irrigation, or returned to the reservoir. From 2002 through 2014, about 127,000 acre-feet of water seeped beneath the reservoir to recharge the underlying Navajo Sandstone aquifer.Water quality continued to be monitored at various wells in Sand Hollow during 2013–14 to evaluate the timing and location of reservoir recharge as it moved through the aquifer. Changing geochemical conditions at monitoring wells WD 4 and WD 12 indicate rising groundwater levels and mobilization of vadose-zone salts, which could be a precursor to the arrival of reservoir recharge.

  13. Assessment of managed aquifer recharge from Sand Hollow Reservoir, Washington County, Utah, updated to conditions in 2010

    Science.gov (United States)

    Heilweil, Victor M.; Marston, Thomas M.

    2011-01-01

    Sand Hollow Reservoir in Washington County, Utah, was completed in March 2002 and is operated primarily for managed aquifer recharge by the Washington County Water Conservancy District. From 2002 through 2009, total surface-water diversions of about 154,000 acre-feet to Sand Hollow Reservoir have allowed it to remain nearly full since 2006. Groundwater levels in monitoring wells near the reservoir rose through 2006 and have fluctuated more recently because of variations in reservoir water-level altitude and nearby pumping from production wells. Between 2004 and 2009, a total of about 13,000 acre-feet of groundwater has been withdrawn by these wells for municipal supply. In addition, a total of about 14,000 acre-feet of shallow seepage was captured by French drains adjacent to the North and West Dams and used for municipal supply, irrigation, or returned to the reservoir.From 2002 through 2009, about 86,000 acre-feet of water seeped beneath the reservoir to recharge the underlying Navajo Sandstone aquifer. Water-quality sampling was conducted at various monitoring wells in Sand Hollow to evaluate the timing and location of reservoir recharge moving through the aquifer. Tracers of reservoir recharge include major and minor dissolved inorganic ions, tritium, dissolved organic carbon, chlorofluorocarbons, sulfur hexafluoride, and noble gases. By 2010, this recharge arrived at monitoring wells within about 1,000 feet of the reservoir.

  14. Sandstone-type uranium deposits

    International Nuclear Information System (INIS)

    Finch, W.I.; Davis, J.F.

    1985-01-01

    World-class sandstone-type uranium deposits are defined as epigenetic concentrations of uranium minerals occurring as uneven impregnations and minor massive replacements primarily in fluvial, lacustrine, and deltaic sandstone formations. The main purpose of this introductory paper is to define, classify, and introduce to the general geologic setting for sandstone-type uranium deposits

  15. Management of Water Quantity and Quality Based on Copula for a Tributary to Miyun Reservoir, Beijing

    Science.gov (United States)

    Zang, N.; Wang, X.; Liang, P.

    2017-12-01

    Due to the complex mutual influence between water quantity and water quality of river, it is difficult to reflect the actual characters of the tributaries to reservoir. In this study, the acceptable marginal probability distributions for water quantity and quality of reservoir inflow were calculated. A bivariate Archimedean copula was further applied to establish the joint distribution function of them. Then multiple combination scenarios of water quantity and water quality were designed to analyze their coexistence relationship and reservoir management strategies. Taking Bai river, an important tributary into the Miyun Reservoir, as a study case. The results showed that it is feasible to apply Frank copula function to describe the jointed distribution function of water quality and water quantity for Bai river. Furthermore, the monitoring of TP concentration needs to be strengthen in Bai river. This methodology can be extended to larger dimensions and is transferable to other reservoirs via establishment of models with relevant data for a particular area. Our findings help better analyzing the coexistence relationship and influence degree of the water quantity and quality of the tributary to reservoir for the purpose of water resources protection.

  16. APPLICATION OF RESERVOIR CHARACTERIZATION AND ADVANCED TECHNOLOGY TO IMPROVE RECOVERY AND ECONOMICS IN A LOWER QUALITY SHALLOW SHELF SAN ANDRES RESERVOIR

    International Nuclear Information System (INIS)

    Hickman, T. Scott

    2003-01-01

    The Class 2 Project at West Welch was designed to demonstrate the use of advanced technologies to enhance the economics of improved oil recovery (IOR) projects in lower quality Shallow Shelf Carbonate (SSC) reservoirs, resulting in recovery of additional oil that would otherwise be left in the reservoir at project abandonment. Accurate reservoir description is critical to the effective evaluation and efficient design of IOR projects in the heterogeneous SSC reservoirs. Therefore, the majority of Budget Period 1 was devoted to reservoir characterization. Technologies being demonstrated include: (1) Advanced petrophysics; (2) Three-dimensional (3-D) seismic; (3) Crosswell bore tomography; (4) Advanced reservoir simulation; (5) Carbon dioxide (CO 2 ) stimulation treatments; (6) Hydraulic fracturing design and monitoring; and (7) Mobility control agents

  17. APPLICATION OF RESERVOIR CHARACTERIZATION AND ADVANCED TECHNOLOGY TO IMPROVE RECOVERY AND ECONOMICS IN A LOWER QUALITY SHALLOW SHELF SAN ANDRES RESERVOIR

    International Nuclear Information System (INIS)

    Raj Kumar; Keith Brown; Hickman, T. Scott; Justice, James J.

    2000-01-01

    The Class 2 Project at West Welch was designed to demonstrate the use of advanced technologies to enhance the economics of improved oil recovery (IOR) projects in lower quality Shallow Shelf Carbonate (SSC) reservoirs, resulting in recovery of additional oil that would otherwise be left in the reservoir at project abandonment. Accurate reservoir description is critical to the effective evaluation and efficient design of IOR projects in the heterogeneous SSC reservoirs. Therefore, the majority of Budget Period 1 was devoted to reservoir characterization. Technologies being demonstrated include: (1) Advanced petrophysics; (2) Three-dimensional (3-D) seismic; (3) Crosswell bore tomography; (4) Advanced reservoir simulation; (5) Carbon dioxide (CO 2 ) stimulation treatments; (6) Hydraulic fracturing design and monitoring; and (7) Mobility control agents

  18. APPLICATION OF RESERVOIR CHARACTERIZATION AND ADVANCED TECHNOLOGY TO IMPROVE RECOVERY AND ECONOMICS IN A LOWER QUALITY SHALLOW SHELF SAN ANDRES RESERVOIR

    International Nuclear Information System (INIS)

    Hickman, T. Scott; Justice, James J.

    2001-01-01

    The Class 2 Project at West Welch was designed to demonstrate the use of advanced technologies to enhance the economics of improved oil recovery (IOR) projects in lower quality Shallow Shelf Carbonate (SSC) reservoirs, resulting in recovery of additional oil that would otherwise be left in the reservoir at project abandonment. Accurate reservoir description is critical to the effective evaluation and efficient design of IOR projects in the heterogeneous SSC reservoirs. Therefore, the majority of Budget Period 1 was devoted to reservoir characterization. Technologies being demonstrated include: (1) Advanced petrophysics; (2) Three-dimensional (3-D) seismic; (3) Crosswell bore tomography; (4) Advanced reservoir simulation; (5) Carbon dioxide (CO 2 ) stimulation treatments; (6) Hydraulic fracturing design and monitoring; and (7) Mobility control agents

  19. APPLICATION OF RESERVOIR CHARACTERIZATION AND ADVANCED TECHNOLOGY TO IMPROVE RECOVERY AND ECONOMICS IN A LOWER QUALITY SHALLOW SHELF SAN ANDRES RESERVOIR

    Energy Technology Data Exchange (ETDEWEB)

    T. Scott Hickman; James J. Justice

    2001-06-16

    The Class 2 Project at West Welch was designed to demonstrate the use of advanced technologies to enhance the economics of improved oil recovery (IOR) projects in lower quality Shallow Shelf Carbonate (SSC) reservoirs, resulting in recovery of additional oil that would otherwise be left in the reservoir at project abandonment. Accurate reservoir description is critical to the effective evaluation and efficient design of IOR projects in the heterogeneous SSC reservoirs. Therefore, the majority of Budget Period 1 was devoted to reservoir characterization. Technologies being demonstrated include: (1) Advanced petrophysics; (2) Three-dimensional (3-D) seismic; (3) Crosswell bore tomography; (4) Advanced reservoir simulation; (5) Carbon dioxide (CO{sub 2}) stimulation treatments; (6) Hydraulic fracturing design and monitoring; and (7) Mobility control agents.

  20. Spatio-Temporal Trends and Identification of Correlated Variables with Water Quality for Drinking-Water Reservoirs.

    Science.gov (United States)

    Gu, Qing; Wang, Ke; Li, Jiadan; Ma, Ligang; Deng, Jinsong; Zheng, Kefeng; Zhang, Xiaobin; Sheng, Li

    2015-10-20

    It is widely accepted that characterizing the spatio-temporal trends of water quality parameters and identifying correlated variables with water quality are indispensable for the management and protection of water resources. In this study, cluster analysis was used to classify 56 typical drinking water reservoirs in Zhejiang Province into three groups representing different water quality levels, using data of four water quality parameters for the period 2006-2010. Then, the spatio-temporal trends in water quality were analyzed, assisted by geographic information systems (GIS) technology and statistical analysis. The results indicated that the water quality showed a trend of degradation from southwest to northeast, and the overall water quality level was exacerbated during the study period. Correlation analysis was used to evaluate the relationships between water quality parameters and ten independent variables grouped into four categories (land use, socio-economic factors, geographical features, and reservoir attributes). According to the correlation coefficients, land use and socio-economic indicators were identified as the most significant factors related to reservoir water quality. The results offer insights into the spatio-temporal variations of water quality parameters and factors impacting the water quality of drinking water reservoirs in Zhejiang Province, and they could assist managers in making effective strategies to better protect water resources.

  1. Spatio-Temporal Trends and Identification of Correlated Variables with Water Quality for Drinking-Water Reservoirs

    Directory of Open Access Journals (Sweden)

    Qing Gu

    2015-10-01

    Full Text Available It is widely accepted that characterizing the spatio-temporal trends of water quality parameters and identifying correlated variables with water quality are indispensable for the management and protection of water resources. In this study, cluster analysis was used to classify 56 typical drinking water reservoirs in Zhejiang Province into three groups representing different water quality levels, using data of four water quality parameters for the period 2006–2010. Then, the spatio-temporal trends in water quality were analyzed, assisted by geographic information systems (GIS technology and statistical analysis. The results indicated that the water quality showed a trend of degradation from southwest to northeast, and the overall water quality level was exacerbated during the study period. Correlation analysis was used to evaluate the relationships between water quality parameters and ten independent variables grouped into four categories (land use, socio-economic factors, geographical features, and reservoir attributes. According to the correlation coefficients, land use and socio-economic indicators were identified as the most significant factors related to reservoir water quality. The results offer insights into the spatio-temporal variations of water quality parameters and factors impacting the water quality of drinking water reservoirs in Zhejiang Province, and they could assist managers in making effective strategies to better protect water resources.

  2. Environmental and Water Quality Operational Studies. General Guidelines for Monitoring Contaminants in Reservoirs

    Science.gov (United States)

    1986-02-01

    espacially trte for the topics of sampling and analytical methods, statistical considerations, and the design of general water quality monitoring networks. For...and to the establishment and habitat differentiation of biological populations within reservoirs. Reservoir operatirn, esp- cially the timing...8217 % - - % properties of bottom sediments, as well as specific habitat associations of biological populations of reservoirs. Thus, such heterogeneities

  3. Characterization of oil and gas reservoir heterogeneity. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Tyler, N.; Barton, M.D.; Bebout, D.G.; Fisher, R.S.; Grigsby, J.D.; Guevara, E.; Holtz, M.; Kerans, C.; Nance, H.S.; Levey, R.A.

    1992-10-01

    Research described In this report addresses the internal architecture of two specific reservoir types: restricted-platform carbonates and fluvial-deltaic sandstones. Together, these two reservoir types contain more than two-thirds of the unrecovered mobile oil remaining ill Texas. The approach followed in this study was to develop a strong understanding of the styles of heterogeneity of these reservoir types based on a detailed outcrop description and a translation of these findings into optimized recovery strategies in select subsurface analogs. Research targeted Grayburg Formation restricted-platform carbonate outcrops along the Algerita Escarpment and In Stone Canyon In southeastern New Mexico and Ferron deltaic sandstones in central Utah as analogs for the North Foster (Grayburg) and Lake Creek (Wilcox) units, respectively. In both settings, sequence-stratigraphic style profoundly influenced between-well architectural fabric and permeability structure. It is concluded that reservoirs of different depositional origins can therefore be categorized Into a ``heterogeneity matrix`` based on varying intensity of vertical and lateral heterogeneity. The utility of the matrix is that it allows prediction of the nature and location of remaining mobile oil. Highly stratified reservoirs such as the Grayburg, for example, will contain a large proportion of vertically bypassed oil; thus, an appropriate recovery strategy will be waterflood optimization and profile modification. Laterally heterogeneous reservoirs such as deltaic distributary systems would benefit from targeted infill drilling (possibly with horizontal wells) and improved areal sweep efficiency. Potential for advanced recovery of remaining mobile oil through heterogeneity-based advanced secondary recovery strategies In Texas is projected to be an Incremental 16 Bbbl. In the Lower 48 States this target may be as much as 45 Bbbl at low to moderate oil prices over the near- to mid-term.

  4. Bluebell Field, Uinta Basin: reservoir characterization for improved well completion and oil recovery

    Science.gov (United States)

    Montgomery, S.L.; Morgan, C.D.

    1998-01-01

    Bluefield Field is the largest oil-producing area in the Unita basin of northern Utah. The field inclucdes over 300 wells and has produced 137 Mbbl oil and 177 bcf gas from fractured Paleocene-Eocene lacustrine and fluvial deposits of the Green River and Wasatch (Colton) formations. Oil and gas are produced at depths of 10 500-13 000 ft (3330-3940 m), with the most prolific reservoirs existing in over-pressured sandstones of the Colton Formation and the underlying Flagstaff Member of the lower Green River Formation. Despite a number of high-recovery wells (1-3 MMbbl), overall field recovery remains low, less than 10% original oil in place. This low recovery rate is interpreted to be at least partly a result of completion practices. Typically, 40-120 beds are perforated and stimulated with acid (no proppant) over intervals of up to 3000 ft (900 m). Little or no evaluation of individual beds is performed, preventing identification of good-quality reservoir zones, water-producing zones, and thief zones. As a result, detailed understanding of Bluebell reservoirs historically has been poor, inhibiting any improvements in recovery strategies. A recent project undertaken in Bluebell field as part of the U.S. Department of Energy's Class 1 (fluvial-deltaic reservoir) Oil Demonstration program has focused considerable effort on reservoir characterization. This effort has involved interdisciplinary analysis of core, log, fracture, geostatistical, production, and other data. Much valuable new information on reservoir character has resulted, with important implications for completion techniques and recovery expectations. Such data should have excellent applicability to other producing areas in the Uinta Basin withi reservoirs in similar lacustrine and related deposits.Bluebell field is the largest oil-producing area in the Uinta basin of northern Utah. The field includes over 300 wells and has produced 137 MMbbl oil and 177 bcf gas from fractured Paleocene-Eocene lacustrine

  5. GREYBULL SANDSTONE PETROLEUM POTENTIAL ON THE CROW INDIAN RESERVATION, SOUTH-CENTRAL MONTANA

    Energy Technology Data Exchange (ETDEWEB)

    David A. Lopez

    2000-12-14

    . With continued transgression, the Greybull fluvial sand graded upward into marginal marine (probably estuarine) sand (upper Greybull) and finally was capped by marine shale and the Fall River Sandstone. Subsurface mapping, incorporated with surface data, has revealed five major Greybull channels crossing the Crow Reservation. The Greybull Sandstone is a proven petroleum reservoir in the Crow Reservation region. Greybull combination traps require the presence of channel sandstone as well as structural closure. With sparse reservation well control, subsurface structural and isopach maps are highly interpretive. Three potential Greybull exploration leads were identified where possible structural closures are coincident with mapped Greybull channels: the Little Woody, Woody Dome, and Crow Agency prospects. Of these, the Crow Agency prospect was confirmed by a significant soil-gas anomaly and appears to have the greatest probability of having trapped a hydrocarbon accumulation.

  6. Morphology of channels and channel-sand bodies in the Glauconitic sandstone member (Upper Mannville), Little Bow area, Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Hopkins, J.C.; Hermanson, S.W.; Lawton, D.C.

    1982-12-01

    Large channels in the Glauconitic sandstone member of southern Alberta have proved to be difficult exploration targets because of an irregular distribution of reservoir sands within the channels. In the Little Bow area, two channels are present in the lower part of the Glauconitic member and have cut into the underlying Calcareous member. The channels can be recognized where they truncate regional markers of the Calcareous member -- the Bantry shale and Ostracod limestone, and where channel-fill deposits exhibit uniform geophysical log characters, indicating sandstone- or mudstone-filled reaches. Sediments of the Glauconitic member adjacent to the channels comprise a series of splay sandstones and mudstones that prograded into interdistributary bays of the lower delta plain. The two channels associated with these deposits are interpreted as distributary channels. Sand bodies within the channels formed as lateral bars and are isolated by mudstones which mark the abandoned stream course. Geological exploration for these discontinuous channel sandstones is difficult, and high-resolutio seismic data integrated with sound geologic modelling are critical for successful prospect delineation.

  7. Effect of flow forecasting quality on benefits of reservoir operation - a case study for the Geheyan reservoir (China)

    NARCIS (Netherlands)

    Dong, Xiaohua; Dohmen-Janssen, Catarine M.; Booij, Martijn J.; Hulscher, Suzanne J.M.H.

    2006-01-01

    This paper presents a methodology to determine the effect of flow forecasting quality on the benefits of reservoir operation. The benefits are calculated in terms of the electricity generated, and the quality of the flow forecasting is defined in terms of lead time and accuracy of the forecasts. In

  8. Chemical composition and water quality of Tashlyk Water-cooling reservoir of South-Ukraine NPP

    International Nuclear Information System (INIS)

    Kosheleva, S.I.; Gajdar, E.M.

    1995-01-01

    Information about water quality in Tashlyk water reservoir (cooler of South-Ukrainian NPP) during 9 years (1980-1992) is presented. Comparative data about Water Quality of South Bug (its source of water nutrition) and this reservoir point on the periodical pollution by surface waters and industrial wastes with a great contain of sulphates and chlorides. The class of water has been changed from hydrocarbonat calcium to sulfur-chlorine-magnesium or chlorine-natrium. The contain of biogenic and organic components in reservoir's water has been corresponded to the main class of waters satisfactory cleanliness

  9. Analysis on the spatiotemporal characteristics of water quality and trophic states in Tiegang Reservoir: A public drinking water supply reservoir in South China

    Science.gov (United States)

    Song, Yun-long; Zhu, Jia; Li, Wang; Tao, Yi; Zhang, Jin-song

    2017-08-01

    Shenzhen is the most densely populated city in China and with a severe shortage of water. The per capita water resource is less than 200 m3, which is approximately 1/12 of the national average level. In 2016, nearly 90% of Shenzhen’s drinking water needed to be imported from the Pearl River. After arrived at Shenzhen, overseas water was firstly stockpiled in local reservoirs and then was supplied to nearby water works. Tiegang Reservoir is the largest drinking water supply reservoir and its water quality has played an important role to the city’s drinking water security. A fifteen-month’s field observation was conducted from April 2013 to June 2014 in Tiegang Reservoir, in order to analyze the temporal and spatial distribution of water quality factors and seasonal variation of trophic states. One-way ANOVA showed that significant difference was found in water quality factors on month (p latter rainy period > high temperature and rain free period > temperature jump period > winter drought period, while SD showed the contrary. Two-way ANOVA showed that months rather than locations were the key influencing factors of water quality factors succession. Tiegang reservoir was seriously polluted by TN, as a result WQI were at IV∼V level. If TN was not taken into account, WQI were atI∼III level. TLI (Σ) were about 35∼60, suggesting Tiegang reservoir was in mesotrophic and light-eutrophic trophic states. The WQI and TLI (Σ) in sampling sites 9 and 10 were poorer than that of other sites. The 14 water quality factors were divided into 5 groups by factor analysis (FA). The total interpretation rate was 73.54%. F1 represents the climatic change represented by water temperature. F2 and F4 represent the concentration of nutrients. F3 and F5 represent the sensory indexes of water body, such as turbidity, transparency. The FA results indicated that water quality potential risk factors was total nitrogen (TN), and potential risk factors also include chlorophyll-a and

  10. Experimental Study on the Effects of Stress Variations on the Permeability of Feldspar-Quartz Sandstone

    Directory of Open Access Journals (Sweden)

    Fugang Wang

    2017-01-01

    Full Text Available The multistage and discontinuous nature of the injection process used in the geological storage of CO2 causes reservoirs to experience repeated loading and unloading. The reservoir permeability changes caused by this phenomenon directly impact the CO2 injection process and the process of CO2 migration in the reservoirs. Through laboratory experiments, variations in the permeability of sandstone in the Liujiagou formation of the Ordos CO2 capture and storage (CCS demonstration project were analyzed using cyclic variations in injection pressure and confining pressure and multistage loading and unloading. The variation in the micropore structure and its influence on the permeability were analyzed based on micropore structure tests. In addition, the effects of multiple stress changes on the permeability of the same type of rock with different clay minerals content were also analyzed. More attention should be devoted to the influence of pressure variations on permeability in evaluations of storage potential and studies of CO2 migration in reservoirs in CCS engineering.

  11. CarbonSAFE Rocky Mountain Phase I : Seismic Characterization of the Navajo Reservoir, Buzzard Bench, Utah

    Science.gov (United States)

    Haar, K. K.; Balch, R. S.; Lee, S. Y.

    2017-12-01

    The CarbonSAFE Rocky Mountain project team is in the initial phase of investigating the regulatory, financial and technical feasibility of commercial-scale CO2 capture and storage from two coal-fired power plants in the northwest region of the San Rafael Swell, Utah. The reservoir interval is the Jurassic Navajo Sandstone, an eolian dune deposit that at present serves as the salt water disposal reservoir for Ferron Sandstone coal-bed methane production in the Drunkards Wash field and Buzzard Bench area of central Utah. In the study area the Navajo sandstone is approximately 525 feet thick and is at an average depth of about 7000 feet below the surface. If sufficient porosity and permeability exist, reservoir depth and thickness would provide storage for up to 100,000 metric tonnes of CO2 per square mile, based on preliminary estimates. This reservoir has the potential to meet the DOE's requirement of having the ability to store at least 50 million metric tons of CO2 and fulfills the DOE's initiative to develop protocols for commercially sequestering carbon sourced from coal-fired power plants. A successful carbon storage project requires thorough structural and stratigraphic characterization of the reservoir, seal and faults, thereby allowing the creation of a comprehensive geologic model with subsequent simulations to evaluate CO2/brine migration and long-term effects. Target formation lithofacies and subfacies data gathered from outcrop mapping and laboratory analysis of core samples were developed into a geologic model. Synthetic seismic was modeled from this, allowing us to seismically characterize the lithofacies of the target formation. This seismic characterization data was then employed in the interpretation of 2D legacy lines which provided stratigraphic and structural control for more accurate model development of the northwest region of the San Rafael Swell. Developing baseline interpretations such as this are crucial toward long-term carbon storage

  12. Characterization of water quality in Bushy Park Reservoir, South Carolina, 2013–15

    Science.gov (United States)

    Conrads, Paul A.; Journey, Celeste A.; Petkewich, Matthew D.; Lanier, Timothy H.; Clark, Jimmy M.

    2018-04-25

    The Bushy Park Reservoir is the principal water supply for 400,000 people in the greater Charleston, South Carolina, area, which includes homes as well as businesses and industries in the Bushy Park Industrial Complex. Charleston Water System and the U.S. Geological Survey conducted a cooperative study during 2013–15 to assess the circulation of Bushy Park Reservoir and its effects on water-quality conditions, specifically, recurring taste-and-odor episodes. This report describes the water-quality data collected for the study that included a combination of discrete water-column sampling at seven locations in the reservoir and longitudinal water-quality profiling surveys of the reservoir and tributaries to characterize the temporal and spatial water-quality dynamics of Bushy Park Reservoir. Water-quality profiling surveys were conducted with an autonomous underwater vehicle equipped with a multiparameter water-quality-sonde bulkhead. Data collected by the autonomous underwater vehicle included water temperature, dissolved oxygen, pH, specific conductance, turbidity, total chlorophyll as fluorescence (estimate of algal biomass), and phycocyanin as fluorescence (estimate of cyanobacteria biomass) data.Characterization of the water-quality conditions in the reservoir included comparison to established State nutrient guidelines, identification of any spatial and seasonal variation in water-quality conditions and phytoplankton community structures, and assessment of the degree of influence of water-quality conditions related to Foster Creek and Durham Canal inflows, especially during periods of elevated taste-and-odor concentrations. Depth-profile and autonomous underwater vehicle survey data were used to identify areas within the reservoir where greater phytoplankton and cyanobacteria densities were most likely occurring.Water-quality survey results indicated that Bushy Park Reservoir tended to stratify thermally at a depth of about 20 feet from June to early October

  13. Environmental Assessment: Geothermal Energy Geopressure Subprogram. Gulf Coast Well Testing Activity, Frio Formation, Texas and Louisiana

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-02-01

    This Environmental Assessment (EA) has been prepared to provide the environmental input into the Division of Geothermal Energy's decisions to expand the geothermal well testing activities to include sites in the Frio Formation of Texas and Louisiana. It is proposed that drilling rigs be leased before they are removed from sites in the formation where drilling for gas or oil exploration has been unsuccessful and that the rigs be used to complete the drilling into the geopressured zone for resource exploration. This EA addresses, on a regional basis, the expected activities, affected environment, and the possible impacts in a broad sense as they apply to the Gulf Coast well testing activity of the Geothermal Energy Geopressure Subprogram of the Department of Energy. Along the Texas and Louisiana Gulf Coast (Plate 1 and Overlay, Atlas) water at high temperatures and high pressures is trapped within Gulf basin sediments. The water is confined within or below essentially impermeable shale sequences and carries most or all of the overburden pressure. Such zones are referred to as geopressured strata. These fluids and sediments are heated to abnormally high temperatures (up to 260 C) and may provide potential reservoirs for economical production of geothermal energy. The obvious need in resource development is to assess the resource. Ongoing studies to define large-sand-volume reservoirs will ultimately define optimum sites for drilling special large diameter wells to perform large volume flow production tests. in the interim, existing well tests need to be made to help define and assess the resource.

  14. Numerical simulation of groundwater movement and managed aquifer recharge from Sand Hollow Reservoir, Hurricane Bench area, Washington County, Utah

    Science.gov (United States)

    Marston, Thomas M.; Heilweil, Victor M.

    2012-01-01

    The Hurricane Bench area of Washington County, Utah, is a 70 square-mile area extending south from the Virgin River and encompassing Sand Hollow basin. Sand Hollow Reservoir, located on Hurricane Bench, was completed in March 2002 and is operated primarily as a managed aquifer recharge project by the Washington County Water Conservancy District. The reservoir is situated on a thick sequence of the Navajo Sandstone and Kayenta Formation. Total recharge to the underlying Navajo aquifer from the reservoir was about 86,000 acre-feet from 2002 to 2009. Natural recharge as infiltration of precipitation was approximately 2,100 acre-feet per year for the same period. Discharge occurs as seepage to the Virgin River, municipal and irrigation well withdrawals, and seepage to drains at the base of reservoir dams. Within the Hurricane Bench area, unconfined groundwater-flow conditions generally exist throughout the Navajo Sandstone. Navajo Sandstone hydraulic-conductivity values from regional aquifer testing range from 0.8 to 32 feet per day. The large variability in hydraulic conductivity is attributed to bedrock fractures that trend north-northeast across the study area.A numerical groundwater-flow model was developed to simulate groundwater movement in the Hurricane Bench area and to simulate the movement of managed aquifer recharge from Sand Hollow Reservoir through the groundwater system. The model was calibrated to combined steady- and transient-state conditions. The steady-state portion of the simulation was developed and calibrated by using hydrologic data that represented average conditions for 1975. The transient-state portion of the simulation was developed and calibrated by using hydrologic data collected from 1976 to 2009. Areally, the model grid was 98 rows by 76 columns with a variable cell size ranging from about 1.5 to 25 acres. Smaller cells were used to represent the reservoir to accurately simulate the reservoir bathymetry and nearby monitoring wells; larger

  15. Diagnosis and analysis of water quality and trophic state of Barra Bonita reservoir, SP

    Directory of Open Access Journals (Sweden)

    Giovanna Moreti Buzelli

    2013-04-01

    Full Text Available As a consequence of the intensification of environmental degradation, we observed a decrease in water availability and a change in water quality. Therefore, the integrated management of watersheds is an issue of extreme importance. Limnological monitoring is an important tool for environmental management, providing information on the quality of inland waters and indicating the main factors responsible for the degradation of water resources. The Barra Bonita reservoir is located in the central region of São Paulo State, in the Superior Middle Tietê Basin, and the adjacent areas of the reservoir are subject to several human activities potentially impacting the environment. In this context, there is a need to determine the nature of negative human impacts on water resources. The present study aimed to analyze and diagnose the water quality of Barra Bonita reservoir using the water quality index (WQI and the trophic state index (TSI. To this end, measurements of specific limnological variables were made in situ and laboratory and an analysis of data from CETESB annual reports was conducted. The results found that the waters of the reservoir were relatively healthy, but hyper eutrophic for the period from2007 to 2012, indicating the importance of environmental management for the restoration and preservation of natural resources in this region. The estimated indices and the land use map of adjacent areas of the Barra Bonita reservoir showed that agriculture was the largest category of land use and that it contributes directly to the degradation of water quality due to contamination by run-off from fertilizers.

  16. Assessment of managed aquifer recharge at Sand Hollow Reservoir, Washington County, Utah, updated to conditions in 2012

    Science.gov (United States)

    Marston, Thomas M.; Heilweil, Victor M.

    2013-01-01

    Sand Hollow Reservoir in Washington County, Utah, was completed in March 2002 and is operated primarily for managed aquifer recharge by the Washington County Water Conservancy District. From 2002 through 2011, surface-water diversions of about 199,000 acre-feet to Sand Hollow Reservoir have allowed the reservoir to remain nearly full since 2006. Groundwater levels in monitoring wells near the reservoir rose through 2006 and have fluctuated more recently because of variations in reservoir altitude and nearby pumping from production wells. Between 2004 and 2011, a total of about 19,000 acre-feet of groundwater was withdrawn by these wells for municipal supply. In addition, a total of about 21,000 acre-feet of shallow seepage was captured by French drains adjacent to the North and West Dams and used for municipal supply, irrigation, or returned to the reservoir. From 2002 through 2011, about 106,000 acre-feet of water seeped beneath the reservoir to recharge the underlying Navajo Sandstone aquifer. Water quality was sampled at various monitoring wells in Sand Hollow to evaluate the timing and location of reservoir recharge as it moved through the aquifer. Tracers of reservoir recharge include major and minor dissolved inorganic ions, tritium, dissolved organic carbon, chlorofluorocarbons, sulfur hexafluoride, and noble gases. By 2012, this recharge arrived at four monitoring wells located within about 1,000 feet of the reservoir. Changing geochemical conditions at five other monitoring wells could indicate other processes, such as changing groundwater levels and mobilization of vadose-zone salts, rather than arrival of reservoir recharge.

  17. Method for detecting and locating sand-producing zones in friable, unconsolidated sandstone formations of subterranean formations

    International Nuclear Information System (INIS)

    Sparlin, D.D.

    1976-01-01

    A sand-producing zone in a friable, unconsolidated sandstone formation traversed by a well bore is found by first introducing into the reservoir about 0.1--10 gallons of a radioactive mixture per foot of vertical formation being treated, the mixture containing about 0.1--1 lb of radioactive material per gallon of carrier fluid. A dispersing agent containing a deemulsifying surfactant may then be injected into the formation. The radioactivity in the well bore is recorded and the reservoir is returned to production. Another radioactivity log is run and a decrease in radioactivity indicates the location of the sand-producing portions of the formation

  18. CO2-induced mechanical behaviour of Hawkesbury sandstone in the Gosford basin: An experimental study

    International Nuclear Information System (INIS)

    Rathnaweera, T.D.; Ranjith, P.G.; Perera, M.S.A.; Haque, A.; Lashin, A.; Al Arifi, N.; Chandrasekharam, D; Yang, SQ; Xu, T; Wang, SH; Yasar, E

    2015-01-01

    Carbon dioxide (CO 2 ) sequestered in saline aquifers undergoes a variety of chemically-coupled mechanical effects, which may cause CO 2 -induced mechanical changes and time-dependent reservoir deformation. This paper investigates the mineralogical and microstructural changes that occur in reservoir rocks following injection of CO 2 in deep saline aquifers and the manner in which these changes influence the mechanical properties of the reservoir rocks. In this study, cylindrical sandstone specimens, 38 mm in diameter and 76 mm high, obtained from the Gosford basin, were used to perform a series of unconfined compressive strength (UCS) tests. Different saturation conditions: dry, water- and brine-saturated sandstone samples with and without scCO 2 (super-critical carbon dioxide) injection, were considered in the study to obtain a comprehensive understanding of the impact of scCO 2 injection during the CO 2 sequestration process on saline aquifer mechanical properties. An acoustic emission (AE) system was employed to identify the stress threshold values of crack closure, crack initiation and crack damage for each testing condition during the whole deformation process of the specimens. Finally, scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray fluorescence (XRF) analyses were performed to evaluate the chemical and mineralogical changes that occur in reservoir rocks during CO 2 injection. From the test results, it is clear that the CO 2 -saturated samples possessed a lower peak strength compared to non-CO 2 saturated samples. According to SEM, XRD and XRF analyses, considerable quartz mineral corrosion and dissolution of calcite and siderite were observed during the interactions of the CO 2 /water/rock and CO 2 /brine/rock systems, which implies that mineralogical and geochemical rock alterations affect rock mechanical properties by accelerating the collapse mechanisms of the pore matrix. AE results also reveal the weakening effect of rock pore

  19. The Bakken - An Unconventional Petroleum and Reservoir System

    Energy Technology Data Exchange (ETDEWEB)

    Sarg, J.

    2011-12-31

    An integrated geologic and geophysical study of the Bakken Petroleum System, in the Williston basin of North Dakota and Montana indicates that: (1) dolomite is needed for good reservoir performance in the Middle Bakken; (2) regional and local fractures play a significant role in enhancing permeability and well production, and it is important to recognize both because local fractures will dominate in on-structure locations; and (3) the organic-rich Bakken shale serves as both a source and reservoir rock. The Middle Bakken Member of the Bakken Formation is the target for horizontal drilling. The mineralogy across all the Middle Bakken lithofacies is very similar and is dominated by dolomite, calcite, and quartz. This Member is comprised of six lithofacies: (A) muddy lime wackestone, (B) bioturbated, argillaceous, calcareous, very fine-grained siltstone/sandstone, (C) planar to symmetrically ripple to undulose laminated, shaly, very fine-grained siltstone/sandstone, (D) contorted to massive fine-grained sandstone, to low angle, planar cross-laminated sandstone with thin discontinuous shale laminations, (E) finely inter-laminated, bioturbated, dolomitic mudstone and dolomitic siltstone/sandstone to calcitic, whole fossil, dolomitic lime wackestone, and (F) bioturbated, shaly, dolomitic siltstone. Lithofacies B, C, D, and E can all be reservoirs, if quartz and dolomite-rich (facies D) or dolomitized (facies B, C, E). Porosity averages 4-8%, permeability averages 0.001-0.01 mD or less. Dolomitic facies porosity is intercrystalline and tends to be greater than 6%. Permeability may reach values of 0.15 mD or greater. This appears to be a determinant of high productive wells in Elm Coulee, Parshall, and Sanish fields. Lithofacies G is organic-rich, pyritic brown/black mudstone and comprises the Bakken shales. These shales are siliceous, which increases brittleness and enhances fracture potential. Mechanical properties of the Bakken reveal that the shales have similar

  20. Anisotropy of sandstone reservoir and shale overburden estimated from spherical sample measurements and cross-dipole logging

    Czech Academy of Sciences Publication Activity Database

    Lokajíček, Tomáš; Brajanovski, M.; Gurevich, B.; Bona, A.; Nadri, D.; Urosevic, M.; Duncan, G.

    2009-01-01

    Roč. 11, - (2009), s. 4956-4956 ISSN 1029-7006. [European Geosciences Union General Assembly. 19.04.2009-24.04.2009, Vienna] R&D Projects: GA ČR GA205/08/0676 Institutional research plan: CEZ:AV0Z30130516 Keywords : anisotropy * sandstones * rocks Subject RIV: DB - Geology ; Mineralogy

  1. Monitoramento da cadeia do frio: novas tecnologias e recentes avanços

    Directory of Open Access Journals (Sweden)

    Wigberto Antonio Spagnol

    2017-11-01

    Full Text Available Resumo A economia, atualmente, é impulsionada pela alta competitividade, exigindo que os setores de produção e logística sejam ágeis, flexíveis e com capacidade de ação para a solução de dificuldades. A logística é de extrema importância para as operações das cadeias de alimentos perecíveis, como carnes, peixes, lácteos, frutas e produtos hortícolas, assim como para determinados produtos da indústria farmacêutica, como vacinas, biomedicamentos e hemoderivados, que necessitam do uso da cadeia do frio devido à sua perecibilidade. A temperatura é o fator mais importante para a conservação da qualidade e manutenção da vida útil destes produtos, sendo a refrigeração um dos métodos mais amplamente utilizados para retardar o desenvolvimento de vários fatores que conduzem à sua deterioração. Dentre os desafios para a melhoria de incertezas da cadeia do frio, há a mitigação de riscos de ruptura da mesma. Sabe-se que há variações inevitáveis das condições de conservação dos produtos durante as etapas da cadeia de frio, as quais causam alteração da vida útil de alimentos perecíveis. Seja no transporte ou nas câmaras frias de armazenagem, há flutuação de temperatura em torno da condição ideal, sendo que ainda hoje, na maioria dos sistemas, o monitoramento da temperatura é realizado por pouquíssimos sensores. Embora poucas tecnologias de monitoração de temperatura sejam utilizadas para inibir os riscos de perda de qualidade e obter a segurança alimentar, estas são utilizadas de forma independente, nos diferentes elos da cadeia logística do frio. Esses desafios têm impulsionado esforços de grupos de pesquisas de países desenvolvidos para o aperfeiçoamento de aplicações de rede de sensores sem fio (RSSF e de identificação por radiofrequência (RFID, com base em dispositivos sensores. Este trabalho aborda aspectos importantes da aplicação destas novas tecnologias, que são capazes de

  2. Advanced Reservoir Characterization and Development through High-Resolution 3C3D Seismic and Horizontal Drilling: Eva South Marrow Sand Unit, Texas County, Oklahoma

    Energy Technology Data Exchange (ETDEWEB)

    Wheeler,David M.; Miller, William A.; Wilson, Travis C.

    2002-03-11

    The Eva South Morrow Sand Unit is located in western Texas County, Oklahoma. The field produces from an upper Morrow sandstone, termed the Eva sandstone, deposited in a transgressive valley-fill sequence. The field is defined as a combination structural stratigraphic trap; the reservoir lies in a convex up -dip bend in the valley and is truncated on the west side by the Teepee Creek fault. Although the field has been a successful waterflood since 1993, reservoir heterogeneity and compartmentalization has impeded overall sweep efficiency. A 4.25 square mile high-resolution, three component three-dimensional (3C3D) seismic survey was acquired in order to improve reservoir characterization and pinpoint the optimal location of a new horizontal producing well, the ESU 13-H.

  3. Sandstone-type uranium deposits

    International Nuclear Information System (INIS)

    Austin, S.R.; D'Andrea, R.F. Jr.

    1978-01-01

    Three overall factors are necessary for formation of uranium deposits in sandstone: a source of uranium, host rocks capable of transmitting uranium-bearing solutions, and a precipitant. Possible sources of uranium in sandstone-type deposits include groundwaters emanating from granitic highlands, arkosic sediments, tuffaceous material within or overlying the host rocks, connate fluids, and overlying black shales. The first three sources are considered the most likely. Host rocks are generally immature sandstones deposited in alluvial-fan, intermontane-basin or marginal-marine environments, but uranium deposits do occur in well-winnowed barrier-bar or eolian sands. Host rocks for uranium deposits generally show coefficients of permeability on the order of 1 to 100 gal/day/ft 2 . Precipitants are normally agents capable of reducing uranium from the uranyl to the uranous state. The association of uranium with organic matter is unequivocal; H 2 S, a powerful reductant, may have been present at the time of formation of some deposits but may go unnoticed today. Vanadium can serve to preserve the tabular characteristics of some deposits in the near-surface environment, but is considered an unlikely primary precipitant for uranium. Uranium deposits in sandstone are divided into two overall types: peneconcordant deposits, which occur in locally reducing environments in otherwise oxidized sandstones; and roll-type deposits, which occur at the margin of an area where an oxidized groundwater has permeated an otherwise reduced sandstone. Uranium deposits are further broken down into four subclasses; these are described

  4. Understanding CO2 Plume Behavior and Basin-Scale Pressure Changes during Sequestration Projects through the use of Reservoir Fluid Modeling

    Science.gov (United States)

    Leetaru, H.E.; Frailey, S.M.; Damico, J.; Mehnert, E.; Birkholzer, J.; Zhou, Q.; Jordan, P.D.

    2009-01-01

    Large scale geologic sequestration tests are in the planning stages around the world. The liability and safety issues of the migration of CO2 away from the primary injection site and/or reservoir are of significant concerns for these sequestration tests. Reservoir models for simulating single or multi-phase fluid flow are used to understand the migration of CO2 in the subsurface. These models can also help evaluate concerns related to brine migration and basin-scale pressure increases that occur due to the injection of additional fluid volumes into the subsurface. The current paper presents different modeling examples addressing these issues, ranging from simple geometric models to more complex reservoir fluid models with single-site and basin-scale applications. Simple geometric models assuming a homogeneous geologic reservoir and piston-like displacement have been used for understanding pressure changes and fluid migration around each CO2 storage site. These geometric models are useful only as broad approximations because they do not account for the variation in porosity, permeability, asymmetry of the reservoir, and dip of the beds. In addition, these simple models are not capable of predicting the interference between different injection sites within the same reservoir. A more realistic model of CO2 plume behavior can be produced using reservoir fluid models. Reservoir simulation of natural gas storage reservoirs in the Illinois Basin Cambrian-age Mt. Simon Sandstone suggest that reservoir heterogeneity will be an important factor for evaluating storage capacity. The Mt. Simon Sandstone is a thick sandstone that underlies many significant coal fired power plants (emitting at least 1 million tonnes per year) in the midwestern United States including the states of Illinois, Indiana, Kentucky, Michigan, and Ohio. The initial commercial sequestration sites are expected to inject 1 to 2 million tonnes of CO2 per year. Depending on the geologic structure and

  5. Seasonal Deep Aquifer Thermal Energy Storage in the Gassum Sandstone Formation

    DEFF Research Database (Denmark)

    Holmslykke, H.D.H.; Kjøller, C.; Fabricius, Ida Lykke

    Seasonal storage of excess heat in hot deep aquifers is considered to optimise the usage of commonly available energy sources. The potential chemical reactions caused by heating the Gassum Sandstone Formation to up to 150°C is investigated by core flooding experiments combined with petrographic...... analysis and geochemical modelling. Synthetic formation water is injected into two sets of Gassum Formation samples at 25°C, 50°C (reservoir temperature), 100°C and 150°C with a velocity of 0.05 PV/hr and 0.1 PV/hr, respectively. A significant increase in the aqueous concentration of silicium and iron...

  6. IMPROVING CO2 EFFICIENCY FOR RECOVERING OIL IN HETEROGENEOUS RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Reid B. Grigg; Robert K. Svec; Zhengwen Zeng; Baojun Bai; Yi Liu

    2004-09-27

    The third annual report of ''Improving CO{sub 2} Efficiency for Recovery Oil in Heterogeneous Reservoirs'' presents results of laboratory studies with related analytical models for improved oil recovery. All studies were designed to optimize utilization and extend the practice of CO{sub 2} flooding to a wider range of reservoirs. Chapter 1 describes the behavior at low concentrations of the surfactant Chaser International CD1045{trademark} (CD) versus different salinity, pressure and temperature. Results of studies on the effects of pH and polymer (hydrolyzed polyacrylamide?HPAM) and CO{sub 2} foam stability after adsorption in the core are also reported. Calcium lignosulfonate (CLS) transport mechanisms through sandstone, description of the adsorption of CD and CD/CLS onto three porous media (sandstone, limestone and dolomite) and five minerals, and the effect of adsorption on foam stability are also reported. In Chapter 2, the adsorption kinetics of CLS in porous Berea sandstone and non-porous minerals are compared by monitoring adsorption density change with time. Results show that adsorption requires a much longer time for the porous versus non-porous medium. CLS adsorption onto sandstone can be divided into three regions: adsorption controlled by dispersion, adsorption controlled by diffusion and adsorption equilibrium. NaI tracer used to characterize the sandstone had similar trends to earlier results for the CLS desorption process, suggesting a dual porosity model to simulate flow through Berea sandstone. The kinetics and equilibrium test for CD adsorption onto five non-porous minerals and three porous media are reported in Chapter 3. CD adsorption and desorption onto non-porous minerals can be established in less than one hour with adsorption densities ranging from 0.4 to 1.2 mg of CD per g of mineral in decreasing order of montmorillonite, dolomite, kaolinite, silica and calcite. The surfactant adsorption onto three porous media takes

  7. Emplacement processes of tuffaceous sandstones at IODP Site C0011B, Nankai Trough, derived from modal analysis

    Science.gov (United States)

    Schindlbeck, J. C.; Kutterolf, S.; Freundt, A.

    2011-12-01

    Tuffaceous sandstones are characterized by their high amount (25 to 75%) of pyroclasts in their modal composition. During IODP Expedition 322 three interbeds of tuffaceous sandstones have been found within a moderately lithified and bioturbated silty claystone sequence in the late Miocene (>7.07 to ~9.0 Ma) upper part of the middle Shikoku Basin facies. Of the three sandstones, units 1 and 2 are single beds whereas unit 3 is composed of three beds. Modal analyses of 29 sandstone thin sections reveal systematic vertical changes within each bed. Generally low-density pyroclasts are enriched at the top (50-60 vol%) of each sandstone bed whereas dense lithic components (25-30 vol%) and minerals (25-30 vol%) are enriched at the bottom. The vertically varying abundance of various types of lithic fragments (sedimentary, volcanoclastic and metamorphic) suggests that these have also been segregated according to their respective densities. The highest amount of fine-grained matrix glass is found in the middle of each bed. Pumice and lithic fragments in the middle and upper parts of the sandstone beds carry ash coatings. For sandstone package 3, in contrast to 1 and 2, core pictures and thin section analyses indicate a subdivision in three units showing the same significant variations in top to bottom enrichment. This suggests three sedimentation events following each other in short time intervals. Glass and mineral chemistry of each sandstone bed show no significant vertical variations. Specifically the matrix glass-shard major element compositions are identical to the pumice clast composition in each tuffaceous sandstone bed. The compositions of amphibole and pyroxene crystals differ only slightly between the sandstone packages. Application of the Ridolfi et al. (2009) thermobarometric calculations to amphiboles of sandstone packages 1 and 2 suggests that each of these was derived from a volcanic system comprising both a deep and a shallow magma reservoir. Thickness and

  8. Integrating sequence stratigraphy and rock-physics to interpret seismic amplitudes and predict reservoir quality

    Science.gov (United States)

    Dutta, Tanima

    This dissertation focuses on the link between seismic amplitudes and reservoir properties. Prediction of reservoir properties, such as sorting, sand/shale ratio, and cement-volume from seismic amplitudes improves by integrating knowledge from multiple disciplines. The key contribution of this dissertation is to improve the prediction of reservoir properties by integrating sequence stratigraphy and rock physics. Sequence stratigraphy has been successfully used for qualitative interpretation of seismic amplitudes to predict reservoir properties. Rock physics modeling allows quantitative interpretation of seismic amplitudes. However, often there is uncertainty about selecting geologically appropriate rock physics model and its input parameters, away from the wells. In the present dissertation, we exploit the predictive power of sequence stratigraphy to extract the spatial trends of sedimentological parameters that control seismic amplitudes. These spatial trends of sedimentological parameters can serve as valuable constraints in rock physics modeling, especially away from the wells. Consequently, rock physics modeling, integrated with the trends from sequence stratigraphy, become useful for interpreting observed seismic amplitudes away from the wells in terms of underlying sedimentological parameters. We illustrate this methodology using a comprehensive dataset from channelized turbidite systems, deposited in minibasin settings in the offshore Equatorial Guinea, West Africa. First, we present a practical recipe for using closed-form expressions of effective medium models to predict seismic velocities in unconsolidated sandstones. We use an effective medium model that combines perfectly rough and smooth grains (the extended Walton model), and use that model to derive coordination number, porosity, and pressure relations for P and S wave velocities from experimental data. Our recipe provides reasonable fits to other experimental and borehole data, and specifically

  9. IMPROVING CO2 EFFICIENCY FOR RECOVERING OIL IN HETEROGENEOUS RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Reid B. Grigg

    2003-10-31

    The second annual report of ''Improving CO{sub 2} Efficiency for Recovery Oil in Heterogeneous Reservoirs'' presents results of laboratory studies with related analytical models for improved oil recovery. All studies have been undertaken with the intention to optimize utilization and extend the practice of CO{sub 2} flooding to a wider range of reservoirs. Many items presented in this report are applicable to other interest areas: e.g. gas injection and production, greenhouse gas sequestration, chemical flooding, reservoir damage, etc. Major areas of studies include reduction of CO{sub 2} mobility to improve conformance, determining and understanding injectivity changes in particular injectivity loses, and modeling process mechanisms determined in the first two areas. Interfacial tension (IFT) between a high-pressure, high-temperature CO{sub 2} and brine/surfactant and foam stability are used to assess and screen surfactant systems. In this work the effects of salinity, pressure, temperature, surfactant concentration, and the presence of oil on IFT and CO{sub 2} foam stability were determined on the surfactant (CD1045{trademark}). Temperature, pressure, and surfactant concentration effected both IFT and foam stability while oil destabilized the foam, but did not destroy it. Calcium lignosulfonate (CLS) can be used as a sacrificial and an enhancing agent. This work indicates that on Berea sandstone CLS concentration, brine salinity, and temperature are dominant affects on both adsorption and desorption and that adsorption is not totally reversible. Additionally, CLS adsorption was tested on five minerals common to oil reservoirs; it was found that CLS concentration, salinity, temperature, and mineral type had significant effects on adsorption. The adsorption density from most to least was: bentonite > kaolinite > dolomite > calcite > silica. This work demonstrates the extent of dissolution and precipitation from co-injection of CO{sub 2} and

  10. Petrographic characterization to build an accurate rock model using micro-CT: Case study on low-permeable to tight turbidite sandstone from Eocene Shahejie Formation.

    Science.gov (United States)

    Munawar, Muhammad Jawad; Lin, Chengyan; Cnudde, Veerle; Bultreys, Tom; Dong, Chunmei; Zhang, Xianguo; De Boever, Wesley; Zahid, Muhammad Aleem; Wu, Yuqi

    2018-03-26

    Pore scale flow simulations heavily depend on petrographic characterizing and modeling of reservoir rocks. Mineral phase segmentation and pore network modeling are crucial stages in micro-CT based rock modeling. The success of the pore network model (PNM) to predict petrophysical properties relies on image segmentation, image resolution and most importantly nature of rock (homogenous, complex or microporous). The pore network modeling has experienced extensive research and development during last decade, however the application of these models to a variety of naturally heterogenous reservoir rock is still a challenge. In this paper, four samples from a low permeable to tight sandstone reservoir were used to characterize their petrographic and petrophysical properties using high-resolution micro-CT imaging. The phase segmentation analysis from micro-CT images shows that 5-6% microporous regions are present in kaolinite rich sandstone (E3 and E4), while 1.7-1.8% are present in illite rich sandstone (E1 and E2). The pore system percolates without micropores in E1 and E2 while it does not percolate without micropores in E3 and E4. In E1 and E2, total MICP porosity is equal to the volume percent of macrospores determined from micro-CT images, which indicate that the macropores are well connected and microspores do not play any role in non-wetting fluid (mercury) displacement process. Whereas in E3 and E4 sandstones, the volume percent of micropores is far less (almost 50%) than the total MICP porosity which means that almost half of the pore space was not detected by the micro-CT scan. PNM behaved well in E1 and E2 where better agreement exists in PNM and MICP measurements. While E3 and E4 exhibit multiscale pore space which cannot be addressed with single scale PNM method, a multiscale approach is needed to characterize such complex rocks. This study provides helpful insights towards the application of existing micro-CT based petrographic characterization methodology

  11. Study on detailed geological modelling for fluvial sandstone reservoir in Daqing oil field

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Hanqing; Fu Zhiguo; Lu Xiaoguang [Institute of Petroleum Exploration and Development, Daqing (China)

    1997-08-01

    Guided by the sedimentation theory and knowledge of modern and ancient fluvial deposition and utilizing the abundant information of sedimentary series, microfacies type and petrophysical parameters from well logging curves of close spaced thousands of wells located in a large area. A new method for establishing detailed sedimentation and permeability distribution models for fluvial reservoirs have been developed successfully. This study aimed at the geometry and internal architecture of sandbodies, in accordance to their hierarchical levels of heterogeneity and building up sedimentation and permeability distribution models of fluvial reservoirs, describing the reservoir heterogeneity on the light of the river sedimentary rules. The results and methods obtained in outcrop and modem sedimentation studies have successfully supported the study. Taking advantage of this method, the major producing layers (PI{sub 1-2}), which have been considered as heterogeneous and thick fluvial reservoirs extending widely in lateral are researched in detail. These layers are subdivided into single sedimentary units vertically and the microfacies are identified horizontally. Furthermore, a complex system is recognized according to their hierarchical levels from large to small, meander belt, single channel sandbody, meander scroll, point bar, and lateral accretion bodies of point bar. The achieved results improved the description of areal distribution of point bar sandbodies, provide an accurate and detailed framework model for establishing high resolution predicting model. By using geostatistic technique, it also plays an important role in searching for enriched zone of residual oil distribution.

  12. Application of advanced reservoir characterization, simulation and production optimization strategies to maximize recovery in slope and basin clastic reservoirs, West Texas (Delaware Basin). Annual report

    Energy Technology Data Exchange (ETDEWEB)

    Dutton, S.P.; Asquith, G.B.; Barton, M.D.; Cole, A.G.; Gogas, J.; Malik, M.A.; Clift, S.J.; Guzman, J.I.

    1997-11-01

    The objective of this project is to demonstrate that detailed reservoir characterization of slope and basin clastic reservoirs in sandstones of the Delaware Mountain Group in the Delaware Basin of West Texas and New Mexico is a cost-effective way to recover a higher percentage of the original oil in place through strategic placement of infill wells and geologically based field development. This project involves reservoir characterization of two Late Permian slope and basin clastic reservoirs in the Delaware Basin, West Texas, followed by a field demonstration in one of the fields. The fields being investigated are Geraldine Ford and Ford West fields in Reeves and Culberson Counties, Texas. Project objectives are divided into two major phases, reservoir characterization and implementation. The objectives of the reservoir characterization phase of the project were to provide a detailed understanding of the architecture and heterogeneity of the two fields, the Ford Geraldine unit and Ford West field. Reservoir characterization utilized 3-D seismic data, high-resolution sequence stratigraphy, subsurface field studies, outcrop characterization, and other techniques. Once reservoir characterized was completed, a pilot area of approximately 1 mi{sup 2} at the northern end of the Ford Geraldine unit was chosen for reservoir simulation. This report summarizes the results of the second year of reservoir characterization.

  13. CABO FRIO - AN ENCLAVE IN SEMI ARID COASTAL MOIST OF RIO DE JANEIRO STATE: INFLUENCES OF CLIMATE AND PRESENT PAST VEGETATION

    Directory of Open Access Journals (Sweden)

    Heloisa Helena Gomes Coe

    2013-04-01

    Full Text Available Localizada na costa NE do Estado do Rio de Janeiro, Brasil, a região de Cabo Frio tem sido considerada um “enclave” fitogeográfico, com um clima mais seco que o restante do litoral fluminense, reduto de vegetação semelhante à caatinga, dominada por florestas xeromórficas, Cactaceae e Bromeliaceae. Objetivando contribuir para esta discussão de modo singular, este trabalho faz análises multivariadas de similaridade de variáveis do clima atual, comparando Cabo Frio com seu entorno mais úmido e com a caatinga do Nordeste brasileiro, e estuda possíveis variações da paleovegetação na região, utilizando como indicadores os fitólitos. Conclui-se que o clima de Cabo Frio se assemelha mais à caatinga que ao seu entorno, e que a vegetação, desde 13.000 anos cal AP, foi sempre de tipo pouco arbórea.

  14. Hydroeconomic optimization of reservoir management under downstream water quality constraints

    DEFF Research Database (Denmark)

    Davidsen, Claus; Liu, Suxia; Mo, Xingguo

    2015-01-01

    water quantity and water quality management and minimizes the total costs over a planning period assuming stochastic future runoff. The outcome includes cost-optimal reservoir releases, groundwater pumping, water allocation, wastewater treatments and water curtailments. The optimization model uses......), and the resulting minimum dissolved oxygen (DO) concentration is computed with the Streeter-Phelps equation and constrained to match Chinese water quality targets. The baseline water scarcity and operational costs are estimated to 15.6. billion. CNY/year. Compliance to water quality grade III causes a relatively...

  15. Characterization of the Lower Cambrian sandstone aquifer in the Swedish Baltic Sea area - assessment regarding its potential suitability for storage of CO2

    Science.gov (United States)

    Erlström, M.; Sivhed, U.

    2012-04-01

    In the Baltic region the Cambrian sandstone is considered to have great economic value concerning its aquifer and reservoir properties. Its potential as petroleum reservoir is well known, especially from the Polish, Lithuanian and Russian sectors of the Baltic Sea where oil and gas has been found in anticline traps in the sandstone sequence. Offshore exploration in the Swedish sector has so far not encountered any significant findings of oil and gas. However, the extensive exploration has generated data, which is now being used for assessing the overall properties regarding suitability for storage of CO2. The Swedish primary industry has a great interest in finding potential sites for storage of CO2. A suitable site in the Baltic Sea would be a most favourable alternative in comparison to more remote alternatives such as deep saline aquifers in the North Sea. The Lower Cambrian is in the Swedish sector of the Baltic Sea composed of three main sandstone units varying in thickness between 5 and 50 m occurring within an up to 250 m thick Cambrian sequence dominated by fine-grained terriclastic sediments. The limit of Lower Palaeozoic sequence in the Baltic area is today defined by erosional truncation because of the gently dipping Lower Palaeozoic sequence. To the north and northwest, the limit is found in the Pre-Quaternary, whereas the erosional limit is deeply buried beneath Permian and Mesozoic sediments to the south. Here the Lower Palaeozoic limit is buried to depths reaching more than 2 km. The Cambrian sequence in the distal parts of the Swedish sector occurs at depths of c. 1300 m while it constitutes the bedrock surface in a narrow zone trending from Öland to the north of of Gotland. Sandstone beds constitute 40-60% of the total Cambrian sequence. The main sandstone units have a regional distribution of several thousands of square kilometres. The up to 50 m thick Faludden sandstone member exhibits the best reservoir properties including porosities in the

  16. The Collyhurst Sandstone as a secondary storage unit for CCS in the East Irish Sea Basin (UK)

    Science.gov (United States)

    Gamboa, D.; Williams, J. D. O.; Kirk, K.; Gent, C. M. A.; Bentham, M.; Schofield, D. I.

    2016-12-01

    Carbon Capture and Storage (CCS) is key technology for low-carbon energy and industry. The UK hosts a large CO2 storage potential offshore with an estimated capacity of 78 Gt. The East Irish Sea Basin (EISB) is the key area for CCS in the western UK, with a CO2 storage potential of 1.7 Gt in hydrocarbon fields and in saline aquifers within the Triassic Sherwood Sandstone Formation. However, this theoretical storage capacity does not consider the secondary storage potential in the lower Permian Collyhurst Sandstone Formation. 3D seismic data were used to characterise the Collyhurst Sandstone Formation in the EISB. On the southern basin domain, numerous fault-bound blocks limit the lateral continuity of the sandstone strata, while on the northern domain the sandstones are intersected by less faults. The caprock for the Collyhurst sandstones is variable. The Manchester Marls predominate in the south, transitioning to the St. Bees evaporites towards the north. The evaporites in the EISB cause overburden faults to terminate or detach along Upper Permian strata, limiting the deformation of the underlying reservoir units. Five main storage closures have been identified in the Permian strata. In the southern and central area these are predominantly fault bounded, occurring at depths over 1000m. Despite the higher Collyhurst sandstone thickness in the southern IESB, the dolomitic nature of the caprock constitutes a storage risk in this area. Closures in the northern area are deeper (around 2000-2500m) and wider, reaching areas of 34Km2, and are overlain by evaporitic caprocks. The larger Collyhurst closures to the north underlie large Triassic fields with high storage potential. The spatial overlap favours storage plans including secondary storage units in the EISB. The results of this work also expand the understanding of prospective areas for CO2 sequestration in the East Irish Sea Basin in locations where the primary Sherwood Sandstone Formation is either too shallow

  17. Study of pressure maintenance in the lower Gassi Touil reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Ribuot, M.

    1969-11-01

    The Gassi Touil reservoir in the Sahara is a faulted anticline; the reservoir rock consists of a series of shales and sandstones. It has a primary gas cap in equilibrium with the oil. The oil-gas interface is at 1,642 m; the oil-water interface at 1,970 m. Initial pressure was substantially above hydrostatic. The reservoir contains about 97 million tons STO. A 3-phase, 3-dimensional computer model was used to study the recovery by primary depletion, and by pressure maintenance by gas or water injection. Water injection yields the maximum recovery, but its full efficiency is limited by the fact that only one row of wells can be drilled to the annulus where the wells penetrate only the oil zone. This operation must be supplemented with gas injection into the expanding gas cap in order to efficiently maintain in the reservoir pressure.

  18. Relationship between characteristics of fan-delta sandstone bodies and in-situ leachable sandstone-type uranium mineralization

    International Nuclear Information System (INIS)

    Nie Fengjun; Zhou Weixun; Guan Taiyang; Li Sitian

    2000-01-01

    Like normal deltas, fan-deltas are composed of three parts, i.e., fan-delta plain, fan-delta front and pre-fin-delta, In-situ leachable uranium deposits are commonly distributed along the margins of in-land basins. The author analyzes the possible relationship between the basic characteristics of fan-delta sandstone bodies and uranium mineralization. Two examples, e.g., the fan delta depositional systems in the eastern part of Jungger basin and the southern part of Yili basin, are given to illustrate the fan-delta vertical sequence and planar distribution of sedimentary facies. It has been pointed out that the braided channel sandstone bodies on delta plain, sub-aqueous distributional channel sandstone bodies and delta front sandstone bodies may be the favourable host rocks for in-situ leachable sandstone uranium deposits

  19. Potential impacts of climate change on water quality in a shallow reservoir in China.

    Science.gov (United States)

    Zhang, Chen; Lai, Shiyu; Gao, Xueping; Xu, Liping

    2015-10-01

    To study the potential effects of climate change on water quality in a shallow reservoir in China, the field data analysis method is applied to data collected over a given monitoring period. Nine water quality parameters (water temperature, ammonia nitrogen, nitrate nitrogen, nitrite nitrogen, total nitrogen, total phosphorus, chemical oxygen demand, biochemical oxygen demand and dissolved oxygen) and three climate indicators for 20 years (1992-2011) are considered. The annual trends exhibit significant trends with respect to certain water quality and climate parameters. Five parameters exhibit significant seasonality differences in the monthly means between the two decades (1992-2001 and 2002-2011) of the monitoring period. Non-parametric regression of the statistical analyses is performed to explore potential key climate drivers of water quality in the reservoir. The results indicate that seasonal changes in temperature and rainfall may have positive impacts on water quality. However, an extremely cold spring and high wind speed are likely to affect the self-stabilising equilibrium states of the reservoir, which requires attention in the future. The results suggest that land use changes have important impact on nitrogen load. This study provides useful information regarding the potential effects of climate change on water quality in developing countries.

  20. Predicting interwell heterogeneity in fluvial-deltaic reservoirs: Outcrop observations and applications of progressive facies variation through a depositional cycle

    Energy Technology Data Exchange (ETDEWEB)

    Knox, P.R.; Barton, M.D. [Univ. of Texas, Austin, TX (United States)

    1997-08-01

    Nearly 11 billion barrels of mobile oil remain in known domestic fluvial-deltaic reservoirs despite their mature status. A large percentage of this strategic resource is in danger of permanent loss through premature abandonment. Detailed reservoir characterization studies that integrate advanced technologies in geology, geophysics, and engineering are needed to identify remaining resources that can be targeted by near-term recovery methods, resulting in increased production and the postponement of abandonment. The first and most critical step of advanced characterization studies is the identification of reservoir architecture. However, existing subsurface information, primarily well logs, provides insufficient lateral resolution to identify low-permeability boundaries that exist between wells and compartmentalize the reservoir. Methods to predict lateral variability in fluvial-deltaic reservoirs have been developed on the basis of outcrop studies and incorporate identification of depositional setting and position within a depositional cycle. The position of a reservoir within the framework of a depositional cycle is critical. Outcrop studies of the Cretaceous Ferron Sandstone of Utah have demonstrated that the architecture and internal heterogeneity of sandstones deposited within a given depositional setting (for example, delta front) vary greatly depending upon whether they were deposited in the early, progradational part of a cycle or the late, retrogradational part of a cycle. The application of techniques similar to those used by this study in other fluvial-deltaic reservoirs will help to estimate the amount and style of remaining potential in mature reservoirs through a quicklook evaluation, allowing operators to focus characterization efforts on reservoirs that have the greatest potential to yield additional resources.

  1. A comparison between the pressure-lag model and the rate-type model for the prediction of reservoir compaction and surface subsidence

    Energy Technology Data Exchange (ETDEWEB)

    Smits, R.M.M.; De Waal, J.A.

    1988-06-01

    A theoretical study has been carried out to investigate whether the nonlinear compaction behavior of sandstone reservoirs, which has been reported for most well-documented field cases, can be explained by pressure lags in interbedding and/or neighboring low-permeability (shale) layers. On the basis of the results obtained, it is concluded that pressure-lag effects in normally encountered production scenarios cannot account for these nonlinearities, even under worst-case conditions. Therefore, the nonlinear field-compaction behavior must be caused by rate effects in the sandstone reservoir rock itself. This is supported by the fact that a rate-type compaction model recently introduced does indeed give a good description of the observed field behavior.

  2. Formation factor in Bentheimer and Fontainebleau sandstones: Theory compared with pore-scale numerical simulations

    Science.gov (United States)

    Ghanbarian, Behzad; Berg, Carl F.

    2017-09-01

    Accurate quantification of formation resistivity factor F (also called formation factor) provides useful insight into connectivity and pore space topology in fully saturated porous media. In particular the formation factor has been extensively used to estimate permeability in reservoir rocks. One of the widely applied models to estimate F is Archie's law (F = ϕ- m in which ϕ is total porosity and m is cementation exponent) that is known to be valid in rocks with negligible clay content, such as clean sandstones. In this study we compare formation factors determined by percolation and effective-medium theories as well as Archie's law with numerical simulations of electrical resistivity on digital rock models. These digital models represent Bentheimer and Fontainebleau sandstones and are derived either by reconstruction or directly from micro-tomographic images. Results show that the universal quadratic power law from percolation theory accurately estimates the calculated formation factor values in network models over the entire range of porosity. However, it crosses over to the linear scaling from the effective-medium approximation at the porosity of 0.75 in grid models. We also show that the effect of critical porosity, disregarded in Archie's law, is nontrivial, and the Archie model inaccurately estimates the formation factor in low-porosity homogeneous sandstones.

  3. Ichthyofaunal Diversity and Water Quality in the Kangsabati Reservoir, West Bengal, India

    OpenAIRE

    Amalesh Bera; Manojit Bhattacharya; Bidhan Chandra Patra; Utpal Kumar Sar

    2014-01-01

    The ichthyofauna in relation to water quality was studied on monthly basis from March, 2010 to February, 2011 in the Kangsabati Reservoir, West Bengal. The study revealed that physicochemical parameters of Kangsabati Reservoir were congenial for 39 fish species of commercial importance, belonging to 7 orders, 15 families, and 26 genera. The Cypriniformes were dominant with 17 species, followed by Siluriformes and Perciformes, with 7 species each, Channiformes with 3 species, Osteoglossifor...

  4. Tolerância ao frio do amendoim forrageiro Cold tolerance of forage peanut

    Directory of Open Access Journals (Sweden)

    Adriana Pires Soares Bresolin

    2008-08-01

    Full Text Available A produtividade de uma pastagem perene tropical, em regiões de clima temperado, é dependente de seu comportamento em relação às condições de temperatura. A avaliação da sensibilidade das plantas, através da sua exposição a temperaturas inferiores a 2°C em ambiente controlado, pode ser um procedimento bastante eficiente na predição de resistência, em função de assegurar uma homogeneidade dos níveis de frio. Considerando-se à reduzida disponibilidade de trabalhos científicos relacionados com a avaliação de leguminosas forrageiras tropicais quanto à tolerância ao frio, este experimento teve como objetivo avaliar o comportamento do amendoim forrageiro (cv. "Amarillo" sob temperaturas inferiores a 2°C. O delineamento experimental adotado foi completamente casualizado com 15 repetições e dois tratamentos, com exposição (CE e sem exposição ao frio (SE. Os caracteres mensurados foram: número de folhas por estolho, espessura do estolho e número de brotações novas. Os resultados indicaram que a exposição do amendoim forrageiro a um intervalo de temperatura de -1,0 a 1,3°C por um período de 3 horas é capaz de causar estresse de frio nas plantas, provocando uma redução no número de folhas e estimulando a formação de novas brotações, sem provocar a morte das plantas.The yield of tropical perennial forages in temperate climate areas depends on its cold tolerance. The exposure of genotypes to temperatures below 2oC, under controlled conditions is an efficient methodology to predict cold tolerance, since it maintains homogeneous levels of cold. Due to absence of information related to cold tolerance of tropical forages, this experiment was developed aiming to evaluate the behavior of forage peanut exposed to temperatures below 2oC. The design adopted was completely randomized with 15 replications and two treatments: exposed and not exposed to cold. The traits measured were: number of leaves per stolon; thickness

  5. Comparative Analysis of Water Quality between the Runoff Entrance and Middle of Recycling Irrigation Reservoirs

    Directory of Open Access Journals (Sweden)

    Haibo Zhang

    2015-07-01

    Full Text Available Recycling irrigation reservoirs (RIRs are an emerging aquatic ecosystem of critical importance, for conserving and protecting increasingly scarce water resources. Here, we compare water quality between runoff entrance and middle of four RIRs in nurseries in Virginia (VA and Maryland (MD. Surface water temperature (T and oxidation-reduction potential (ORP were lower in the middle than at the entrance, while the trend was opposite for dissolved oxygen (DO, pH and chlorophyll a (Chla. The magnitude of these differences between the entrance and middle decreased with increasing depth. These differences were magnified by water stratification from April to October. Minimum differences were observed for electrical conductivity (EC, total dissolved solids (TDS and turbidity (TUR. Cluster analyses were performed on water quality difference data to evaluate whether the differences vary with respect to reservoirs. Two clusters were formed with one consisting primarily of VA reservoirs, and the other consisting mostly of MD reservoirs in both years. Water quality in the middle and at the entrance of RIRs was expected to vary greatly because of runoff inflow. The two-point water quality differences observed here, although statistically significant, are not large enough to cause significant impact on crop health and productivity for most water quality parameters except pH. Additional analysis of outlet data shows that the range and magnitude of water quality difference between the middle and the outlet are comparable to those between the middle and entrance of RIRs. These results indicate that monitoring at a single point is sufficient to obtain reliable water quality estimates for most water quality parameters in RIRs except pH. This is important when considering the cost of labor and equipment necessary for documenting water quality in agricultural production systems. However, additional pH measurements are still necessary to make practical water quality

  6. Composition of natural gas and crude oil produced from 10 wells in the Lower Silurian "Clinton" Sandstone, Trumbull County, Ohio: Chapter G.7 in Coal and petroleum resources in the Appalachian basin: distribution, geologic framework, and geochemical character

    Science.gov (United States)

    Burruss, Robert A.; Ryder, Robert T.; Ruppert, Leslie F.; Ryder, Robert T.

    2014-01-01

    Natural gases and associated crude oils in the “Clinton” sandstone, Medina Group sandstones, and equivalent Tuscarora Sandstone in the northern Appalachian basin are part of a regional, continuous-type or basin-centered accumulation. The origin of the hydrocarbon charge to regional continuoustype accumulations is poorly understood. We have analyzed the molecular and stable isotopic composition of gases and oils produced from 10 wells in the “Clinton” sandstone in Trumbull County, Ohio, in an initial attempt to identify the characteristics of the accumulated fluids. The analyses show that the fluids have remarkably uniform compositions that are similar to previously published analyses of oils (Cole and others, 1987) and gases (Laughrey and Baldasarre, 1998) in Early Silurian reservoirs elsewhere in Ohio; however, geochemical parameters in the oils and gases suggest that the fluids have experienced higher levels of thermal stress than the present-day burial conditions of the reservoir rocks. The crude oils have an unusual geochemical characteristic: they do not contain detectable levels of sterane and triterpane biomarkers. The origin of these absences is unknown.

  7. Application of Advanced Reservoir Characterization, Simulation, and Production Optimization Strategies to Maximize Recovery in Slope and Basin Clastic Reservoirs, West Texas (Delaware Basin)

    International Nuclear Information System (INIS)

    Dutton, Shirley

    1999-01-01

    The objective of this Class 3 project was demonstrate that detailed reservoir characterization of slope and basin clastic reservoirs in sandstones of the Delaware Mountain Group in the Delaware Basin of West Texas and New Mexico is a cost effective way to recover a higher percentage of the original oil in place through strategic placement of infill wells and geologically based field development. Project objectives are divided into two main phases. The original objectives of the reservoir-characterization phase of the project were (1) to provide a detailed understanding of the architecture and heterogeneity of two representative fields of the Delaware Mountain Group, Geraldine Ford and Ford West, which produce from the Bell Canyon and Cherry Canyon Formations, respectively, (2) to chose a demonstration area in one of the fields, and (3) to simulate a CO 2 flood in the demonstration area

  8. Mathematical simulation of oil reservoir properties

    International Nuclear Information System (INIS)

    Ramirez, A.; Romero, A.; Chavez, F.; Carrillo, F.; Lopez, S.

    2008-01-01

    The study and computational representation of porous media properties are very important for many industries where problems of fluid flow, percolation phenomena and liquid movement and stagnation are involved, for example, in building constructions, ore processing, chemical industries, mining, corrosion sciences, etc. Nevertheless, these kinds of processes present a noneasy behavior to be predicted and mathematical models must include statistical analysis, fractal and/or stochastic procedures to do it. This work shows the characterization of sandstone berea core samples which can be found as a porous media (PM) in natural oil reservoirs, rock formations, etc. and the development of a mathematical algorithm for simulating the anisotropic characteristics of a PM based on a stochastic distribution of some of their most important properties like porosity, permeability, pressure and saturation. Finally a stochastic process is used again to simulated the topography of an oil reservoir

  9. Water quality in four reservoirs of the metropolitan region of São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Denise Amazonas Pires

    2015-12-01

    Full Text Available Abstract Aim: This paper describes some limnological variables of four reservoirs with different trophic status (Billings, Guarapiranga, Jundiaí and Paiva Castro of the Metropolitan Region of São Paulo, Brazil, aiming to characterize the water quality in these reservoirs. Methods Water sampling occurred between October 2011 and September 2012, on subsurface, at the pelagic compartment. Physical and chemical characteristics of water were evaluated, and the Trophic State Index (TSI was calculated. Multivariate Principal Components Analysis (PCA was used to ordinate sampling sites and periods in relation to environmental data. Results Two reservoirs were classified as eutrophic (Billings and Guarapiranga, one as mesotrophic (Jundiaí and one as oligotrophic (Paiva Castro. The highest concentrations of total phosphorus, nitrogen and chlorophyll a were recorded in the eutrophic reservoirs. The lowest values of dissolved oxygen concentration were registered at Guarapiranga reservoir. Residence time in Paiva Castro reservoir was very low (one day; on the other hand, the highest value was recorded in Billings reservoir: 428 days.

  10. Feasibility of a data-constrained prediction of hydrocarbon reservoir sandstone microstructures

    International Nuclear Information System (INIS)

    Yang, Y S; Gureyev, T E; Tulloh, A; Clennell, M B; Pervukhina, M

    2010-01-01

    Microstructures are critical for defining material characteristics such as permeability, mechanical, electrical and other physical properties. However, the available techniques for determining compositional microstructures through segmentation of x-ray computed tomography (CT) images are inadequate when there are finer structures than the CT spatial resolution, i.e. when there is more than one material in each voxel. This is the case for CT imaging of geomaterials characterized with submicron porosity and clay coating that control petrophysical properties of rock. This note outlines our data-constrained modelling (DCM) approach for prediction of compositional microstructures, and our investigation of the feasibility of determining sandstone microstructures using multiple CT data sets with different x-ray beam energies. In the DCM approach, each voxel is assumed to contain a mixture of multiple materials, optionally including voids. Our preliminary comparisons using model samples indicate that the DCM-predicted compositional microstructure is consistent with the known original microstructure under low noise conditions. The approach is quite generic and is applicable to predictions of microstructure of various materials. (technical design note)

  11. Delta 37Cl and Characterisation of Petroleum-gas Reservoirs

    Science.gov (United States)

    Woulé Ebongué, V.; Jendrzejewski, N.; Walgenwitz, F.; Pineau, F.; Javoy, M.

    2003-04-01

    The geochemical characterisation of formation waters from oil/gas fields is used to detect fluid-flow barriers in reservoirs and to reconstruct the system dynamic. During the progression of the reservoir filling, the aquifer waters are pushed by hydrocarbons toward the reservoir bottom and their compositions evolve due to several parameters such as water-rock interactions, mixing with oil-associated waters, physical processes etc. The chemical and isotopic evolution of these waters is recorded in irreducible waters that have been progressively "fossilised" in the oil/gas column. Residual salts precipitated from these waters were recovered. Chloride being the most important dissolved anion in these waters and not involved in diagenetic reactions, its investigation should give insights into the different transport or mixing processes taking place in the sedimentary basin and point out to the formation waters origins. The first aim of our study was to test the Cl-RSA technique (Chlorine Residual Salts Analysis) based on the well-established Sr-RSA technique. The main studied area is a turbiditic sandstone reservoir located in the Lower Congo basin in Angola. Present-day aquifer waters, irreducible waters from sandstone and shale layers as well as drilling mud and salt dome samples were analysed. Formation waters (aquifer and irreducible trapped in shale) show an overall increase of chlorinity with depth. Their δ37Cl values range from -1.11 ppm to +2.30 ppm ± 0.05 ppm/ SMOC. Most Cl-RSA data as well as the δ37Cl obtained on a set of water samples (from different aquifers in the same area) are lower than -0.13 ppm with lower δ37Cl values at shallower depths. In a δ37Cl versus chlorinity diagram, they are distributed along a large range of chlorinity: 21 to 139 g/l, in two distinct groups. (1) Irreducible waters from one of the wells display a positive correlation between chlorinity and the δ37Cl values. (2) In contrary, the majority of δ37Cl measured on aquifers

  12. Conversion of Crude Oil to Methane by a Microbial Consortium Enriched From Oil Reservoir Production Waters

    Directory of Open Access Journals (Sweden)

    Carolina eBerdugo-Clavijo

    2014-05-01

    Full Text Available The methanogenic biodegradation of crude oil is an important process occurring in petroleum reservoirs and other oil-containing environments such as contaminated aquifers. In this process, syntrophic bacteria degrade hydrocarbon substrates to products such as acetate, and/or H2 and CO2 that are then used by methanogens to produce methane in a thermodynamically dependent manner. We enriched a methanogenic crude oil-degrading consortium from production waters sampled from a low temperature heavy oil reservoir. Alkylsuccinates indicative of fumarate addition to C5 and C6 n-alkanes were identified in the culture (above levels found in controls, corresponding to the detection of an alkyl succinate synthase gene (assA in the culture. In addition, the enrichment culture was tested for its ability to produce methane from residual oil in a sandstone-packed column system simulating a mature field. Methane production rates of up 5.8 μmol CH4/g of oil/day were measured in the column system. Amounts of produced methane were in relatively good agreement with hydrocarbon loss showing depletion of more than 50% of saturate and aromatic hydrocarbons. Microbial community analysis revealed that the enrichment culture was dominated by members of the genus Smithella, Methanosaeta, and Methanoculleus. However, a shift in microbial community occurred following incubation of the enrichment in the sandstone columns. Here, Methanobacterium sp. were most abundant, as were bacterial members of the genus Pseudomonas and other known biofilm forming organisms. Our findings show that microorganisms enriched from petroleum reservoir waters can bioconvert crude oil components to methane both planktonically and in sandstone-packed columns as test systems. Further, the results suggest that different organisms may contribute to oil biodegradation within different phases (e.g., planktonic versus sessile within a subsurface crude oil reservoir.

  13. Thermochemical sulphate reduction can improve carbonate petroleum reservoir quality

    Science.gov (United States)

    Jiang, Lei; Worden, Richard H.; Yang, Changbing

    2018-02-01

    Interest in the creation of secondary pore spaces in petroleum reservoirs has increased because of a need to understand deeper and more complex reservoirs. The creation of new secondary porosity that enhances overall reservoir quality in deeply buried carbonate reservoirs is controversial and some recent studies have concluded it is not an important phenomenon. Here we present petrography, geochemistry, fluid inclusion data, and fluid-rock interaction reaction modeling results from Triassic Feixianguan Formation, Sichuan Basin, China, core samples and explore the relative importance of secondary porosity due to thermochemical sulphate reduction (TSR) during deep burial diagenesis. We find that new secondary pores result from the dissolution of anhydrite and possibly from dissolution of the matrix dolomite. Assuming porosity before TSR was 16% and the percentage of anhydrite was 6%, modelling shows that, due to TSR, 1.6% additional porosity was created that led to permeability increasing from 110 mD (range 72-168 mD within a 95% confidence interval) to 264 mD (range 162-432 mD within a 95% confidence interval). Secondary porosity results from the density differences between reactant anhydrite and product calcite, the addition of new water during TSR, and the generation of acidity during the reaction of new H2S with the siderite component in pre-existing dolomite in the reservoir. Fluid pressure was high during TSR, and approached lithostatic pressure in some samples; this transient overpressure may have led to the maintenance of porosity due to the inhibition of compactional processes. An additional 1.6% porosity is significant for reserve calculations, especially considering that it occurs in conjunction with elevated permeability that results in faster flow rates to the production wells.

  14. Chemical, physical characterization and salinity distribution of the oilfield water in the Upper Sandstone Member of the Zubair reservoir at Rumaila North Oilfield, Southern Iraq

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    Salih Awadh

    2018-01-01

    Full Text Available The oilfield water in the Upper Sandstone Member of the Zubair reservoir (Barriemian-Hauterivian at Rumaila North Oil Field was investigated for the interpretation of salinity and geochemical evolution of brine compositions. The interaction of the oilfield water with reservoir rock resulted in a brine water derived from the marine water origin of partial mixing with meteoric water similar to the compositional ranges of formation water from Gulf of Mexico offshore/onshore Mesozoic reservoirs. The high TDS (207350- 230100; average 215625 mg/L is consistent with the electrical conductivity (340362-372762; average 351024μs, and predominantly represented by Cl (123679 mg/L as anions and (29200 and 14674 mg/L for Na and Ca as cations respectively. The contribution of cation (epm% are as Na (70.2, Ca (18.9, Mg (8.1 and K (1.7; and anion as Cl (99.7, SO4 (0.25, HCO3 (0.07 and CO3 (0.005. sodium (57550-60500mg/L is greater than of seawater six times, calcium and magnesium three times greater, and chloride 6.5 times greater, but Sulfate is depleted to six times less due to a sulfur release from sulphates and link with different hydrocarbon species, precipices as native sulphur and link with hydrogen forming H2S. The Zubair oilfield water is characterised by acidic pH (pH=5.2- 5.77 enhanced petrophysical properties, high specific gravity (1.228 predicts a high fluid pressure (4866 psi, hydrocarbon saturation (0.43%, water saturation (0.57% and porosity (12.7. The Mineral saturation model indicates that the Zubair oilfield water is an unsaturated water with respect to all suggested minerals at 5.45, but at simulated pH, brucite being an equilibrium at pH 9.12, but brucite and portlandite being supersaturated at pH 11.9. The mineral solubility responses to the changes in temperature, pressure, pH, Eh, and ionic strength, thereby formation damage is proportionally developed.

  15. APPLICATION OF INTEGRATED RESERVOIR MANAGEMENT AND RESERVOIR CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Jack Bergeron; Tom Blasingame; Louis Doublet; Mohan Kelkar; George Freeman; Jeff Callard; David Moore; David Davies; Richard Vessell; Brian Pregger; Bill Dixon; Bryce Bezant

    2000-03-01

    Reservoir performance and characterization are vital parameters during the development phase of a project. Infill drilling of wells on a uniform spacing, without regard to characterization does not optimize development because it fails to account for the complex nature of reservoir heterogeneities present in many low permeability reservoirs, especially carbonate reservoirs. These reservoirs are typically characterized by: (1) large, discontinuous pay intervals; (2) vertical and lateral changes in reservoir properties; (3) low reservoir energy; (4) high residual oil saturation; and (5) low recovery efficiency. The operational problems they encounter in these types of reservoirs include: (1) poor or inadequate completions and stimulations; (2) early water breakthrough; (3) poor reservoir sweep efficiency in contacting oil throughout the reservoir as well as in the nearby well regions; (4) channeling of injected fluids due to preferential fracturing caused by excessive injection rates; and (5) limited data availability and poor data quality. Infill drilling operations only need target areas of the reservoir which will be economically successful. If the most productive areas of a reservoir can be accurately identified by combining the results of geological, petrophysical, reservoir performance, and pressure transient analyses, then this ''integrated'' approach can be used to optimize reservoir performance during secondary and tertiary recovery operations without resorting to ''blanket'' infill drilling methods. New and emerging technologies such as geostatistical modeling, rock typing, and rigorous decline type curve analysis can be used to quantify reservoir quality and the degree of interwell communication. These results can then be used to develop a 3-D simulation model for prediction of infill locations. The application of reservoir surveillance techniques to identify additional reservoir ''pay'' zones

  16. A Rock Physics Feasibility Study of the Geothermal Gassum Reservoir, Copenhagen Area, Denmark

    DEFF Research Database (Denmark)

    Bredesen, Kenneth; Dalgaard, Esben Borch; Mathiesen, Anders

    The subsurface of Denmark stores significant amounts of renewable geothermal energy which may contribute to domestic heating for centuries. However, establishing a successful geothermal plant with robust production capacity require reservoirs with sufficient high porosity and permeability. Modern...... quantitative seismic interpretation is a good approach to de-risk prospects and gain reservoir insight, but is so far not widely used for geothermal applications. In this study we perform a rock physics feasibility study as a pre-step towards quantitative seismic interpretation of geothermal reservoirs......, primarily in areas around Copenhagen. The results argue that it may be possible to use AVO and seismic inversion data to distinguish geothermal sandstone reservoirs from surrounding shales and to estimate porosity and permeability. Moreover, this study may represent new possibilities for future rock physics...

  17. Features of Composition and Cement Type of the Lower Triassic Reservoirs in the North of the Timan-Pechora Oil and Gas Province

    Directory of Open Access Journals (Sweden)

    N.N. Timonina

    2017-03-01

    Full Text Available The work is devoted to the study of cement type and composition of the Lower Triassic deposits of the Timan-Pechora province, their influence on reservoir properties of rocks. The work was based on laboratory studies of core, generalization of published data. Morphological and genetic analysis of clay minerals was carried out using X-ray and electron-microscopic methods. As a result of the conducted studies it was established that the type, composition and distribution of the cement is influenced by the composition of demolition sources, sedimentation conditions, and post-sedimentation transformations. Kaolinite, chlorite, smectite and hydromica associations are distinguished according to the predominance of clay mineral in the sandstone cement. Kaolinite cement of sandstones is most typical for continental fluvial facies, especially channel beds. Smectite association is most characteristic of the floodplain, oxbow and lake facies of the zone. The revealed regularities will contribute to the improvement of accurate reconstruction of sedimentation conditions, construction of more adequate geological models of the reservoir, taking into account its reservoir heterogeneity both at the level of the reservoir and its constituent interlayers.

  18. Climate Change Impacts on Sediment Quality of Subalpine Reservoirs: Implications on Management

    Directory of Open Access Journals (Sweden)

    Marziali Laura

    2017-09-01

    Full Text Available Reservoirs are characterized by accumulation of sediments where micropollutants may concentrate, with potential toxic effects on downstream river ecosystems. However, sediment management such as flushing is needed to maintain storage capacity. Climate change is expected to increase sediment loads, but potential effects on their quality are scarcely known. In this context, sediment contamination by trace elements (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn and organics (Polycyclic Aromatic Hydrocarbons PAHs, Polychlorinated Biphenyls PCBs and C > 12 hydrocarbons was analyzed in 20 reservoirs located in Italian Central Alps. A strong As and a moderate Cd, Hg and Pb enrichment was emphasized by Igeo, with potential ecotoxicological risk according to Probable Effect Concentration quotients. Sedimentation rate, granulometry, total organic carbon (TOC and altitude resulted as the main drivers governing pollutant concentrations in sediments. According to climate change models, expected increase of rainfall erosivity will enhance soil erosion and consequently the sediment flow to reservoirs, potentially increasing coarse grain fractions and thus potentially diluting pollutants. Conversely, increased weathering may enhance metal fluxes to reservoirs. Increased vegetation cover will potentially result in higher TOC concentrations, which may contrast contaminant bioavailability and thus toxicity. Our results may provide elements for a proper management of contaminated sediments in a climate change scenario aiming at preserving water quality and ecosystem functioning.

  19. Oligo-Miocene reservoir sequence characterization and structuring in the Sisseb El Alem-Kalaa Kebira regions (Northeastern Tunisia)

    Science.gov (United States)

    Houatmia, Faten; Khomsi, Sami; Bédir, Mourad

    2015-11-01

    The Sisseb El Alem-Enfidha basin is located in the northeastern Tunisia, It is borded by Nadhour - Saouaf syncline to the north, Kairouan plain to the south, the Mediterranean Sea to the east and Tunisian Atlassic "dorsale" to the west. Oligocene and Miocene deltaic deposits present the main potential deep aquifers in this basin with high porosity (25%-30%). The interpretation of twenty seismic reflection profiles, calibrated by wire line logging data of twelve oil wells, hydraulic wells and geologic field sections highlighted the impact of tectonics on the structuring geometry of Oligo-Miocene sandstones reservoirs and their distribution in raised structures and subsurface depressions. Miocene seismostratigraphy analysis from Ain Ghrab Formation (Langhian) to the Segui Formation (Quaternary) showed five third-order seismic sequence deposits and nine extended lenticular sandy bodies reservoirs limited by toplap and downlap surfaces unconformities, Oligocene deposits presented also five third- order seismic sequences with five extended lenticular sandy bodies reservoirs. The Depth and the thickness maps of these sequence reservoir packages exhibited the structuring of this basin in sub-basins characterized by important lateral and vertical geometric and thichness variations. Petroleum wells wire line logging correlation with clay volume calculation showed an heterogeneous multilayer reservoirs of Oligocene and Miocene formed by the arrangement of fourteen sandstone bodies being able to be good reservoirs, separated by impermeable clay packages and affected by faults. Reservoirs levels correspond mainly to the lower system tract (LST) of sequences. Intensive fracturing by deep seated faults bounding the different sub-basins play a great role for water surface recharge and inter-layer circulations between affected reservoirs. The total pore volume of the Oligo-Miocene reservoir sandy bodies in the study area, is estimated to about 4 × 1012 m3 and equivalent to 4

  20. On the effect of operation of the hydropower plant on the water quality of Rapel reservoir, central Chile

    Science.gov (United States)

    Rossel, V.; De La Fuente, A.

    2013-12-01

    Eutrophication of lakes and reservoirs is a common problem in systems with high incoming loads of nutrients. The consequent algae bloom related to the eutrophication alters the water quality and generates an incompatibility with the tourist and recreational activities. This study is focused on Rapel reservoir: an old, dentritic and monomictic reservoir, located in central Chile (34°S, 71.6°W), that has experienced numerous algae bloom events in the past years produced by high loads of nutrients, sediments and metals. This reservoir was originally constructed in 1968 for hydropower generation without environmental restrictions on its operation. Rapel is part of Chile's Central Interconnected System (SIC), and is controlled by an independent system operator (ISO) that decides the optimal allocation of water by minimizing the SIC's operation cost. As a result of this framework, Rapel reservoir operates based on a hydropeaking scheme, thus producing energy few hours a day while zero outflows are observed the remaining hours, impacting on Rapel river located downstream the reservoir. However, previous research showed that this hydropeaking has important effects on the hydrodynamic of the reservoir as well. Particularly, it enhances vertical mixing nears the dam, and reduces horizontal dispersion. Furthermore, hydropeaking defines the outflows water temperature, and the temperature profile near the dam. As a consequence of this role of hydropeaking on the hydrodynamics and mixing of Rapel reservoir, it is expected to be a link between hydropeaking and water quality. The aim of the study is to evaluate the impact of the operation of hydropower plant on the water quality of Rapel reservoir, for which the reservoir system is modeled using the three dimensional hydrodynamic and water quality model ELCOM-CAEDYM. Field data to validate the results and to define boundary and initial conditions are available for the austral summer period of 2009-2010. Different scenarios of

  1. Revestimento de Níquel Depositado pela Soldagem MIG e MIG com Arame Frio

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Mendes da Mota

    Full Text Available Resumo: Este artigo apresenta um estudo das características operacionais, geométricas e microestruturais de soldas MIG e MIGAF (MIG com arame frio aplicadas no revestimento de chapa de um aço AISI 1020, com uma superliga de níquel ER NiCrMo-4, tipo Hastelloy 276C. A soldagem foi automatizada, na posição plana, e realizada por uma fonte eletrônica em CC+ com aquisição instantânea dos oscilogramas de corrente e tensão de soldagem. As variáveis de entrada foram às velocidades do arame eletrodo e do arame frio, e a velocidade de soldagem. Foram avaliadas a operacionalidade dos processos e o efeito da energia de soldagem sobre as características geométricas (reforço e largura, diluição, microestrutura e microdureza do revestimento. Os resultados indicaram um bom desempenho operacional, a ausência de defeitos nos passes isolados e nos revestimentos para as soldagens com MIGAF. Além disso, constataram-se menores níveis de diluição.

  2. Cathodoluminescence characteristics of sandstone and the implications for sandstone type No. 512 uranium deposit

    International Nuclear Information System (INIS)

    Liu Xiaodong; Guan Taiyang

    1998-12-01

    Cathodoluminescence (CL) technique, as a special petrologic tool, has been applied to the studies of uranium hosted sandstone from No. 512 uranium deposit located in Xinjiang Autonomous Region, Northwest China. The detrital grains including quartz, feldspar, debris and cements display distinguishing CL properties. The quartz grains mainly demonstrate brown and dark blue CL, feldspar grains demonstrate blue and bright blue CL, calcite cement displays bright yellow-orange and orange-red CL with significant CL zoning, while the debris, mud and sand cements have dark red CL, multicolor CL or non-luminescence. The characteristics of overgrowth, fracture healing, and the original contact relations of detrital grains appear much more significant with CL than that with conventional visual methods. Much more information can be contributed by CL technique to decipher the provenance area, to explain the cementation, consolidation and other diagenesis processes of sandstone. The CL technique also provides and efficient tool for identifying detrital grains and cements, and for more precisely estimating the proportions of various detrital grains and cement components in sandstone. The CL emission of uranium hosted sandstone revealed the existence of radiation-damage rims of quartz grains at the places with a little or no uranium minerals nearby, which may imply a uranium-leaching episode during the diagenesis of sandstone

  3. An Evaluation of the Carbon Sequestration Potential of the Cambro-Ordovician Strata of the Illinois and Michigan Basins. Part 1. Evaluation of Phase 2 CO2 Injection Testing in the Deep Saline Gunter Sandstone Reservoir (Cambro-Ordovician Knox Group), Marvin Blan No. 1 Hancock County, Kentucky Part 2. Time-lapse Three-Dimensional Vertical Seismic Profile (3D-VSP) of Sequestration Target Interval with Injected Fluids

    Energy Technology Data Exchange (ETDEWEB)

    Bowersox, Richard [Univ. of Illinois, Champaign, IL (United States); Hickman, John [Univ. of Illinois, Champaign, IL (United States); Leetaru, Hannes [Univ. of Illinois, Champaign, IL (United States)

    2012-12-20

    Part 1 of this report focuses on results of the western Kentucky carbon storage test, and provides a basis for evaluating injection and storage of supercritical CO2 in Cambro-Ordovician carbonate reservoirs throughout the U.S. Midcontinent. This test demonstrated that the Cambro- Ordovician Knox Group, including the Beekmantown Dolomite, Gunter Sandstone, and Copper Ridge Dolomite in stratigraphic succession from shallowest to deepest, had reservoir properties suitable for supercritical CO2 storage in a deep saline reservoir hosted in carbonate rocks, and that strata with properties sufficient for long-term confinement of supercritical CO2 were present in the deep subsurface. Injection testing with brine and CO2 was completed in two phases. The first phase, a joint project by the Kentucky Geological Survey and the Western Kentucky Carbon Storage Foundation, drilled the Marvin Blan No. 1 carbon storage research well and tested the entire Knox Group section in the open borehole – including the Beekmantown Dolomite, Gunter Sandstone, and Copper Ridge Dolomite – at 1152–2255 m, below casing cemented at 1116 m. During Phase 1 injection testing, most of the 297 tonnes of supercritical CO2 was displaced into porous and permeable sections of the lowermost Beekmantown below 1463 m and Gunter. The wellbore was then temporarily abandoned with a retrievable bridge plug in casing at 1105 m and two downhole pressure-temperature monitoring gauges below the bridge plug pending subsequent testing. Pressure and temperature data were recorded every minute for slightly more than a year, providing a unique record of subsurface reservoir conditions in the Knox. In contrast, Phase 2 testing, this study, tested a mechanically-isolated dolomitic-sandstone interval in the Gunter.

  4. PHOSPHORUS CONTAMINATION AS A BARRIER TO WATER QUALITY OF SMALL RETENTION RESERVOIRS IN PODLASIE REGION

    Directory of Open Access Journals (Sweden)

    Joanna Ewa Szczykowska

    2016-06-01

    Full Text Available Dam retention reservoirs created on the rivers play a special role as an environmentally friendly forms of stopping and slowing of water runoff. The aim of this study was to evaluate the quality of water flowing into small retention reservoirs in terms of the concentration of total phosphorus and phosphates. The study involved three small retention reservoirs located in the municipalities of: Bransk, Dubicze Cerkiewne and Kleszczele in Podlasie region. Selection of the research facilities was made due to the similarity in the soil management type within catchment of the flowing watercourse, retained water utilization ways, and a small surface of reservoirs. Watercourse reaching the reservoir provides biogens along with water, which directly affect the water quality resulting in high concentrations in water, either indirectly by initiating or accelerating the process of degradation of the reservoir and the loss of its usability. Given the concentration of total phosphorus, it can be said that only in the case of 20.8% of water samples from Nurzec river feeding the Otapy-Kiersnówek reservoir, about 25% of water samples of Orlanka river feeding Bachmaty reservoir, and 17% of samples taken from the watercourse supplying Repczyce reservoir, corresponded to values specified for the second class in the current Regulation of the Minister of the Environment [Regulation 2014]. It can be assumed that this situation is caused by a long-term fertilization using manure, which in consequence led to the oversaturation of soils and phosphorus compounds penetration into the river waters in areas used for agricultural purposes. Especially in the early spring periods, rising temperature together with rainfall caused soil thawing resulting in increasing concentrations of contaminants carried along with the washed soil particles during the surface and subsurface runoff. Values of TSI(TP calculated for Otapy-Kiersnówek reservoir amounted to 112.4 in hydrological

  5. "Sydney sandstone": Heritage Stone from Australia

    Science.gov (United States)

    Cooper, Barry; Kramar, Sabina

    2014-05-01

    Sydney is Australia's oldest city being founded in 1788. The city was fortunate to be established on an extensive and a relatively undeformed layer of lithified quartz sandstone of Triassic age that has proved to be an ideal building stone. The stone has been long identified by geologists as the Hawkesbury Sandstone. On the other hand the term "Sydney sandstone" has also been widely used over a long period, even to the extent of being utilised as the title of published books, so its formal designation as a heritage stone will immediately formalise this term. The oldest international usage is believed to be its use in the construction of the Stone Store at Kerikeri, New Zealand (1832-1836). In the late 19th century, public buildings such as hospitals, court houses as well as the prominent Sydney Town Hall, Sydney General Post Office, Art Gallery of New South Wales, State Library of New South Wales as well as numerous schools, churches, office building buildings, University, hotels, houses, retaining walls were all constructed using Sydney sandstone. Innumerable sculptures utilising the gold-coloured stone also embellished the city ranging from decorative friezes and capitals on building to significant monuments. Also in the late 19th and early 20th century, Sydney sandstone was used for major construction in most other major Australian cities especially Melbourne, Adelaide and Brisbane to the extent that complaints were expressed that suitable local stone materials were being neglected. Quarrying of Sydney sandstone continues today. In 2000 it was recorded noted that there were 33 significant operating Sydney sandstone quarries including aggregate and dimension stone operations. In addition sandstone continues to be sourced today from construction sites across the city area. Today major dimension stone producers (eg Gosford Quarries) sell Sydney sandstone not only into the Sydney market but also on national and international markets as cladding and paving products

  6. The water-quality monitoring program for the Baltimore reservoir system, 1981-2007—Description, review and evaluation, and framework integration for enhanced monitoring

    Science.gov (United States)

    Koterba, Michael T.; Waldron, Marcus C.; Kraus, Tamara E.C.

    2011-01-01

    The City of Baltimore, Maryland, and parts of five surrounding counties obtain their water from Loch Raven and Liberty Reservoirs. A third reservoir, Prettyboy, is used to resupply Loch Raven Reservoir. Management of the watershed conditions for each reservoir is a shared responsibility by agreement among City, County, and State jurisdictions. The most recent (2005) Baltimore Reservoir Watershed Management Agreement (RWMA) called for continued and improved water-quality monitoring in the reservoirs and selected watershed tributaries. The U.S. Geological Survey (USGS) conducted a retrospective review of the effectiveness of monitoring data obtained and analyzed by the RWMA jurisdictions from 1981 through 2007 to help identify possible improvements in the monitoring program to address RWMA water-quality concerns. Long-term water-quality concerns include eutrophication and sedimentation in the reservoirs, and elevated concentrations of (a) nutrients (nitrogen and phosphorus) being transported from the major tributaries to the reservoirs, (b) iron and manganese released from reservoir bed sediments during periods of deep-water anoxia, (c) mercury in higher trophic order game fish in the reservoirs, and (d) bacteria in selected reservoir watershed tributaries. Emerging concerns include elevated concentrations of sodium, chloride, and disinfection by-products (DBPs) in the drinking water from both supply reservoirs. Climate change and variability also could be emerging concerns, affecting seasonal patterns, annual trends, and drought occurrence, which historically have led to declines in reservoir water quality. Monitoring data increasingly have been used to support the development of water-quality models. The most recent (2006) modeling helped establish an annual sediment Total Maximum Daily Load to Loch Raven Reservoir, and instantaneous and 30-day moving average water-quality endpoints for chlorophyll-a (chl-a) and dissolved oxygen (DO) in Loch Raven and Prettyboy

  7. Influence of watershed activities on the water quality and fish assemblages of a tropical African reservoir.

    Science.gov (United States)

    Mustapha, Moshood K

    2009-09-01

    Agricultural and fisheries activities around the watershed of an African tropical reservoir (Oyun reservoir, Offa, Nigeria) were found to contribute significantly to water quality deterioration of the dam axis of the reservoir, leading to eutrophication of that part of the reservoir. This is evident from the high amount of nitrate (6.4 mg/l), phosphate (2.2 mg/l) and sulphate (16.9 mg/l) in the water body which was higher than most other reservoirs in Nigeria. These nutrients originate in fertilizer run-offs from nearby farmlands and were found in higher concentrations in the rainy season which is usually the peak of agricultural activities in the locality. The eutrophication was more pronounced on the dam axis because it is the point of greatest human contact where pressure and run-off of sediments were high. The eutrophication altered the food web cycle which consequently affected the fish species composition and abundance with the dominance of cichlids (planktivorous group) and decline of some species in the fish population. Best management practices (BMP) to control and reduce the eutrophication and improve water quality and fish assemblages should be adopted and adapted to suit the situation in the reservoir.

  8. Small reservoir effects on headwater water quality in the rural-urban fringe, Georgia Piedmont, USA

    Directory of Open Access Journals (Sweden)

    Dr.. Amber R. Ignatius, Geographer

    2016-12-01

    Full Text Available Small reservoirs are prevalent landscape features that affect the physical, chemical, and biological characteristics of headwater streams. Tens of thousands of small reservoirs, often less than a hectare in size, were constructed over the past century within the United States. While remote-sensing and geographic-mapping technologies assist in identifying and quantifying these features, their localized influence on water quality is uncertain. We report a year-long physicochemical study of nine small reservoirs (0.15–2.17 ha within the Oconee and Broad River Watersheds in the Georgia Piedmont. Study sites were selected along an urban-rural gradient with differing amounts of agricultural, forested, and developed land covers. Sites were sampled monthly for discharge and inflow/outflow water quality parameters (temperature, specific conductance, pH, dissolved oxygen, turbidity, alkalinity, total phosphorus, total nitrogen, nitrate, ammonium. While the proportion of developed land cover within watersheds had positive correlations with reservoir specific conductivity values, agricultural and forested land covers showed correlations (positive and negative, respectively with reservoir alkalinity, total nitrogen, nitrate, and specific conductivity. The majority of outflow temperatures were warmer than inflows for all land uses throughout the year, especially in the summer. Outflows had lower nitrate concentrations, but higher ammonium. The type of outflow structure was also influential; top-release dams showed higher dissolved oxygen and pH than bottom-release dams. Water quality effects were still evident 250 m below the dam, albeit reduced.

  9. Water quality and trend analysis of Colorado--Big Thompson system reservoirs and related conveyances, 1969 through 2000

    Science.gov (United States)

    Stevens, Michael R.

    2003-01-01

    The U.S. Geological Survey, in an ongoing cooperative monitoring program with the Northern Colorado Water Conservancy District, Bureau of Reclamation, and City of Fort Collins, has collected water-quality data in north-central Colorado since 1969 in reservoirs and conveyances, such as canals and tunnels, related to the Colorado?Big Thompson Project, a water-storage, collection, and distribution system. Ongoing changes in water use among agricultural and municipal users on the eastern slope of the Rocky Mountains in Colorado, changing land use in reservoir watersheds, and other water-quality issues among Northern Colorado Water Conservancy District customers necessitated a reexamination of water-quality trends in the Colorado?Big Thompson system reservoirs and related conveyances. The sampling sites are on reservoirs, canals, and tunnels in the headwaters of the Colorado River (on the western side of the transcontinental diversion operations) and the headwaters of the Big Thompson River (on the eastern side of the transcontinental diversion operations). Carter Lake Reservoir and Horsetooth Reservoir are off-channel water-storage facilities, located in the foothills of the northern Colorado Front Range, for water supplied from the Colorado?Big Thompson Project. The length of water-quality record ranges from approximately 3 to 30 years depending on the site and the type of measurement or constituent. Changes in sampling frequency, analytical methods, and minimum reporting limits have occurred repeatedly over the period of record. The objective of this report was to complete a retrospective water-quality and trend analysis of reservoir profiles, nutrients, major ions, selected trace elements, chlorophyll-a, and hypolimnetic oxygen data from 1969 through 2000 in Lake Granby, Shadow Mountain Lake, and the Granby Pump Canal in Grand County, Colorado, and Horsetooth Reservoir, Carter Lake, Lake Estes, Alva B. Adams Tunnel, and Olympus Tunnel in Larimer County, Colorado

  10. CO{sub 2}-induced mechanical behaviour of Hawkesbury sandstone in the Gosford basin: An experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Rathnaweera, T.D. [Department of Civil Engineering, Monash University, Building 60, Melbourne, Victoria 3800 (Australia); Ranjith, P.G., E-mail: ranjith.pg@monash.edu [Department of Civil Engineering, Monash University, Building 60, Melbourne, Victoria 3800 (Australia); Perera, M.S.A.; Haque, A. [Department of Civil Engineering, Monash University, Building 60, Melbourne, Victoria 3800 (Australia); Lashin, A. [King Saud University, College of Engineering-Petroleum and Natural Gas Engineering Department, P.O. Box 800, Riyadh 11421, Saudi Arabia. (Saudi Arabia); Benha University, Faculty of Science-Geology Department, P.O. Box 13518, Benha (Egypt); Al Arifi, N. [King Saud University, College of Science-Geology and Geophysics Department, P.O. Box 2455, Riyadh 11451, Saudi Arabia. (Saudi Arabia); Chandrasekharam, D [King Saud University, College of Science-Geology and Geophysics Department, P.O. Box 2455, Riyadh 11451, Saudi Arabia. (Saudi Arabia); Department of Earth Sciences, Indian Institute of Technology Bombay, 400076 India (India); Yang, SQ [Department of Civil Engineering, Monash University, Building 60, Melbourne, Victoria 3800 (Australia); State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Xuzhou 221116 (China); Xu, T; Wang, SH [Center for Rock Instability & Seismicity Research, Northeastern University, Shenyang 110819 (China); Yasar, E [Iskenderun Technical University, Faculty of Mechanical Engineering, Dept. of Petroleum & Natural Gas Engineering, 31200 (Turkey)

    2015-08-12

    Carbon dioxide (CO{sub 2}) sequestered in saline aquifers undergoes a variety of chemically-coupled mechanical effects, which may cause CO{sub 2}-induced mechanical changes and time-dependent reservoir deformation. This paper investigates the mineralogical and microstructural changes that occur in reservoir rocks following injection of CO{sub 2} in deep saline aquifers and the manner in which these changes influence the mechanical properties of the reservoir rocks. In this study, cylindrical sandstone specimens, 38 mm in diameter and 76 mm high, obtained from the Gosford basin, were used to perform a series of unconfined compressive strength (UCS) tests. Different saturation conditions: dry, water- and brine-saturated sandstone samples with and without scCO{sub 2} (super-critical carbon dioxide) injection, were considered in the study to obtain a comprehensive understanding of the impact of scCO{sub 2} injection during the CO{sub 2} sequestration process on saline aquifer mechanical properties. An acoustic emission (AE) system was employed to identify the stress threshold values of crack closure, crack initiation and crack damage for each testing condition during the whole deformation process of the specimens. Finally, scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray fluorescence (XRF) analyses were performed to evaluate the chemical and mineralogical changes that occur in reservoir rocks during CO{sub 2} injection. From the test results, it is clear that the CO{sub 2}-saturated samples possessed a lower peak strength compared to non-CO{sub 2} saturated samples. According to SEM, XRD and XRF analyses, considerable quartz mineral corrosion and dissolution of calcite and siderite were observed during the interactions of the CO{sub 2}/water/rock and CO{sub 2}/brine/rock systems, which implies that mineralogical and geochemical rock alterations affect rock mechanical properties by accelerating the collapse mechanisms of the pore matrix. AE results

  11. Ephemeral-fluvial sediments as potential hydrocarbon reservoirs. Vol. 1: Sedimentology

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, K.S.

    1994-12-31

    Although reservoirs formed from ephemeral-fluvial sandstones have previously been considered relatively simple, unresolved problems of sandbody correlation and production anomalies demonstrate the need for improved understanding of their internal complexity. Outcropping ephemeral-fluvial systems have been studied in order to determine the main features and processes occurring in sand-rich ephemeral systems and to identify which features will be of importance in a hydrocarbon reservoir. The Lower Jurassic Upper Moenave and Kayenta Formations of south-eastern Utah and northern Arizona comprise series of stacked, sand-dominated sheet-like palaeochannels suggestive of low sinuosity, braided systems. Low subsidence rates and rapid lateral migration rates enabled channels to significantly modify their widths during high discharge. (author)

  12. Application of Nemerow Index Method and Integrated Water Quality Index Method in Water Quality Assessment of Zhangze Reservoir

    Science.gov (United States)

    Zhang, Qian; Feng, Minquan; Hao, Xiaoyan

    2018-03-01

    [Objective] Based on the water quality historical data from the Zhangze Reservoir from the last five years, the water quality was assessed by the integrated water quality identification index method and the Nemerow pollution index method. The results of different evaluation methods were analyzed and compared and the characteristics of each method were identified.[Methods] The suitability of the water quality assessment methods were compared and analyzed, based on these results.[Results] the water quality tended to decrease over time with 2016 being the year with the worst water quality. The sections with the worst water quality were the southern and northern sections.[Conclusion] The results produced by the traditional Nemerow index method fluctuated greatly in each section of water quality monitoring and therefore could not effectively reveal the trend of water quality at each section. The combination of qualitative and quantitative measures of the comprehensive pollution index identification method meant it could evaluate the degree of water pollution as well as determine that the river water was black and odorous. However, the evaluation results showed that the water pollution was relatively low.The results from the improved Nemerow index evaluation were better as the single indicators and evaluation results are in strong agreement; therefore the method is able to objectively reflect the water quality of each water quality monitoring section and is more suitable for the water quality evaluation of the reservoir.

  13. [Coupling SWAT and CE-QUAL-W2 models to simulate water quantity and quality in Shanmei Reservoir watershed].

    Science.gov (United States)

    Liu, Mei-Bing; Chen, Dong-Ping; Chen, Xing-Wei; Chen, Ying

    2013-12-01

    A coupled watershed-reservoir modeling approach consisting of a watershed distributed model (SWAT) and a two-dimensional laterally averaged model (CE-QUAL-W2) was adopted for simulating the impact of non-point source pollution from upland watershed on water quality of Shanmei Reservoir. Using the daily serial output from Shanmei Reservoir watershed by SWAT as the input to Shanmei Reservoir by CE-QUAL-W2, the coupled modeling was calibrated for runoff and outputs of sediment and pollutant at watershed scale and for elevation, temperature, nitrate, ammonium and total nitrogen in Shanmei Reservoir. The results indicated that the simulated values agreed fairly well with the observed data, although the calculation precision of downstream model would be affected by the accumulative errors generated from the simulation of upland model. The SWAT and CE-QUAL-W2 coupled modeling could be used to assess the hydrodynamic and water quality process in complex watershed comprised of upland watershed and downstream reservoir, and might further provide scientific basis for positioning key pollution source area and controlling the reservoir eutrophication.

  14. Remote Sensing of Water Quality in Multipurpose Reservoirs: Case Study Applications in Indonesia, Mexico, and Uruguay

    Science.gov (United States)

    Miralles-Wilhelm, F.; Serrat-Capdevila, A.; Rodriguez, D.

    2017-12-01

    This research is focused on development of remote sensing methods to assess surface water pollution issues, particularly in multipurpose reservoirs. Three case study applications are presented to comparatively analyze remote sensing techniquesforo detection of nutrient related pollution, i.e., Nitrogen, Phosphorus, Chlorophyll, as this is a major water quality issue that has been identified in terms of pollution of major water sources around the country. This assessment will contribute to a better understanding of options for nutrient remote sensing capabilities and needs and assist water agencies in identifying the appropriate remote sensing tools and devise an application strategy to provide information needed to support decision-making regarding the targeting and monitoring of nutrient pollution prevention and mitigation measures. A detailed review of the water quality data available from ground based measurements was conducted in order to determine their suitability for a case study application of remote sensing. In the first case study, the Valle de Bravo reservoir in Mexico City reservoir offers a larger database of water quality which may be used to better calibrate and validate the algorithms required to obtain water quality data from remote sensing raw data. In the second case study application, the relatively data scarce Lake Toba in Indonesia can be useful to illustrate the value added of remote sensing data in locations where water quality data is deficient or inexistent. The third case study in the Paso Severino reservoir in Uruguay offers a combination of data scarcity and persistent development of harmful algae blooms. Landsat-TM data was obteined for the 3 study sites and algorithms for three key water quality parameters that are related to nutrient pollution: Chlorophyll-a, Total Nitrogen, and Total Phosphorus were calibrated and validated at the study sites. The three case study applications were developed into capacity building/training workshops

  15. Effects of reduction in porosity and permeability with depth on storage capacity and injectivity in deep saline aquifers: A case study from the Mount Simon Sandstone aquifer

    Science.gov (United States)

    Medina, C.R.; Rupp, J.A.; Barnes, D.A.

    2011-01-01

    The Upper Cambrian Mount Simon Sandstone is recognized as a deep saline reservoir that has significant potential for geological sequestration in the Midwestern region of the United States. Porosity and permeability values collected from core analyses in rocks from this formation and its lateral equivalents in Indiana, Kentucky, Michigan, and Ohio indicate a predictable relationship with depth owing to a reduction in the pore structure due to the effects of compaction and/or cementation, primarily as quartz overgrowths. The regional trend of decreasing porosity with depth is described by the equation: ??(d)=16.36??e-0.00039*d, where ?? is the porosity and d is the depth in m. The decrease of porosity with depth generally holds true on a basinwide scale. Bearing in mind local variations in lithologic and petrophysical character within the Mount Simon Sandstone, the source data that were used to predict porosity were utilized to estimate the pore volume available within the reservoir that could potentially serve as storage space for injected CO2. The potential storage capacity estimated for the Mount Simon Sandstone in the study area, using efficiency factors of 1%, 5%, 10%, and 15%, is 23,680, 118,418, 236,832, and 355,242 million metric tons of CO2, respectively. ?? 2010 Elsevier Ltd.

  16. Clay squirt: Local flow dispersion in shale-bearing sandstones

    DEFF Research Database (Denmark)

    Sørensen, Morten Kanne; Fabricius, Ida Lykke

    2017-01-01

    Dispersion of elastic-wave velocity is common in sandstone and larger in shaly sandstone than in clean sandstone. Dispersion in fluid-saturated shaly sandstone often exceeds the level expected from the stress-dependent elastic moduli of dry sandstone. The large dispersion has been coined clay...... squirt and is proposed to originate from a pressure gradient between the clay microporosity and the effective porosity. We have formulated a simple model that quantifies the clay-squirt effect on bulk moduli of sandstone with homogeneously distributed shale laminae or dispersed shale. The model...... predictions were compared with the literature data. For sandstones with dispersed shale, agreement was found, whereas other sandstones have larger fluid-saturated bulk modulus, possibly due to partially load-bearing shales or heterogeneous shale distribution. The data that agree with the clay-squirt model...

  17. Estimates the Effects of Benthic Fluxes on the Water Quality of the Reservoir

    Science.gov (United States)

    Lee, H.; Huh, I. A.; Park, S.; Choi, J. H.

    2014-12-01

    Reservoirs located in highly populated and industrialized regions receive discharges of nutrients and pollutants from the watershed that have great potential to impair water quality and threaten aquatic life. The Euiam reservoir is a multiple-purpose water body used for tourism, fishery, and water supply and has been reported as eutrophic since 1990s. The external nutrients loading is considered to be the main cause of eutrophication of water bodies, and control strategies therefore focus on its reduction. However, algae blooms often continue even after external nutrients loading has been controlled, being benthic nutrient loading the main source of nutrients in the water column. Attempts to quantify benthic nutrients fluxes and their role as a source of nutrients to the water column have produced ambiguous results. Benthic flux is dependent on the upward flow of pore water caused by hydrostatic pressure, molecular diffusion, and mixing of sediment and water. In addition, it is controlled by dissolved oxygen (DO) levels, pH values and temperature in the overlying water. Therefore, linking a benthic flux to a water quality model should give us more insight on the effects of benthic fluxes to better quantify nutrient concentration within an entire reservoir system where physical, chemical, biological properties are variable. To represent temporal and spatial variations in the nutrient concentrations of the reservoir, a three-dimensional time variable model, Generalized Longitudinal-Lateral-Vertical Hydrodynamic and Transport (GLLVHT) was selected. The GLLVHT model is imbedded within the Generalized Environmental Modeling System for Surface waters (GEMSS). The computational grid of the three-dimensional model was developed using the GIS. The horizontal grid is composed of 580 active cells at the surface layer with spacing varies from 54.2 m to 69.8 m. There are 15 vertical layers with uniform thickness of 1.9 m resolution. To calibrate the model, model prediction for

  18. Wettability of Oil-Producing Reservoir Rocks as Determined from X-ray Photoelectron Spectroscopy

    Science.gov (United States)

    Toledo; Araujo; Leon

    1996-11-10

    Wettability has a dominant effect in oil recovery by waterflooding and in many other processes of industrial and environmental interest. Recently, the suggestion has been made that surface science analytical techniques (SSAT) could be used to rapidly determine the wettability of reservoir materials. Here, we bring the capability of X-ray photoelectron spectroscopy (XPS) to bear on the wettability evaluation of producing reservoir rocks. For a suite of freshly exposed fracture surfaces of rocks we investigate the relationship between wettability and surface composition as determined from XPS. The classical wettability index as measured with the Amott-Harvey test is used here as an indicator of the wettability of natural sandstones. The XPS spectra of oil-wet surfaces of rocks reveal the existence of organic carbon and also of an "organic" silicon species, of the kind Si-CH relevant to silanes, having a well-defined binding energy which differs from that of the Si-O species of mineral grains. We provide quantifiable evidence that chemisorbed organic material on the pore surfaces defines the oil-wetting character of various reservoir sandstones studied here which on a mineralogic basis are expected to be water-wet. This view is supported by a strong correlation between C content of pore surfaces and rock wettability. The results also suggest a correlation between organic silicon content on the pore surfaces and rock hydrophobicity.

  19. Provenance of the Lower Triassic Bunter Sandstone Formation: implications for distribution and architecture of aeolian vs. fluvial reservoirs in the North German Basin

    DEFF Research Database (Denmark)

    Olivarius, Mette; Weibel, Rikke; Friis, Henrik

    2017-01-01

    Zircon U–Pb geochronometry, heavy mineral analyses and conventional seismic reflection data were used to interpret the provenance of the Lower Triassic Bunter Sandstone Formation. The succession was sampled in five Danish wells in the northern part of the North German Basin. The results show...... Shield did not supply much sediment to the basin as opposed to what was previously believed. Sediment from the Variscan belt was transported by wind activity across the North German Basin when it was dried out during deposition of the aeolian part of the Volpriehausen Member (lower Bunter Sandstone......). Fluvial sand was supplied from the Ringkøbing-Fyn High to the basin during precipitation events which occurred most frequently when the Solling Member was deposited (upper Bunter Sandstone). Late Neoproterozoic to Carboniferous zircon ages predominate in the Volpriehausen Member where the dominant age...

  20. Water-quality trends in the Scituate reservoir drainage area, Rhode Island, 1983-2012

    Science.gov (United States)

    Smith, Kirk P.

    2015-01-01

    The Scituate Reservoir is the primary source of drinking water for more than 60 percent of the population of Rhode Island. Water-quality and streamflow data collected at 37 surface-water monitoring stations in the Scituate Reservoir drainage area, Rhode Island, from October 2001 through September 2012, water years (WYs) 2002-12, were analyzed to determine water-quality conditions and constituent loads in the drainage area. Trends in water quality, including physical properties and concentrations of constituents, were investigated for the same period and for a longer period from October 1982 through September 2012 (WYs 1983-2012). Water samples were collected and analyzed by the Providence Water Supply Board, the agency that manages the Scituate Reservoir. Streamflow data were collected by the U.S. Geological Survey. Median values and other summary statistics for pH, color, turbidity, alkalinity, chloride, nitrite, nitrate, total coliform bacteria, Escherichia coli (E. coli), and orthophosphate were calculated for WYs 2003-12 for all 37 monitoring stations. Instantaneous loads and yields (loads per unit area) of total coliform bacteria and E. coli, chloride, nitrite, nitrate, and orthophosphate were calculated for all sampling dates during WYs 2003-12 for 23 monitoring stations with streamflow data. Values of physical properties and concentrations of constituents were compared with State and Federal water-quality standards and guidelines and were related to streamflow, land-use characteristics, varying classes of timber operations, and impervious surface areas.

  1. Experimental strain analysis of Clarens Sandstone colonised by endolithic lichens

    Directory of Open Access Journals (Sweden)

    D. Wessels

    1995-08-01

    Full Text Available Endolithic lichens occur commonly on Clarens Sandstone in South Africa, where they significantly contribute to the weathering of sandstone by means of mechanical and chemical weathering processes. This preliminary investigation reports on the success- ful use of strain gauges in detecting strain differences between sandstone without epilithic lichens and sandstone colonised by the euendolithic lichen Lecidea aff. sarcogynoides Korb. Mechanical weathering, expressed as strain changes, in Clarens Sandstone was studied during the transition from relatively dry winter to wet summer conditions. Daily weathering of sandstone due to thermal expansion and contraction of colonised and uncolonised sandstone could be shown. Our results show that liquid water in sandstone enhances the mechanical weathering of uncolonised Clarens Sandstone while water in the gaseous phase enhances mechanical weathering of sandstone by euendolithic lichens.

  2. Potential petrophysical and chemical property alterations in a compressed air energy storage porous rock reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Stottlemyre, J.A.; Erikson, R.L.; Smith, R.P.

    1979-10-01

    Successful commercialization of Compressed Air Energy Storage (CAES) systems depends on long-term stability of the underground reservoirs subjected to somewhat unique operating conditions. Specifically, these conditions include elevated and time varying temperatures, effective stresses, and air humidities. To minimize the requirements for premium fuels, it may be desirable to retain the thermal energy of compression. Porous media, e.g., sandstone, may hold promise as elevated temperature reservoirs. In this study, a reservoir composed of clean quartz sandstone and injection air temperatures of 300 to 575/sup 0/K are assumed. Numerical modeling is used to estimate temperature, stress, and humidity conditions within this reference porous media reservoir. A discussion on relative importance to CAES of several potential porous media damage mechanisms is presented. In this context, damage is defined as a reduction in intrinsic permeability (measure of air transport capability), a decrease in effective porosity (measure of storage capability), or an increase in elastic and/or inelastic deformation of the porous material. The potential damage mechanisms presented include: (1) disaggregation, (2) particulate plugging, (3) boundary layer viscosity anomalies, (4) inelastic microstructural consolidation, (5) clay swelling and dispersion, (6) hydrothermal mineral alteration, (7) oxidation reactions, and (8) well casing corrosion. These mechanisms are placed in perspective with respect to anticipated CAES conditions and mechanisms suggested are: (1) of academic interest only, (2) readily identified and controlled via engineering, or (3) potential problem areas requiring additional investigation.

  3. Frictional behaviour and transport properties of simulated fault gouges derived from a natural CO2 reservoir

    NARCIS (Netherlands)

    Bakker, E.; Hangx, S.J.T.|info:eu-repo/dai/nl/30483579X; Niemeijer, A.R.|info:eu-repo/dai/nl/370832132; Spiers, C.J.|info:eu-repo/dai/nl/304829323

    2016-01-01

    We investigated the effects of long-term CO2-brine-rock interactions on the frictional and transport properties of reservoir-derived fault gouges, prepared from both unexposed and CO2-exposed sandstone, and from aragonite-cemented fault rock of an active CO2-leaking conduit, obtained from a natural

  4. Acoustic and mechanical response of reservoir rocks under variable saturation and effective pressure.

    Science.gov (United States)

    Ravazzoli, C L; Santos, J E; Carcione, J M

    2003-04-01

    We investigate the acoustic and mechanical properties of a reservoir sandstone saturated by two immiscible hydrocarbon fluids, under different saturations and pressure conditions. The modeling of static and dynamic deformation processes in porous rocks saturated by immiscible fluids depends on many parameters such as, for instance, porosity, permeability, pore fluid, fluid saturation, fluid pressures, capillary pressure, and effective stress. We use a formulation based on an extension of Biot's theory, which allows us to compute the coefficients of the stress-strain relations and the equations of motion in terms of the properties of the single phases at the in situ conditions. The dry-rock moduli are obtained from laboratory measurements for variable confining pressures. We obtain the bulk compressibilities, the effective pressure, and the ultrasonic phase velocities and quality factors for different saturations and pore-fluid pressures ranging from normal to abnormally high values. The objective is to relate the seismic and ultrasonic velocity and attenuation to the microstructural properties and pressure conditions of the reservoir. The problem has an application in the field of seismic exploration for predicting pore-fluid pressures and saturation regimes.

  5. OPTIMIZATION OF INFILL DRILLING IN NATURALLY-FRACTURED TIGHT-GAS RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence W. Teufel; Her-Yuan Chen; Thomas W. Engler; Bruce Hart

    2004-05-01

    A major goal of industry and the U.S. Department of Energy (DOE) fossil energy program is to increase gas reserves in tight-gas reservoirs. Infill drilling and hydraulic fracture stimulation in these reservoirs are important reservoir management strategies to increase production and reserves. Phase II of this DOE/cooperative industry project focused on optimization of infill drilling and evaluation of hydraulic fracturing in naturally-fractured tight-gas reservoirs. The cooperative project involved multidisciplinary reservoir characterization and simulation studies to determine infill well potential in the Mesaverde and Dakota sandstone formations at selected areas in the San Juan Basin of northwestern New Mexico. This work used the methodology and approach developed in Phase I. Integrated reservoir description and hydraulic fracture treatment analyses were also conducted in the Pecos Slope Abo tight-gas reservoir in southeastern New Mexico and the Lewis Shale in the San Juan Basin. This study has demonstrated a methodology to (1) describe reservoir heterogeneities and natural fracture systems, (2) determine reservoir permeability and permeability anisotropy, (3) define the elliptical drainage area and recoverable gas for existing wells, (4) determine the optimal location and number of new in-fill wells to maximize economic recovery, (5) forecast the increase in total cumulative gas production from infill drilling, and (6) evaluate hydraulic fracture simulation treatments and their impact on well drainage area and infill well potential. Industry partners during the course of this five-year project included BP, Burlington Resources, ConocoPhillips, and Williams.

  6. APPLICATION OF RESERVOIR CHARACTERIZATION AND ADVANCED TECHNOLOGY TO IMPROVE RECOVERY AND ECONOMICS IN A LOWER QUALITY SHALLOW SHELF SAN ANDRES RESERVOIR

    Energy Technology Data Exchange (ETDEWEB)

    Tom Beebe

    2003-05-05

    The OXY-operated Class 2 Project at West Welch is designed to demonstrate how the use of advanced technology can improve the economics of miscible CO{sub 2} injection projects in lower quality Shallow Shelf Carbonate reservoirs. The research and design phase (Budget Period 1) primarily involved advanced reservoir characterization. The current demonstration phase (Budget Period 2) is the implementation of the reservoir management plan for an optimum miscible CO{sub 2} flood design based on the reservoir characterization. Although Budget Period 1 for the Project officially ended 12/31/96, reservoir characterization and simulation work continued during the Budget Period 2. During the seventh annual reporting period (8/3/00-8/2/01) covered by this report, work continued on interpretation of the interwell seismic data to create porosity and permeability profiles which were distributed into the reservoir geostatistically. The initial interwell seismic CO{sub 2} monitor survey was conducted and the acquired data processed and interpretation started. Only limited well work and facility construction were conducted in the project area. The CO{sub 2} injection initiated in October 1997 was continued, although the operator had to modify the operating plan in response to low injection rates, well performance and changes in CO{sub 2} supply. CO{sub 2} injection was focused in a smaller area to increase the reservoir processing rate. By the end of the reporting period three producers had shown sustained oil rate increases and six wells had experienced gas (CO{sub 2}) breakthrough.

  7. Analysis of the influence of reservoirs utilization to water quality profiles in Indonesia (Saguling - Jatiluhur) and Malaysia (Temengor - Chenderoh) with special references to cascade reservoirs

    Science.gov (United States)

    Subehi, Luki; Norasikin Ismail, Siti; Ridwansyah, Iwan; Hamid, Muzzalifah Abd; Mansor, Mashhor

    2018-02-01

    Tropical reservoir is the one ecosystem which is functioning in both ecological and economical services. As the settling of water volume, it harbors many species of fish. The objective of this study is to analyze the utilization and management of reservoirs related to their water quality conditions, represent by tropical reservoirs from Indonesia and Malaysia. Survey at Jatiluhur and Saguling (Indonesia) was conducted in March 2014 and September 2015, respectively while in Temengor and Chenderoh (Malaysia), the survey was done in January 2014 and April 2017, respectively. Based on elevation, Saguling and Temengor are upstream reservoirs. On the contrary, Jatiluhur and Chenderoh are downstream reservoirs. The results of the surveys in Jatiluhur and Saguling reservoirs showed that the average depths are 32.9m and 17.9m, respectively. On the other hand, Temengor and Chenderoh reservoirs are 100m and 16.2m, respectively. All of them play multi-functional roles including as a source of power plant, fisheries and tourism, as well as water sources for irrigation. In addition, Saguling and Temengor reservoirs are relatively dendritic in shape. In Indonesia, there are three consecutive reservoirs along Citarum River, whereas in Malaysia there are four consecutive reservoirs along Perak River. The results showed the potential impact of fish cages as pollutant, especially at Indonesian reservoirs. In addition, these tropical reservoirs have become famous tourism getaway. The capabilities of economic values of these reservoirs and ecosystem should be balanced. Basic ecological information is necessary for the next study.

  8. Area of Interest 1, CO2 at the Interface. Nature and Dynamics of the Reservoir/Caprock Contact and Implications for Carbon Storage Performance

    Energy Technology Data Exchange (ETDEWEB)

    Mozley, Peter [New Mexico Institute Of Mining And Technology, Socorro, NM (United States); Evans, James [New Mexico Institute Of Mining And Technology, Socorro, NM (United States); Dewers, Thomas [New Mexico Institute Of Mining And Technology, Socorro, NM (United States)

    2014-10-31

    We examined the influence of geologic features present at the reservoir/caprock interface on the transmission of supercritical CO2 into and through caprock. We focused on the case of deformation-band faults in reservoir lithologies that intersect the interface and transition to opening-mode fractures in caprock lithologies. Deformation-band faults are exceeding common in potential CO2 injection units and our fieldwork in Utah indicates that this sort of transition is common. To quantify the impact of these interface features on flow and transport we first described the sedimentology and permeability characteristics of selected sites along the Navajo Sandstone (reservoir lithology) and Carmel Formation (caprock lithology) interface, and along the Slickrock Member (reservoir lithology) and Earthy Member (caprock lithology) of the Entrada Sandstone interface, and used this information to construct conceptual permeability models for numerical analysis. We then examined the impact of these structures on flow using single-phase and multiphase numerical flow models for these study sites. Key findings include: (1) Deformation-band faults strongly compartmentalize the reservoir and largely block cross-fault flow of supercritical CO2. (2) Significant flow of CO2 through the fractures is possible, however, the magnitude is dependent on the small-scale geometry of the contact between the opening-mode fracture and the deformation band fault. (3) Due to the presence of permeable units in the caprock, caprock units are capable of storing significant volumes of CO2, particularly when the fracture network does not extend all the way through the caprock. The large-scale distribution of these deformation-bandfault-to-opening-mode-fractures is related to the curvature of the beds, with greater densities of fractures in high curvature regions. We also examined core and outcrops from the Mount Simon Sandstone and Eau Claire

  9. Micro-Ct Imaging of Multi-Phase Flow in Carbonates and Sandstones

    Science.gov (United States)

    Andrew, M. G.; Bijeljic, B.; Blunt, M. J.

    2013-12-01

    One of the most important mechanisms that limits the escape of CO2 when injected into the subsurface for the purposes of carbon storage is capillary trapping, where CO2 is stranded as pore-scale droplets (ganglia). Prospective storage sites are aquifers or reservoirs that tend to be at conditions where CO2 will reside as a super-critical phase. In order to fully describe physical mechanisms characterising multi-phase flow during and post CO2 injection, experiments need to be conducted at these elevated aquifer/reservoir conditions - this poses a considerable experimental challenge. A novel experimental apparatus has been developed which uses μCT scanning for the non-invasive imaging of the distribution of CO2 in the pore space of rock with resolutions of 7μm at temperatures and pressures representative of the conditions present in prospective saline aquifer CO2 storage sites. The fluids are kept in chemical equilibrium with one-another and with the rock into which they are injected. This is done to prevent the dissolution of the CO2 in the brine to form carbonic acid, which can then react with the rock, particularly carbonates. By eliminating reaction we study the fundamental mechanisms of capillary trapping for an unchanging pore structure. In this study we present a suite of results from three carbonate and two sandstone rock types, showing that, for both cases the CO2 acts as the non-wetting phase and significant quantities of CO2 is trapped. The carbonate examined represent a wide variety of pore topologies with one rock with a very well connected, high porosity pore space (Mt Gambier), one with a lower porosity, poorly connected pore space (Estaillades) and one with a cemented bead pack type pore space (Ketton). Both sandstones (Doddington and Bentheimer) were high permeability granular quartzites. CO2 was injected into each rock, followed by brine injection. After brine injection the entire length of the rock core was scanned, processed and segmented into

  10. Experimental measurements of the SP response to concentration and temperature gradients in sandstones with application to subsurface geophysical monitoring

    Science.gov (United States)

    Leinov, E.; Jackson, M. D.

    2014-09-01

    Exclusion-diffusion potentials arising from temperature gradients are widely neglected in self-potential (SP) surveys, despite the ubiquitous presence of temperature gradients in subsurface settings such as volcanoes and hot springs, geothermal fields, and oil reservoirs during production via water or steam injection. Likewise, with the exception of borehole SP logging, exclusion-diffusion potentials arising from concentration gradients are also neglected or, at best, it is assumed that the diffusion potential dominates. To better interpret these SP sources requires well-constrained measurements of the various coupling terms. We report measurements of thermoelectric and electrochemical exclusion-diffusion potentials across sandstones saturated with NaCl brine and find that electrode effects can dominate the measured voltage. After correcting for these, we find that Hittorf transport numbers are the same within experimental error regardless of whether ion transport occurs in response to temperature or concentration gradients over the range of NaCl concentration investigated that is typical of natural systems. Diffusion potentials dominate only if the pore throat radius is more than approximately 4000 times larger than the diffuse layer thickness. In fine-grained sandstones with small pore throat diameter, this condition is likely to be met only if the saturating brine is of relatively high salinity; thus, in many cases of interest to earth scientists, exclusion-diffusion potentials will comprise significant contributions from both ionic diffusion through, and ionic exclusion from, the pore space of the rock. However, in coarse-grained sandstones, or sandstones saturated with high-salinity brine, exclusion-diffusion potentials can be described using end-member models in which ionic exclusion is neglected. Exclusion-diffusion potentials in sandstones depend upon pore size and salinity in a complex way: they may be positive, negative, or zero depending upon sandstone

  11. Iron speciation and mineral characterization of upper Jurassic reservoir rocks in the Minhe Basin, NW China

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Xiangxian; Zheng, Guodong, E-mail: gdzhbj@mail.iggcas.ac.cn; Xu, Wang [Chinese Academy of Sciences, Key Laboratory of Petroleum Resources, Gansu Province / Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics (China); Liang, Minliang [Chinese Academy of Geological Sciences, Institute of Geomechanics, Key Lab of Shale Oil and Gas Geological Survey (China); Fan, Qiaohui; Wu, Yingzhong; Ye, Conglin [Chinese Academy of Sciences, Key Laboratory of Petroleum Resources, Gansu Province / Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics (China); Shozugawa, Katsumi; Matsuo, Motoyuki [The University of Tokyo, Graduate School of Arts and Sciences (Japan)

    2016-12-15

    Six samples from a natural outcrop of reservoir rocks with oil seepage and two control samples from surrounding area in the Minhe Basin, northwestern China were selectively collected and analyzed for mineralogical composition as well as iron speciation using X-ray powder diffraction (XRD) and Mössbauer spectroscopy, respectively. Iron species revealed that: (1) the oil-bearing reservoir rocks were changed by water-rock-oil interactions; (2) even in the same site, there was a different performance between sandstone and mudstone during the oil and gas infusion to the reservoirs; and (3) this was evidence indicating the selective channels of hydrocarbon migration. In addition, these studies showed that the iron speciation by Mössbauer spectroscopy could be useful for the study of oil and gas reservoirs, especially the processes of the water-rock interactions within petroleum reservoirs.

  12. Multi-scale nitrate transport in a sandstone aquifer system under intensive agriculture

    Science.gov (United States)

    Paradis, Daniel; Ballard, Jean-Marc; Lefebvre, René; Savard, Martine M.

    2018-03-01

    Nitrate transport in heterogeneous bedrock aquifers is influenced by mechanisms that operate at different spatial and temporal scales. To understand these mechanisms in a fractured sandstone aquifer with high porosity, a groundwater-flow and nitrate transport model—reproducing multiple hydraulic and chemical targets—was developed to explain the actual nitrate contamination observed in groundwater and surface water in a study area on Prince Edward Island, Canada. Simulations show that nitrate is leached to the aquifer year-round, with 61% coming from untransformed and transformed organic sources originating from fertilizers and manure. This nitrate reaches the more permeable shallow aquifer through fractures in weathered sandstone that represent only 1% of the total porosity (17%). Some of the nitrate reaches the underlying aquifer, which is less active in terms of groundwater flow, but most of it is drained to the main river. The river-water quality is controlled by the nitrate input from the shallow aquifer. Groundwater in the underlying aquifer, which has long residence times, is also largely influenced by the diffusion of nitrate in the porous sandstone matrix. Consequently, following a change of fertilizer application practices, water quality in domestic wells and the river would change rapidly due to the level of nitrate found in fractures, but a lag time of up to 20 years would be necessary to reach a steady level due to diffusion. This demonstrates the importance of understanding nitrate transport mechanisms when designing effective agricultural and water management plans to improve water quality.

  13. The role of mineral heterogeneity on the hydrogeochemical response of two fractured reservoir rocks in contact with dissolved CO2

    Science.gov (United States)

    Garcia Rios, Maria; Luquot, Linda; Soler, Josep M.; Cama, Jordi

    2017-04-01

    In this study we compare the hydrogeochemical response of two fractured reservoir rocks (limestone composed of 100 wt.% calcite and sandstone composed of 66 wt.% calcite, 28 wt.% quartz and 6 wt.% microcline) in contact with CO2-rich sulfate solutions. Flow-through percolation experiments were performed using artificially fractured limestone and sandstone cores and injecting a CO2-rich sulfate solution under a constant volumetric flow rate (from 0.2 to 60 mL/h) at P = 150 bar and T = 60 °C. Measurements of the pressure difference between the inlet and the outlet of the samples and of the aqueous chemistry enabled the determination of fracture permeability changes and net reaction rates. Additionally, X-ray computed microtomography (XCMT) was used to characterize and localized changes in fracture volume induced by dissolution and precipitation reactions. In all reacted cores an increase in fracture permeability and in fracture volume was always produced even when gypsum precipitation happened. The presence of inert silicate grains in sandstone samples favored the occurrence of largely distributed dissolution structures in contrast to localized dissolution in limestone samples. This phenomenon promoted greater dissolution and smaller precipitation in sandstone than in limestone experiments. As a result, in sandstone reservoirs, the larger increase in fracture volume as well as the more extended distribution of the created volume would favor the CO2 storage capacity. The different distribution of created volume between limestone and sandstone experiments led to a different variation in fracture permeability. The progressive stepped permeability increase for sandstone would be preferred to the sharp permeability increase for limestone to minimize risks related to CO2 injection, favor capillary trapping and reduce energetic storage costs. 2D reactive transport simulations that reproduce the variation in aqueous chemistry and the fracture geometry (dissolution pattern

  14. 3D Sedimentological and geophysical studies of clastic reservoir analogs: Facies architecture, reservoir properties, and flow behavior within delta front facies elements of the Cretaceous Wall Creek Member, Frontier Formation, Wyoming

    Energy Technology Data Exchange (ETDEWEB)

    Christopher D. White

    2009-12-21

    rock types (\\Eg sandstones and mudstones) and the variation of transport properties (\\Eg permeability and porosity) within bodies of a particular rock type. Both basin-wide processes such as sea-level change and the autocyclicity of deltaic processes commonly cause deltaic reservoirs to have large variability in rock properties; in particular, alternations between mudstones and sandstones may form baffles and trends in rock body permeability can influence productivity and recovery efficiency. In addition, diagenetic processes such as compaction, dissolution, and cementation can alter the spatial pattern of flow properties. A better understanding of these properties, and improved methods to model the properties and their effects, will allow improved reservoir development planning and increased recovery of oil and gas from deltaic reservoirs. Surface exposures of ancient deltaic rocks provide a high resolution, low uncertainty view of subsurface variability. Patterns and insights gleaned from these exposures can be used to model analogous reservoirs, for which data is much sparser. This approach is particularly attractive when reservoir formations are exposed at the surface. The Frontier Formation in central Wyoming provides an opportunity for high resolution characterization. The same rocks exposed in the vicinity of the Tisdale anticline are productive in nearby oil fields, including Salt Creek. Many kilometers of good-quality exposure are accessible, and the common bedding-plane exposures allow use of shallow-penetration, high-resolution electromagnetic methods known as ground-penetrating radar. This study combined geologic interpretations, maps, vertical sections, core data, and ground-penetrating radar to construct high-resolution geostatistical and flow models for the Wall Creek Member of the Frontier Formation. Stratal-conforming grids were use to reproduce the progradational and aggradational geometries observed in outcrop and radar data. A new, Bayesian method

  15. Sandstone-body and shale-body dimensions in a braided fluvial system: Salt wash sandstone member (Morrison formation), Garfield County, Utah

    Science.gov (United States)

    Robinson, J.W.; McCabea, P.J.

    1997-01-01

    Excellent three-dimensional exposures of the Upper Jurassic Salt Wash Sandstone Member of the Morrison Formation in the Henry Mountains area of southern Utah allow measurement of the thickness and width of fluvial sandstone and shale bodies from extensive photomosaics. The Salt Wash Sandstone Member is composed of fluvial channel fill, abandoned channel fill, and overbank/flood-plain strata that were deposited on a broad alluvial plain of low-sinuosity, sandy, braided streams flowing northeast. A hierarchy of sandstone and shale bodies in the Salt Wash Sandstone Member includes, in ascending order, trough cross-bedding, fining-upward units/mudstone intraclast conglomerates, singlestory sandstone bodies/basal conglomerate, abandoned channel fill, multistory sandstone bodies, and overbank/flood-plain heterolithic strata. Trough cross-beds have an average width:thickness ratio (W:T) of 8.5:1 in the lower interval of the Salt Wash Sandstone Member and 10.4:1 in the upper interval. Fining-upward units are 0.5-3.0 m thick and 3-11 m wide. Single-story sandstone bodies in the upper interval are wider and thicker than their counterparts in the lower interval, based on average W:T, linear regression analysis, and cumulative relative frequency graphs. Multistory sandstone bodies are composed of two to eight stories, range up to 30 m thick and over 1500 m wide (W:T > 50:1), and are also larger in the upper interval. Heterolithic units between sandstone bodies include abandoned channel fill (W:T = 33:1) and overbank/flood-plain deposits (W:T = 70:1). Understanding W:T ratios from the component parts of an ancient, sandy, braided stream deposit can be applied in several ways to similar strata in other basins; for example, to (1) determine the width of a unit when only the thickness is known, (2) create correlation guidelines and maximum correlation lengths, (3) aid in interpreting the controls on fluvial architecture, and (4) place additional constraints on input variables to

  16. Advances in nuclear medicine and in radiopharmaceuticals, International meeting in Cabo Frio. Program and abstracts

    International Nuclear Information System (INIS)

    2002-01-01

    The meeting of Advances in Nuclear Medicine and in Radiopharmaceuticals, held in Cabo Frio, Rio de Janeiro State, Brazil, in September 26-28, 2002, has provided an excellent opportunity for the presentation and the discussion of the latest achievements and new trends of nuclear medicine techniques and radiopharmaceuticals for the clinical evaluation of inflammation, infection, oncology and therapy of diseases with radionuclides

  17. The influence of clay minerals on acoustic properties of sandstones

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Olav

    1997-12-31

    This thesis aims to provide better understanding of the relationship between the acoustic properties and the petrophysical/mineralogical properties in sand-prone rock. It emphasizes the influence of clay minerals. The author develops a method to deposit clay minerals/mineral aggregates in pore space of a rigid rock framework. Kaolinite aggregates were flushed into porous permeable Bentheimer sandstone to evaluate the effect of pore filling minerals on porosity, permeability and acoustic properties. The compressional velocity was hardly affected by the clay content and it was found that the effect of minor quantities of pore filling minerals may be acoustically modelled as an ideal suspension, where the pore fluid bulk modulus is modified by the bulk modulus of the clay minerals. The influence of clays on acoustic velocities in petroleum reservoir rocks was investigated through ultrasonic measurements of compressional- and shear-waves on core material from reservoir and non-reservoir units on the Norwegian Continental Shelf. The measured velocities decrease as the porosity increases, but are not strongly dependent on the clay content. The measured velocities are less dependent on the petrophysical and lithological properties than indicated by previous authors and published mathematical models, and stiffness reduction factors are introduced in two of the models to better match the data. Velocities are estimated along the wellbores based on non-sonic well logs and reflect well the actual sonic log well measurements. In some wells the compressional velocity cannot be modelled correctly by the models suggested. Very high compressional wave anisotropy was measured in the dry samples at atmospheric conditions. As the samples were saturated, the anisotropy was reduced to a maximum of about 30% and decreases further upon pressurization. Reservoir rocks retrieved from 2500 m are more stress dependent than those retrieved from less than 200 m depth. 168 refs., 117 figs., 24

  18. Sudden water pollution accidents and reservoir emergency operations: impact analysis at Danjiangkou Reservoir.

    Science.gov (United States)

    Zheng, Hezhen; Lei, Xiaohui; Shang, Yizi; Duan, Yang; Kong, Lingzhong; Jiang, Yunzhong; Wang, Hao

    2018-03-01

    Danjiangkou Reservoir is the source reservoir of the Middle Route of the South-to-North Water Diversion Project (MRP). Any sudden water pollution accident in the reservoir would threaten the water supply of the MRP. We established a 3-D hydrodynamic and water quality model for the Danjiangkou Reservoir, and proposed scientific suggestions on the prevention and emergency management for sudden water pollution accidents based on simulated results. Simulations were performed on 20 hypothetical pollutant discharge locations and 3 assumed amounts, in order to model the effect of pollutant spreading under different reservoir operation types. The results showed that both the location and mass of pollution affected water quality; however, different reservoir operation types had little effect. Five joint regulation scenarios, which altered the hydrodynamic processes of water conveyance for the Danjiangkou and Taocha dams, were considered for controlling pollution dispersion. The results showed that the spread of a pollutant could be effectively controlled through the joint regulation of the two dams and that the collaborative operation of the Danjiangkou and Taocha dams is critical for ensuring the security of water quality along the MRP.

  19. Optimising inflow performance of a long multi-lateral offshore well in low permeability, gas-bearing sandstone: K14-FB 102 case study

    Energy Technology Data Exchange (ETDEWEB)

    Hands, N. [Shell Canada Ltd., Calgary, AB (Canada); Francis, P. [Shell International Exploration and Production (Netherlands); Whittle, A.; Rajasingam, D. [NAM B. V. (Netherlands)

    1998-12-31

    Successful completion of the sub-horizontal dual-lateral well, K14-FB 102, to optimize production capacity and reservoir drainage in an offshore gas play in the Dutch sector of the North Sea is described. The two 5-7/8 inch horizontal production intervals were drilled and completed using a rheologically engineered, minimal solids, non-damaging sodium formate brine- based fluid designed as a drill-in fluid for reservoir intervals. The completion was made possible by the selection of the appropriate reservoir drill-in and completion fluid, appropriate level of contingency planning and a fully integrated team approach and custom-made well solution. Inflow performance has matched the performance of cemented and high-performance wells at a much lower cost. It was found that openhole reservoir completion techniques offer relatively inexpensive `fit-for-purpose` well solutions for low permeability sandstone in this region of the North Sea.3 refs., 6 tabs., 7 figs.

  20. Interdisciplinary study of reservoir compartments and heterogeneity. Final report, October 1, 1993--December 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Van Kirk, C.

    1998-01-01

    A case study approach using Terry Sandstone production from the Hambert-Aristocrat Field, Weld County, Colorado was used to document the process of integration. One specific project goal is to demonstrate how a multidisciplinary approach can be used to detect reservoir compartmentalization and improve reserve estimates. The final project goal is to derive a general strategy for integration for independent operators. Teamwork is the norm for the petroleum industry where teams of geologists, geophysicists, and petroleum engineers work together to improve profits through a better understanding of reservoir size, compartmentalization, and orientation as well as reservoir flow characteristics. In this manner, integration of data narrows the uncertainty in reserve estimates and enhances reservoir management decisions. The process of integration has proven to be iterative. Integration has helped identify reservoir compartmentalization and reduce the uncertainty in the reserve estimates. This research report documents specific examples of integration and the economic benefits of integration.

  1. The Paleozoic-Mesozoic recycling of the Rakaia Terrane, South Island, New Zealand : sandstone clast and sandstone petrology, geochemistry, and geochronology

    International Nuclear Information System (INIS)

    Wandres, A.M.; Bradshaw, J.D.; Ireland, T.

    2005-01-01

    The Torlesse terranes - part of the New Zealand Eastern Province - are accretionary complexes that comprise an enormous volume of quartzofeldspathic sandstones and mudstones with subsidiary conglomerates plus minor oceanic assemblages. Two terranes are recognised in the South Island - the Permian to Late Triassic Rakaia Terrane and the Late Jurassic to Early Cretaceous Pahau Terrane. Sandstone clasts from two Rakaia Terrane and two Pahau Terrane conglomerates were collected. We present the first combined detailed information on petrography and geochemistry of Torlesse conglomerate sandstone clasts and use our own and published U-Pb SHRIMP detrital zircon age data to demonstrate the recycling of the Rakaia Terrane into Rakaia strata itself and into Pahau Terrane strata. Sandstone clast major and trace element chemical data largely support petrographic observations derived from thin-section analysis. The similarities of petrographic and geochemical data between sandstone clasts from the Rakaia Terrane and Rakaia sandstones suggest that clasts in the Permian Te Moana and Late Triassic Lake Hill Conglomerates were derived by autocannibalistic reworking of older, consolidated, Rakaia sediments. Data from sandstone clasts from the Pahau Terrane suggest that uplift of the Rakaia Terrane continued into the Cretaceous. These Pahau Terrane clasts indicate that at the time of the Pahau sedimentation Permian to early Late Triassic Rakaia rocks were exposed and recycled into the Pahau Basin. (author). 57 refs., 8 figs., 3 tables

  2. Pore Structure and Limit Pressure of Gas Slippage Effect in Tight Sandstone

    Science.gov (United States)

    You, Lijun; Xue, Kunlin; Kang, Yili; Liao, Yi

    2013-01-01

    Gas slip effect is an important mechanism that the gas flow is different from liquid flow in porous media. It is generally considered that the lower the permeability in porous media is, the more severe slip effect of gas flow will be. We design and then carry out experiments with the increase of backpressure at the outlet of the core samples based on the definition of gas slip effect and in view of different levels of permeability of tight sandstone reservoir. This study inspects a limit pressure of the gas slip effect in tight sandstones and analyzes the characteristic parameter of capillary pressure curves. The experimental results indicate that gas slip effect can be eliminated when the backpressure reaches a limit pressure. When the backpressure exceeds the limit pressure, the measured gas permeability is a relatively stable value whose range is less than 3% for a given core sample. It is also found that the limit pressure increases with the decreasing in permeability and has close relation with pore structure of the core samples. The results have an important influence on correlation study on gas flow in porous medium, and are beneficial to reduce the workload of laboratory experiment. PMID:24379747

  3. The Tiehchanshan structure of NW Taiwan: A potential geological reservoir for CO2 sequestration

    Directory of Open Access Journals (Sweden)

    Kenn-Ming Yang

    2017-01-01

    Full Text Available The Tiehchanshan structure is the largest gas-field in the outer foothills of northwestern Taiwan and has been regarded as the best site for CO2 sequestration. This study used a grid of seismic sections and wellbore data to establish a new 3-D geometry of subsurface structure, which was combined with lithofacies characters of the target reservoir rock, the Yutengping Sandstone, to build a geological model for CO2 sequestration. On the surface, the Tiehchanshan structure is characterized by two segmented anticlines offset by a tear fault. The subsurface geometry of the Tiehchanshan structure is, however, composed of two thrust-related anticlines with opposite vergence and laterally increasing fold symmetry toward each other. The folds are softly linked via the transfer zone in the subsurface, implying that the suspected tear fault in the surface transfer zone may not exist in the subsurface. The Yutengping Sandstone is composed of several sandstone units characterized by coarsening-upward cycles. The sandstone member can be further divided into four well-defined sandstone layers, separated by laterally continuous shale layers. In view of the structural and stratigraphic characteristics, the optimum area for CO2 injection and storage is in the structurally high in the northern part of the Tiehchanshan structure. The integrity of the closure and the overlying seal are not disrupted by the pre-orogenic high-angle faults. On the other hand, a thick continuous shale layer within the Yutengping Sandstone isolates the topmost sandy layer from the underlying ones and gives another important factor to the CO2 injection simulation.

  4. Seasonal Changes and Spatial Variation in Water Quality of a Large Young Tropical Reservoir and Its Downstream River

    Directory of Open Access Journals (Sweden)

    Teck-Yee Ling

    2017-01-01

    Full Text Available This study examined the water quality of the large young tropical Bakun hydroelectric reservoir in Sarawak, Malaysia, and the influence of the outflow on the downstream river during wet and dry seasons. Water quality was determined at five stations in the reservoir at three different depths and one downstream station. The results show that seasons impacted the water quality of the Bakun Reservoir, particularly in the deeper water column. Significantly lower turbidity, SRP, and TP were found during the wet season. At 3–6 m, the oxygen content fell below 5 mg/L and hypoxia was also recorded. Low NO2--N, NO3--N, and SRP and high BOD5, OKN, and TP were observed in the reservoir indicating organic pollution. Active logging activities and the dam construction upstream resulted in water quality deterioration. The outflow decreased the temperature, DO, and pH and increased the turbidity and TSS downstream. Elevated organic matter and nutrients downstream are attributable to domestic discharge along the river. This study shows that the downstream river was affected by the discharge through the turbines, the spillway operations, and domestic waste. Therefore, all these factors should be taken into consideration in the downstream river management for the health of the aquatic organisms.

  5. Experimental studies of low salinity water flooding in carbonate reservoirs: A new promising approach

    DEFF Research Database (Denmark)

    Zahid, Adeel; Shapiro, Alexander; Skauge, Arne

    2012-01-01

    Low salinity water flooding is well studied for sandstone reservoirs, both laboratory and field tests have showed improvement in the oil recovery in many cases. Up to very recently, the low salinity effect has been indeterminated for carbonates. Most recently, Saudi Aramco reported that substantial...... additional oil recovery can be achieved when successively flooding composite carbonate core plugs with various diluted versions of seawater. The experimental data on carbonates is very limited, so more data and better understanding of the mechanisms involved is needed to utilize this method for carbonate...... reservoirs. In this paper, we have experimentally investigated the oil recovery potential of low salinity water flooding for carbonate rocks. We used both reservoir carbonate and outcrop chalk core plugs. The flooding experiments were carried out initially with the seawater, and afterwards additional oil...

  6. The quality of surface waters of the dam reservoir Mexa, Northeast of Algeria

    Directory of Open Access Journals (Sweden)

    Bahroun Sofia

    2017-09-01

    Full Text Available In this work, we have conducted a physicochemical study that assesses the impact of agricultural activities and urban domestic wastewater on the surface water quality of the dam reservoir Mexa in the area of El-Taref, which is located in the eastern coastal basin of Constantine. 36 samplings have been conducted for three years (2010, 2011 and 2012, at the rate of one sampling per month on the dam reservoir water; 36 samples have been analysed. The samples taken have been subjected to an in situ measurement of physicochemical parameters (temperature, hydrogen potential, electric conductivity and dissolved oxygen and laboratory analysis (anions, cations, biological oxygen demand, chemical oxygen demand, organic matter, phosphate, nitrate, nitrite and ammonium. Concentrations of various organic and inorganic pollutants varied from one month to another and from one year to another. From a temporal point of view, the contamination of water of the dam reservoir Mexa varies according to climatic conditions, being generally low during the winter period and high during the low-flow periods. The results obtained reveal that water of the dam reservoir Mexa is fairly contaminated. It is certain that the dam reservoir is subject to pollution of agricultural and urban origin.

  7. An Integrated Rock Typing Approach for Unraveling the Reservoir Heterogeneity of Tight Sands in the Whicher Range Field of Perth Basin, Western Australia

    DEFF Research Database (Denmark)

    Ilkhchi, Rahim Kadkhodaie; Rezaee, Reza; Harami, Reza Moussavi

    2014-01-01

    Tight gas sands in Whicher Range Field of Perth Basin show large heterogeneity in reservoir characteristics and production behavior related to depositional and diagenetic features. Diagenetic events (compaction and cementation) have severely affected the pore system. In order to investigate...... the petrophysical characteristics, reservoir sandstone facies were correlated with core porosity and permeability and their equivalent well log responses to describe hydraulic flow units and electrofacies, respectively. Thus, very tight, tight, and sub-tight sands were differentiated. To reveal the relationship...... between pore system properties and depositional and diagenetic characteristics in each sand type, reservoir rock types were extracted. The identified reservoir rock types are in fact a reflection of internal reservoir heterogeneity related to pore system properties. All reservoir rock types...

  8. Sandstone Turning by Abrasive Waterjet

    Czech Academy of Sciences Publication Activity Database

    Hlaváček, Petr; Cárach, J.; Hloch, Sergej; Vasilko, K.; Klichová, Dagmar; Klich, Jiří; Lehocká, D.

    2015-01-01

    Roč. 48, č. 6 (2015), s. 2489-2493 ISSN 0723-2632 R&D Projects: GA MŠk ED2.1.00/03.0082; GA MŠk(CZ) LO1406 Institutional support: RVO:68145535 Keywords : turning away from the jet * conventional turning towards the jet * sandstone * abrasive water jet Subject RIV: JQ - Machines ; Tools Impact factor: 2.386, year: 2015 http://www.springerprofessional.de/sandstone-turning-by-abrasive-waterjet/6038028.html

  9. Geological characteristic of the main oil and gas producing formations of the upper Austrian molasse basin. Pt. 1. The Eocene sandstones

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, L [Rohoel-Aufsuchungs-Gesellschaft m.b.H., Vienna (Austria)

    1980-09-01

    The sandstones of the Upper Eocene are the main oil carriers within RAG's Upper Austrian concession area. The attempt is being made to reconstruct the paleogeography of the Eocene-in which time the sea transgressed the Molasse basin towards N and E - from core and log evidence. From deep Lower Tertiary onwards the mesozoic and older sediments were exposed to intensive erosion, which resulted in a slightly undulating peneplane sloping in a S to SW direction. This erosion plane was - still in Lower Tertiary times - in some areas dissected into horst and graben structures which greatly influenced the deposition of the early Eocene sediments. During the Upper Eocene the Molasse basin began to subside and subsided more strongly in the SW than in the N and NE, so that neritic deposits could form in the first area, whereas lagoonal and brackish sedimentation still prevailed in the latter. The Eocene sandstones are being classified according to their environment of deposition, and their reservoir, characteristics are being studied. Sandstones are absent in the neritic environment of the Discocyclina-marls only. Sand deposits have been encountered as: 1) transgressive horizons directly overlying the pretertiary substrate, 2) infills of channels cut into limnic-brackish sediments, 3) littoral deposits, partly interfingering with Lithothamnium limestone, 4) fine grained sandy marls and nummulitic sandstones within sublittoral to neritic sediments.

  10. Constitutive Modelling and Deformation Band Angle Predictions for High Porosity Sandstones

    Science.gov (United States)

    Richards, M. C.; Issen, K. A.; Ingraham, M. D.

    2017-12-01

    The development of a field-scale deformation model requires a constitutive framework that is capable of representing known material behavior and able to be calibrated using available mechanical response data. This work employs the principle of hyperplasticity (e.g., Houlsby and Puzrin, 2006) to develop such a constitutive framework for high porosity sandstone. Adapting the works of Zimmerman et al. (1986) and Collins and Houlsby (1997), the mechanical data set of Ingraham et al. (2013 a, b) was used to develop a specific constitutive framework for Castlegate sandstone, a high porosity fluvial-deposited reservoir analog rock. Using the mechanical data set of Ingraham et al. (2013 a, b), explicit expressions and material parameters of the elastic moduli and strain tensors were obtained. With these expressions, analytical and numerical techniques were then employed to partition the total mechanical strain into elastic, coupled, and plastic strain components. With the partitioned strain data, yield surfaces in true-stress space, coefficients of internal friction, dilatancy factors, along with the theorectical predictions of the deformation band angles were obtained. These results were also evaluated against band angle values obtained from a) measurements on specimen jackets (Ingraham et al., 2013a), b) plane fits through located acoustic emissions (AE) events (Ingraham et al. 2013b), and c) X-ray micro-computed tomography (micro-CT) calculations.

  11. Assessment of the water quality in a large reservoir in semiarid region of Brazil

    Directory of Open Access Journals (Sweden)

    Fernando B. Lopes

    2014-04-01

    Full Text Available The aim of this study was to identify spatial and temporal variations in water quality of Orós reservoir, Ceará, Brazil, as well as the sources of contamination. To get this information the Principal Component Analysis (PCA and Cluster Analysis (CA was used. Water samples were collected at seven (geo-referenced points, from April 2008 to March 2011, totalling 4,032 samples. The following attributes of the waters were analysed: temperature, pH, CE, Ca2+, Mg2+, Na+, K+, Cl-, HCO3-, SO4--, turbidity, colour, Sechi transparency, TS, TVS, TFS, TSS, VSS, FSS, TDS, DO, BO5D, total phosphorus, soluble orthophosphate, EC, TTC, total ammonia, TKN, nitrate, SAR and chlorophyll-a. The PCA promoted the reduction from the 32 initial variables to 14, accounting for 84.39% of the total variance. The major factors responsible for water quality composition are: the natural weathering of geological soil components; the entrainment of suspended solids through surface runoff from agricultural areas; and anthropogenic action in the Upper Jaguaribe basin in Ceará. The similarity of the water of the Orós reservoir allows a reduction in the number of sampling points, which may result in significant cost savings without sacrificing the water quality monitoring. The similarity of the waters was influenced by anthropic activities being carried out near the reservoir and all along the watershed.

  12. Predicting permeability of low enthalpy geothermal reservoirs: A case study from the Upper Triassic − Lower Jurassic Gassum Formation, Norwegian–Danish Basin

    DEFF Research Database (Denmark)

    Weibel, Rikke; Olivarius, Mette; Kristensen, Lars

    2017-01-01

    This paper aims at improving the predictability of permeability in low enthalpy geothermal reser-voirs by investigating the effect of diagenesis on sandstone permeability. Applying the best fittedporosity–permeability trend lines, obtained from conventional core analysis, to log-interpreted poros...

  13. Water Quality and Trophic Status Study in Sembrong Reservoir during Monsoon Season

    Science.gov (United States)

    Hashim, S. I. N. S.; Talib, S. H. A.; Abustan, M. S.; Tajuddin, S. A. M.

    2018-04-01

    Sembrong is one of the reservoirs in Johor that supplies raw water to consumer for daily activities usage. Cleanliness and quality of water must be maintained to ensure that contamination is not applicable. This study is to determine the effects of sedimentation on water quality due to the deposition of sediment in the reservoir and to identify the rate of ammonia based on the location of the study area. There are several parameters required to obtain the data and reading for this study namely the temperature, dissolved oxygen, pH value, ammonia nitrogen and trophic status parameter that are consisting of Chlorophyll, total phosphorus and secchi depth. Seventeen (17) locations along Sembrong reservoir had been identified for sampling activities. From the result obtained, the reading of temperature and pH value has less significant differences between the locations involved. However, for dissolved oxygen, the highest readings were taken at location 6 and 7 which are 9.12 mg/L and 9.05 mg/L respectively compared to other location with the average reading of 8 mg/L. For ammonia nitrogen, the highest reading was at location 1 which is 2.24 mg/L, while the lowest reading at location 13 and 14 with 0.29 mg/L. Chlorophyll readings showed the highest reading of 92.33 μg/L at location 2 which is near to the inlet area while the lowest reading were taken at location 14 with 55.97 μg/L. For total phosphorus, location 1 has the highest reading of 19.50 μg/L compared to location 15 with 9.15 μg/L. The overall result indicates that the reading is high near the inlet and decreasing at the next location. So roughly, the river that connects to the Sembrong reservoir was carrying contaminants.

  14. Regional distribution regularity of sandstone uranium deposits in Asian continent and prospecting strategy for sandstone uranium deposits in China

    International Nuclear Information System (INIS)

    Chen Zuyi

    2002-01-01

    Since the 1980's, after the discovery of numerous sandstone uranium deposits in Middle Asia (Kazakhstan, Uzbekistan) many large sandstone uranium deposits have been found in both Russia and Mongolia. So that Asia has become the most concentrated region of sandstone uranium deposits. The known sandstone uranium deposits occur mostly in a arcual tectonic belt constrained from the north by the Siberian continental block, and the Tarim-North China continental block from the south. This belt is named by Russian geologists as the Central Asian Mobile Belt, and some Chinese geologists call it the 'Mongolian Arc'. A lot of large and super large metallic, non-metallic, gold, polymetallic, porphyry copper and gold, massive sulphide and uranium deposits (of sandstone and volcanic types) with different origin and various types concentrated occur in this belt. The abundant and colourful mineral resources in the region are closely associated with the specific geologic-tectonic evolution of the above belt. It is necessary to strengthen the detailed geologic research and uranium prospecting in the region

  15. Dynamic fluid connectivity during steady-state multiphase flow in a sandstone.

    Science.gov (United States)

    Reynolds, Catriona A; Menke, Hannah; Andrew, Matthew; Blunt, Martin J; Krevor, Samuel

    2017-08-01

    The current conceptual picture of steady-state multiphase Darcy flow in porous media is that the fluid phases organize into separate flow pathways with stable interfaces. Here we demonstrate a previously unobserved type of steady-state flow behavior, which we term "dynamic connectivity," using fast pore-scale X-ray imaging. We image the flow of N 2 and brine through a permeable sandstone at subsurface reservoir conditions, and low capillary numbers, and at constant fluid saturation. At any instant, the network of pores filled with the nonwetting phase is not necessarily connected. Flow occurs along pathways that periodically reconnect, like cars controlled by traffic lights. This behavior is consistent with an energy balance, where some of the energy of the injected fluids is sporadically converted to create new interfaces.

  16. Discussion on the origin of bleached sandstone of Qianjiadian uranium deposit

    International Nuclear Information System (INIS)

    Pang Yaqing; Xiang Weidong; Li Tiangang; Chen Xiaolin; Xia Yuliang

    2007-01-01

    Qianjiadian uranium deposit is a sandstone-type uranium deposit that has been discovered in Songliao Basin in recent years. Uranium ore bodies are planar or lenticular in shape and under the control of the contact between gray sandstones and bleached sandstones. The bleached sandstone is white in color, cemented loosely, nearly without TOC and pyrite contained and rich in uranium. Geochemical characteristics and types and assemblages of clay minerals of the bleached sandstone reveal that the bleached sandstone is the product of oxidation of the interlayer oxidation zone, and it is a part of the interlayer oxidation zone. The main reasons for white color of the bleached sandstone are transfer of iron ion, oxidation of TOC and kaolinization of sandstone. (authors)

  17. Chickamauga reservoir embayment study - 1990

    Energy Technology Data Exchange (ETDEWEB)

    Meinert, D.L.; Butkus, S.R.; McDonough, T.A.

    1992-12-01

    The objectives of this report are three-fold: (1) assess physical, chemical, and biological conditions in the major embayments of Chickamauga Reservoir; (2) compare water quality and biological conditions of embayments with main river locations; and (3) identify any water quality concerns in the study embayments that may warrant further investigation and/or management actions. Embayments are important areas of reservoirs to be considered when assessments are made to support water quality management plans. In general, embayments, because of their smaller size (water surface areas usually less than 1000 acres), shallower morphometry (average depth usually less than 10 feet), and longer detention times (frequently a month or more), exhibit more extreme responses to pollutant loadings and changes in land use than the main river region of the reservoir. Consequently, embayments are often at greater risk of water quality impairments (e.g. nutrient enrichment, filling and siltation, excessive growths of aquatic plants, algal blooms, low dissolved oxygen concentrations, bacteriological contamination, etc.). Much of the secondary beneficial use of reservoirs occurs in embayments (viz. marinas, recreation areas, parks and beaches, residential development, etc.). Typically embayments comprise less than 20 percent of the surface area of a reservoir, but they often receive 50 percent or more of the water-oriented recreational use of the reservoir. This intensive recreational use creates a potential for adverse use impacts if poor water quality and aquatic conditions exist in an embayment.

  18. Reservoir petrophysics and hydrocarbon occurrences of the Bahariya Formation, Alamein-Yidma fields, Western Desert of Egypt

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-Aziz Younes, Mohamed [Alexandria Univ. (Egypt). Geology Dept.

    2012-12-15

    The Bahariya Formation of Cenomanian age is considered to be one of the main oil and gas accumulations in most of the fields of the Western Desert basins. The lithostratigraphic succession of the Bahariya Formation is classified into two main sand units (Unit I and Unit III) separated by shalesiltstone (Unit II). The sandstone of unit-I and III is characterized by being highly enriched in shale content especially glauconite in all wells of the Alamein Field, that has an obvious negative effect on the porosity and oil saturation, where the glauconite increases the grain density of sandstone reservoirs from 2.65 g/cm{sup 3} up to 2.71 g/cm{sup 3}. The well logging data and petrophysical characteristics conducted on Alamein well-28 involving analysis of 30 core samples, were used to evaluate the reservoir characterization and hydrocarbon potentialities. The petrophysical parameters indicate that the primary porosity values are between 8.7 and 29.1%. Decreasing porosity is related to the increase of shale content from 9 to 13%, which occurs as a dispersed habitat. The water saturation changes from 43 to 80%, while the hydrocarbon saturation ranges from 12.1 to 37%. Promising hydrocarbon accumulations are displayed by the sandstone of unit-III due to increased hydrocarbon saturation and effective porosity, thus reflecting the high quality reservoir of this unit. The irreducible and movable hydrocarbon distribution shows a general increase at the eastern and western flanks of the faulted anticline in the Alamein-Yidma fields. The biomarker characteristics and stable carbonisotopic composition of the Bahariya crude oils recovered from the Alamein Field show no obvious variations among them. These oils are paraffinic, containing little branched or cyclic materials waxy n-alkanes(C{sub 25}-C{sub 31}) and characterized by high API gravity, low sulfur content, oleanane index < 2% and moderately high pristane/phytaneratio > 1 and CPI > 1 and the canonical variable parameter is

  19. Comparison of the diagenetic and reservoir quality evolution between the anticline crest and flank of an Upper Jurassic carbonate gas reservoir, Abu Dhabi, United Arab Emirates

    Science.gov (United States)

    Morad, Daniel; Nader, Fadi H.; Gasparrini, Marta; Morad, Sadoon; Rossi, Carlos; Marchionda, Elisabetta; Al Darmaki, Fatima; Martines, Marco; Hellevang, Helge

    2018-05-01

    This petrographic, stable isotopic and fluid inclusion microthermometric study of the Upper Jurassic limestones of an onshore field, Abu Dhabi, United Arab Emirates (UAE) compares diagenesis in flanks and crest of the anticline. The results revealed that the diagenetic and related reservoir quality evolution occurred during three phases, including: (i) eogenesis to mesogenesis 1, during which reservoir quality across the field was either deteriorated or preserved by calcite cementation presumably derived from marine or evolved marine pore waters. Improvement of reservoir quality was due to the formation of micropores by micritization of allochems and creation of moldic/intragranular pores by dissolution of peloids and skeletal fragments. (ii) Obduction of Oman ophiolites and formation of the anticline of the studied field was accompanied by cementation by saddle dolomite and blocky calcite. High homogenization temperatures (125-175 °C) and high salinity (19-26 wt% NaCl eq) of the fluid inclusions, negative δ18OVPDB values (-7.7 to -2.9‰), saddle shape of dolomite, and the presence of exotic cements (i.e. fluorite and sphalerite) suggest that these carbonates were formed by flux of hot basinal brines, probably related to this tectonic compression event. (iii) Mesogenesis 2 during subsidence subsequent to the obduction event, which resulted in extensive stylolitization and cementation by calcite. This calcite cement occluded most of the remaining moldic and inter-/intragranular pores of the flank limestones (water zone) whereas porosity was preserved in the crest. This study contributes to: (1) our understanding of differences in the impact of diagenesis on reservoir quality evolution in flanks and crests of anticlines, i.e. impact of hydrocarbon emplacement on diagenesis, and (2) relating various diagenetic processes to burial history and tectonic events of foreland basins in the Arabian Gulf area and elsewhere.

  20. Efeito do armazenamento a frio e desidratação sobre o enraizamento de estacas herbáceas de Dendranthema grandiflora

    Directory of Open Access Journals (Sweden)

    Natalia Teixeira Schwab

    2013-02-01

    Full Text Available O experimento foi desenvolvido no setor de floricultura do Departamento de Fitotecnia da Universidade Federal de Santa Maria – Santa Maria, RS, no período de novembro a dezembro de 2007 e teve como objetivo avaliar o efeito do armazenamento a frio e da desidratação sobre o enraizamento de estacas herbáceas de Dendranthema grandiflora, cultivares ‘Satllion’ e ‘Toon Hermans’, tratadas com Ácido Indol Butírico (AIB 0,1%. As estacas herbáceas foram coletadas no matrizeiro localizado no Setor de Floricultura, apresentando 6 cm de comprimento final, e foram então armazenadas a frio por diferentes períodos de tempo (0; 7; 14 e 21 dias, sendo que cada tratamento constou de 20 repetições. As estacas depois de tratadas com AIB 0,1% foram pesadas antes e após o armazenamento para obter o percentual de perda de umidade e, logo após, foram plantadas em bandejas de enraizamento contendo casca de arroz carbonizada e colocadas em estufa onde permaneceram 15 dias até sua avaliação. Para a avaliação do efeito da estocagem a frio e desidratação, foram realizadas as seguintes medições: comprimento total das raízes nas estacas e número de raízes por estaca. Os resultados obtidos neste trabalho mostraram que certo nível de frio é favorável ao enraizamento, porém este efeito deve ser observado quanto a cultivar e ao tempo de exposição das estacas às baixas temperaturas. Além disso, foi possível observar que a capacidade de formação e crescimento das raízes pelas estacas é um caráter varietal, o que determina um melhor desempenho das plantas.

  1. Core Flooding Experiments and Reactive Transport Modeling of Seasonal Heat Storage in the Hot Deep Gassum Sandstone Formation

    DEFF Research Database (Denmark)

    Holmslykke, Hanne D.; Kjøller, Claus; Fabricius, Ida Lykke

    2017-01-01

    Seasonal storage of excess heat in hot deep aquifers is considered to optimize the usage of commonly available energy sources. The chemical effects of heating the Gassum Sandstone Formation to up to 150 degrees C is investigated by combining laboratory core flooding experiments with petrographic ...... minor effects on the properties of the reservoir and that storage of excess heat in the Gassum Formation in the Stenlille area may be possible provided operational precautions are taken....... analysis and geochemical modeling. Synthetic formation water is injected into two sets of Gassum Formation samples at 25, 50 (reservoir temperature), 100, and 150 degrees C with a velocity of 0.05 and 0.1 PV/h, respectively. Results show a significant increase in the aqueous concentration of silicium...... and iron with increasing temperature due to dissolution of silica and siderite. Increasing the reservoir temperature from 50 to 100 degrees C enhanced the naturally occurring weathering of Na-rich feldspar to kaolinite. Dissolution of quartz increased sharply above 100 degrees C and was the dominating...

  2. Deformation bands in porous sandstone: case study in basins of northeast Brazil; Bandas de deformacao em arenitos porosos: estudo de casos em bacias do nordeste do Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Talles Souza [PETROBRAS, RN (Brazil). Interpretacao e Avaliacao de bacias da Costa Leste do Brasil E and P. Gerencia de Interpretacao], e-mail: tallesferreira@petrobras.com.br; Silva, Fernando Cesar Alves da [Universidade Federal do Rio Grande do Norte (UFRN). Dept. de Geologia Programa de Pos-Graduacao em Geodinamica e Geofisica (Brazil)], e-mail: fernando@geologia.ufrn.br

    2010-05-15

    The meso and microscopic scale sandstone characterizations of the deformation bands of three sedimentary basins in northeastern Brazil; the Potiguar and Sergipe-Alagoas basins (Brazilian Atlantic Margin) and the Tucano Basin (aborted rift basin) were compared for their similarities and differences. Deformation bands are structures commonly developed in porous sandstones that make up the main reservoir-rock in siliciclastic petroleum systems. These structures influence the permo-porous properties and consequently the migration pathway into a sandstone reservoir. To understand their formation process and development has been the focus of a great number of articles in recent petroleum geology literature. This study highlights the similarities and the differences in the features and deformation mechanisms that provoked the development of deformation bands in the damage zones of major faults in three different sedimentary basins. In terms of basin tectonics, the deformation bands' formation and geometric arrangements are associated with major structures. In the case of the Acu Formation, a correlation was observed with the dextral Afonso Bezerra fault system, whereas in the Sergipe-Alagoas Basin the normal dextral strike-slip faults can be associated with the faulting of the boarder basin. In the Tucano Basin case, the deformation basins are related to the Jeremoabo transpressional fault, a major structure a few kilometers to the north. This study applies structural geology tools to better understand the geometric arrangement and growing mechanisms of deformation bands in different lithological and tectonic settings. Although the deformation bands present a similar aspect in a macroscopic view, the interplay between depositional and mineralogical parameters of the host rock, as well as the basin's burial and tectonic history resulted in the development of different sandstone deformation bands in three northeastern brazilian basins. (author)

  3. Core Flooding Experiments and Reactive Transport Modeling of Seasonal Heat Storage in the Hot Deep Gassum Sandstone Formation

    DEFF Research Database (Denmark)

    Holmslykke, Hanne D.; Kjøller, Claus; Fabricius, Ida Lykke

    2017-01-01

    Seasonal storage of excess heat in hot deep aquifers is considered to optimize the usage of commonly available energy sources. The chemical effects of heating the Gassum Sandstone Formation to up to 150 degrees C is investigated by combining laboratory core flooding experiments with petrographic...... analysis and geochemical modeling. Synthetic formation water is injected into two sets of Gassum Formation samples at 25, 50 (reservoir temperature), 100, and 150 degrees C with a velocity of 0.05 and 0.1 PV/h, respectively. Results show a significant increase in the aqueous concentration of silicium...

  4. Effects of bubbling operations on a thermally stratified reservoir: implications for water quality amelioration.

    Science.gov (United States)

    Fernandez, R L; Bonansea, M; Cosavella, A; Monarde, F; Ferreyra, M; Bresciano, J

    2012-01-01

    Artificial thermal mixing of the water column is a common method of addressing water quality problems with the most popular method of destratification being the bubble curtain. The air or oxygen distribution along submerged multiport diffusers is based on similar basic principles as those of outfall disposal systems. Moreover, the disposal of sequestered greenhouse gases into the ocean, as recently proposed by several researchers to mitigate the global warming problem, requires analogous design criteria. In this paper, the influence of a bubble-plume is evaluated using full-scale temperature and water quality data collected in San Roque Reservoir, Argentina. A composite system consisting of seven separated diffusers connected to four 500 kPa compressors was installed at this reservoir by the end of 2008. The original purpose of this air bubble system was to reduce the stratification, so that the water body may completely mix under natural phenomena and remain well oxygenated throughout the year. By using a combination of the field measurements and modelling, this work demonstrates that thermal mixing by means of compressed air may improve water quality; however, if improperly sized or operated, such mixing can also cause deterioration. Any disruption in aeration during the destratification process, for example, may result in a reduction of oxygen levels due to the higher hypolimnetic temperatures. Further, the use of artificial destratification appears to have insignificant influence on reducing evaporation rates in relatively shallow impoundments such as San Roque reservoir.

  5. Proactive modeling of water quality impacts of extreme precipitation events in a drinking water reservoir.

    Science.gov (United States)

    Jeznach, Lillian C; Hagemann, Mark; Park, Mi-Hyun; Tobiason, John E

    2017-10-01

    Extreme precipitation events are of concern to managers of drinking water sources because these occurrences can affect both water supply quantity and quality. However, little is known about how these low probability events impact organic matter and nutrient loads to surface water sources and how these loads may impact raw water quality. This study describes a method for evaluating the sensitivity of a water body of interest from watershed input simulations under extreme precipitation events. An example application of the method is illustrated using the Wachusett Reservoir, an oligo-mesotrophic surface water reservoir in central Massachusetts and a major drinking water supply to metropolitan Boston. Extreme precipitation event simulations during the spring and summer resulted in total organic carbon, UV-254 (a surrogate measurement for reactive organic matter), and total algae concentrations at the drinking water intake that exceeded recorded maximums. Nutrient concentrations after storm events were less likely to exceed recorded historical maximums. For this particular reservoir, increasing inter-reservoir transfers of water with lower organic matter content after a large precipitation event has been shown in practice and in model simulations to decrease organic matter levels at the drinking water intake, therefore decreasing treatment associated oxidant demand, energy for UV disinfection, and the potential for formation of disinfection byproducts. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Real-time detection of dielectric anisotropy or isotropy in unconventional oil-gas reservoir rocks supported by the oblique-incidence reflectivity difference technique.

    Science.gov (United States)

    Zhan, Honglei; Wang, Jin; Zhao, Kun; Lű, Huibin; Jin, Kuijuan; He, Liping; Yang, Guozhen; Xiao, Lizhi

    2016-12-15

    Current geological extraction theory and techniques are very limited to adequately characterize the unconventional oil-gas reservoirs because of the considerable complexity of the geological structures. Optical measurement has the advantages of non-interference with the earth magnetic fields, and is often useful in detecting various physical properties. One key parameter that can be detected using optical methods is the dielectric permittivity, which reflects the mineral and organic properties. Here we reported an oblique-incidence reflectivity difference (OIRD) technique that is sensitive to the dielectric and surface properties and can be applied to characterization of reservoir rocks, such as shale and sandstone core samples extracted from subsurface. The layered distribution of the dielectric properties in shales and the uniform distribution in sandstones are clearly identified using the OIRD signals. In shales, the micro-cracks and particle orientation result in directional changes of the dielectric and surface properties, and thus, the isotropy and anisotropy of the rock can be characterized by OIRD. As the dielectric and surface properties are closely related to the hydrocarbon-bearing features in oil-gas reservoirs, we believe that the precise measurement carried with OIRD can help in improving the recovery efficiency in well-drilling process.

  7. Lithofacies Architecturing and Hydrocarbon Reservoir Potential of Lumshiwal Formation: Surghar Range, Trans-Indus Ranges, North Pakistan

    Directory of Open Access Journals (Sweden)

    Iftikhar Alam

    2015-12-01

    directed Paleo-current system prevailed during deposition of Lumshiwal Formation. Diagenetic and tectonically induced fractures make the formation exceedingly porous and permeable as suitable reservoir horizon for the accumulation of hydrocarbon in the Trans-Indus ranges. The same formation has already been proven as potential reservoir horizon for hydrocarbon in the Kohat Plateau of northwest Pakistan. Secondly, the formation is dominantly comprised of silica/quartz sandstone (quartzarenite which can be used as silica sand, one of the essential raw materials for glass industries. The formation is also comprised of local coal seams which can be mined for production of coal in the region.

  8. The Potential of a Surfactant/Polymer Flood in a Middle Eastern Reservoir

    Directory of Open Access Journals (Sweden)

    Meshal Algharaib

    2012-01-01

    Full Text Available An integrated full-field reservoir simulation study has been performed to determine the reservoir management and production strategies in a mature sandstone reservoir. The reservoir is a candidate for an enhanced oil recovery process or otherwise subject to abandonment. Based on its charateristics, the reservoir was found to be most suited for a surfactant/polymer (SP flood. The study started with a large data gathering and the building of a full-field three-dimensional geological model. Subsequently, a full field simulation model was built and used to history match the water flood. The history match of the water flood emphasizes the areas with remaining high oil saturations, establishes the initial condition of the reservoir for an SP flood, and generates a forecast of reserves for continued water flood operations. A sector model was constructed from the full field model and then used to study different design parameters to maximize the project profitability from the SP flood. An economic model, based on the estimated recovery, residual oil in-place, oil price, and operating costs, has been implemented in order to optimize the project profitability. The study resulted in the selection of surfactant and polymer concentrations and slug size that yielded the best economic returns when applied in this reservoir. The study shows that, in today’s oil prices, surfactant/polymer flood when applied in this reservoir has increased the ultimate oil recovery and provide a significant financial returns.

  9. Impact of socioeconomic and meteorological factors on reservoirs' air quality: a case in the Three Gorges Reservoir of Chongqing (TGRC), China over a 10-year period.

    Science.gov (United States)

    Peng, Ying; Zhou, Fengwu; Cui, Jian; Du, Ke; Leng, Qiangmei; Yang, Fumo; Chan, Andy; Zhao, Hongting

    2017-07-01

    The Three Gorges Dam's construction and industrial transfer have resulted in a new air pollution pattern with the potential to threaten the reservoir eco-environment. To assess the impact of socioeconomic factors on the pattern of air quality vairation and economical risks, concentrations of SO 2 , NO 2 , and PM 10 , industry genres, and meteorological conditions were selected in the Three Gorges Reservoir of Chongqing (TGRC) during 2006-2015. Results showed that air quality had improved to some extent, but atmospheric NO 2 showed an increased trend during 2011-2015. Spatially, higher atmospheric NO 2 extended to the surrounding area. The primary industry, especially for agriculture, had shown to be responsible for the remarkable increase of atmospheric NO 2 (p air pollutant reductions, but construction industries had inhibited the improvement of regional air quality. In the tertiary industry, the cargo industry at ports had significantly decreased atmospheric NO 2 as a result of eliminating the obsoleted small ships. Contrarily, the highway transportation had brought more air pollutants. The relative humidity was shown to be the main meteorological factor, which had an extremely remarkable relation with atmospheric SO 2 (p air quality improvement difficult, and atmospheric SO 2 , NO 2 , and PM 10 deposition would aggravate regional soil and water acidification and reactivate heavy metal in soil and sediment, further to pose a high level of ecological risk in the TGRC and other countries with reservoirs in the world.

  10. Sedimentary uranium occurrences in Eastern Europe with special reference to sandstone formations

    International Nuclear Information System (INIS)

    Barthel, F.; Hahn, L.

    1985-01-01

    Sedimentary uranium deposits, especially in sandstones, play an important role in uranium mining in Eastern Europe. The paper reviews recent publications on uranium occurrences in sandstone formations in the German Democratic Republic, Poland, CSSR, Hungary, Romania, Bulgaria and Albania. The uranium deposits in sandstones in Yugoslavia are described in a separate paper in this volume. Sandstone deposits of the USSR are not reviewed. Uranium mineralizations occur in sandstones from Ordovician to Tertiary age. Major deposits are developed in Upper Carboniferous sandstones in association with coal (GDR, Poland), in Permian strata (CSSR, Hungary, Romania), in Cretaceous sandstones (GDR, CSSR), and in Tertiary sediments (CSSR). The Permian deposits can be compared with deposits of similar age in Northern Italy and Northern Yugoslavia. Roll-type orebodies are developed in some of the Cenomanian sandstones. Tertiary deposits are mainly associated with lignites. Uranium deposits in sandstones of Albania and Bulgaria are not described in the literature. Geologic similarities with sandstone basins in adjacent countries suggest the presence of uranium mineralizations in Permian, Lower Triassic, and Tertiary sandstones. (author)

  11. Effects of a Reservoir Water on the GW Quality in a Coastal Aquifer of Semi-arid Region, North-east of Tunisia

    Science.gov (United States)

    Uchida, C.; Kawachi, A.; Tsujimura, M.; Tarhouni, J.

    2015-12-01

    This study investigated effects of a reservoir water in a salinized shallow aquifer based on spatial distribution of geochemical properties in groundwater (GW). In many coastal shallow aquifers of arid and semi-arid regions, groundwater table (GWT) depression and salinization have occurred due to GW overexploitation. In Korba aquifer, north-east of Tunisia, after a dam reservoir has been constructed in order to assure a water resource for irrigation, improvement of GW level and quality have been observed in the downstream area of the dam (area-A), while the GW in the other area (area-B) still has high salinity. This study, therefore, aimed to investigate the effects of the reservoir water on the GW quality. In June 2013, water quality survey and sampling were carried out at 60 wells (GW), a dam reservoir, river and the sea. Major ions, boron, bromide, and oxygen-18 and deuterium in collected samples were analyzed. From the results, in the area-B, the GWT was lower than the sea level and the high salinity were observed. The Br- concentration of the GW was correlated with the Cl- concentration, and the values of B/Cl- and Br-/Cl- of the GW were similar to the seawater. Since the GWT depression allowed the seawater to intrude into the aquifer, the GW salinization occurred in this area. On the other hand, in the area-A, GWT was higher than the seawater level, and the Na+ and Cl- concentrations were lower than the area-B. Especially, in the irrigated areas by using the reservoir water, the isotopic values, B/Cl- and Br-/Cl- of the GW were relatively higher than the others. The reservoir water has high isotopic values due to evaporation effect, and the B/Cl- and Br-/Cl- values become higher due to organic matters in sediment of the reservoir or soil in the filtration process. Thus, in addition to the direct infiltration from the reservoir into the aquifer, irrigation using a reservoir water probably has a positive impact on the GW quality in this area.

  12. REQUERIMENTO EM FRIO, DINÂMICA E HETEROGENEIDADE DE DORMÊNCIA DE GEMAS EM RAMOS DE Salix x rubens CULTIVADO EM LAGES, SC

    Directory of Open Access Journals (Sweden)

    Tássio Dresch Rech

    2006-09-01

    Full Text Available A intensidade de dormência e o requerimento em frio do vimeiro (Salix x rubens Shrank foram avaliados pelo método de estacas de gema isolada. As observações foram realizadas em ramos coletados em Lages, SC, a intervalos regulares de 21 dias, de 29/03/2004 a 2/08/2004. A brotação de gemas dos segmentos basal, mediano e distal de ramos do ano foi avaliada na ausência ou após suplementação de frio (500 ou de 1000 horas a 5  3ºC. A brotação de gemas foi avaliada nos estádios: a gemas inchadas; b início da abertura das gemas; c broto alongado e; d broto alongado com folha aberta. A intensidade de dormência das gemas foi crescente da base para a ponta dos ramos e foi máxima em 10 de maio, para todas as regiões do ramo. O tratamento com 500 horas de frio foi efetivo em reduzir o tempo para a brotação, em todas as épocas e posições das gemas no ramo. A avaliação até o aparecimento de folhas abertas foi importante para identificar a real capacidade de brotação das gemas.

  13. Factors affecting reservoir and stream-water quality in the Cambridge, Massachusetts, drinking-water source area and implications for source-water protection

    Science.gov (United States)

    Waldron, Marcus C.; Bent, Gardner C.

    2001-01-01

    This report presents the results of a study conducted by the U.S. Geological Survey, in cooperation with the city of Cambridge, Massachusetts, Water Department, to assess reservoir and tributary-stream quality in the Cambridge drinking-water source area, and to use the information gained to help guide the design of a comprehensive water-quality monitoring program for the source area. Assessments of the quality and trophic state of the three primary storage reservoirs, Hobbs Brook Reservoir, Stony Brook Reservoir, and Fresh Pond, were conducted (September 1997-November 1998) to provide baseline information on the state of these resources and to determine the vulnerability of the reservoirs to increased loads of nutrients and other contaminants. The effects of land use, land cover, and other drainage-basin characteristics on sources, transport, and fate of fecal-indicator bacteria, highway deicing chemicals, nutrients, selected metals, and naturally occurring organic compounds in 11 subbasins that contribute water to the reservoirs also was investigated, and the data used to select sampling stations for incorporation into a water-quality monitoring network for the source area. All three reservoirs exhibited thermal and chemical stratification, despite artificial mixing by air hoses in Stony Brook Reservoir and Fresh Pond. The stratification produced anoxic or hypoxic conditions in the deepest parts of the reservoirs and these conditions resulted in the release of ammonia nitrogen orthophosphate phosphorus, and dissolved iron and manganese from the reservoir bed sediments. Concentrations of sodium and chloride in the reservoirs usually were higher than the amounts recommended by the U.S. Environmental Protection agency for drinking-water sources (20 milligrams per liter for sodium and 250 milligrams per liter for chloride). Maximum measured sodium concentrations were highest in Hobbs Brook Reservoir (113 milligrams per liter), intermediate in Stony Brook Reservoir (62

  14. Water-quality trends in the Rio Grande/Rio Bravo Basin using sediment cores from reservoirs

    Science.gov (United States)

    Van Metre, Peter C.; Mahler, B.J.; Callender, Edward C.

    1997-01-01

    Water-quality trends reflect the relation between water quality and human activities, chronicling changes in concentrations of environmental contaminants, introduction of new contaminants, and successful efforts in environmental pollution remediation. Historical data available for analyzing trends often have severe limitations, from questionable accuracy to unknown sampling and analytic methodologies. Where data are unavailable or have such limitations, water-quality trends sometimes can be reconstructed using sediment cores from lakes and reservoirs.

  15. Long-term trend analysis of reservoir water quality and quantity at the landscape scale in two major river basins of Texas, USA.

    Science.gov (United States)

    Patino, Reynaldo; Asquith, William H.; VanLandeghem, Matthew M.; Dawson, D.

    2016-01-01

    Trends in water quality and quantity were assessed for 11 major reservoirs of the Brazos and Colorado river basins in the southern Great Plains (maximum period of record, 1965–2010). Water quality, major contributing-stream inflow, storage, local precipitation, and basin-wide total water withdrawals were analyzed. Inflow and storage decreased and total phosphorus increased in most reservoirs. The overall, warmest-, or coldest-monthly temperatures increased in 7 reservoirs, decreased in 1 reservoir, and did not significantly change in 3 reservoirs. The most common monotonic trend in salinity-related variables (specific conductance, chloride, sulfate) was one of no change, and when significant change occurred, it was inconsistent among reservoirs. No significant change was detected in monthly sums of local precipitation. Annual water withdrawals increased in both basins, but the increase was significant (P < 0.05) only in the Colorado River and marginally significant (P < 0.1) in the Brazos River. Salinity-related variables dominated spatial variability in water quality data due to the presence of high- and low-salinity reservoirs in both basins. These observations present a landscape in the Brazos and Colorado river basins where, in the last ∼40 years, reservoir inflow and storage generally decreased, eutrophication generally increased, and water temperature generally increased in at least 1 of 3 temperature indicators evaluated. Because local precipitation remained generally stable, observed reductions in reservoir inflow and storage during the study period may be attributable to other proximate factors, including increased water withdrawals (at least in the Colorado River basin) or decreased runoff from contributing watersheds.

  16. Microstructure parameters evaluation of Botucatu formation sandstone by X-ray microtomography

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Jaquiel S.; Appoloni, Carlos R.; Marques, Leonardo C., E-mail: jaquielfernandes@yahoo.com.b, E-mail: appoloni@uel.b, E-mail: leocarma@yahoo.com.b [Universidade Estadual de Londrina (UEL), PR (Brazil). Dept. de Fisica. Lab. de Fisica Nuclear Aplicada; Fernandes, Celso P., E-mail: celso@lmpt.ufsc.b [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica. Lab. de Meios Porosos e Propriedades TermoFisicas (LMPT)

    2009-07-01

    Microstructural parameters evaluation of reservoir rocks are very important to petroleum industry. This work presents total porosity and pore size distribution measurement of a silicified sandstone sample from the Botucatu formation, collected at municipal district of Faxinal, Parana, Brazil. Porosity and pores size distribution were determined using X-Ray microtomography and imaging techniques. Acquired images had 2.9 mum spatial resolution. 800 2-D images where reconstructed for the microstructure analysis. The determined average porosity was 6.1 +- 2.1 %. 95 % of the porous phase refers to pores with radius ranging from 2.9 to 167.4 mum, presenting the larger frequency (6 %) at 5.9 mum radius. The 3-D volume of the sample was reconstructed and compared with the 3-D model obtained through the autocorrelation functions from the 2-D images analysis. (author)

  17. Petroliferous basin analysis in Taegu area (II)

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, T J; Oh, J H; Son, J D; Bong, P Y; Lee, H Y; Ryu, B J; Son, B K; Kwon, Y I; Hwang, I G; Lee, Y J; Kim, H J [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)

    1997-12-01

    Sandstones of the Sindong and Hayang groups belong to the arkose-feldspar arenite. In the Sindong Group, sandstones are dominated by quartz. In the Hayang Group, however, feldspar and tuffaceous sandstones are abundant. Sand grains are subangular to subrounded and moderately-sorted, in which the sand grains show point- and long-contact. Primary pores are filled with diagenetic minerals such as calcite, silica and authigenic clay minerals. Replacement and dissolution of calcite, and alternation of feldspar form the minor secondary pores. Reservoir quality of the sandstones is poor with less than 5% of porosity. In the study area, illite crystallinity is strongly affected by the post depositional intrusion, regardless of stratigraphic position. The burial temperature of the study area could be estimated at about 150-180 deg.C based on illite crystallinity data. In the Sindong Group, vitrinite reflectance ranges from 2.51% to 3.85% Ro and Rock-Eval Tmax ranges from 613 deg. to 711 deg.C, indicating that thermal maturity of the organic matter reached at the last stage of dry gas generation. These data also indicate that all of the transformable organic matter has been transformed into hydrocarbon and that considerable hydrocarbons could have been generated. Geophysical study on the Jinju Formation suggests that P-wave velocity of the sediments is very high and high frequency seismic source should be used to identify main depositional units. In this case, some depositional units can not be recognized, using ordinary seismic data acquisition method. In summary, the Nakdong and Jinju formations contain abundant black shales, and thermal maturity of the organic matter reached at the final stage of dry gas generation. These formations also contain thick sandstones which can act as a petroleum reservoir. However, reservoir quality of the sandstones is poor (porosity: < 5%; permeability: < 0.001 md). In these sandstones, secondary pores such as dissolution pores and

  18. Investigation on water quality of zabol chahnimeh reservoirs from drinking water and agricultural viewpoint with focus on schuler & vilcoks diagrams

    International Nuclear Information System (INIS)

    Homayoonnezhad, I.; Amirian, P.; Piri, I.

    2016-01-01

    Because of the water deficiency, people's requirements and high costs of refining especially in urban zones, water resources management is very essential. Zabol Chahnimeh reservoirs are three natural and big cavities in the south of Sistan Plain Located in South-Eastern Iran and It Includes 50 Millions square meter extent. Stored Water In These Cavities Are Used To Sistan Earth And For Providing Drink Water of Zabol And Zahedan Cities. Because of the drink and agricultural usage and for investigation of water quality of chah-nimeh reservoirs, this research has been done in one year. Methods: In this research density of Na"+ ,Mg"2"+, Ca"2"+ ,Cl"-, SO_4"2"- and EC, TDS,TH parameters have been analyzed in 9 stations, then results have been rebounded on schuler & vilcoks diagrams. Results: Results showed the quality of water in reservoirs viewpoint of drinking sited in acceptable stage and viewpoint of agricultural sited in C_3S_1 (average quality) stage. Discussion & conclusion: finally, if the texture of soil be light, we can use water of these reservoirs for agricultural activities.

  19. Quantification of oil recovery efficiency, CO 2 storage potential, and fluid-rock interactions by CWI in heterogeneous sandstone oil reservoirs

    DEFF Research Database (Denmark)

    Seyyedi, Mojtaba; Sohrabi, Mehran; Sisson, Adam

    2017-01-01

    Significant interest exists in improving recovery from oil reservoirs while addressing concerns about increasing CO2 concentrations in the atmosphere. The combination of Enhanced Oil Recovery (EOR) and safe geologic storage of CO2 in oil reservoirs is appealing and can be achieved by carbonated (CO...... for oil recovery and CO2 storage potential on heterogeneous cores. Since not all the oil reservoirs are homogenous, understanding the potential of CWI as an integrated EOR and CO2 storage scenario in heterogeneous oil reservoirs is essential....

  20. Full-scale laboratory drilling tests on sandstone and dolomite. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Black, A. D.; Green, S. J.; Rogers, L. A.

    1977-08-01

    Full-scale laboratory drilling experiments were performed under simulated downhole conditions to determine what effect changing various drilling parameters has on penetration rate. The two rock types, typical of deep oil and gas reservoirs, used for the tests were Colton Sandstone and Bonne Terre Dolomite. Drilling was performed with standard 7/sup 7///sub 8/ inch rotary insert bits and water base mud. The results showed the penetration rate to be strongly dependent on bit weight, rotary speed and borehole mud pressure. There was only a small dependence on mud flow rate. The drilling rate decreased rapidly with increasing borehole mud pressure for borehole pressures up to about 2,000 psi. Above this pressure, the borehole pressure and rotary speeds had a smaller effect on penetration rate. The penetration rate was then dependent mostly on the bit weight. Penetration rate per horsepower input was also shown to decrease at higher mud pressures and bit weights. The ratio of horizontal confining stress to axial overburden stress was maintained at 0.7 for simulated overburden stresses between 0 and 12,800 psi. For this simulated downhole stress state, the undrilled rock sample was within the elastic response range and the confining pressures were found to have only a small or negligible effect on the penetration rate. Visual examination of the bottomhole pattern of the rocks after simulated downhole drilling, however, revealed ductile chipping of the Sandstone, but more brittle behavior in the Dolomite.

  1. Alternative procedure for the cold test for soybean seeds Procedimento alternativo para o teste de frio em semente de soja

    Directory of Open Access Journals (Sweden)

    Bruno Guilherme Torres Licursi Vieira

    2010-10-01

    Full Text Available The growing demand for high quality soybean [Glycine max (L. Merrill] seeds requires a precise seed quality control system from the seed industry. One way to accomplish this is by improving vigor testing. Cold test has been traditionally employed for corn seeds. However, it has also been used for other seed crops such as cotton (Gossypium spp., soybean (Glycine Max, dry bean (Phaseolus vulgaris and pea (Pisum sativum. This study was carried out with the objective of adjusting an alternative procedure for the cold test to determine soybean seed vigor. Six commercial soybean seed lots of the cultivar BRS 133 were used. The physiological potential of the seed lots was evaluated by germination on paper towel and sand box, seedling field emergence, tetrazolium, accelerated aging and electrical conductivity tests. Seed moisture content was also determined. The temperature used for the cold test procedures was 10ºC during five days. Four cold test procedures were evaluated: i plastic boxes with soil; ii rolled paper towel with soil; iii rolled paper towel without soil, and iv an alternative procedure, using rolled paper towel without soil under cold water. A completely randomized experimental design with eight replications was used and the means were compared by the Tukey test (p = 0.05. To verify the dependence between the alternative test and others single linear correlation was used. All cold test procedures had similar coefficients of variation (CV, highlighting that rolled paper towel with soil and the alternative procedure had the best performance, with an average of 94% and 93% normal seedlings and CV of 3.2% and 3.6%, respectively. The alternative procedure has satisfactory results for estimating soybean seed vigor, yielding consistent results compared to the traditional procedure.A crescente demanda por semente de soja [Glycine max (L. Merrill] de alta qualidade tem requerido da indústria de sementes um controle de qualidade mais preciso

  2. High-resolution mapping of yield curve shape and evolution for high porosity sandstones

    Science.gov (United States)

    Bedford, J. D.; Faulkner, D.; Wheeler, J.; Leclere, H.

    2017-12-01

    The onset of permanent inelastic deformation for porous rock is typically defined by a yield curve plotted in P-Q space, where P is the effective mean stress and Q is the differential stress. Sandstones usually have broadly elliptical shaped yield curves, with the low pressure side of the ellipse associated with localized brittle faulting (dilation) and the high pressure side with distributed ductile deformation (compaction). However recent works have shown that these curves might not be perfectly elliptical and that significant evolution in shape occurs with continued deformation. We therefore use a novel stress-probing methodology to map in high-resolution the yield curve shape for Boise and Idaho Gray sandstones (36-38% porosity) and also investigate curve evolution with increasing deformation. The data reveal yield curves with a much flatter geometry than previously recorded for porous sandstone and that the compactive side of the curve is partly comprised of a near vertical limb. The yield curve evolution is found to be strongly dependent on the nature of inelastic strain. Samples that were compacted under a deviatoric load, with a component of inelastic shear strain, were found to have yield curves with peaks that are approximately 50% higher than similar porosity samples that were hydrostatically compacted (i.e. purely volumetric strain). The difference in yield curve evolution along the different loading paths is attributed to mechanical anisotropy that develops during deviatoric loading by the closure of preferentially orientated fractures. Increased shear strain also leads to the formation of a plateau at the peak of the yield curve as samples deform along the deviatoric loading path. These results have important implications for understanding how the strength of porous rock evolves along different stress paths, including during fluid extraction from hydrocarbon reservoirs where the stress state is rarely isotropic.

  3. Assessing ecosystem effects of reservoir operations using food web-energy transfer and water quality models

    Science.gov (United States)

    Saito, L.; Johnson, B.M.; Bartholow, J.; Hanna, R.B.

    2001-01-01

    We investigated the effects on the reservoir food web of a new temperature control device (TCD) on the dam at Shasta Lake, California. We followed a linked modeling approach that used a specialized reservoir water quality model to forecast operation-induced changes in phytoplankton production. A food web–energy transfer model was also applied to propagate predicted changes in phytoplankton up through the food web to the predators and sport fishes of interest. The food web–energy transfer model employed a 10% trophic transfer efficiency through a food web that was mapped using carbon and nitrogen stable isotope analysis. Stable isotope analysis provided an efficient and comprehensive means of estimating the structure of the reservoir's food web with minimal sampling and background data. We used an optimization procedure to estimate the diet proportions of all food web components simultaneously from their isotopic signatures. Some consumers were estimated to be much more sensitive than others to perturbations to phytoplankton supply. The linked modeling approach demonstrated that interdisciplinary efforts enhance the value of information obtained from studies of managed ecosystems. The approach exploited the strengths of engineering and ecological modeling methods to address concerns that neither of the models could have addressed alone: (a) the water quality model could not have addressed quantitatively the possible impacts to fish, and (b) the food web model could not have examined how phytoplankton availability might change due to reservoir operations.

  4. 57Fe Mössbauer and X-ray characterisation of sandstones

    International Nuclear Information System (INIS)

    Mulaba-Bafubiandi, A. F.; Waanders, F. B.

    2013-01-01

    Sandstones from the Free State province in South Africa have been mined and processed mainly by small scale and artisanal miners in the rural areas. In the present investigation basic fire proof and water absorption tests, X-ray and γ-ray based characterisation techniques were used to study the sandstones. The collected samples were grouped according to their apparent colour in day light conditions and the elemental analysis showed the presence of a high amount of oxygen (>52%) and silicon (>38%) with Mn, Al, Fe and Ca as major elements in proportions related to the colour distribution of the various sandstones. The uniaxial compressive stress was found to be the highest (56 MPa) for the greyish sandstone and the lowest (8 MPa) for the white sandstone sample, also associated with the lowest (Al+Fe)/Si value of 0.082. The humidity test showed that the 6 % water absorption was lower than the recommended ASTM value of 8 %. The sandstone samples were also subjected to various high temperatures to simulate possible fire conditions and it was found that the non alteration of the mineral species might be one of the reasons why the sandstones are regarded as the most refractory amongst the building materials typically used. Mössbauer spectroscopy revealed that iron is present in all the sandstones, mainly as Fe 3 +  with the black sandstone showing an additional presence of 3 % Fe 2 +  indicating that a higher iron content coupled to higher silicon content, contributes to an increase in the uniaxial compressive strength.

  5. Modelling spatial and temporal variations in the water quality of an artificial water reservoir in the semiarid Midwest of Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Cid, Fabricio D., E-mail: fabricio.cid@gmail.com [Laboratory of Biology ' Prof. E. Caviedes Codelia' , Facultad de Ciencias Humanas, Universidad Nacional de San Luis, San Luis (Argentina); Laboratory of Integrative Biology, Institute for Multidisciplinary Research in Biology (IMIBIO-SL), Consejo Nacional de Investigaciones Cientificas y Tecnicas, San Luis (Argentina); Department of Biochemistry and Biological Sciences, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, San Luis (Argentina); Anton, Rosa I. [Department of Analytical Chemistry, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, San Luis (Argentina); Pardo, Rafael; Vega, Marisol [Department of Analytical Chemistry, Facultad de Ciencias, Universidad de Valladolid, Valladolid (Spain); Caviedes-Vidal, Enrique [Laboratory of Biology ' Prof. E. Caviedes Codelia' , Facultad de Ciencias Humanas, Universidad Nacional de San Luis, San Luis (Argentina); Laboratory of Integrative Biology, Institute for Multidisciplinary Research in Biology (IMIBIO-SL), Consejo Nacional de Investigaciones Cientificas y Tecnicas, San Luis (Argentina); Department of Biochemistry and Biological Sciences, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, San Luis (Argentina)

    2011-10-31

    Highlights: {yields} Water quality of an Argentinean reservoir has been investigated by N-way PCA. {yields} PARAFAC mode modelled spatial and seasonal variations of water composition. {yields} Two factors related with organic and lead pollution have been identified. {yields} The most polluted areas of the reservoir were located, and polluting sources identified. - Abstract: Temporal and spatial patterns of water quality of an important artificial water reservoir located in the semiarid Midwest of Argentina were investigated using chemometric techniques. Surface water samples were collected at 38 points of the water reservoir during eleven sampling campaigns between October 1998 and June 2000, covering the warm wet season and the cold dry season, and analyzed for dissolved oxygen (DO), conductivity, pH, ammonium, nitrate, nitrite, total dissolved solids (TDS), alkalinity, hardness, bicarbonate, chloride, sulfate, calcium, magnesium, fluoride, sodium, potassium, iron, aluminum, silica, phosphate, sulfide, arsenic, chromium, lead, cadmium, chemical oxygen demand (COD), biochemical oxygen demand (BOD), viable aerobic bacteria (VAB) and total coliform bacteria (TC). Concentrations of lead, ammonium, nitrite and coliforms were higher than the maximum allowable limits for drinking water in a large proportion of the water samples. To obtain a general representation of the spatial and temporal trends of the water quality parameters at the reservoir, the three-dimensional dataset (sampling sites x parameters x sampling campaigns) has been analyzed by matrix augmentation principal component analysis (MA-PCA) and N-way principal component analysis (N-PCA) using Tucker3 and PARAFAC (Parallel Factor Analysis) models. MA-PCA produced a component accounting for the general behavior of parameters associated with organic pollution. The Tucker3 models were not appropriate for modelling the water quality dataset. The two-factor PARAFAC model provided the best picture to understand the

  6. Modelling spatial and temporal variations in the water quality of an artificial water reservoir in the semiarid Midwest of Argentina

    International Nuclear Information System (INIS)

    Cid, Fabricio D.; Anton, Rosa I.; Pardo, Rafael; Vega, Marisol; Caviedes-Vidal, Enrique

    2011-01-01

    Highlights: → Water quality of an Argentinean reservoir has been investigated by N-way PCA. → PARAFAC mode modelled spatial and seasonal variations of water composition. → Two factors related with organic and lead pollution have been identified. → The most polluted areas of the reservoir were located, and polluting sources identified. - Abstract: Temporal and spatial patterns of water quality of an important artificial water reservoir located in the semiarid Midwest of Argentina were investigated using chemometric techniques. Surface water samples were collected at 38 points of the water reservoir during eleven sampling campaigns between October 1998 and June 2000, covering the warm wet season and the cold dry season, and analyzed for dissolved oxygen (DO), conductivity, pH, ammonium, nitrate, nitrite, total dissolved solids (TDS), alkalinity, hardness, bicarbonate, chloride, sulfate, calcium, magnesium, fluoride, sodium, potassium, iron, aluminum, silica, phosphate, sulfide, arsenic, chromium, lead, cadmium, chemical oxygen demand (COD), biochemical oxygen demand (BOD), viable aerobic bacteria (VAB) and total coliform bacteria (TC). Concentrations of lead, ammonium, nitrite and coliforms were higher than the maximum allowable limits for drinking water in a large proportion of the water samples. To obtain a general representation of the spatial and temporal trends of the water quality parameters at the reservoir, the three-dimensional dataset (sampling sites x parameters x sampling campaigns) has been analyzed by matrix augmentation principal component analysis (MA-PCA) and N-way principal component analysis (N-PCA) using Tucker3 and PARAFAC (Parallel Factor Analysis) models. MA-PCA produced a component accounting for the general behavior of parameters associated with organic pollution. The Tucker3 models were not appropriate for modelling the water quality dataset. The two-factor PARAFAC model provided the best picture to understand the spatial and

  7. An observational study of the evolution of the atmospheric boundary-layer over Cabo Frio, Brazil

    Directory of Open Access Journals (Sweden)

    S. H. Franchito

    2007-08-01

    Full Text Available The effect of coastal upwelling on the evolution of the atmospheric boundary layer (ABL in Cabo Frio (Brazil is investigated. For this purpose, radiosounding data collected in two experiments made during the austral summer (upwelling case and austral winter (no upwelling case are analysed. The results show that during the austral summer, cold waters that crop up near the Cabo Frio coast favour the formation of an atmospheric stable layer, which persists during the upwelling episode. Due to the low SSTs, the descending branch of the sea-breeze circulation is located close to the coast, inhibiting the development of a mixed layer mainly during the day. At night, with the reduction of the land-sea thermal contrast the descending motion is weaker, allowing a vertical mixing. The stable ABL favours the formation of a low level jet, which may also contribute to the development of a nocturnal atmospheric mixed layer. During the austral winter, due to the higher SSTs observed near the coast, the ABL is less stable compared with that in the austral summer. Due to warming, a mixed layer is observed during the day. The observed vertical profiles of the zonal winds show that the easterlies at low levels are stronger in the austral summer, indicating that the upwelling modulates the sea-breeze signal, thus confirming model simulations.

  8. Lacustrine Environment Reservoir Properties on Sandstone Minerals and Hydrocarbon Content: A Case Study on Doba Basin, Southern Chad

    Science.gov (United States)

    Sumery, N. F. Mohd; Lo, S. Z.; Salim, A. M. A.

    2017-10-01

    The contribution of lacustrine environment as the hydrocarbon reservoir has been widely known. However, despite its growing importance, the lacustrine petroleum geology has received far less attention than marine due to its sedimentological complexity. This study therefore aims in developing an understanding of the unique aspects of lacustrine reservoirs which eventually impacts the future exploration decisions. Hydrocarbon production in Doba Basin, particularly the northern boundary, for instance, has not yet succeeded due to the unawareness of its depositional environment. The drilling results show that the problems were due to the: radioactive sand and waxy oil/formation damage, which all are related to the lacustrine depositional environment. Detailed study of geological and petrophysical integration on wireline logs and petrographic thin sections analysis of this environment helps in distinguishing reservoir and non-reservoir areas and determining the possible mechanism causing the failed DST results. The interpretations show that the correlation of all types> of logs and rho matrix analysis are capable in identifying sand and shale bed despite of the radioactive sand present. The failure of DST results were due to the presence of arkose in sand and waxy oil in reservoir bed. This had been confirmed by the petrographic thin section analysis where the arkose has mineral twinning effect indicate feldspar and waxy oil showing bright colour under fluorescent light. Understanding these special lacustrine environment characteristics and features will lead to a better interpretation of hydrocarbon prospectivity for future exploration.

  9. Producing Light Oil from a Frozen Reservoir: Reservoir and Fluid Characterization of Umiat Field, National Petroleum Reserve, Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Hanks, Catherine

    2012-12-31

    Umiat oil field is a light oil in a shallow, frozen reservoir in the Brooks Range foothills of northern Alaska with estimated oil-in-place of over 1 billion barrels. Umiat field was discovered in the 1940’s but was never considered viable because it is shallow, in the permafrost, and far from any transportation infrastructure. The advent of modern drilling and production techniques has made Umiat and similar fields in northern Alaska attractive exploration and production targets. Since 2008 UAF has been working with Renaissance Alaska Inc. and, more recently, Linc Energy, to develop a more robust reservoir model that can be combined with rock and fluid property data to simulate potential production techniques. This work will be used to by Linc Energy as they prepare to drill up to 5 horizontal wells during the 2012-2013 drilling season. This new work identified three potential reservoir horizons within the Cretaceous Nanushuk Formation: the Upper and Lower Grandstand sands, and the overlying Ninuluk sand, with the Lower Grandstand considered the primary target. Seals are provided by thick interlayered shales. Reserve estimates for the Lower Grandstand alone range from 739 million barrels to 2437 million barrels, with an average of 1527 million bbls. Reservoir simulations predict that cold gas injection from a wagon-wheel pattern of multilateral injectors and producers located on 5 drill sites on the crest of the structure will yield 12-15% recovery, with actual recovery depending upon the injection pressure used, the actual Kv/Kh encountered, and other geologic factors. Key to understanding the flow behavior of the Umiat reservoir is determining the permeability structure of the sands. Sandstones of the Cretaceous Nanushuk Formation consist of mixed shoreface and deltaic sandstones and mudstones. A core-based study of the sedimentary facies of these sands combined with outcrop observations identified six distinct facies associations with distinctive permeability

  10. Técnicas de análise multivariada na avaliação de injúrias pelo frio em mangas cv. Tommy Atkins

    Directory of Open Access Journals (Sweden)

    Ana Carolina Almeida Miguel

    2011-10-01

    Full Text Available Este trabalho objetivou identificar as variáveis que se associam às injúrias pelo frio e determinar as diferenças nos parâmetros de qualidade que melhor caracterizam mangas 'Tommy Atkins' submetidas à condição de injúria pelo frio, utilizando-se da análise de fatores em componentes principais e a análise de agrupamentos. Frutos colhidos no estádio "de vez" foram cuidadosamente transportados, selecionados, padronizados quanto a coloração, tamanho e ausência de injúrias, e tratados com fungicida antes de serem armazenados a 2 ºC (74,8% UR, 5 °C (75,4% UR e 12 °C (76,4% UR, por até 28 dias. Os frutos foram avaliados semanalmente quanto à ocorrência de danos pelo frio, coloração da casca e da polpa, firmeza da polpa, teores de sólidos solúveis, acidez titulável, açúcares solúveis e redutores, ácido ascórbico e atividade das enzimas peroxidase, polifenoloxidase e fenilalanina amônia-liase. A análise estatística multivariada dos fatores em componentes principais e agrupamentos permitiram melhor compreensão do efeito do armazenamento, sob condição de chilling, no metabolismo de mangas 'Tommy Atkins' e indicaram que o dano está intimamente relacionado com a casca e que a resposta da polpa ao estresse ocorre de forma tardia.

  11. Petrography and geochemistry of Jurassic sandstones from the ...

    Indian Academy of Sciences (India)

    V Periasamy

    On the basis of geochemical results, sandstones are classified into arkose, ..... Geochemical classification diagram of sandstone samples from the Jhuran Formation based on log(SiO2/Al2O3)– ..... 1993) showing single trend for the Jhuran.

  12. The streaming potential of liquid carbon dioxide in BreaSandstone

    Energy Technology Data Exchange (ETDEWEB)

    Moore, J.; Glaser, S.; Morrison, F.; Hoversten, G.M.

    2004-10-01

    We report here, for the first time, evolution of the streaming potential coupling coefficient as liquid carbon dioxide infiltrates Berea sandstone. Using 125 Omega-m tap water, the coupling coefficient determined before and after each CO2 flood of five samples averaged approximately -30 mV/0.1 MPa. After liquid CO2 passed through the specimens displacing all mobile pore water, trapped water remained and the coupling coefficient was approximately -3 mV/0.1 MPa. A bound water limit of the coupling coefficient for liquid CO2 flow was found using an air-dried sample to be -0.02 mV/0.1 MPa. For initially water-saturated samples, bulk resistivity varied during CO2 invasion from 330 Ohm-m, to 150 Ohm-m during CO2/water mixing, to a final value of 380 Ohm-m. Results suggest that trapped and bound water control electrical conduction and the electrokinetic response. Applications include monitoring CO2 injectate in subsurface reservoirs using the self potential method.

  13. Petrofacies analysis - the petrophysical tool for geologic/engineering reservoir characterization

    Energy Technology Data Exchange (ETDEWEB)

    Watney, W.L.; Guy, W.J.; Gerlach, P.M. [Kansas Geological Survey, Lawrence, KS (United States)] [and others

    1997-08-01

    Petrofacies analysis is defined as the characterization and classification of pore types and fluid saturations as revealed by petrophysical measures of a reservoir. The word {open_quotes}petrofacies{close_quotes} makes an explicit link between petroleum engineers concerns with pore characteristics as arbiters of production performance, and the facies paradigm of geologists as a methodology for genetic understanding and prediction. In petrofacies analysis, the porosity and resistivity axes of the classical Pickett plot are used to map water saturation, bulk volume water, and estimated permeability, as well as capillary pressure information, where it is available. When data points are connected in order of depth within a reservoir, the characteristic patterns reflect reservoir rock character and its interplay with the hydrocarbon column. A third variable can be presented at each point on the crossplot by assigning a color scale that is based on other well logs, often gamma ray or photoelectric effect, or other derived variables. Contrasts between reservoir pore types and fluid saturations will be reflected in changing patterns on the crossplot and can help discriminate and characterize reservoir heterogeneity. Many hundreds of analyses of well logs facilitated by spreadsheet and object-oriented programming have provided the means to distinguish patterns typical of certain complex pore types for sandstones and carbonate reservoirs, occurrences of irreducible water saturation, and presence of transition zones. The result has been an improved means to evaluate potential production such as bypassed pay behind pipe and in old exploration holes, or to assess zonation and continuity of the reservoir. Petrofacies analysis is applied in this example to distinguishing flow units including discrimination of pore type as assessment of reservoir conformance and continuity. The analysis is facilitated through the use of color cross sections and cluster analysis.

  14. Aplication Of Life Cycle Assessment On Water Quality Caesed By Fish Culture Activity In Cirata Reservoir, Indonesia

    Directory of Open Access Journals (Sweden)

    Tri Heru Prihadi

    2017-12-01

    Full Text Available Life Cycle Assessment (LCA is an environmental analytical tool used for evaluating the environmental performance of products by compiling and evaluation of the inputs, outputs and potential environmental impacts of a product system throughout the life cycle of product.Sources of the decomposition at Cirata Reservoir are from industrial activities, household waste, agricultural waste, and the leftover from the activities of floating net fish cages. The wastes are in the form of fat, protein and carbohydrat. In decomposition process and the rate of destruction process of organic matters in the sediment  is carried our by bacteria, resulting in the oxygen dissolved in the waters will decrease. This lessens the oxygen at Cirata reservoir so that decomposition process takes place anaerobically at the bottom of the waters. The methodology was conducted by  water and sediment sampling, measuring water quality on location and laboratory analysis for samples of water and sediment. Analysis result showed that the data of water quality collected in every station was relatively homogeneous. The quality of water at measuring time approached critical treshold required for fish raising. The result showed that the level of decomposition Sediment Organic Metter, water quality in Cirata reservoir based on IKA_STORET valued class I, II, and III catagorized as worse. Valued DO, sulfide, Fenol, BOD, COD, Total Fosfat byone  water quality standar. The destruction will occur by itself, depending on the availability of oxygen on the sediment and interface when there is bacteria serving as heterotraphic aerobic in line with the availability of dissolved oxygen for bacteria to do the decomposition activity in the sediment. The result would be confirmed on dendogram classification hierarchy, result revealed that stations of observation were divided into 2 groups according to affecting characteristics. Group 1 covering stasion 1 and 2, group 2 which covering station 3

  15. Processing of reservoir data for diagenesis simulation; Traitement des donnees de reservoir en vue d`une simulation de la diagenese

    Energy Technology Data Exchange (ETDEWEB)

    Pelletier, I.

    1997-12-18

    Diagenetic minerals frequently damage reservoir permeability. A numerical model which couples chemical reactions and transport of dissolved elements can help to predict both location and magnitude of cementations. The present Ph.D. examines how can be applied such a modelling approach to a complex heterogeneous reservoir. Petrographical data from core samples are used as input data, or alternatively as controls for validating the modelling results. The measurements, acquired with dm-to-m spacing are too numerous to be integrated in a reactions-transport code. The usual up-scaling methods, called Homogenization, conserve only the fluid flow properties. A new method, called `Gathering` takes into account material transport balance. It is proposed in the first part of the dissertation. In the second part, an application of Gathering is done simulating illitization in the sub-arkosic sandstones of the Ness formation (Brent Group) in a North Sea field, Dunbar.. As a prerequisite, data accuracy is examined for a set of `routine measurements` (100 points counting on thin section, XR-diffractometry and gas porosity/permeability). (author) 60 refs.

  16. Sensing, Measuring and Modelling the Mechanical Properties of Sandstone

    Science.gov (United States)

    Antony, S. J.; Olugbenga, A.; Ozerkan, N. G.

    2018-02-01

    We present a hybrid framework for simulating the strength and dilation characteristics of sandstone. Where possible, the grain-scale properties of sandstone are evaluated experimentally in detail. Also, using photo-stress analysis, we sense the deviator stress (/strain) distribution at the micro-scale and its components along the orthogonal directions on the surface of a V-notch sandstone sample under mechanical loading. Based on this measurement and applying a grain-scale model, the optical anisotropy index K 0 is inferred at the grain scale. This correlated well with the grain contact stiffness ratio K evaluated using ultrasound sensors independently. Thereafter, in addition to other experimentally characterised structural and grain-scale properties of sandstone, K is fed as an input into the discrete element modelling of fracture strength and dilation of the sandstone samples. Physical bulk-scale experiments are also conducted to evaluate the load-displacement relation, dilation and bulk fracture strength characteristics of sandstone samples under compression and shear. A good level of agreement is obtained between the results of the simulations and experiments. The current generic framework could be applied to understand the internal and bulk mechanical properties of such complex opaque and heterogeneous materials more realistically in future.

  17. Use of LANDSAT 8 images for depth and water quality assessment of El Guájaro reservoir, Colombia

    Science.gov (United States)

    González-Márquez, Luis Carlos; Torres-Bejarano, Franklin M.; Torregroza-Espinosa, Ana Carolina; Hansen-Rodríguez, Ivette Renée; Rodríguez-Gallegos, Hugo B.

    2018-03-01

    The aim of this study was to evaluate the viability of using Landsat 8 spectral images to estimate water quality parameters and depth in El Guájaro Reservoir. On February and March 2015, two samplings were carried out in the reservoir, coinciding with the Landsat 8 images. Turbidity, dissolved oxygen, electrical conductivity, pH and depth were evaluated. Through multiple regression analysis between measured water quality parameters and the reflectance of the pixels corresponding to the sampling stations, statistical models with determination coefficients between 0.6249 and 0.9300 were generated. Results indicate that from a small number of measured parameters we can generate reliable models to estimate the spatial variation of turbidity, dissolved oxygen, pH and depth, as well the temporal variation of electrical conductivity, so models generated from Landsat 8 can be used as a tool to facilitate the environmental, economic and social management of the reservoir.

  18. Temporal variability in water quality parameters--a case study of drinking water reservoir in Florida, USA.

    Science.gov (United States)

    Toor, Gurpal S; Han, Lu; Stanley, Craig D

    2013-05-01

    Our objective was to evaluate changes in water quality parameters during 1983-2007 in a subtropical drinking water reservoir (area: 7 km(2)) located in Lake Manatee Watershed (area: 338 km(2)) in Florida, USA. Most water quality parameters (color, turbidity, Secchi depth, pH, EC, dissolved oxygen, total alkalinity, cations, anions, and lead) were below the Florida potable water standards. Concentrations of copper exceeded the potable water standard of water quality threshold of 20 μg l(-1). Concentrations of total N showed significant increase from 1983 to 1994 and a decrease from 1997 to 2007. Total P showed significant increase during 1983-2007. Mean concentrations of total N (n = 215; 1.24 mg l(-1)) were lower, and total P (n = 286; 0.26 mg l(-1)) was much higher than the EPA numeric criteria of 1.27 mg total N l(-1) and 0.05 mg total P l(-1) for Florida's colored lakes, respectively. Seasonal trends were observed for many water quality parameters where concentrations were typically elevated during wet months (June-September). Results suggest that reducing transport of organic N may be one potential option to protect water quality in this drinking water reservoir.

  19. Elevated Uranium in Aquifers of the Jacobsville Sandstone

    Science.gov (United States)

    Sherman, H.; Gierke, J.

    2003-12-01

    The EPA has announced a new standard for uranium in drinking water of 30 parts per billion (ppb). This maximum contaminant level (MCL) takes effect for community water supplies December 2003. The EPA's ruling has heightened awareness among residential well owners that uranium in drinking water may increase the risk of kidney disease and cancer and has created a need for a quantified, scientific understanding of the occurrence and distribution of uranium isotopes in aquifers. The authors are investigating the occurrence of elevated uranium in northern Michigan aquifers of the Middle Proterozoic Jacobsville sandstone, a red to mottled sequence of sandstones, conglomerates, siltstones and shales deposited as basin fill in the 1.1 Ga Midcontinent rift. Approximately 25% of 300 well water samples tested for isotopic uranium have concentrations above the MCL. Elevated uranium occurrences are distributed throughout the Jacobsville sandstone aquifers stretching across Michigan's Upper Peninsula. However, there is significant variation in well water uranium concentrations (from 0.01 to 190 ppb) and neighboring wells do not necessarily have similar concentrations. The authors are investigating hydrogeologic controls on ground water uranium concentrations in the Jacobsville sandstone, e.g. variations in lithology, mineralogy, groundwater residence time and geochemistry. Approximately 2000' of Jacobsville core from the Amoco St. Amour well was examined in conjunction with the spectral gamma ray log run in the borehole. Spikes in equivalent uranium (eU) concentration from the log are frequently associated with clay and heavy mineral layers in the sandstone core. The lithology and mineralogy of these layers will be determined by analysis of thin sections and x-ray diffraction. A portable spectrometer, model GRS-2000/BL, will be used on the sandstone cliffs along Lake Superior to characterize depositional and lithologic facies of the Jacobsville sandstone in terms of

  20. Mercury speciation in fish of the Cabo Frio upwelling region, SE-Brazil

    Directory of Open Access Journals (Sweden)

    Carlos Alberto da Silva

    2011-09-01

    Full Text Available Mercury distribution in the oceans is controlled by complex biogeochemical cycles, resulting in retention of trace amounts of this metal in marine biota. The impact of upwelling processes in this metal behavior has been overlooked. Data from literature are insufficient to evaluate the risks associated with the presence of mercury in the fish collected in upwelling areas and its consumers. Therefore, the aim of the present work was to perform a study of mercury speciation in four fish species belonging to different trophic levels from Cabo Frio-Brazil upwelling region. The total mercury content vary of 53 ng g-1 (Sardinella brasiliensis -sardine to 1215 ng g-1 (Cynoscion striatus -striped weakfish and, with exception of the planktivorous fish, methylmercury levels reaches circa 90% of total mercury concentration.A distribuição de Mercúrio nos oceanos é controlada por um complexo ciclo biogeoquímico, resultando na retenção de pequenas quantidades na biota marinha. O impacto dos processos de ressurgência costeira no comportamento desse metal tem sido negligenciado. Dados da literatura são insuficientes para elucidar o risco associado com a presença de mercúrio em peixes capturados em áreas de ressurgência e seus consumidores. Portanto o objetivo do presente trabalho foi realizar um estudo de especiação de mercúrio em quatro espécies de peixes pertencentes a diferentes níveis tróficos da região de ressurgência de Cabo Frio-Brasil. O conteúdo total de mercúrio variou de 53 ng g-1 (Sardinella brasiliensis -sardinha to 1215 ng g-1 (Cynoscion striatus -pescada e, com exceção da espécie planctivora, os níveis de metilmercúrio atingem cerca de 90% da concentração total de mercúrio.

  1. Microbiological water quality and its relation to nitrogen and phosphorus at the Pareja limno-reservoir (Guadalajara, Spain).

    Science.gov (United States)

    Molina-Navarro, E; Martínez-Pérez, S; Sastre-Merlín, A; Soliveri, J; Fernández-Monistrol, I; Copa-Patiño, J L

    2011-03-01

    Bordering on the edge of the Entrepeñas reservoir (Guadalajara, Spain), next to the village of Pareja, a small dam that allows a body of water to develop with a constant level has been built. Initiatives like this (which we have termed "limno-reservoirs") are innovative in Spain and around the world. Earlier reservoirs such as this one were constructed to create a habitat for birds, but the Pareja limno-reservoir is the first to promote socio-economic development. In order to study this limno-reservoir, this research group set up an environmental observatory, analyzing, among other variables, microbiological water quality and nutrient content. After a year and a half of research, it was observed that the concentration of microorganisms is lower in the limno-reservoir than in the river that feeds it, possibly due to the nutrient depletion in the lentic ecosystem. In the limno-reservoir, the total coliforms and enterococci concentrations fall within the European Bathing Water Directive limits, but in the river these concentrations are sometimes higher. The nutrient load in the limno-reservoir is low, with nutrient variations influencing native microorganisms, but not for total coliforms and enterococci. However, the development of special conditions in the bottom has been observed in winter, facilitating coliforms and enterococci survival. This research is very interesting since the creation of limno-reservoirs is rising in Spain and no research is being done on their behaviour. Copyright © 2010 Elsevier Ltd. All rights reserved.

  2. Transport of silver nanoparticles in single fractured sandstone

    Science.gov (United States)

    Neukum, Christoph

    2018-02-01

    Silver nanoparticles (Ag-NP) are used in various consumer products and are one of the most prevalent metallic nanoparticle in commodities and are released into the environment. Transport behavior of Ag-NP in groundwater is one important aspect for the assessment of environmental impact and protection of drinking water resources in particular. Ag-NP transport processes in saturated single-fractured sandstones using triaxial flow cell experiments with different kind of sandstones is investigated. Ag-NP concentration and size are analyzed using flow field-flow fractionation and coupled SEM-EDX analysis. Results indicate that Ag-NP are more mobile and show generally lower attachment on rock surface compared to experiments in undisturbed sandstone matrix and partially fractured sandstones. Ag-NP transport is controlled by the characteristics of matrix porosity, time depending blocking of attachment sites and solute chemistry. Where Ag-NP attachment occur, it is heterogeneously distributed on the fracture surface.

  3. Anatomy of anomalously thick sandstone units in the Brent Delta of the northern North Sea

    Science.gov (United States)

    Wei, Xiaojie; Steel, Ronald J.; Ravnås, Rodmar; Jiang, Zaixing; Olariu, Cornel; Ma, Yinsheng

    2018-05-01

    Some potentially attractive reservoirs, containing anomalously thick (10s to a few 100 m), cross-stratified sandstone, have been locally encountered within both the classic regressive (lower Brent) and the transgressive (upper Brent) segments of the Brent Delta. Three documented cases of these sandstone bodies are re-examined. They are internally dominated by simple or compound dunes, and typified by two types of deepening-upward succession, recording a retrogradational or transgressive shoreline history. Type I is expressed as a single estuarine succession changing upwards from erosive, coarse-grained channelized deposits into outer estuary tidal bar deposits. The estuary is underlain and overlain by deltaic deposits. Type II lacks significant basal river deposits but is composed by stacked mixed-energy and tide-dominated estuarine deposits. It is underlain by deltaic deposits and overlain by open marine sediments. Considering the structural evolution in the northern North Sea basin, we suggest (as did some earlier researchers) that these sandstone bodies were local, but sometimes broad transgressive estuaries, formed at any time during large-scale Brent Delta growth and decay. The estuary generation was likely triggered by fluvial incision coupled with active faulting, producing variable accommodation embayments, where tidal currents became focused and deposition became transgressive. The spatial variations of the interpreted estuary deposits were linked with variable, fault-generated accommodation. The relatively simple, lower Brent estuarine units were created by short-lived, fault activity in places, whereas the complex, stacked upper-Brent estuarine units were likely a result of more long-lived, punctuated fault-induced subsidence leading into the northern North Sea main rifting stage. The thick cross-stratified units potentially accumulated in the hangingwall of large bounding faults.

  4. Drag reduction in reservoir rock surface: Hydrophobic modification by SiO_2 nanofluids

    International Nuclear Information System (INIS)

    Yan, Yong-Li; Cui, Ming-Yue; Jiang, Wei-Dong; He, An-Le; Liang, Chong

    2017-01-01

    Graphical abstract: The micro-nanoscale hierarchical structures at the sandstone core surface are constructed by adsorption of the modified silica nanoparticles, which leads to the effect of drag reduction to improve the low injection rate in ultra-low permeability reservoirs. - Highlights: • A micro-nanoscale hierarchical structure is formed at the reservoir rock surface. • An inversion has happened from hydrophilic into hydrophobic modified by nanofluids. • The effect of drag reduction to improve the low injection rate is realized. • The mechanism of drag reduction induced from the modified core surface was unclosed. - Abstract: Based on the adsorption behavior of modified silica nanoparticles in the sandstone core surface, the hydrophobic surface was constructed, which consists of micro-nanoscale hierarchical structure. This modified core surface presents a property of drag reduction and meets the challenge of high injection pressure and low injection rate in low or ultra-low permeability reservoir. The modification effects on the surface of silica nanoparticles and reservoir cores, mainly concerning hydrophobicity and fine structure, were determined by measurements of contact angle and scanning electron microscopy. Experimental results indicate that after successful modification, the contact angle of silica nanoparticles varies from 19.5° to 141.7°, exhibiting remarkable hydrophobic properties. These modified hydrophobic silica nanoparticles display a good adsorption behavior at the core surface to form micro-nanobinary structure. As for the wettability of these modified core surfaces, a reversal has happened from hydrophilic into hydrophobic and its contact angle increases from 59.1° to 105.9°. The core displacement experiments show that the relative permeability for water has significantly increased by an average of 40.3% via core surface modification, with the effects of reducing injection pressure and improving injection performance of water

  5. Fracture-related fluid flow in sandstone reservoirs - Insights from outcrop analogues of South-eastern Utah

    NARCIS (Netherlands)

    Ogata, K.; Senger, K.; Braathen, A.; Tveranger, J.; Petrie, E.; Evans, J.P.

    2012-01-01

    Fault- And fold-related fractures influence the fluid circulation in the subsurface, thus being of high importance for CO2 storage site assessment, especially in terms of reservoir connectivity and leakage. In this context, discrete regions of concentrated sub-parallel fracturing known as fracture

  6. Assessment of microbiological quality of water in the Nowohucki Reservoir with particular regard to microorganisms potentially dangerous to humans

    Directory of Open Access Journals (Sweden)

    Katarzyna Wolny-Koładka

    2016-12-01

    Full Text Available Introduction. This study was aimed to assess the microbiological quality of water in the Nowohucki Reservoir (Kraków, Poland as well as to determine whether its waters contain microorganisms potentially dangerous from an epidemiological point of view. Material and methods. Microbiological analyses included the determination of the number of mesophilic and psychrophilic bacteria, coliforms, fecal E. coli, as well as E. faecalis, C. perfringens, Staphylococcus spp. and Salmonella spp.. Water samples were collected 4 times per year on April 27th 2015 (spring, July 10th 2015 (summer, October 12th 2015 (autumn and December 29th 2015 (winter at 5 points within the area of the reservoir. Water and air temperature was measured onsite. Results. It was found that the prevalence of the analyzed microorganisms was affected by changing water and air temperature as well as by using this reservoir during holiday season for swimming purposes by local residents. All analyzed microbiological indicators of poor water quality were found in the analyzed water samples, which may pose a potential health risk to people swimming in the considered reservoir. Conclusions. From an epidemiological point of view, it is reasonable to include the Nowohucki Reservoir into a constant sanitary monitoring programme.

  7. The tectonic significance of the Cabo Frio Tectonic Domain in the SE Brazilian margin: a Paleoproterozoic through Cretaceous saga of a reworked continental margin

    Directory of Open Access Journals (Sweden)

    Renata da Silva Schmitt

    Full Text Available ABSTRACT: The Cabo Frio Tectonic Domain is composed of a Paleoproterozoic basement tectonically interleaved with Neoproterozoic supracrustal rocks (Buzios-Palmital successions. It is in contact with the Neoproterozoic-Cambrian Ribeira Orogen along the SE Brazilian coast. The basement was part of at least three continental margins: (a 1.97 Ga; (b 0.59 - 0.53 Ga; (c 0.14 Ga to today. It consists of continental magmatic arc rocks of 1.99 to 1.94 Ga. Zircon cores show a 2.5 - 2.6 Ga inheritance from the ancient margin of the Congo Craton. During the Ediacaran, this domain was thinned and intruded by tholeiitic mafic dykes during the development of an oceanic basin at ca. 0.59 Ma. After the tectonic inversion, these basin deposits reached high P-T metamorphic conditions, by subduction of the oceanic lithosphere, and were later exhumed as nappes over the basement. The Cabo Frio Tectonic Domain collided with the arc domain of the Ribeira Orogen at ca. 0.54 Ga. It is not an exotic block, but the eastern transition between this orogen and the Congo Craton. Almost 400 m.y. later, the South Atlantic rift zone followed roughly this suture, not coincidently. It shows how the Cabo Frio Tectonic Domain was reactivated as a continental margin in successive extensional and convergent events through geological time.

  8. Fortescue reservoir development and reservoir studies

    Energy Technology Data Exchange (ETDEWEB)

    Henzell, S.T.; Hicks, G.J.; Horden, M.J.; Irrgang, H.R.; Janssen, E.J.; Kable, C.W.; Mitchell, R.A.H.; Morrell, N.W.; Palmer, I.D.; Seage, N.W.

    1985-03-01

    The Fortescue field in the Gippsland Basin, offshore southeastern Australia is being developed from two platforms (Fortescue A and Cobia A) by Esso Australia Ltd. (operator) and BHP Petroleum. The Fortescue reservoir is a stratigraphic trap at the top of the Latrobe Group of sediments. It overlies the western flank of the Halibut and Cobia fields and is separated from them by a non-net sequence of shales and coals which form a hydraulic barrier between the two systems. Development drilling into the Fortescue reservoir commenced in April 1983 with production coming onstream in May 1983. Fortescue, with booked reserves of 44 stock tank gigalitres (280 million stock tank barrels) of 43/sup 0/ API oil, is the seventh major oil reservoir to be developed in the offshore Gippsland Basin by Esso/BHP. In mid-1984, after drilling a total of 20 exploration and development wells, and after approximately one year of production, a detailed three-dimensional, two-phase reservoir simulation study was performed to examine the recovery efficiency, drainage patterns, pressure performance and production rate potential of the reservoir. The model was validated by history matching an extensive suite of Repeat Formation Test (RFT) pressure data. The results confirmed the reserves basis, and demonstrated that the ultimate oil recovery from the reservoir is not sensitive to production rate. This result is consistent with studies on other high quality Latrobe Group reservoirs in the Gippsland Basin which contain undersaturated crudes and receive very strong water drive from the Basin-wide aquifer system. With the development of the simulation model during the development phase, it has been possible to more accurately define the optimal well pattern for the remainder of the development.

  9. INAA and petrological study of sandstones from the Angkor monuments

    International Nuclear Information System (INIS)

    Kucera, J.; Kranda, K.; Soukal, L.; Novak, J.K.; Lang, M.; Poncar, J.; Krausova, I.; Cunin, O.

    2008-01-01

    We determined 35 major, minor and trace elements in sandstone samples taken from building blocks of 19 Angkor temples and from an old and a new quarry using INAA. We also characterized the sandstone samples with conventional microscopy and electron microprobe analysis. Using cluster analysis, we found no straightforward correlation between the chemical/petrological properties of the sandstones and a presumed period of individual temples construction. The poor correlation may result either from the inherent inhomogeneity of sandstone or just reflect the diversity of quarries that supplied building blocks for the construction of any particular temple. (author)

  10. The Baltic Basin: structure, properties of reservoir rocks, and capacity for geological storage of CO2

    Directory of Open Access Journals (Sweden)

    Vaher, Rein

    2009-12-01

    Full Text Available Baltic countries are located in the limits of the Baltic sedimentary basin, a 700 km long and 500 km wide synclinal structure. The axis of the syneclise plunges to the southwest. In Poland the Precambrian basement occurs at a depth of 5 km. The Baltic Basin includes the Neoproterozoic Ediacaran (Vendian at the base and all Phanerozoic systems. Two aquifers, the lower Devonian and Cambrian reservoirs, meet the basic requirements for CO2 storage. The porosity and permeability of sandstone decrease with depth. The average porosity of Cambrian sandstone at depths of 80–800, 800–1800, and 1800–2300 m is 18.6, 14.2, and 5.5%, respectively. The average permeability is, respectively, 311, 251, and 12 mD. Devonian sandstone has an average porosity of 26% and permeability in the range of 0.5–2 D. Prospective Cambrian structural traps occur only in Latvia. The 16 largest ones have CO2 storage capacity in the range of 2–74 Mt, with total capacity exceeding 400 Mt. The structural trapping is not an option for Lithuania as the uplifts there are too small. Another option is utilization of CO2 for enhanced oil recovery (EOR. The estimated total EOR net volume of CO2 (part of CO2 remaining in the formation in Lithuania is 5.6 Mt. Solubility and mineral trapping are a long-term option. The calculated total solubility trapping capacity of the Cambrian reservoir is as high as 11 Gt of CO2 within the area of the supercritical state of carbon dioxide.

  11. Métodos alternativos do teste de frio para avaliação do vigor de sementes de milho Alternative methods of the cold test for evaluation of corn seed vigor

    OpenAIRE

    Roseli Fátima Caseiro; Júlio Marcos Filho

    2000-01-01

    O presente trabalho teve como objetivo básico estudar comparativamente quatro métodos para a condução do teste de frio, visando a avaliação do potencial fisiológico das sementes de milho. Para tanto, foram utilizados dois cultivares de milho (AG 3010 e AG 5011), cada um representado por 5 lotes com potenciais fisiológicos distintos. Amostras de sementes de todos os lotes foram submetidas a quatro procedimentos do teste de frio, a saber: "terra" (mistura de terra e areia) em caixas empilhadas ...

  12. Monitoring water quality in a hypereutrophic reservoir using Landsat ETM+ and OLI sensors: how transferable are the water quality algorithms?

    Science.gov (United States)

    Deutsch, Eliza S; Alameddine, Ibrahim; El-Fadel, Mutasem

    2018-02-15

    The launch of the Landsat 8 in February 2013 extended the life of the Landsat program to over 40 years, increasing the value of using Landsat to monitor long-term changes in the water quality of small lakes and reservoirs, particularly in poorly monitored freshwater systems. Landsat-based water quality hindcasting often incorporate several Landsat sensors in an effort to increase the temporal range of observations; yet the transferability of water quality algorithms across sensors remains poorly examined. In this study, several empirical algorithms were developed to quantify chlorophyll-a, total suspended matter (TSM), and Secchi disk depth (SDD) from surface reflectance measured by Landsat 7 ETM+ and Landsat 8 OLI sensors. Sensor-specific multiple linear regression models were developed by correlating in situ water quality measurements collected from a semi-arid eutrophic reservoir with band ratios from Landsat ETM+ and OLI sensors, along with ancillary data (water temperature and seasonality) representing ecological patterns in algae growth. Overall, ETM+-based models outperformed (adjusted R 2 chlorophyll-a = 0.70, TSM = 0.81, SDD = 0.81) their OLI counterparts (adjusted R 2 chlorophyll-a = 0.50, TSM = 0.58, SDD = 0.63). Inter-sensor differences were most apparent for algorithms utilizing the Blue spectral band. The inclusion of water temperature and seasonality improved the power of TSM and SDD models.

  13. Sedimentation, sediment quality, and upstream channel stability, John Redmond Reservoir, east-central Kansas, 1964-2009

    Science.gov (United States)

    Juracek, Kyle E.

    2010-01-01

    A combination of available bathymetric-survey information, bottom-sediment coring, and historical streamgage information was used to investigate sedimentation, sediment quality, and upstream channel stability for John Redmond Reservoir, east-central Kansas. Ongoing sedimentation is reducing the ability of the reservoir to serve several purposes including flood control, water supply, and recreation. The total estimated volume and mass of bottom sediment deposited between 1964 and 2009 in the conservation pool of the reservoir was 1.46 billion cubic feet and 55.8 billion pounds, respectively. The estimated sediment volume occupied about 41 percent of the conservation-pool, water-storage capacity of the reservoir. Water-storage capacity in the conservation pool has been lost to sedimentation at a rate of about 1 percent annually. Mean annual net sediment deposition since 1964 in the conservation pool of the reservoir was estimated to be 1.24 billion pounds per year. Mean annual net sediment yield from the reservoir basin was estimated to be 411,000 pounds per square mile per year Information from sediment cores shows that throughout the history of John Redmond Reservoir, total nitrogen concentrations in the deposited sediment generally were uniform indicating consistent nitrogen inputs to the reservoir. Total phosphorus concentrations in the deposited sediment were more variable than total nitrogen indicating the possibility of changing phosphorus inputs to the reservoir. As the principal limiting factor for primary production in most freshwater environments, phosphorus is of particular importance because increased inputs can contribute to accelerated reservoir eutrophication and the production of algal toxins and taste-and-odor compounds. The mean annual net loads of total nitrogen and total phosphorus deposited in the bottom sediment of the reservoir were estimated to be 2,350,000 pounds per year and 1,030,000 pounds per year, respectively. The estimated mean annual

  14. Contribution to the tectonic characterization of fractured reservoirs, I: photo-elasticimetric modelling of the stress perturbations near faults and the associated fracture network: application to oil reserves, II mechanisms for the 3D joint organization in a natural reservoir analogue (flat-lying Devonian Old Red Sandstones of Caitness in North Scotland); Contribution a la caracterisation tectonique des reservoirs fractures, I: modelisation photoelecticimetrique des perturbations de contrainte au voisinage des failles et de la fracturation associee: application petroliere, II: mecanismes de developpement en 3D des diaclases dans un analogue de reservoir, le Devonien tabulaire du caithness (Ecosse)

    Energy Technology Data Exchange (ETDEWEB)

    Auzias, V

    1995-10-27

    In order to understand joint network organisation in oil reservoirs, as a first step we have adapted to technique (the photo-elasticimetry) to study stress fields in 2D. This method allows to determine the principal stress trajectories near faults, as well as the associated joint network organisation. Natural joint networks perturbed near faults are modeled and the parameters that control stress perturbation are proposed. With the aim of extrapolating joint data from a well to the entire reservoir our modelling is based on both 3 D seismic data and local joint data. The second part of our research was dedicated to studying joint propagation mechanisms in a natural reservoir analogue (flat-lying Devonian Old Red Sandstones of Caitness in North Scotland). Several exposure observation at different scales and in 3D (horizontal and cliff sections) allow to reconstitute the fracturing geometry from centimeter to kilometer scale and to link these to the regional tectonic history. This study shows that it is possible to differentiate three types of joints major joints, `classic` joints and micro-joints, each with different vertical persistence. New concepts on the 3D joint organisation have been deduced from field quantitative data, which can be applied to reservoir fracture modeling. In particular the non-coexistence phenomenon in a single bed of two regional joint sets with close strikes. Some joint development mechanisms are discussed: interaction between joints and sedimentary interfaces, joint distribution near faults, origin of en echelon arrays associated with joints. (author) 142 refs.

  15. Formation conditions and prospecting criteria for sandstone uranium deposit of interlayer oxidation type

    International Nuclear Information System (INIS)

    Huang Shijie

    1994-01-01

    This paper comprehensively analyses the geotectonic setting and favourable conditions, such as structure of the basin, sedimentary facies and paleogeography, geomorphology and climate, hydrodynamics and hydrogeochemistry, the development of interlayered oxidation etc, necessary for the formation of sandstone uranium deposit of interlayered oxidation type. The following prospecting criteria is proposed, namely: abundant uranium source, arid climate, stable big basin, flat-lying sandstone bed, big alluvial fan, little change in sedimentary facies, intercalation of sandstone and mudstone beds, shallow burying of sandstone bed, well-aquiferous sandstone bed, high permeability of sandstone bed, development of interlayered oxidation, and high content of reductant in sandstone. In addition, the 6 in 1 hydrogenic genetic model is proposed

  16. Channel sandstone and bar morphology of the Beaufort group uranium district near Beaufort West

    International Nuclear Information System (INIS)

    Stear, W.M.

    1980-01-01

    Sheet-like and lenticular sandstone bodies in the Lower Beaufort Group (Adelaide Subgroup) uranium district occur in megacyclic repetition as superimposed systems of ephemeral fluvial channels that display characteristics of complex lateral and vertical accretion. Channel sandstone bodies are defined on morphological grounds into two types. Sheet sandstone bodies are the commonest type and comprise the bulk of sandstone packages in arenaceous zones of megacycles. Composite sandstone sheets result from multilateral coalescence of individual sandstone bodies. Isolated lenticular sandstone units in argillaceous zones of megacycles comprise sheet and ribbon sandstone types. Multi-storeying is a prominent feature of most channel sandstone bodies and often results in local sandstone thickening. Bedforms relate to the formation of compound bars and record periods of dynamic accretion and erosion. Rarely preserved palaeosurfaces vividly illustrate the fluctuating hydrodynamic conditions that typified ephemeral fluvial sedimentation in a semi-arid environment during Lower Beaufort times

  17. Channel sandstone and bar morphology of the Beaufort group uranium district near Beaufort West

    Energy Technology Data Exchange (ETDEWEB)

    Stear, W M

    1980-01-01

    Sheet-like and lenticular sandstone bodies in the Lower Beaufort Group (Adelaide Subgroup) uranium district occur in megacyclic repetition as superimposed systems of ephemeral fluvial channels that display characteristics of complex lateral and vertical accretion. Channel sandstone bodies are defined on morphological grounds into two types. Sheet sandstone bodies are the commonest type and comprise the bulk of sandstone packages in arenaceous zones of megacycles. Composite sandstone sheets result from multilateral coalescence of individual sandstone bodies. Isolated lenticular sandstone units in argillaceous zones of megacycles comprise sheet and ribbon sandstone types. Multi-storeying is a prominent feature of most channel sandstone bodies and often results in local sandstone thickening. Bedforms relate to the formation of compound bars and record periods of dynamic accretion and erosion. Rarely preserved palaeosurfaces vividly illustrate the fluctuating hydrodynamic conditions that typified ephemeral fluvial sedimentation in a semi-arid environment during Lower Beaufort times.

  18. Fracture properties from tight reservoir outcrop analogues with application to geothermal exploration

    Science.gov (United States)

    Philipp, Sonja L.; Reyer, Dorothea; Afsar, Filiz; Bauer, Johanna F.; Meier, Silke; Reinecker, John

    2015-04-01

    In geothermal reservoirs, similar to other tight reservoirs, fluid flow may be intensely affected by fracture systems, in particular those associated with fault zones. When active (slipping) the fault core, that is, the inner part of a fault zone, which commonly consists of breccia or gouge, can suddenly develop high permeability. Fault cores of inactive fault zones, however, may have low permeabilities and even act as flow barriers. In the outer part of a fault zone, the damage zone, permeability depends mainly on the fracture properties, that is, the geometry (orientation, aperture, density, connectivity, etc.) of the fault-associated fracture system. Mineral vein networks in damage zones of deeply eroded fault zones in palaeogeothermal fields demonstrate their permeability. In geothermal exploration, particularly for hydrothermal reservoirs, the orientation of fault zones in relation to the current stress field as well as their internal structure, in particular the properties of the associated fracture system, must be known as accurately as possible for wellpath planning and reservoir engineering. Here we present results of detailed field studies and numerical models of fault zones and associated fracture systems in palaeogeo¬thermal fields and host rocks for geothermal reservoirs from various stratigraphies, lithologies and tectonic settings: (1) 74 fault zones in three coastal sections of Upper Triassic and Lower Jurassic age (mudstones and limestone-marl alternations) in the Bristol Channel Basin, UK. (2) 58 fault zones in 22 outcrops from Upper Carboniferous to Upper Cretaceous in the Northwest German Basin (siliciclastic, carbonate and volcanic rocks); and (3) 16 fault zones in 9 outcrops in Lower Permian to Middle Triassic (mainly sandstone and limestone) in the Upper Rhine Graben shoulders. Whereas (1) represent palaeogeothermal fields with mineral veins, (2) and (3) are outcrop analogues of reservoir horizons from geothermal exploration. In the study

  19. Improved Oil Recovery in Fluvial Dominated Deltaic Reservoirs of Kansas - Near-Term

    International Nuclear Information System (INIS)

    Green, Don W.; McCune, A.D.; Michnick, M.; Reynolds, R.; Walton, A.; Watney, L.; Willhite, G. Paul

    1999-01-01

    The objective of this project is to address waterflood problems of the type found in Morrow sandstone reservoirs in southwestern Kansas and in Cherokee Group reservoirs in southeastern Kansas. Two demonstration sites operated by different independent oil operators are involved in this project. The Stewart Field is located in Finney County, Kansas and is operated by PetroSantander, Inc. Te Nelson Lease is located in Allen County, Kansas, in the N.E. Savonburg Field and is operated by James E. Russell Petroleum, Inc. General topics to be addressed are (1) reservoir management and performance evaluation, (2) waterflood optimization, and (3) the demonstration of recovery processes involving off-the-shelf technologies which can be used to enhance waterflood recovery, increase reserves, and reduce the abandonment rate of these reservoir types. In the Stewart Project, the reservoir management portion of the project conducted during Budget Period 1 involved performance evaluation. This included (1) reservoir characterization and the development of a reservoir database, (2) volumetric analysis to evaluate production performance, (3) reservoir modeling, (4) laboratory work, (5) identification of operational problems, (6) identification of unrecovered mobile oil and estimation of recovery factors, and (7) Identification of the most efficient and economical recovery process. To accomplish these objectives the initial budget period was subdivided into three major tasks. The tasks were (1) geological and engineering analysis, (2) laboratory testing, and (3) unitization. Due to the presence of different operators within the field, it was necessary to unitize the field in order to demonstrate a field-wide improved recovery process. This work was completed and the project moved into Budget Period 2

  20. Benthic macroinvertebrates as bioindicators of water quality in Billings Reservoir fishing sites (SP, Brazil

    Directory of Open Access Journals (Sweden)

    José Ricardo Baroldi Ciqueto Gargiulo

    Full Text Available Abastract: Aim The Billings Reservoir is the largest reservoir in the metropolitan region of São Paulo and has multiple uses, including artisanal fishing. Its surroundings present intense occupation, resulting in various environmental impacts. Although the water is degraded, affecting the composition and quality of the fish, this reservoir supports artisanal fishermen who survive through this activity. This study aimed to analyze the water quality in the main sites of artisanal fishing activity, with an emphasis on the benthic community as a bioindicator. Methods Three sampling sites were selected, in which water and zoobenthos samples were collected monthly from April 2012 to March 2013. Water analyses consisted of the determination of pH, temperature, conductivity, turbidity, total dissolved solids, dissolved oxygen, total nitrogen, total phosphorus, and trophic state as well as a principal components analysis. The zoobenthos analysis consisted of determining the relative abundance and total density of taxa, the Shannon-Weaver diversity index, taxa richness, uniformity, Simpson’s dominance index, and the benthic community index and conducting a canonical correspondence analysis. The non-parametric Kruskal-Wallis test followed by the Student-Newman-Keuls test were used to investigate the existence of significant differences in the abiotic and biotic variables among the sites. Results The studied sites showed a high degree of eutrophication, with nitrogen and phosphorus totals levels above the limits defined by current Brazilian legislation. Taquacetuba (P1 showed the best environmental conditions for the development of fishing activity, with the presence of sensitive organisms (Polymitarcyidae and higher levels of dissolved oxygen. Alvarenga (P2 had the worst water quality, with a predominance of tolerant organisms (Oligochaeta and lower levels of dissolved oxygen. Conclusion In conclusion, the benthic community in association with abiotic

  1. Sedimentology, Sequence Stratigraphy and Reservoir Characterization of Samana Suk Formation Exposed in Namal Gorge Section, Salt Range, Mianwali, Punjab, Pakistan

    Directory of Open Access Journals (Sweden)

    Muhammad Hayat

    2016-06-01

    Full Text Available Samana Suk Formation of Bathonian-callovain age, exposed in Nammal Gorge Salt Range, has been studied for microfacies and sequence stratigraphic investigation. The formation is mainly composed of limestone, with minor beds of sandstone and marl. The limestone is grey, yellowish and purple in color. Limestone is fine grained, thin to medium bedded and inter-bedded with algal laminations. The sandstone is light yellowish brown, brick red in color, calcareous and quartzose. Within Samana Suk Formation one 2ndorder sequence and two 3rdorder sequences have been identified. Their regional correlation through fine-tuned dating helped to develop basin fill model and to understand facies dynamics. A facie belt comprising a wide belt of carbonate facies characterized by Peloidal Packstone microfacies represents inner ramp setting and Pelletal/ Peloidal Wackstone, Mud-Wackstone and Mudstone microfacies represent the low energy lagoonal environment. The sandstone lithofacies represents high energy beach environment which indicates aggrading to pro-grading pattern. The porosity analysis has been done on different samples of limestone and sandstone. For the porosity analysis the Image J software is used. In limestone the porosity ranges up to 6% while in sandstone the porosity ranging up to 18%. From the field and porosity analysis it is concluded that Samana Suk Formation in study area is good reservoir.

  2. Effect of retrograde gas condensate in low permeability natural gas reservoir; Efeito da condensacao retrograda em reservatorios de gas natural com baixa permeabilidade

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Paulo Lee K.C. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Faculdade de Engenharia Mecanica; Ligero, Eliana L.; Schiozer, Denis J. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Faculdade de Engenharia Mecanica. Dept. de Engenharia de Petroleo

    2008-07-01

    Most of Brazilian gas fields are low-permeability or tight sandstone reservoirs and some of them should be gas condensate reservoir. In this type of natural gas reservoir, part of the gaseous hydrocarbon mixture is condensate and the liquid hydrocarbon accumulates near the well bore that causes the loss of productivity. The liquid hydrocarbon formation inside the reservoir should be well understood such as the knowledge of the variables that causes the condensate formation and its importance in the natural gas production. This work had as goal to better understanding the effect of condensate accumulation near a producer well. The influence of the porosity and the absolute permeability in the gas production was studied in three distinct gas reservoirs: a dry gas reservoir and two gas condensate reservoirs. The refinement of the simulation grid near the producer well was also investigated. The choice of simulation model was shown to be very important in the simulation of gas condensate reservoirs. The porosity was the little relevance in the gas production and in the liquid hydrocarbon formation; otherwise the permeability was very relevant. (author)

  3. A New Method for Fracturing Wells Reservoir Evaluation in Fractured Gas Reservoir

    Directory of Open Access Journals (Sweden)

    Jianchun Guo

    2014-01-01

    Full Text Available Natural fracture is a geological phenomenon widely distributed in tight formation, and fractured gas reservoir stimulation effect mainly depends on the communication of natural fractures. Therefore it is necessary to carry out the evaluation of this reservoir and to find out the optimal natural fractures development wells. By analyzing the interactions and nonlinear relationships of the parameters, it establishes three-level index system of reservoir evaluation and proposes a new method for gas well reservoir evaluation model in fractured gas reservoir on the basis of fuzzy logic theory and multilevel gray correlation. For this method, the Gaussian membership functions to quantify the degree of every factor in the decision-making system and the multilevel gray relation to determine the weight of each parameter on stimulation effect. Finally through fuzzy arithmetic operator between multilevel weights and fuzzy evaluation matrix, score, rank, the reservoir quality, and predicted production will be gotten. Result of this new method shows that the evaluation of the production coincidence rate reaches 80%, which provides a new way for fractured gas reservoir evaluation.

  4. Application of advanced reservoir characterization, simulation, and production optimization strategies to maximize recovery in slope and basin clastic reservoirs, West Texas (Delaware Basin). Quarterly report, October 1 - December 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Dutton, S.P.

    1997-01-01

    The objective of this project is to demonstrate that detailed reservoir characterization of slope and basin clastic reservoirs in sandstones of the Delaware Mountain Group in the Delaware Basin of West Texas and New Mexico is a cost effective way to recover a higher percentage of the original oil in place through strategic placement of infill wells and geologically based field development. Project objectives are divided into two major phases. The objectives of the reservoir characterization phase of the project are to provide a detailed understanding of the architecture and heterogeneity of two fields, the Ford Geraldine unit and Ford West field, which produce from the Bell Canyon and Cherry Canyon Formations, respectively, of the Delaware Mountain Group and to compare Bell Canyon and Cherry Canyon reservoirs. Reservoir characterization will utilize 3-D seismic data, high-resolution sequence stratigraphy, subsurface field studies, outcrop characterization, and other techniques. Once the reservoir-characterization study of both fields is completed, a pilot area of approximately 1 mi{sup 2} in one of the fields will be chosen for reservoir simulation. The objectives of the implementation phase of the project are to (1) apply the knowledge gained from reservoir characterization and simulation studies to increase recovery from the pilot area, (2) demonstrate that economically significant unrecovered oil remains in geologically resolvable untapped compartments, and (3) test the accuracy of reservoir characterization and flow simulation as predictive tools in resource preservation of mature fields. A geologically designed, enhanced-recovery program (CO{sub 2} flood, waterflood, or polymer flood) and well-completion program will be developed, and one to three infill wells will be drilled and cored. Technical progress is summarized for: geophysical characterization; reservoir characterization; outcrop characterization; and recovery technology identification and analysis.

  5. Water quality control in Third River Reservoir (Argentina using geographical information systems and linear regression models

    Directory of Open Access Journals (Sweden)

    Claudia Ledesma

    2013-08-01

    Full Text Available Water quality is traditionally monitored and evaluated based upon field data collected at limited locations. The storage capacity of reservoirs is reduced by deposits of suspended matter. The major factors affecting surface water quality are suspended sediments, chlorophyll and nutrients. Modeling and monitoring the biogeochemical status of reservoirs can be done through data from remote sensors. Since the improvement of sensors’ spatial and spectral resolutions, satellites have been used to monitor the interior areas of bodies of water. Water quality parameters, such as chlorophyll-a concentration and secchi disk depth, were found to have a high correlation with transformed spectral variables derived from bands 1, 2, 3 and 4 of LANDSAT 5TM satellite. We created models of estimated responses in regard to values of chlorophyll-a. To do so, we used population models of single and multiple linear regression, whose parameters are associated with the reflectance data of bands 2 and 4 of the sub-image of the satellite, as well as the data of chlorophyll-a obtained in 25 selected stations. According to the physico-chemical analyzes performed, the characteristics of the water in the reservoir of Rio Tercero, correspond to somewhat hard freshwater with calcium bicarbonate. The water was classified as usable as a source of plant treatment, excellent for irrigation because of its low salinity and low residual sodium carbonate content, but unsuitable for animal consumption because of its low salt content.

  6. Reservoir management under consideration of stratification and hydraulic phenomena

    OpenAIRE

    Nandalal, K.D.W.

    1995-01-01


    Reservoirs are the most important components in a water resources system. They are used to store water to extend its temporal availability. The physical, chemical and biological characteristics of water change when impounded in reservoirs. This implies the possibility of using reservoirs for the control of the quality of water besides merely satisfying the quantity requirement. This study presents several techniques formulated to manage a reservoir when both quantity and quality of...

  7. Drag reduction in reservoir rock surface: Hydrophobic modification by SiO{sub 2} nanofluids

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Yong-Li, E-mail: yylhill@163.com [College of Chemistry & Chemical Engineering, Xi’an Shiyou University, Xi’an 710065 (China); Cui, Ming-Yue; Jiang, Wei-Dong; He, An-Le; Liang, Chong [Langfang Branch of Research Institute of Petroleum Exploration & Development, Langfang 065007 (China)

    2017-02-28

    Graphical abstract: The micro-nanoscale hierarchical structures at the sandstone core surface are constructed by adsorption of the modified silica nanoparticles, which leads to the effect of drag reduction to improve the low injection rate in ultra-low permeability reservoirs. - Highlights: • A micro-nanoscale hierarchical structure is formed at the reservoir rock surface. • An inversion has happened from hydrophilic into hydrophobic modified by nanofluids. • The effect of drag reduction to improve the low injection rate is realized. • The mechanism of drag reduction induced from the modified core surface was unclosed. - Abstract: Based on the adsorption behavior of modified silica nanoparticles in the sandstone core surface, the hydrophobic surface was constructed, which consists of micro-nanoscale hierarchical structure. This modified core surface presents a property of drag reduction and meets the challenge of high injection pressure and low injection rate in low or ultra-low permeability reservoir. The modification effects on the surface of silica nanoparticles and reservoir cores, mainly concerning hydrophobicity and fine structure, were determined by measurements of contact angle and scanning electron microscopy. Experimental results indicate that after successful modification, the contact angle of silica nanoparticles varies from 19.5° to 141.7°, exhibiting remarkable hydrophobic properties. These modified hydrophobic silica nanoparticles display a good adsorption behavior at the core surface to form micro-nanobinary structure. As for the wettability of these modified core surfaces, a reversal has happened from hydrophilic into hydrophobic and its contact angle increases from 59.1° to 105.9°. The core displacement experiments show that the relative permeability for water has significantly increased by an average of 40.3% via core surface modification, with the effects of reducing injection pressure and improving injection performance of water

  8. Response of currents and water quality to changes in dam operations in Hoover Reservoir, Columbus, Ohio, August 24–28, 2015

    Science.gov (United States)

    Vonins, Branden L.; Jackson, P. Ryan

    2017-05-25

    Hoover Reservoir, an important drinking water supply for the City of Columbus, Ohio, has been the source of a series of taste and odor problems in treated drinking water during the past few years. These taste and odor problems were caused by the compounds geosmin and 2-methylisoborneol, which are thought to have been related to cyanobacteria blooms. In an effort to reduce the phosphorus available for cyanobacteria blooms at fall turnover, the City of Columbus began experimenting with the dam’s selective withdrawal system to remove excess phosphorus in the hypolimnion, which is released from bottom sediments during summer anoxic conditions.The U.S. Geological Survey completed two synoptic survey campaigns to assess distributions of water quality and water velocity in the lower part of Hoover Reservoir to provide information on the changes to reservoir dynamics caused by changing dam operations. One campaign (campaign 1) was done while water was being withdrawn from the reservoir through the dam’s middle gate and the other (campaign 2) while water was being withdrawn through the dam’s lower gate. Velocities were measured using an acoustic Doppler current profiler, and water-quality parameters were measured using an autonomous underwater vehicle equipped with water-quality sensors. Along with the water-quality and water-velocity data, meteorological, inflow and outflow discharges, and independent water-quality data were compiled to monitor changes in other parameters that affect reservoir behavior. Monthly nutrient data, collected by the City of Columbus, were also analyzed for trends in concentration during periods of expected stratification.Based on the results of the two campaigns, when compared to withdrawing water through the middle gate, withdrawing water through the lower gate seemed to increase shear-driven mixing across the thermocline, which resulted in an increase in the depth of the epilimnion throughout the lower part of Hoover Reservoir. The

  9. Distinguishing of uranium-bearing sandstone by the geochemical characteristics in northern Sichuan

    International Nuclear Information System (INIS)

    Wang Wangzhang; Zhang Zhufeng; Wang Yunliang; Sun Shuqin.

    1994-01-01

    Expounding geochemical characteristics of sandstone-type uranium deposits in northern Sichuan, the authors demonstrate the favourable and unfavourable conditions for enrichment of uranium on the basis of element abundances and ratios of U, Th and K measured by the gamma-ray spectroscopy surveying. The differences between uranium-bearing and non-uranium sandstones and between red sandstone (clay stone) and greenish sandstone can be determined by the gamma-ray spectroscopy (measuring U, Th and K) and XRF analysis (measuring As and Ba). Therefore, the prospecting of the sandstone-type uranium deposits in northern Sichuan can be concentrated in a certain range

  10. Distribution characteristics of Shihongtan uranium deposits calcareous sandstone and discussion on their genesis

    International Nuclear Information System (INIS)

    Zhu Huanqiao; Jia Heng; Xu Gaozhong; Li Zhanyou

    2007-12-01

    It is considered that the calcareous sandstone appear at layer along of a bunch of pear lens on and off, localled near up and down surface of sandbody or washed surface, has sandstone of more macro-grain and more gradation through statistics and analysis of calcareous sandstone in goal layer in Shihongtan uranium deposits. The calcareous sandstone accumulation thickness chorogram demonstrated that the calcareous sandstone centralized distribution in the ore body growth area, thus it can be seen, in the oxidation reduction intermediate belt the calcareous sandstone forms with the uranium mine has the certain origin relation. Choropleth map of summed thickness of calcareous sandstone deserves that it mainly appear in area of uranium body and related cause of formation of ore body of interlayer deacidizing--oxidation belt. (authors)

  11. Integrated Sedimentological Approach to Assess Reservoir Quality and Architecture of Khuff Carbonates: Outcrop Analog, Central Saudi Arabia

    Science.gov (United States)

    Osman, Mutsim; Abdullatif, Osman

    2017-04-01

    and evaluate Khuff reservoir heterogeneity, quality and architecture. It might also help to fill the gap in knowledge in reservoir characterization models based on low resolution subsurface data alone.

  12. Chemical and physical hydrogeology of coal, mixed coal-sandstone and sandstone aquifers from coal-bearing formations in the Alberta Plains region, Alberta

    International Nuclear Information System (INIS)

    Lemay, T.G.

    2003-09-01

    With the decline of conventional oil and gas reserves, natural gas from coal (NGC) is an unconventional gas resource that is receiving much attention from petroleum exploration and development companies in Alberta. Although the volume of the NGC resource is large, there are many challenges facing NGC development in Alberta, including technical and economic issues, land access, water disposal, water diversion and access to information. Exploration and development of NGC in Alberta is relatively new, therefore there is little baseline data on which to base regulatory strategies. Some important information gaps have been filled through water well sampling in coal, mixed coal-sandstone and sandstone aquifers throughout Alberta. Analyses focused on the chemical and physical characteristics aquifers in use for domestic or agricultural purposes. Aquifer depths were generally less than 100 metres. Samples collected from Paskapoo-Scollard Formation, Horseshoe Canyon Formation and Belly River Group aquifers exceed Canadian water quality guideline values with respect to pH, sodium, manganese, chloride, chromium, sulphate, phenols and total dissolved solids. Pump tests conducted within the aquifers indicate that the groundwater flow is complicated. Water quality will have to be carefully managed to ensure responsible disposal practices are followed. Future studies will focus on understanding the chemical and biological process that occur within the aquifers and the possible link between these processes and gas generation. Mitigation and disposal strategies for produced water will also be developed along with exploration strategies using information obtained from hydrogeologic studies. 254 refs., 182 tabs., 100 figs., 3 appendices

  13. Advances in coalbed methane reservoirs using integrated reservoir characterization and hydraulic fracturing in Karaganda coal basin, Kazakhstan

    Science.gov (United States)

    Ivakhnenko, Aleksandr; Aimukhan, Adina; Kenshimova, Aida; Mullagaliyev, Fandus; Akbarov, Erlan; Mullagaliyeva, Lylia; Kabirova, Svetlana; Almukhametov, Azamat

    2017-04-01

    Coalbed methane from Karaganda coal basin is considered to be an unconventional source of energy for the Central and Eastern parts of Kazakhstan. These regions are situated far away from the main traditional sources of oil and gas related to Precaspian petroleum basin. Coalbed methane fields in Karaganda coal basin are characterized by geological and structural complexity. Majority of production zones were characterized by high methane content and extremely low coal permeability. The coal reservoirs also contained a considerable natural system of primary, secondary, and tertiary fractures that were usually capable to accommodate passing fluid during hydraulic fracturing process. However, after closing was often observed coal formation damage including the loss of fluids, migration of fines and higher pressures required to treat formation than were expected. Unusual or less expected reservoir characteristics and values of properties of the coal reservoir might be the cause of the unusual occurred patterns in obtained fracturing, such as lithological peculiarities, rock mechanical properties and previous natural fracture systems in the coals. Based on these properties we found that during the drilling and fracturing of the coal-induced fractures have great sensitivity to complex reservoir lithology and stress profiles, as well as changes of those stresses. In order to have a successful program of hydraulic fracturing and avoid unnecessary fracturing anomalies we applied integrated reservoir characterization to monitor key parameters. In addition to logging data, core sample analysis was applied for coalbed methane reservoirs to observe dependence tiny lithological variations through the magnetic susceptibility values and their relation to permeability together with expected principal stress. The values of magnetic susceptibility were measured by the core logging sensor, which is equipped with the probe that provides volume magnetic susceptibility parameters

  14. Evaluating reservoir aspects from database on infill/step-out wells

    Energy Technology Data Exchange (ETDEWEB)

    Springer, S.J. [Springer Consulting Services, Calgary, AB (Canada)

    2006-07-01

    Statistical plots of production data were used as the basis for calculating simple parameters in order to develop insights into the performance of infill wells drilled in the Western Canadian Sedimentary Basin (WCSB). Unique characteristics of the performance of wells drilled in different parts of the basin were also discussed with the aim of assisting in the screening of future infill drilling projects. The aim of the paper was to demonstrate the effectiveness of a simple statistical analysis of the performance curves and to determine a method of characterizing lateral heterogeneity as well as risks in developing similar pools by infill drilling. The main data sources were the provincial Oil and Gas Reserves Books. Production data were obtained from a commercial data base. Data from wells at a heavy oil sandstone reservoir and a shallow sandstone gas reservoir were evaluated. In both pools, the horizontal infill wells performed better than the vertical wells.The initial rate of the median well was obtained by referencing the wells to its start time. A rate time plot for the first 5 years was prepared for the median wells. Similar plots for the average, 25 and 75 percentile wells were also generated. A cumulative production-frequency plot was generated for each pool. Most of the plots showed a fairly linear trend, reflecting a lognormal distribution. The slope of the lognormal plot reflected the lateral heterogeneity within the prospect. It was concluded that the analysis of the rate-cumulative production plot provided a method of accessing which percentages of the production were incremental reserves and which percentage were accelerated production. 7 refs., 9 tabs., 7 figs.

  15. Water Vapor Diffusion and Adsorption of Sandstones: Influence of Rock Texture and Composition

    Directory of Open Access Journals (Sweden)

    Martin Keppert

    2016-01-01

    Full Text Available The term sandstone is used for wide range of rocks containing quartz clasts which can be cemented by secondary precipitated quartz or calcite; moreover the space between clasts can be filled by matrix. These facts result in existence of numerous rocks having highly various properties. Sandstones have been used as construction materials due to their good accessibility and workability. Since most of sandstones are porous, water vapor can penetrate through sandstone constructions. The rate of water vapor diffusion, as well as the vapor sorption isotherm, was determined for range of sandstone types. The diffusion resistance factor was found to be dependent on the total porosity of sandstone but the sorption behavior was strongly influenced by nature of the particular sandstone; the specific surface area of stone and presence of clay matrix are determining its sorption isotherm. The published data enable estimating (i diffusion resistance factor of a sandstone via knowledge of its total porosity and (ii the sorption isotherm via knowledge of the stone’s nature and specific surface area. This approach can significantly reduce the time necessary to acquire vapor-related properties of a sandstone.

  16. Determination of the Representative Elementary Volume for the study of sandstones and siltstones by X-Ray microtomography

    Directory of Open Access Journals (Sweden)

    Jaquiel Salvi Fernandes

    2012-08-01

    Full Text Available X-Ray computerized microtomography (µ-CT besides providing two-dimensional images (2-D of the transversal sections of the sample, the biggest attraction of the methodology is the rendering of three-dimensional images (3-D, enabling a more real analysis of the porous structure of the rock. However, the reconstruction, visualization and analysis of such 3-D images are limited in computer terms. Thus, it is not always possible to reconstruct the images with the total size of the microtomographed sample. Therefore, this study aims at determining the Representative Elementary Volume (REV in reservoir rocks concerning their porosity. In order to collect microtomographic data from reservoir rocks, a microtomograph Skyscan model 1172 was utilized for the sandstone and siltstone samples scanning. After the analysis of the graphs obtained by REV, it was concluded that the most adequate dimensions for the reconstructed volume in each analyzed sample were approximately 1400 × 1400 × 1400 µm, which are dimensions that can easily be reconstructed, visualized and analyzed.

  17. PP and PS seismic response from fractured tight gas reservoirs: a case study

    International Nuclear Information System (INIS)

    Jianming, Tang; Shaonan, Zhang; Li, Xiang-Yang

    2008-01-01

    In this paper, we present an example of using PP and PS converted-wave data recorded by digital micro-eletro-mechanical-systems (MEMS) to evaluate a fractured tight gas reservoir from the Xinchang gas field in Sichuan, China. For this, we analyse the variations in converted shear-wave splitting, Vp/Vs ratio and PP and PS impedance, as well as other attributes based on absorption and velocity dispersion. The reservoir formation is tight sandstone, buried at a depth of about 5000 m, and the converted-wave data reveal significant shear-wave splitting over the reservoir formation. We utilize a rotation technique to extract the shear-wave polarization and time delay from the data, and a small-window correlation method to build time-delay spectra that allow the generation of a time-delay section. At the reservoir formation, the shear-wave time delay is measured at 20 ms, about 15% shear-wave anisotropy, correlating with the known gas reservoirs. Furthermore, the splitting anomalies are consistent with the characteristics of other attributes such as Vp/Vs ratio and P- and S-wave acoustic and elastic impedance. The P-wave shows consistent low impedance over the reservoir formation, whilst the S-wave impedance shows relatively high impedance. The calculated gas indicator based on absorption and velocity dispersion yields a high correlation with the gas bearing formations. This confirms the benefit of multicomponent seismic data from digital MEMS sensors

  18. Understanding creep in sandstone reservoirs – theoretical deformation mechanism maps for pressure solution in granular materials

    NARCIS (Netherlands)

    Hangx, Suzanne; Spiers, Christopher

    Subsurface exploitation of the Earth’s natural resources removes the natural system from its chemical and physical equilibrium. As such, groundwater extraction and hydrocarbon production from subsurface reservoirs frequently causes surface subsidence and induces (micro)seismicity. These effects are

  19. Effects of Coordinated Operation of Weirs and Reservoirs on the Water Quality of the Geum River

    Directory of Open Access Journals (Sweden)

    Jung Min Ahn

    2017-06-01

    Full Text Available Multifunctional weirs can be used to maintain water supply during dry seasons and to improve downstream water quality during drought conditions through discharge based on retained flux. Sixteen multifunctional weirs were recently constructed in four river systems as part of the Four Rivers Restoration Project. In this study, three multifunctional weirs in the Geum River Basin were investigated to analyze the environmental effects of multifunctional weir operation on downstream flow. To determine seasonal vulnerability to drought, the basin was evaluated using the Palmer Drought Severity Index (PDSI. Furthermore, the downstream flow regime and the effect on water quality improvement of a coordinated dam–multifunctional weir operation controlled by: (a a rainfall–runoff model; (b a reservoir optimization model; and (c a water quality model, were examined. A runoff estimate at each major location in the Geum River Basin was performed using the water quality model, and examined variation in downstream water quality depending on the operational scenario of each irrigation facility such as dams and weirs. Although the water quality was improved by the coordinated operation of the dams and weirs, when the discharged water quality is poor, the downstream water quality is not improved. Therefore, it is necessary to first improve the discharged water quality on the lower Geum River. Improvement of the water quality of main stream in the Geum River is important, but water quality from tributaries should also be improved. By applying the estimated runoff data to the reservoir optimization model, these scenarios will be utilized as basic parameters for assessing the optimal operation of the river.

  20. [Aquatic insects and water quality in Peñas Blancas watershed and reservoir].

    Science.gov (United States)

    Mora, Meyer Guevara

    2011-06-01

    The aquatic insects have been used to evaluate water quality of aquatic environments. The population of aquatic insects and the water quality of the area were characterized according to the natural and human alterations present in the study site. During the monthly-survey, pH, DO, temperature, water level, DBO, PO4 and NO3 were measured. Biological indexes (abundance, species richness and the BMWP-CR) were used to evaluate the water quality. No relation between environmental and aquatic insects was detected. Temporal and spatial differences attributed to the flow events (temporal) and the presence of Peñas Blancas reservoir (spatial). In the future, the investigations in Peñas Blancas watershed need to be focused on determining the real influence of the flows, sediment release and the possible water quality degradation because of agriculture activities.

  1. Study of the reactive processes during CO2 injection into sedimentary reservoirs: Experimental quantification of the processes at meso-scale

    International Nuclear Information System (INIS)

    Luquot, L.

    2008-11-01

    In order to minimize CO 2 atmospheric concentration, a solution consists in sequestrating CO 2 in geological reservoirs. To estimate long term risks, it is necessary to quantify the couplings between reaction processes as well as structural and hydrodynamical modifications. We realised two experimental benches enabling injecting CO 2 -enriched-brine in conditions corresponding to in situ storage (T ≤ 200 C and P ≤ 200 bar) and developed an experimental protocol using X-Ray microtomography and fluid and rock analyses in order to measure the variations of physical and chemical parameters. The study of carbonated reservoirs near the injection well, allows quantifying different k-phi relationships depending on the dissolution processes and triggered by the local fluid chemical composition and initials conditions. Away from the injection well, we observe carbonate precipitation decreasing the permeability. The study of fractured cap-rock samples shows that alternative percolation of CO 2 -enriched-brine and CO 2 gas increases the fracture permeability. The study of silicated rocks indicates carbonate precipitation in zeolite sandstone and sintered dunite grains. Nevertheless, in zeolite sandstone we also observe the precipitation of clay particles located in the fluid pathways which decrease strongly the permeability. (author)

  2. Mittelplate A23/A23M1. Geological and reservoir engineering concept of a dual-lateral well; Mittelplate A23/A23M1. Geologisches und lagerstaettentechnisches Konzept einer Duolateralbohrung

    Energy Technology Data Exchange (ETDEWEB)

    Osivandi, K.; Racher, D. [RWE Dea AG, Hamburg (Germany)

    2011-07-15

    The Mittelplate Oil Field is situated in the German Wadden Sea in the West Holstein Trough in the concession Heide/Buesum, about 100 km northwest of Hamburg. Operator is RWE Dea AG (50%), and the partner is Wintershall Holding GmbH (50%). Besides the reservoir layers of the Dogger Gamma, Delta, Epsilon, and Zeta, the shallow-marine/deltaic sandstone-shale-succession of the Dogger Beta (with its five oil-bearing sandstones of 1-5 m thickness each) forms the laterally widespread reservoir which was the target for Germany's and RWE Dea AG's first pressure-tight multilateral well. So far the Dogger-Beta-Reservoir has been developed with wells from the artificial island Mittelplate A using a 5-spot pattern with a successive concentric concept. In order to reduce the costs and effectively make use of the limited amount of slots, the development concept should be improved by implementing the multilateral technology. By targeting three drainage areas in total, the multilateral well Mittelplate A23/A23M1 was planned to produce oil at an initial rate of ca. 400 m{sup 3}/d. In order to achieve a horizontal interval of ca. 2640 m length, several LWD measurements including Gamma Ray- and Density- Images and Deep-Directional-Resistivity logs were necessary. The long horizontal exposure of the oil-bearing sandstone layers as well as the tangent sections for placement of the electrical submersible pump (ESP) and junction above the reservoir represented the main challenges during geological planning and realtime geosteering. A total perforation length of 1360 m was achieved, taking into account the required distances to neighboring producer wells and the laterally varying pore pressures. According to the latest production history of the well, a cumulative production of about 10% more than initially planned are expected after an initial production rate of 735 m{sup 3}/d. Thanks to the successful application of the multilateral technology and geosteering within the thin

  3. Elementary analysis on the main factors affecting the permeability of sandstones

    International Nuclear Information System (INIS)

    Gong Binli

    2006-01-01

    Researches show that in the early stage of sandstone diagenesis, compaction, pressure solution, cementation and replacement reduce both the porosity and the permeability. The cementation of authigenic kaolinite may preserve the tiny intergranular pore-space, and slightly influence the porosity, and even increase the permeability. During the middle to late stage of diagenesis, the organic matter becomes matured, hydrocarbon and acidic water are produced, which forms secondary porosity by the dissolution and the corrosion, and greatly increases the permeability of sandstones and provides a favorable prerequisite for the formation of sandstone-type uranium deposits. The interlayered oxidation alteration, oil-gas reduction and low-temperature hydrothermal alteration also produce secondary porosity in epigenetic reforming stage, which finally decides the permeability after the formation of sandstone-type uranium deposits. This is an important condition for in-situ leaching of sandstone-type uranium deposit. (authors)

  4. Evolution of the Petrophysical and Mineralogical Properties of Two Reservoir Rocks Under Thermodynamic Conditions Relevant for CO2 Geological Storage at 3 km Depth

    International Nuclear Information System (INIS)

    Rimmel, G.; Barlet-Gouedard, V.; Renard, F.

    2010-01-01

    Injection of carbon dioxide (CO 2 ) underground, for long-term geological storage purposes, is considered as an economically viable option to reduce greenhouse gas emissions in the atmosphere. The chemical interactions between supercritical CO 2 and the potential reservoir rock need to be thoroughly investigated under thermodynamic conditions relevant for geological storage. In the present study, 40 samples of Lavoux limestone and Adamswiller sandstone, both collected from reservoir rocks in the Paris basin, were experimentally exposed to CO 2 in laboratory autoclaves specially built to simulate CO 2 -storage-reservoir conditions. The two types of rock were exposed to wet supercritical CO 2 and CO 2 -saturated water for one month, at 28 MPa and 90 C, corresponding to conditions for a burial depth approximating 3 km. The changes in mineralogy and micro-texture of the samples were measured using X-ray diffraction analyses, Raman spectroscopy, scanning-electron microscopy, and energy-dispersion spectroscopy microanalysis. The petrophysical properties were monitored by measuring the weight, density, mechanical properties, permeability, global porosity, and local porosity gradients through the samples. Both rocks maintained their mechanical and mineralogical properties after CO 2 exposure despite an increase of porosity and permeability. Microscopic zones of calcite dissolution observed in the limestone are more likely to be responsible for such increase. In the sandstone, an alteration of the petro-fabric is assumed to have occurred due to clay minerals reacting with CO 2 . All samples of Lavoux limestone and Adamswiller sandstone showed a measurable alteration when immersed either in wet supercritical CO 2 or in CO 2 -saturated water. These batch experiments were performed using distilled water and thus simulate more severe conditions than using formation water (brine). (authors)

  5. Nanofósseis Calcários da Área de Ressurgência de Cabo Frio, Brasil

    Directory of Open Access Journals (Sweden)

    Deise de Oliveira Delfino

    2013-01-01

    Full Text Available Nanofósseis calcários são um grupo de microfósseis, com representantes viventes e um abundante registro fóssil nos sedimentos marinhos. A maioria das pesquisas voltadas para estes fósseis apresenta como foco regiões de mar profundo (talude e bacia oceânica. São de interesse para a indústria do petróleo por sua aplicação em uma bioestratigrafia de alta resolução e em reconstruções paleoambientais. No Brasil ainda são incipientes os esforços para estudos dos nanofósseis nas áreas costeiras e de plataforma continental. O presente artigo tem por objetivo caracterizar a assembleia de nanofósseis calcários presente em testemunhos da área de ressurgência costeira de Cabo Frio e avaliar seu potencial como indicador paleoambiental na região. Para isto foram elaboradas lâminas com material do testemunho CF02-01B (23º16’S e 41º48’W, que corresponde a 268 cm do perfil sedimentar da plataforma de Cabo Frio. Vinte e sete espécies de nanofósseis calcários foram encontradas, sendo predominantes os táxons Emiliania huxleyi, Florisphaera profunda e Gephyrocapsa oceanica. Com base no perfil de distribuição destes táxons e sua paleoecologia foi possível subdividir os primeiros 151 cm do perfil sedimentar em quatro intervalos: 1 (~2800 a ~2300 anos AP e 3 (~1800 a ~1000 anos AP representativos de períodos de fortalecimento do sistema de ressurgência na área com predomínio da atuação da ACAS, menores temperaturas das águas superficiais, maiores taxas de nutrientes e aumento da produtividade; e 2 (~2300 a ~1800 anos AP e 4 (~1000 a ~700 anos AP representativos do enfraquecimento do sistema de ressurgência em Cabo Frio, com predomínio da influência da CB, águas superficiais mais quentes, com poucos nutrientes e baixa produtividade. Portanto, esta pesquisa ratificou a importância e eficiência do estudo dos nanofósseis calcários em regiões costeiras para reconstruções paleoambientais.

  6. Characterization of application of acu sandstone in ceramic mass

    International Nuclear Information System (INIS)

    Nobrega, L.F.P.M.; Souza, M.M.; Gomes, Y.S.; Fernandes, D.L.

    2016-01-01

    The sandstone is a sedimentary rock formed mainly by quartz grains. In Rio Grande do Norte, there is the Potiguar Basin with the Jandaira and Acu Formations. The latter consists of thick layers of whitish-colored sandstones. It stands out as a water storage facility in the state, but it is also used for building aggregates. This article aimed at the use of the sandstone of this formation in the ceramic mass for coating. Initially, the material was sampled. It went through the comminution process to achieve the required granulometry. After this, three formulations were made to incorporate this new material into the traditional ones. The methods were performed according to ISO 13816. After sintering at 1200 °C, the specimens were subjected to the physical tests. A positive result was obtained for the use of the Acu sandstone in low concentrations. It is clear, therefore, its use in ceramics for coating

  7. Teste de frio na avaliação do vigor de sementes de feijão Cold test for bean seed vigor evaluation

    Directory of Open Access Journals (Sweden)

    Marcelo Hissnauer Miguel

    1999-01-01

    Full Text Available O presente trabalho teve como objetivo estudar o comportamento de sementes de feijão submetidas a diferentes metodologias do teste de frio, comparativamente a outros testes de vigor tradicionalmente utilizados na avaliação da qualidade fisiológica dessas sementes. As metodologias do teste de frio utilizadas foram: caixa plástica com terra, rolo de papel com terra e rolo de papel sem terra, nas temperaturas de 10ºC e de 15ºC e períodos de exposição, de três, cinco e sete dias. Paralelamente foram conduzidos teste padrão de germinação, primeira contagem de germinação, envelhecimento acelerado, condutividade elétrica e emergência de plântulas em campo. As diferentes metodologias do teste de frio foram comparadas pelo teste de Tukey e, posteriormente, foram estabelecidas correlações com os demais testes de vigor. A análise dos dados e a interpretação dos resultados permitiram concluir que a metodologia do rolo de papel sem terra, nos períodos de três e cinco dias à 10ºC e à 15ºC, proporcionou melhor correlação com a primeira contagem de germinação e emergência de plântulas em campo.To assess the efficiency of cold test for bean seed vigor determination, two cultivars were evaluated by three different methodologies under two temperatures (10ºC and 15ºC and three cold period (3, 5 and 7 days regimes. The results were compared to the routine seed quality tests, such as the standard germination test, first germination count, accelerated aging, electrical conductivity and emergence in the field. Tests were conducted in two seasons, four months apart. The results obtained using the various assays were compared by Tukey's test. Correlation analysis between the cold test methods and other vigor tests were carried out. Paper rolls without soil for a period of three to five days at 10ºC and 15ºC correlated better with the standard vigor tests, especially the first germination count and field emergence. To assess the

  8. The Springhill Formation (Jurassic-Cretaceous) as a potential low enthalpy geothermal reservoir in the Cerro Sombrero area, Magallanes Basin, Chile.

    Science.gov (United States)

    Lagarrigue, S. C.; Elgueta, S.; Arancibia, G.; Morata, D.; Sanchez, J.; Rojas, L.

    2017-12-01

    Low enthalpy geothermal energy technologies are being developed around the world as part of policies to replace the use of conventional sources of energy by renewable ones. The reuse of abandoned oil and gas wells in sedimentary basins, whose reservoirs are saturated with water at temperatures above 120°C, is of increasing interest due to the low initial cost.In Chile, interest in applying this technology is focused on the Magallanes Basin (Austral Basin in Argentina) in the extreme south of the country, where important hydrocarbon deposits have been exploited for more than six decades with more than 3,500 wells drilled to depths of over 4,000m. Hydrocarbons have been extracted mainly from the Upper Jurassic to lowermost Cretaceous Springhill Formation, which includes sandstone lithofacies with porosities of 12% to 19% and permeability of 10mD and 1100mD. This formation has been drilled mainly at depths of 1500m to 3000m, the estimated geothermal gradient in the zone is 4.9 °C/100m with well bottom temperature measurements oscillating between 60° and 170°C, sufficient for district heating, and even, electricity generation by means of ORC technologies.To understand in detail the behavior and distribution of the different lithofacies of the Springhill Formation in the Sombrero Oil and Gas Field, sedimentological and geological 3D models have been generated from existing well logs and seismic data. To comprehend the quality of the reservoirs on the other hand, many petrophysical studies of drill core samples representative of the different lithofacies, complemented by electric well log interpretations, were carried out. Results confirm the existence of at least two quartz-rich sandstone lithofacies as potential geothermal reservoirs. In the principal settlement in this area, Cerro Sombrero township (1,800 population), the annual average temperature is 6.4°C, requiring constant domestic heating which, at present comes exclusively from natural gas. The study shows

  9. Examples from the 1.6 Ga Chorhat Sandstone, Vindhyan

    Indian Academy of Sciences (India)

    This paper addresses macroscopic signatures of microbial mat-related structures within the 1.6 Ga-old Chorhat Sandstone of the Semri Group –the basal stratigraphic unit of the Vindhyan succession in Son valley.The Chorhat Sandstone broadly represents a prograding succession of three depositional facies ranging from ...

  10. Streamflow, water quality, and constituent loads and yields, Scituate Reservoir drainage area, Rhode Island, water year 2013

    Science.gov (United States)

    Smith, Kirk P.

    2015-01-01

    Streamflow and concentrations of sodium and chloride estimated from records of specific conductance were used to calculate loads of sodium and chloride during water year (WY) 2013 (October 1, 2012, through September 30, 2013) for tributaries to the Scituate Reservoir, Rhode Island. Streamflow and water-quality data used in the study were collected by the U.S. Geological Survey (USGS) or the Providence Water Supply Board (PWSB) in the cooperative study. Streamflow was measured or estimated by the USGS following standard methods at 23 streamgages; 14 of these streamgages are equipped with instrumentation capable of continuously monitoring water level, specific conductance, and water temperature. Water-quality samples were collected at 37 sampling stations by the PWSB and at 14 continuous-record streamgages by the USGS during WY 2013 as part of a long-term sampling program; all stations are in the Scituate Reservoir drainage area. Water-quality data collected by the PWSB are summarized by using values of central tendency and are used, in combination with measured (or estimated) streamflows, to calculate loads and yields (loads per unit area) of selected water-quality constituents for WY 2013.

  11. Trilobites from the Middle Ordovician Stairway Sandstone, Amadeus Basin, central Australia

    DEFF Research Database (Denmark)

    Jakobsen, Kristian Grube; Nielsen, Arne Thorshøj; Harper, David Alexander Taylor

    2014-01-01

    During the Middle Ordovician (Darriwilian) sandstones and siltstones were deposited in the epicontinental Larapintine Sea, which covered large parts of central Australia. The Darriwilian Stairway Sandstone has, for the first time, been sampled stratigraphically for macrofossils to track marine...... benthic biodiversity in this clastic-dominated shallow-water palaeoenvironment situated along the margin of northeastern Gondwana. The faunas from the Stairway Sandstone are generally of low diversity and dominated by bivalves but include several animal groups, with trilobites representing 25......% of the entire shelly fauna. Thirteen trilobite taxa are described from the Stairway Sandstone; the fauna displays a high degree of endemism. One new species, Basilicus (Parabasilicus) brumbyensis sp. nov. is described....

  12. Conjunctively optimizing flash flood control and water quality in urban water reservoirs by model predictive control and dynamic emulation

    Science.gov (United States)

    Galelli, Stefano; Goedbloed, Albert; Schmitter, Petra; Castelletti, Andrea

    2014-05-01

    Urban water reservoirs are a viable adaptation option to account for increasing drinking water demand of urbanized areas as they allow storage and re-use of water that is normally lost. In addition, the direct availability of freshwater reduces pumping costs and diversifies the portfolios of drinking water supply. Yet, these benefits have an associated twofold cost. Firstly, the presence of large, impervious areas increases the hydraulic efficiency of urban catchments, with short time of concentration, increased runoff rates, losses of infiltration and baseflow, and higher risk of flash floods. Secondly, the high concentration of nutrients and sediments characterizing urban discharges is likely to cause water quality problems. In this study we propose a new control scheme combining Model Predictive Control (MPC), hydro-meteorological forecasts and dynamic model emulation to design real-time operating policies that conjunctively optimize water quantity and quality targets. The main advantage of this scheme stands in its capability of exploiting real-time hydro-meteorological forecasts, which are crucial in such fast-varying systems. In addition, the reduced computational requests of the MPC scheme allows coupling it with dynamic emulators of water quality processes. The approach is demonstrated on Marina Reservoir, a multi-purpose reservoir located in the heart of Singapore and characterized by a large, highly urbanized catchment with a short (i.e. approximately one hour) time of concentration. Results show that the MPC scheme, coupled with a water quality emulator, provides a good compromise between different operating objectives, namely flood risk reduction, drinking water supply and salinity control. Finally, the scheme is used to assess the effect of source control measures (e.g. green roofs) aimed at restoring the natural hydrological regime of Marina Reservoir catchment.

  13. Volcanic settings and their reservoir potential: An outcrop analog study on the Miocene Tepoztlán Formation, Central Mexico

    Science.gov (United States)

    Lenhardt, Nils; Götz, Annette E.

    2011-07-01

    The reservoir potential of volcanic and associated sedimentary rocks is less documented in regard to groundwater resources, and oil and gas storage compared to siliciclastic and carbonate systems. Outcrop analog studies within a volcanic setting enable to identify spatio-temporal architectural elements and geometric features of different rock units and their petrophysical properties such as porosity and permeability, which are important information for reservoir characterization. Despite the wide distribution of volcanic rocks in Mexico, their reservoir potential has been little studied in the past. In the Valley of Mexico, situated 4000 m above the Neogene volcanic rocks, groundwater is a matter of major importance as more than 20 million people and 42% of the industrial capacity of the Mexican nation depend on it for most of their water supply. Here, we present porosity and permeability data of 108 rock samples representing five different lithofacies types of the Miocene Tepoztlán Formation. This 800 m thick formation mainly consists of pyroclastic rocks, mass flow and fluvial deposits and is part of the southern Transmexican Volcanic Belt, cropping out south of the Valley of Mexico and within the two states of Morelos and Mexico State. Porosities range from 1.4% to 56.7%; average porosity is 24.8%. Generally, permeabilities are low to median (0.2-933.3 mD) with an average permeability of 88.5 mD. The lavas are characterized by the highest porosity values followed by tuffs, conglomerates, sandstones and tuffaceous breccias. On the contrary, the highest permeabilities can be found in the conglomerates, followed by tuffs, tuffaceous breccias, sandstones and lavas. The knowledge of these petrophysical rock properties provides important information on the reservoir potential of volcanic settings to be integrated to 3D subsurface models.

  14. Uranium distribution and sandstone depositional environments: oligocene and upper Cretaceous sediments, Cheyenne basin, Colorado

    International Nuclear Information System (INIS)

    Nibbelink, K.A.; Ethridge, F.G.

    1984-01-01

    Wyoming-type roll-front uranium deposits occur in the Upper Cretaceous Laramie and Fox Hills sandstones in the Cheyenne basin of northeastern Colorado. The location, geometry, and trend of specific depositional environments of the Oligocene White River and the Upper Cretaceous Laramie and Fox Hills formations are important factors that control the distribution of uranium in these sandstones. The Fox Hills Sandstone consists of up to 450 ft (140 m) of nearshore marine wave-dominated delta and barrier island-tidal channel sandstones which overlie offshore deposits of the Pierre Shale and which are overlain by delta-plain and fluvial deposits of the Laramie Formation. Uranium, which probably originated from volcanic ash in the White River Formation, was transported by groundwater through the fluvial-channel deposits of the White River into the sandstones of the Laramie and Fox Hills formations where it was precipitated. Two favorable depositional settings for uranium mineralization in the Fox Hills Sandstone are: (1) the landward side of barrier-island deposits where barrier sandstones thin and interfinger with back-barrier organic mudstones, and (2) the intersection of barrier-island and tidal channel sandstones. In both settings, sandstones were probably reduced during early burial by diagenesis of contained and adjacent organic matter. The change in permeability trends between the depositional strike-oriented barrier sandstones and the dip-oriented tidal-channel sandstones provided sites for dispersed groundwater flow and, as demonstrated in similar settings in other depositional systems, sites for uranium mineralization

  15. Petroleum resources assessment (I)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-01

    This report consists of 2 subjects. 1) Petroleum resources assessment on the western part of the Kunsan Basin: Palynomorphs including spores, pollen and organic-walled microfossils and calcareous microfossils such as ostracods, charophytes and gastropods were studied for the biostratigraphic work of Kachi-1 and IIH-1Xa wells. Based on available well data, the rifting probably began in the Cretaceous time had continued until Paleocene. It is considered that compressional force immediately after rifting event deformed sedimentary sections. During the period of Paleocene to middle Miocene, the sediments were deposited in stable environment without particular tectonic event. 2) Petroliferous basin analysis in Taegu area (II): The Nakdong and Jinju formations contain abundant black shales, and thermal maturity of the organic matter reached at the final stage of dry gas generation. These formations also contain thick sandstones which can act as a petroleum reservoir. However, reservoir quality of the sandstones is poor (porosity: < 5%; permeability: < 0.001 md). In these sandstones, secondary pores such as dissolution pores and micropores can act as a tight gas reservoir. (author). 56 refs., 24 tabs., 68 figs.

  16. Fault features and enrichment laws of narrow-channel distal tight sandstone gas reservoirs: A case study of the Jurassic Shaximiao Fm gas reservoir in the Zhongjiang Gas Field, Sichuan Basin

    Directory of Open Access Journals (Sweden)

    Zhongping Li

    2016-11-01

    Full Text Available The Jurassic Shaximiao Fm gas reservoir in the Zhongjiang Gas Field, Sichuan Basin, is the main base of Sinopec Southwest Oil & Gas Company for gas reserves and production increase during the 12th Five-Year Plan. However, its natural gas exploration and development process was restricted severely, since the exploration wells cannot be deployed effectively in this area based on the previous gas accumulation and enrichment pattern of “hydrocarbon source fault + channel sand body + local structure”. In this paper, the regional fault features and the gas accumulation and enrichment laws were discussed by analyzing the factors like fault evolution, fault elements, fault-sand body configuration (the configuration relationship between hydrocarbon source faults and channel sand bodies, trap types, and reservoir anatomy. It is concluded that the accumulation and enrichment of the Shaximiao Fm gas reservoir in this area is controlled by three factors, i.e., hydrocarbon source, sedimentary facies and structural position. It follows the accumulation laws of source controlling region, facies controlling zone and position controlling reservoir, which means deep source and shallow accumulation, fault-sand body conductivity, multiphase channel, differential accumulation, adjusted enrichment and gas enrichment at sweet spots. A good configuration relationship between hydrocarbon source faults and channel sand bodies is the basic condition for the formation of gas reservoirs. Natural gas accumulated preferentially in the structures or positions with good fault-sand body configuration. Gas reservoirs can also be formed in the monoclinal structures which were formed after the late structural adjustment. In the zones supported by multiple faults or near the crush zones, no gas accumulation occurs, but water is dominantly produced. The gas-bearing potential is low in the area with undeveloped faults or being 30 km away from the hydrocarbon source faults. So

  17. Cultivo do mirtilo: atualizações e desempenho inicial de variedades de baixa exigência em frio no Estado de Säo Paulo

    Directory of Open Access Journals (Sweden)

    Tatiana Cantuarias-Avilés

    2014-03-01

    Full Text Available A produção comercial de mirtilos na América do Sul tem passado por mudanças importantes nos últimos anos, em função do aumento da oferta de frutos frescos dos principais países produtores, causando forte queda de preços em plena safra, entre os meses de dezembro e fevereiro. Uma alternativa para esta situação é a produção de mirtileiros de maturação precoce ou muito tardia, fora da época de meia-estação, caracterizada pelos menores preços da fruta. Em 2010, foram introduzidas no Brasil novas variedades de mirtileiros de baixa exigência em frio desenvolvidas pela Universidade da Flórida, que podem ser cultivadas em regiões quentes e apresentam uma frutificação mais precoce, quando comparadas com as variedades tradicionalmente cultivadas no Brasil. Essas novas variedades apresentam grande potencial para a produção precoce de mirtilos no País em regiões sem frio hibernal, aumentando significativamente a rentabilidade da cultura. Para viabilizar esta produção, é necessário validar estratégias de manejo para estas variedades, devido à falta de informação técnica sobre seu cultivo nas condições edafoclimáticas brasileiras. Atualmente, estäo sendo conduzidas as primeiras pesquisas fitotécnicas no Estado de Säo Paulo para avaliar o crescimento e a produção destas variedades na ausência total de frio, situação de ocorrência particular em poucos países produtores do mundo.

  18. Water- and air-quality and surficial bed-sediment monitoring of the Sweetwater Reservoir watershed, San Diego County, California, 2003-09

    Science.gov (United States)

    Mendez, Gregory O.; Majewski, Michael S.; Foreman, William T.; Morita, Andrew Y.

    2015-01-01

    In 1998, the U.S. Geological Survey, in cooperation with the Sweetwater Authority, began a study to assess the overall health of the Sweetwater watershed in San Diego County, California. This study was designed to provide a data set that could be used to evaluate potential effects from the construction and operation of State Route 125 within the broader context of the water quality and air quality in the watershed. The study included regular sampling of water, air, and surficial bed sediment at Sweetwater Reservoir (SWR) for chemical constituents, including volatile organic compounds (VOCs), base-neutral and acid- extractable organic compounds (BNAs) that include polycyclic aromatic hydrocarbons (PAHs), pesticides, and metals. Additionally, water samples were collected for anthropogenic organic indicator compounds in and around SWR. Background water samples were collected at Loveland Reservoir for VOCs, BNAs, pesticides, and metals. Surficial bed-sediment samples were collected for PAHs, organochlorine pesticides, and metals at Sweetwater and Loveland Reservoirs.

  19. Retrospective analysis of associations between water quality and toxic blooms of golden alga (Prymnesium parvum) in Texas reservoirs: Implications for understanding dispersal mechanisms and impacts of climate change

    Science.gov (United States)

    Patino, Reynaldo; Dawson, D.; VanLandeghem, Matthew M.

    2014-01-01

    Toxic blooms of golden alga (GA, Prymnesium parvum) in Texas typically occur in winter or early spring. In North America, they were first reported in Texas in the 1980s, and a marked range expansion occurred in 2001. Although there is concern about the influence of climate change on the future distribution of GA, factors responsible for past dispersals remain uncertain. To better understand the factors that influence toxic bloom dispersal in reservoirs, this study characterized reservoir water quality associated with toxic GA blooms since 2001, and examined trends in water quality during a 20-year period bracketing the 2001 expansion. Archived data were analyzed for six impacted and six nonimpacted reservoirs from two major Texas basins: Brazos River and Colorado River. Data were simplified for analysis by pooling spatially (across sampling stations) and temporally (winter, December-February) within reservoirs and generating depth-corrected (1 m) monthly values. Classification tree analysis [period of record (POR), 2001-2010] using salinity-associated variables (specific conductance, chloride, sulfate), dissolved oxygen (DO), pH, temperature, total hardness, potassium, nitrate+nitrite, and total phosphorus indicated that salinity best predicts the toxic bloom occurrence. Minimum estimated salinities for toxic bloom formation were 0.59 and 1.02 psu in Brazos and Colorado River reservoirs, respectively. Principal component analysis (POR, 2001-2010) indicated that GA habitat is best defined by higher salinity relative to nonimpacted reservoirs, with winter DO and pH also being slightly higher and winter temperature slightly lower in impacted reservoirs. Trend analysis, however, did not reveal monotonic changes in winter water quality of GA-impacted reservoirs during the 20-year period (1991-2010) bracketing the 2001 dispersal. Therefore, whereas minimum levels of salinity are required for GA establishment and toxic blooms in Texas reservoirs, the lack of trends in

  20. Dinâmica da dormência de gemas de videira e quivizeiro em região de baixa ocorrência de frio

    Directory of Open Access Journals (Sweden)

    Luiz Antonio Biasi

    2010-12-01

    Full Text Available O objetivo desta pesquisa foi determinar a dinâmica da dormência de gemas de videira cv. Niagara Branca e de quivizeiro cv. Bruno, em região de baixa ocorrência de frio. Os experimentos foram realizados nos anos de 2007 e 2008, com coletas de ramos a cada duas semanas, em pomares localizados em Pinhais-PR. Na última coleta, um grupo adicional de ramos foi coletado e mantido em refrigerador a temperatura de 4 a 7º C, por 1.440 horas. A avaliação da dormência foi realizada por meio do teste biológico de estacas de nós isolados em sala de crescimento, à temperatura de 25º C e fotoperíodo de 16 horas. Foi realizada a quantificação de horas de frio (HF e de unidades de frio (UF ocorridas na região. As duas espécies foram avaliadas como experimentos distintos. O delineamento experimental adotado foi o completamente casualizado, com doze tratamentos em 2007 e onze tratamentos em 2008, ambos com quatro repetições e dez estacas por unidade experimental. A endodormência de gemas de quivizeiro 'Bruno' instala-se a partir de abril e atinge maior intensidade do final de maio à segunda metade de junho. A saída da endodormência pode ocorrer naturalmente até o fim de agosto, mas com variações entre os anos. A endodormência de gemas de videira 'Niagara Branca' instala-se em abril e mantém-se intensa até maio. A saída natural da endodormência ocorre da metade de agosto ao início de setembro.

  1. Sandstone-type uranium deposits. Summary and conclusions

    International Nuclear Information System (INIS)

    Finch, W.I.

    1985-01-01

    The similarity of most of the deposits described in this report is striking even though they occur in sandstone host rocks ranging in age from Carboniferous to Tertiary and on every continent outside the polar regions. Geologic environments of the uranium deposits consist of distinctive sets of tectonic and sedimentary-depositional systems, all of which have some common threads of favorable geologic processes. In this summary paper it is hoped that this report has sharpened an understanding of the deposit's ''home environment'' that will aid future exploration for these resource-important sandstone-type uranium ores

  2. Selection of reservoirs amenable to micellar flooding. First annual report, October 1978-December 1979

    Energy Technology Data Exchange (ETDEWEB)

    Goldburg, A.; Price, H.

    1980-12-01

    The overall project objective is to build a solid engineering base upon which the Department of Energy (DOE) can improve and accelerate the application of micellar-polymer recovery technology to Mid-Continent and California sandstone reservoirs. The purpose of the work carried out under these two contracts is to significantly aid, both DOE and the private sector, in gaining the following Project Objectives: to select the better micellar-polymer prospects in the Mid-Continent and California regions; to assess all of the available field and laboratory data which has a bearing on recovering oil by micellar-polymer projects in order to help identify and resolve both the technical and economic constraints relating thereto; and to design and analyze improved field pilots and tests and to develop a micellar-polymer applications matrix for use by the potential technology users; i.e., owner/operators. The report includes the following: executive summary and project objectives; development of a predictive model for economic evaluation of reservoirs; reservoir data bank for micellar-polymer recovery evaluation; PECON program for preliminary economic evaluation; ordering of candidate reservoirs for additional data acquisition; validation of predictive model by numerical simulation; and work forecast. Tables, figures and references are included.

  3. Geological principles of exploration for sandstone-hosted uranium deposits

    International Nuclear Information System (INIS)

    Le Roux, J.P.

    1982-10-01

    Although the importance of sandstone-hosted uranium deposits has seemingly faded in recent years due to the discovery of large, high -grade deposits elsewhere, a forecasted energy shortage in the near future will probably necessitate a new look at sedimentary basins as a source of uranium. Back-arc basins adjacent to calcalkaline source areas are especially favourable if they are filled with fluvial, post-Devonian sediments. Syn- and post-depositional tectonics play an important role in the sedimentation-mineralisation process and should be investigated. The oxidation-reduction state of the sandstones is a valid prospecting tool. Sedimentological environments govern the permeability and vegetal matter content of sandstones and directly control uranium mineralisation

  4. Analyzing the Sand-fixing Effect of Feldspathic Sandstone from the Texture Characteristics

    Science.gov (United States)

    Zhang, lu; Ban, Jichang

    2018-01-01

    The purpose of this research was aimed to study the sand fixing effect of feldspathic sandstone in Mu Us Sandy Land, to provide a scienticic basis for desertification control, soil and water conservation and development of farming there. Methods of mixing feldspathic sandstone and aeolian sandy soil according to 1: 0, 1: 1, 1: 2, 1: 5, and 0: 1 mass ratioes, the graded composition and characteristics were studied with laser particle size analyzer. The result showed that these features of sand-based, loosely structured, easy to wind erosion of aeolian sandy soil were changed before feldspathic sandstone and aeolian sandy soil compounding. The <0.05 mm particle mass increased with feldspathic sandstone mass increasing. The texture presented this kind of change from sand to sandy loam to loam to silt loam. The small particle size distribution, good homogeneity and other features of aeolian sandy soil were improved to a certain degree, and the particle size distribution became broad before feldspathic sandstone and aeolian sandy soil compounding. The particle grading was continuous, and the grading characteristic was good when m(F): m(S) was 1: 5(Cu was 54.71 and Cc was 2.54) or when m(F): m(S) was 1: 2(Cu was 76.21, Cc was 1.12). The conclusion is that feldspathic sandstone has sand-fixing effect in texture characteristics, which heightens with feldspathic sandstone mass increasing, and when the mass ratio of feldspathic sandstone: aeolian sandy soil is 1: 2 or 1: 5 which compound better.

  5. Effects of heat-flow and hydrothermal fluids from volcanic intrusions on authigenic mineralization in sandstone formations

    Directory of Open Access Journals (Sweden)

    Wolela Ahmed

    2002-06-01

    Full Text Available Volcanic intrusions and hydrothermal activity have modified the diagenetic minerals. In the Ulster Basin, UK, most of the authigenic mineralization in the Permo-Triassic sandstones pre-dated tertiary volcanic intrusions. The hydrothermal fluids and heat-flow from the volcanic intrusions did not affect quartz and feldspar overgrowths. However, clay mineral-transformation, illite-smectite to illite and chlorite was documented near the volcanic intrusions. Abundant actinolite, illite, chlorite, albite and laumontite cementation of the sand grains were also documented near the volcanic intrusions. The abundance of these cementing minerals decreases away from the volcanic intrusions.In the Hartford Basin, USA, the emplacement of the volcanic intrusions took place simultaneous with sedimentation. The heat-flow from the volcanic intrusions and hydrothermal activity related to the volcanics modified the texture of authigenic minerals. Microcrystalline mosaic albite and quartz developed rather than overgrowths and crystals near the intrusions. Chlorite clumps and masses were also documented with microcrystalline mosaic albite and quartz. These features are localized near the basaltic intrusions. Laumontite is also documented near the volcanic intrusions. The reservoir characteristics of the studied sandstone formations are highly affected by the volcanic and hydrothermal fluids in the Hartford and the Ulster Basin. The porosity dropped from 27.4 to zero percent and permeability from 1350 mD to 1 mD.

  6. Mechanism for calcite dissolution and its contribution to development of reservoir porosity and permeability in the Kela 2 gas field,Tarim Basin,China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This study is undertaken to understand how calcite precipitation and dissolution contributes to depth-related changes in porosity and permeability of gas-bearing sandstone reservoirs in the Kela 2 gas field of the Tarim Basin, Northwestern China. Sandstone samples and pore water samples are col-lected from well KL201 in the Tarim Basin. Vertical profiles of porosity, permeability, pore water chem-istry, and the relative volume abundance of calcite/dolomite are constructed from 3600 to 4000 m below the ground surface within major oil and gas reservoir rocks. Porosity and permeability values are in-versely correlated with the calcite abundance, indicating that calcite dissolution and precipitation may be controlling porosity and permeability of the reservoir rocks. Pore water chemistry exhibits a sys-tematic variation from the Na2SO4 type at the shallow depth (3600-3630 m), to the NaHCO3 type at the intermediate depth (3630―3695 m),and to the CaCl2 type at the greater depth (3728―3938 m). The geochemical factors that control the calcite solubility include pH, temperature, pressure, Ca2+ concen-tration, the total inorganic carbon concentration (ΣCO2), and the type of pore water. Thermodynamic phase equilibrium and mass conservation laws are applied to calculate the calcite saturation state as a function of a few key parameters. The model calculation illustrates that the calcite solubility is strongly dependent on the chemical composition of pore water, mainly the concentration difference between the total dissolved inorganic carbon and dissolved calcium concentration (i.e., [ΣCO2] -[Ca2+]). In the Na2SO4 water at the shallow depth, this index is close to 0, pore water is near the calcite solubility. Calcite does not dissolve or precipitate in significant quantities. In the NaHCO3 water at the intermedi-ate depth, this index is greater than 0, and pore water is supersaturated with respect to calcite. Massive calcite precipitation was observed at this depth

  7. Pore Fluid Evolution Influenced by Volcanic Activities and Related Diagenetic Processes in a Rift Basin: Evidence from the Paleogene Medium-Deep Reservoirs of Huanghekou Sag, Bohai Bay Basin, China

    Directory of Open Access Journals (Sweden)

    Zhongheng Sun

    2017-01-01

    Full Text Available Volcanic activities exert a significant influence on pore fluid property and related diagenetic processes that substantially controlled reservoirs quality. Analysis of Paleogene medium-deep sandstones on the Huanghekou Sag provides insight into relating the diagenetic processes to pore fluid property evolution influenced by volcanic activities. Three distinct types of pore fluids were identified on the basis of an integrated and systematic analysis including core and thin section observation, XRD, SEM, CL, and trace element. Alkaline aqueous medium environment occurred in E2s1+2 where volcanic activities have insignificant influence on pore fluids, evidenced by typical alkaline diagenetic events such as K-feldspar albitization, quartz dissolution, feldspar dissolution, and carbonate cementation. During the deposition of E3d3, influx of terrestrial freshwater and alteration of ferromagnesian-rich pore water result in the formation of mixing aqueous medium environment through volcanic eruption dormancy causing zeolite dissolution, clay mineral transformation, and K-feldspar albitization. Ferromagnesian-rich aqueous medium environment developed resulting from the intensive hydrolysis of the unstable ferromagnesian minerals formed due to intense volcanic activities during E3d1+2 and corresponding predominant diagenetic processes were characterized by the precipitation and dissolution of low-silica zeolites. Therefore, the differential properties of pore fluids caused various diagenetic processes controlling reservoir quality.

  8. Understanding and Mitigating Reservoir Compaction: an Experimental Study on Sand Aggregates

    Science.gov (United States)

    Schimmel, M.; Hangx, S.; Spiers, C. J.

    2016-12-01

    Fossil fuels continue to provide a source for energy, fuels for transport and chemicals for everyday items. However, adverse effects of decades of hydrocarbons production are increasingly impacting society and the environment. Production-driven reduction in reservoir pore pressure leads to a poro-elastic response of the reservoir, and in many occasions to time-dependent compaction (creep) of the reservoir. In turn, reservoir compaction may lead to surface subsidence and could potentially result in induced (micro)seismicity. To predict and mitigate the impact of fluid extraction, we need to understand production-driven reservoir compaction in highly porous siliciclastic rocks and explore potential mitigation strategies, for example, by using compaction-inhibiting injection fluids. As a first step, we investigate the effect of chemical environment on the compaction behaviour of sand aggregates, comparable to poorly consolidated, highly porous sandstones. The sand samples consist of loose aggregates of Beaujean quartz sand, sieved into a grainsize fraction of 180-212 µm. Uniaxial compaction experiments are performed at an axial stress of 35 MPa and temperature of 80°C, mimicking conditions of reservoirs buried at three kilometres depth. The chemical environment during creep is either vacuum-dry or CO2-dry, or fluid-saturated, with fluids consisting of distilled water, acid solution (CO2-saturated water), alkaline solution (pH 9), aluminium solution (pH 3) and solution with surfactants (i.e., AMP). Preliminary results show that compaction of quartz sand aggregates is promoted in a wet environment compared to a dry environment. It is inferred that deformation is controlled by subcritical crack growth when dry and stress corrosion cracking when wet, both resulting in grain failure and subsequent grain rearrangement. Fluids inhibiting these processes, have the potential to inhibit aggregate compaction.

  9. Hydrogeology of the Potsdam Sandstone in northern New York

    Science.gov (United States)

    Williams, John H.; Reynolds, Richard J.; Franzi, David A.; Romanowicz, Edwin A.; Paillet, Frederick L.

    2010-01-01

    The Potsdam Sandstone of Cambrian age forms a transboundary aquifer that extends across northern New York and into southern Quebec. The Potsdam Sandstone is a gently dipping sequence of arkose, subarkose, and orthoquartzite that unconformably overlies Precambrian metamorphic bedrock. The Potsdam irregularly grades upward over a thickness of 450 m from a heterogeneous feldspathic and argillaceous rock to a homogeneous, quartz-rich and matrix-poor rock. The hydrogeological framework of the Potsdam Sandstone was investigated through an analysis of records from 1,500 wells and geophysical logs from 40 wells, and through compilation of GIS coverages of bedrock and surficial geology, examination of bedrock cores, and construction of hydrogeological sections. The upper several metres of the sandstone typically is weathered and fractured and, where saturated, readily transmits groundwater. Bedding-related fractures in the sandstone commonly form sub-horizontal flow zones of relatively high transmissivity. The vertical distribution of sub-horizontal flow zones is variable; spacings of less than 10 m are common. Transmissivity of individual flow zones may be more than 100 m2/d but typically is less than 10 m2/d. High angle fractures, including joints and faults, locally provide vertical hydraulic connection between flow zones. Hydraulic head gradients in the aquifer commonly are downward; a laterally extensive series of sub-horizontal flow zones serve as drains for the groundwater flow system. Vertical hydraulic head differences between shallow and deep flow zones range from 1 m to more than 20 m. The maximum head differences are in recharge areas upgradient from the area where the Chateauguay and Chazy Rivers, and their tributaries, have cut into till and bedrock. Till overlies the sandstone in much of the study area; its thickness is generally greatest in the western part, where it may exceed 50 m. A discontinuous belt of bedrock pavements stripped of glacial drift extends

  10. Cense Explosion Test Program. Report 1. Cense 1. Explosions in Sandstone

    Science.gov (United States)

    1977-09-01

    series, "Analysis and Summary of CENSE Data." 10 * _ CHAPTER 2 APPROACH 2.1 DESCRIPTION OF TEST SITE An exposed outcrop of Kayenta sandstone with 180...ft/s seismic velocity previously determined (References 12-14) for the unweathered upper zone of the Kayenta sandstone. 16 I The P-wave propagation...Propagation along the horizontal radial was 8400 ft/s. The seismic velocity pre- viously determined for Kayenta sandstone in this area was 7500 ft/s

  11. Brief analysis on relationship between red beds and sandstone-type uranium ore-formation

    International Nuclear Information System (INIS)

    Ji Zengxian

    2006-01-01

    Red beds are sandy gravel beds deposited under the arid and hot climates and correspondent to the oxidation environment of continental basins. As an exogenetic epigenetic uranium deposit, the formation of the sandstone-type uranium deposit needs a large chronologic gap between the diagenesis and the subsequent uranium metallogenesis of the ore-hosting target layer with a sedimentary discontinuity and an alternative humid-arid climate. Red beds are the product of this time. The evolutionary times of red beds are in accordance with the formation of the sandstone-type uranium deposit. Both domestic and abroad researches indicate that each times evolution of a red bed might be associated with uranium ore-formation in one or more sandstone layers in the region. In China, red beds are developed in many geologic periods, but sandstone-type uranium mineralization occurs mostly in Mesozoic-Cenozoic. Taking five known sandstone-type uranium deposits as examples, the author makes a primary analysis on the relationship between red beds and the subsequent sandstone-type uranium mineralization. It is suggested that the deposition of red beds and sandstone-type uranium metallogenesis are of 'cogenesis and coexistence' and that the deposition of red beds and its evolutionary times can be regarded as the prerequisites to judge the potential of sandstone-type uranium mineralization in a Mesozoic-Cenozoic sedimentary basin. (authors)

  12. Mechanical Weakening during Fluid Injection in Critically Stressed Sandstones with Acoustic Monitoring

    Science.gov (United States)

    David, C.; Dautriat, J. D.; Sarout, J.; Macault, R.; Bertauld, D.

    2014-12-01

    Water weakening is a well-known phenomenon which can lead to subsidence during the production of hydrocarbon reservoirs. The example of the Ekofisk oil field in the North Sea has been well documented for years. In order to assess water weakening effects in reservoir rocks, previous studies have focused on changes in the failure envelopes derived from mechanical tests conducted on rocks saturated either with water or with inert fluids. However, little attention has been paid so far on the mechanical behaviour during the fluid injection stage, like in enhanced oil recovery operations. We studied the effect of fluid injection on the mechanical behaviour of Sherwood sandstone, a weakly-consolidated sandstone sampled at Ladram Bay in UK. In order to highlight possible weakening effects, water and inert oil have been injected into critically-loaded samples to assess their effect on strength and elastic properties and to derive the acoustic signature of the saturation front for each fluid. The specimens were instrumented with 16 ultrasonic P-wave transducers for both passive and active acoustic monitoring during fluid injection and loading. After conducting standard triaxial tests on three samples saturated with air, water and oil respectively, mechanical creep tests were conducted on dry samples loaded at 80% of the compressive strength of the dry rock. While these conditions are kept constant, a fluid is injected at the bottom end of the sample with a low back pressure (0.5 MPa) to minimize effective stress variations during injection. Both water and oil were used as the injected pore fluid in two experiments. As soon as the fluids start to flow into the samples, creep is taking place with a much higher strain rate for water injection compared to oil injection. A transition from secondary creep to tertiary creep is observed in the water injection test whereas in the oil injection test no significant creep acceleration is observed after one pore volume of oil was

  13. Sandstone landforms shaped by negative feedback between stress and erosion

    Czech Academy of Sciences Publication Activity Database

    Bruthans, J.; Soukup, J.; Vaculíková, J.; Filippi, Michal; Schweigstillová, Jana; Mayo, A. L.; Mašín, D.; Kletetschka, Günther; Řihošek, J.

    2014-01-01

    Roč. 7, č. 8 (2014), s. 597-601 ISSN 1752-0894 R&D Projects: GA ČR GA13-28040S Institutional support: RVO:67985831 ; RVO:67985891 Keywords : sandstone * sandstone landsforms * stress * erosion Subject RIV: DB - Geology ; Mineralogy Impact factor: 11.740, year: 2014

  14. Characterizing flow pathways in a sandstone aquifer: Tectonic vs sedimentary heterogeneities

    Science.gov (United States)

    Medici, G.; West, L. J.; Mountney, N. P.

    2016-11-01

    Sandstone aquifers are commonly assumed to represent porous media characterized by a permeable matrix. However, such aquifers may be heavy fractured when rock properties and timing of deformation favour brittle failure and crack opening. In many aquifer types, fractures associated with faults, bedding planes and stratabound joints represent preferential pathways for fluids and contaminants. In this paper, well test and outcrop-scale studies reveal how strongly lithified siliciclastic rocks may be entirely dominated by fracture flow at shallow depths (≤ 180 m), similar to limestone and crystalline aquifers. However, sedimentary heterogeneities can primarily control fluid flow where fracture apertures are reduced by overburden pressures or mineral infills at greater depths. The Triassic St Bees Sandstone Formation (UK) of the East Irish Sea Basin represents an optimum example for study of the influence of both sedimentary and tectonic aquifer heterogeneities in a strongly lithified sandstone aquifer-type. This fluvial sedimentary succession accumulated in rapidly subsiding basins, which typically favours preservation of complete depositional cycles including fine grained layers (mudstone and silty sandstone) interbedded in sandstone fluvial channels. Additionally, vertical joints in the St Bees Sandstone Formation form a pervasive stratabound system whereby joints terminate at bedding discontinuities. Additionally, normal faults are present through the succession showing particular development of open-fractures. Here, the shallow aquifer (depth ≤ 180 m) was characterized using hydro-geophysics. Fluid temperature, conductivity and flow-velocity logs record inflows and outflows from normal faults, as well as from pervasive bed-parallel fractures. Quantitative flow logging analyses in boreholes that cut fault planes indicate that zones of fault-related open fractures characterize 50% of water flow. The remaining flow component is dominated by bed-parallel fractures

  15. Geothermal prospection in the Greater Geneva Basin (Switzerland and France): Structural and reservoir quality assessment

    Science.gov (United States)

    Rusillon, Elme; Clerc, Nicolas; Makhloufi, Yasin; Brentini, Maud; Moscariello, Andrea

    2017-04-01

    A reservoir assessment was performed in the Greater Geneva Basin to evaluate the geothermal resources potential of low to medium enthalpy (Moscariello, 2016). For this purpose, a detail structural analysis of the basin was performed (Clerc et al., 2016) simultaneously with a reservoir appraisal study including petrophysical properties assessment in a consistent sedimentological and stratigraphical frame (Brentini et al., 2017). This multi-disciplinary study was organised in 4 steps: (1) investigation of the surrounding outcrops to understand the stratigraphy and lateral facies distribution of the sedimentary sequence from Permo-Carboniferous to Lower Cretaceous units; (2) development of 3D geological models derived from 2D seismic and well data focusing on the structural scheme of the basin to constrain better the tectonic influence on facies distribution and to assess potential hydraulic connectivity through faults between reservoir units ; (3) evaluation of the distribution, geometry, sedimentology and petrophysical properties of potential reservoir units from well data; (4) identification and selection of the most promising reservoir units for in-depth rock type characterization and 3D modeling. Petrophysical investigations revealed that the Kimmeridgian-Tithonian Reef Complex and the underlying Calcaires de Tabalcon units are the most promising geothermal reservoir targets (porosity range 10-20%; permeability to 1mD). Best reservoir properties are measured in patch reefs and high-energy peri-reefal depositional environments, which are surrounded by synchronous tight lagoonal deposits. Associated highly porous dolomitized intervals reported in the western part of the basin also provide enhanced reservoir quality. The distribution and geometry of best reservoir bodies is complex and constrained by (1) palaeotopography, which can be affected by synsedimentary fault activity during Mesozoic times, (2) sedimentary factors such as hydrodynamics, sea level variations

  16. Identifying the Relationships between Water Quality and Land Cover Changes in the Tseng-Wen Reservoir Watershed of Taiwan

    Directory of Open Access Journals (Sweden)

    Hone-Jay Chu

    2013-01-01

    Full Text Available The effects on water quality of land use and land cover changes, which are associated with human activities and natural factors, are poorly identified. Fine resolution satellite imagery provides opportunities for land cover monitoring and assessment. The multiple satellite images after typhoon events collected from 2001 to 2010 covering land areas and land cover conditions are evaluated by the Normalized Difference Vegetation Index (NDVI. The relationship between land cover and observed water quality, such as suspended solids (SS and nitrate-nitrogens (NO3-N, are explored in the study area. Results show that the long-term variations in water quality are explained by NDVI data in the reservoir buffer zones. Suspended solid and nitrate concentrations are related to average NDVI values on multiple spatial scales. Annual NO3-N concentrations are positively correlated with an average NDVI with a 1 km reservoir buffer area, and the SS after typhoon events associated with landslides are negatively correlated with the average NDVI in the entire watershed. This study provides an approach for assessing the influences of land cover on variations in water quality.

  17. Electrokinetic desalination of sandstones for NaCl removal

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Christensen, Iben V.

    2012-01-01

    of reliable methods to remove the damaging salts in order to stop the decay. Electrokinetic desalination of fired clay bricks have previously shown efficient in laboratory scale and in the present work the method is tested for desalination of Cotta and Posta sandstones, which both have lower porosity than...... each stone, but electroosmosis in the poultices may have caused suction/pressure over the interface between stone and poultice causing the differences in poultice water content. The transport numbers for Cl− and Na+ differed in the two stones and were highest in the most porous Cotta sandstone in spite...... of similar high pore water concentrations and the same applied electric current. The hypotheses is that a layered structure of the sandstones could be the cause for this, as the electric current may preferentially flow in certain paths through the stone, which are thus desalinated first. After...

  18. On the migration of uranium isotopes in sandstone aquifers

    International Nuclear Information System (INIS)

    Froehlich, K.; Gellermann, R.

    1982-01-01

    Measurements of natural 238 U and 234 U activity in groundwater of sandstone aquifers have been used to study the migration of these uranium isotopes. Regarding the uranium exchange between liquid phase and rock surface during migration, two different models were applied for evaluating the experimental results. Values of corresponding parameters (retardation factor K, removal rate R) reflecting different behaviour concerning this exchange were determined. For example, the values obtained for 238 U in a Triassic sandstone aquifer of the GDR are K = 8.6 x 10 6 and R = 1.3 x 10 -3 a -1 , respectively. It was found that, under the conditions of the sandstone aquifer concerned, the removal rate model is better suited for calculating uranium-isotope migration in groundwater. (author)

  19. Model documentation for relations between continuous real-time and discrete water-quality constituents in Cheney Reservoir near Cheney, Kansas, 2001--2009

    Science.gov (United States)

    Stone, Mandy L.; Graham, Jennifer L.; Gatotho, Jackline W.

    2013-01-01

    Cheney Reservoir, located in south-central Kansas, is one of the primary water supplies for the city of Wichita, Kansas. The U.S. Geological Survey has operated a continuous real-time water-quality monitoring station in Cheney Reservoir since 2001; continuously measured physicochemical properties include specific conductance, pH, water temperature, dissolved oxygen, turbidity, fluorescence (wavelength range 650 to 700 nanometers; estimate of total chlorophyll), and reservoir elevation. Discrete water-quality samples were collected during 2001 through 2009 and analyzed for sediment, nutrients, taste-and-odor compounds, cyanotoxins, phytoplankton community composition, actinomycetes bacteria, and other water-quality measures. Regression models were developed to establish relations between discretely sampled constituent concentrations and continuously measured physicochemical properties to compute concentrations of constituents that are not easily measured in real time. The water-quality information in this report is important to the city of Wichita because it allows quantification and characterization of potential constituents of concern in Cheney Reservoir. This report updates linear regression models published in 2006 that were based on data collected during 2001 through 2003. The update uses discrete and continuous data collected during May 2001 through December 2009. Updated models to compute dissolved solids, sodium, chloride, and suspended solids were similar to previously published models. However, several other updated models changed substantially from previously published models. In addition to updating relations that were previously developed, models also were developed for four new constituents, including magnesium, dissolved phosphorus, actinomycetes bacteria, and the cyanotoxin microcystin. In addition, a conversion factor of 0.74 was established to convert the Yellow Springs Instruments (YSI) model 6026 turbidity sensor measurements to the newer YSI

  20. Particle Fluxes and Bulk Geochemical Characterization of the Cabo Frio Upwelling System in Southeastern Brazil: Sediment Trap Experiments between Spring 2010 and Summer 2012

    Directory of Open Access Journals (Sweden)

    ANA LUIZA S. ALBUQUERQUE

    2014-06-01

    Full Text Available Physical and biogeochemical processes in continental shelves act synergistically in both transporting and transforming suspended material, and ocean dynamics control the dispersion of particles by the coastal zone and their subsequent mixing and dilution within the shelf area constrained by oceanic boundary currents, followed by their gradual settling in a complex sedimentary scenario. One of these regions is the Cabo Frio Upwelling System located in a significantly productive area of Southeastern Brazil, under the control of the nutrient-poor western boundary Brazil Current but also with a wind-driven coastal upwelling zone, inducing cold-water intrusions of South Atlantic Central Water on the shelf. To understand these synergic interactions among physical and biogeochemical processes in the Cabo Frio shelf, a series of four experiments with a total of 98 discrete samples using sediment traps was performed from November 2010 to March 2012, located on the 145 m isobath on the edge of the continental shelf. The results showed that lateral transport might be relevant in some cases, especially in deep layers, although no clear seasonal cycle was detected. Two main physical-geochemical coupling scenarios were identified: singular downwelling events that can enhance particles fluxes and are potentially related to the Brazil Current oscillations; and events of significant fluxes related to the intrusion of the 18°C isotherm in the euphotic zone. The particulate matter settling in the Cabo Frio shelf area seems to belong to multiple marine and terrestrial sources, in which both Paraiba do Sul River and Guanabara Bay could be potential land-sources, although the particulate material might subject intense transformation (diagenesis during its trajectory to the shelf edge.

  1. Particle Fluxes and Bulk Geochemical Characterization of the Cabo Frio Upwelling System in Southeastern Brazil: Sediment Trap Experiments between Spring 2010 and Summer 2012.

    Science.gov (United States)

    Albuquerque, Ana Luiza S; Belém, André L; Zuluaga, Francisco J B; Cordeiro, Livia G M; Mendoza, Ursula; Knoppers, Bastiaan A; Gurgel, Marcio H C; Meyers, Philip A; Capilla, Ramsés

    2014-05-14

    Physical and biogeochemical processes in continental shelves act synergistically in both transporting and transforming suspended material, and ocean dynamics control the dispersion of particles by the coastal zone and their subsequent mixing and dilution within the shelf area constrained by oceanic boundary currents, followed by their gradual settling in a complex sedimentary scenario. One of these regions is the Cabo Frio Upwelling System located in a significantly productive area of Southeastern Brazil, under the control of the nutrient-poor western boundary Brazil Current but also with a wind-driven coastal upwelling zone, inducing cold-water intrusions of South Atlantic Central Water on the shelf. To understand these synergic interactions among physical and biogeochemical processes in the Cabo Frio shelf, a series of four experiments with a total of 98 discrete samples using sediment traps was performed from November 2010 to March 2012, located on the 145 m isobath on the edge of the continental shelf. The results showed that lateral transport might be relevant in some cases, especially in deep layers, although no clear seasonal cycle was detected. Two main physical-geochemical coupling scenarios were identified: singular downwelling events that can enhance particles fluxes and are potentially related to the Brazil Current oscillations; and events of significant fluxes related to the intrusion of the 18°C isotherm in the euphotic zone. The particulate matter settling in the Cabo Frio shelf area seems to belong to multiple marine and terrestrial sources, in which both Paraiba do Sul River and Guanabara Bay could be potential land-sources, although the particulate material might subject intense transformation (diagenesis) during its trajectory to the shelf edge.

  2. Discussion on distribution characteristics of calcareous sandstone in Shihongtan uranium deposit and its genesis

    International Nuclear Information System (INIS)

    Zhu Huanqiao; Qiao Haiming; Jia Heng; Xu Gaozhong

    2007-01-01

    Based on the observation and statistics on the calcareous sandstone in the ore host layer in Shihongtan uranium deposit, this paper finds that the calcareous sandstone occurs on and off near the top or wash surface of the sandbody as beads-strings lens along the layer and concentrates in the area where the ore bodies are rich. In lithology, the calcareous sandstone is of coarse grain and fairly well sorted. According to the analysis on the lithogeochemical features and the carbon and oxygen isotopes of calcareous sandstones, it is realized that there some genetic relation between the formation of calcareous sandstone and uranium mineralization in the oxidation-deoxidation transitional belt, that is the precipitation and enrichment of uranium is accompanied by the deposition of carbonate and formation of calcareous sandstone. (authors)

  3. A complex investigation of building sandstones from Saxony (Germany)

    International Nuclear Information System (INIS)

    Goetze, Jens; Siedel, Heiner

    2007-01-01

    The present paper provides a methodology for the investigation and characterization of building sandstones. This analytical scheme was designed for distinguishing mature arenites, which in general show very similar properties and are difficult to distinguish. This is shown for Cretaceous sandstones from various occurrences in Saxony (Germany), which have been used for centuries as building materials. The procedure is mainly based on the combination of macroscopic rock description, thin section polarizing microscopy (phase composition, texture, grain-size distribution) and cathodoluminescence (CL) microscopy (quartz types, feldspar and kaolinite content) coupled with image analysis, scanning electron microscopy (accessories, pore cement, diagenetic grain surface features), and analysis of pore space data. Sometimes, additional data from X-ray diffraction or chemical analyses (major and trace elements) can be used. Especially in the case of quartz rich arenites, CL is a powerful tool for provenance analysis. The detailed analysis of sandstone material in most cases allows us to assign historically used building material to a specific sandstone occurrence. These results are important for both interpreting the weathering behaviour of the building material and the conservation, reconstruction and stone replacement of historical monuments

  4. Assessment of undiscovered sandstone copper deposits of the Kodar-Udokan area, Russia: Chapter M in Global mineral resource assessment

    Science.gov (United States)

    Zientek, Michael L.; Chechetkin, Vladimir S.; Parks, Heather L.; Box, Stephen E.; Briggs, Deborah A.; Cossette, Pamela M.; Dolgopolova, Alla; Hayes, Timothy S.; Seltmann, Reimar; Syusyura, Boris; Taylor, Cliff D.; Wintzer, Niki E.

    2014-01-01

    Mineral resource assessments integrate and synthesize available information as a basis for estimating the location, quality, and quantity of undiscovered mineral resources. This probabilistic mineral resource assessment of undiscovered sandstone copper deposits within Paleoproterozoic metasedimentary rocks of the Kodar-Udokan area in Russia is a contribution to a global assessment led by the U.S. Geological Survey (USGS). The purposes of this study are to (1) delineate permissive areas (tracts) to indicate where undiscovered sandstone-hosted copper deposits may occur within 2 km of the surface, (2) provide a database of known sandstone copper deposits and significant prospects, (3) estimate numbers of undiscovered deposits within these permissive tracts at several levels of confidence, and (4) provide probabilistic estimates of amounts of copper (Cu) and mineralized rock that could be contained in undiscovered deposits within each tract. The workshop for the assessment, held in October 2009, used a three-part form of mineral resource assessment as described by Singer (1993) and Singer and Menzie (2010).

  5. Nutrient budget for Saguling Reservoir, West Java, Indonesia.

    Science.gov (United States)

    Hart, Barry T; van Dok, Wendy; Djuangsih, Nani

    2002-04-01

    A preliminary nutrient budget for Saguling Reservoir is reported as a first attempt to quantify the behaviour of nutrients entering this reservoir. This work is part of a larger Indonesia-Australia collaborative research and training project, involving Padjadjaran University and Monash University, established to study nutrient dynamics in Saguling Reservoir. Saguling Reservoir, the first of a chain of three large reservoirs (Saguling, Cirata and Jatilahur), built on the Citarum River in central Java, was completed in 1985. It has already become highly polluted, particularly with domestic and industrial effluent (organic matter, nutrients, heavy metals) from the urban areas of Bandung (population 2 million). The reservoir experiences major water quality problems, including excessive growths of floating plants, toxic cyanobacterial blooms and regular fish-kills. The work reported in this paper shows that Saguling receives a very large nutrient load from the city of Bandung and because of this, is highly eutrophic. It is unlikely that the water quality of Saguling will improve until a substantial part of Bandung is sewered and adequate discharge controls are placed on the many industries in the region upstream of the reservoir.

  6. Effects of Pisha sandstone content on solute transport in a sandy soil.

    Science.gov (United States)

    Zhen, Qing; Zheng, Jiyong; He, Honghua; Han, Fengpeng; Zhang, Xingchang

    2016-02-01

    In sandy soil, water, nutrients and even pollutants are easily leaching to deeper layers. The objective of this study was to assess the effects of Pisha sandstone on soil solute transport in a sandy soil. The miscible displacement technique was used to obtain breakthrough curves (BTCs) of Br(-) as an inert non-adsorbed tracer and Na(+) as an adsorbed tracer. The incorporation of Pisha sandstone into sandy soil was able to prevent the early breakthrough of both tracers by decreasing the saturated hydraulic conductivity compared to the controlled sandy soil column, and the impeding effects increased with Pisha sandstone content. The BTCs of Br(-) were accurately described by both the convection-dispersion equation (CDE) and the two-region model (T-R), and the T-R model fitted the experimental data slightly better than the CDE. The two-site nonequilibrium model (T-S) accurately fit the Na(+) transport data. Pisha sandstone impeded the breakthrough of Na(+) not only by decreasing the saturated hydraulic conductivity but also by increasing the adsorption capacity of the soil. The measured CEC values of Pisha sandstone were up to 11 times larger than those of the sandy soil. The retardation factors (R) determined by the T-S model increased with increasing Pisha sandstone content, and the partition coefficient (K(d)) showed a similar trend to R. According to the results of this study, Pisha sandstone can successfully impede solute transport in a sandy soil column. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Geophysical signature recognition of aquifuge and relatively impermeable interbed in ore-hosting sandstone layer at sandstone-type uranium deposit

    International Nuclear Information System (INIS)

    Zhao Xigang; Wu Hanning; Bai Guanjun; Zhu Huanqiao; Jia Heng

    2006-01-01

    Geophysical signature recognition of aquifuge and relatively impermeable interbed in ore-hosting aquifer has been carried out a Shihongtan uranium deposit by using comprehensive logging data. The spatial distribution of above aquifuge and impermeable interbed is discussed, and the relation of these layers to sandstone-type uranium deposit, and their impact to in-situ leach mining technology are discussed. It is suggested that the aquifuge and relatively impermeable interbed bring about significant effect to the formation of interlayer oxidation zone sandstone-type uranium deposit, as well as to in-situ leach mining of the deposit. (authors)

  8. Streamflow, water quality, and constituent loads and yields, Scituate Reservoir Drainage Area, Rhode Island, water year 2015

    Science.gov (United States)

    Smith, Kirk P.

    2018-05-11

    Streamflow and concentrations of sodium and chloride estimated from records of specific conductance were used to calculate loads of sodium and chloride during water year (WY) 2015 (October 1, 2014, through September 30, 2015) for tributaries to the Scituate Reservoir, Rhode Island. Streamflow and water-quality data used in the study were collected by the U.S. Geological Survey and the Providence Water Supply Board. Streamflow was measured or estimated by the U.S. Geological Survey following standard methods at 23 streamgages; 14 of these streamgages are equipped with instrumentation capable of continuously monitoring water level, specific conductance, and water temperature. Water-quality samples were collected at 36 sampling stations by the Providence Water Supply Board and at 14 continuous-record streamgages by the U.S. Geological Survey during WY 2015 as part of a long-term sampling program; all stations are in the Scituate Reservoir drainage area. Water-quality data collected by the Providence Water Supply Board are summarized by using values of central tendency and are used, in combination with measured (or estimated) streamflows, to calculate loads and yields (loads per unit area) of selected water-quality constituents for WY 2015.The largest tributary to the reservoir (the Ponaganset River, which was monitored by the U.S. Geological Survey) contributed a mean streamflow of 25 cubic feet per second to the reservoir during WY 2015. For the same time period, annual mean streamflows measured (or estimated) for the other monitoring stations in this study ranged from about 0.38 to about 14 cubic feet per second. Together, tributaries (equipped with instrumentation capable of continuously monitoring specific conductance) transported about 1,500,000 kilograms of sodium and 2,400,000 kilograms of chloride to the Scituate Reservoir during WY 2015; sodium and chloride yields for the tributaries ranged from 8,000 to 54,000 kilograms per square mile and from 12,000 to 91

  9. On the CO2 Wettability of Reservoir Rocks: Addressing Conflicting Information

    Science.gov (United States)

    Garing, C.; Wang, S.; Tokunaga, T. K.; Wan, J.; Benson, S. M.

    2017-12-01

    Conventional wisdom is that siliclastic rocks are strongly water wet for the CO2-brine system, leading to high irreducible water saturation, moderate residual gas trapping and implying that tight rocks provide efficient seals for buoyant CO2. If the wetting properties become intermediate or CO2 wet, the conclusions regarding CO2 flow and trapping could be very different. Addressing the CO2 wettability of seal and reservoir rocks is therefore essential to predict CO2 storage in geologic formation. Although a substantial amount of work has been dedicated to the topic, contact angle data show a large variability and experiments on plates, micromodels and cores report conflicting results regarding the influence of supercritical CO2 (scCO2) exposure on wetting properties: whereas some experimental studies suggest dewetting upon reaction with scCO2, some others observe no wettability alteration under reservoir scCO2 conditions. After reviewing evidences for and against wettability changes associated with scCO2, we discuss potential causes for differences in experimental results. They include the presence of organic matter and impact of sample treatment, the type of media (non consolidated versus real rock), experimental time and exposure to scCO2, and difference in measurement system (porous plate versus stationary fluid method). In order to address these points, new scCO2/brine drainage-imbibition experiments were conducted on a same Berea sandstone rock core, first untreated, then fired and finally exposed to scCO2 for three weeks, using the stationary fluid method. The results are compared to similar experiments performed on quartz sands, untreated and then baked, using the porous plate method. In addition, a comparative experiment using the same Idaho gray sandstone rock core was performed with both the porous plate and the stationary fluid methods to investigate possible method-dependent results.

  10. Application of magnetic techniques to lateral hydrocarbon migration - Lower Tertiary reservoir systems, UK North Sea

    Science.gov (United States)

    Badejo, S. A.; Muxworthy, A. R.; Fraser, A.

    2017-12-01

    Pyrolysis experiments show that magnetic minerals can be produced inorganically during oil formation in the `oil-kitchen'. Here we try to identify a magnetic proxy that can be used to trace hydrocarbon migration pathways by determining the morphology, abundance, mineralogy and size of the magnetic minerals present in reservoirs. We address this by examining the Tay formation in the Western Central Graben in the North Sea. The Tertiary sandstones are undeformed and laterally continuous in the form of an east-west trending channel, facilitating long distance updip migration of oil and gas to the west. We have collected 179 samples from 20 oil-stained wells and 15 samples from three dry wells from the British Geological Survey Core Repository. Samples were selected based on geological observations (water-wet sandstone, oil-stained sandstone, siltstones and shale). The magnetic properties of the samples were determined using room-temperature measurements on a Vibrating Sample Magnetometer (VSM), low-temperature (0-300K) measurements on a Magnetic Property Measurement System (MPMS) and high-temperature (300-973K) measurements on a Kappabridge susceptibility meter. We identified magnetite, pyrrhotite, pyrite and siderite in the samples. An increasing presence of ferrimagnetic iron sulphides is noticed along the known hydrocarbon migration pathway. Our initial results suggest mineralogy coupled with changes in grain size are possible proxies for hydrocarbon migration.

  11. Large reservoirs: Chapter 17

    Science.gov (United States)

    Miranda, Leandro E.; Bettoli, Phillip William

    2010-01-01

    expressed effects, such as turbidity and water quality, zooplankton density and size composition, or fish growth rates and assemblage composition, are the upshot of large-scale factors operating outside reservoirs and not under the direct control of reservoir managers. Realistically, abiotic and biotic conditions in reservoirs are shaped by factors working inside and outside reservoirs, with the relative importance of external factors differing among reservoirs. With this perspective, large reservoirs are viewed from a habitat standpoint within the framework of a conceptual model in which individual reservoir characteristics are influenced by both local- and landscape-scale factors (Figure 17.1). In the sections that follow, how each element of this hierarchical model influences habitat and fish assemblages in reservoirs is considered. Important in-reservoir habitat issues and reservoirs as part of larger systems, where reservoir management requires looking for real solutions outside individual reservoirs are described.

  12. Experimental Investigation on the Behavior of Supercritical CO2 during Reservoir Depressurization.

    Science.gov (United States)

    Li, Rong; Jiang, Peixue; He, Di; Chen, Xue; Xu, Ruina

    2017-08-01

    CO 2 sequestration in saline aquifers is a promising way to address climate change. However, the pressure of the sequestration reservoir may decrease in practice, which induces CO 2 exsolution and expansion in the reservoir. In this study, we conducted a core-scale experimental investigation on the depressurization of CO 2 -containing sandstone using NMR equipment. Three different series of experiments were designed to investigate the influence of the depressurization rate and the initial CO2 states on the dynamics of different trapping mechanisms. The pressure range of the depressurization was from 10.5 to 4.0 MPa, which covered the supercritical and gaseous states of the CO 2 (named as CO 2 (sc) and CO 2 (g), respectively). It was found that when the aqueous phase saturated initially, the exsolution behavior strongly depended on the depressurization rate. When the CO 2 and aqueous phase coexisting initially, the expansion of the CO 2 (sc/g) contributed to the incremental CO 2 saturation in the core only when the CO 2 occurred as residually trapped. It indicates that the reservoir depressurization has the possibility to convert the solubility trapping to the residual trapping phase, and/or convert the residual trapping to mobile CO 2 .

  13. Well pattern optimization in a low permeability sandstone reservoir: a case study from Erlian Basin in China

    Science.gov (United States)

    Wang, Xia; Fu, Lixia; Yan, Aihua; Guo, Fajun; Wu, Cong; Chen, Hong; Wang, Xinying; Lu, Ming

    2018-02-01

    Study on optimization of development well patterns is the core content of oilfield development and is a prerequisite for rational and effective development of oilfield. The study on well pattern optimization mainly includes types of well patterns and density of well patterns. This paper takes the Aer-3 fault block as an example. Firstly, models were built for diamond-shaped inverted 9-spot patterns, rectangular 5-spot patterns, square inverted 9-spot patterns and inverted 7-spot patterns under the same well pattern density to correlate the effect of different well patterns on development; secondly, comprehensive analysis was conducted to well pattern density in terms of economy and technology using such methods as oil reservoir engineering, numerical simulation, economic limits and economic rationality. Finally, the development mode of vertical well + horizontal well was presented according to the characteristics of oil reservoirs in some well blocks, which has realized efficient development of this fault block.

  14. Temperature effect on microstructure and P-wave propagation in Linyi sandstone

    International Nuclear Information System (INIS)

    Sun, Hui; Sun, Qiang; Deng, Wenni; Zhang, Weiqiang; Lü, Chao

    2017-01-01

    Highlights: • Mass loss rate, P-wave velocity change rate and damage factor increase exponentially as temperatures rise. • The damage threshold temperature of sandstone samples is 300 °C and limit temperature is 900 °C. • P-wave velocity change rate of sandstone exhibits excellent linearity with mass loss rate. • Damage factor can be well expressed by mass loss rate. - Abstract: In order to study the effect of high temperature on the sandstone, scanning electron microscope (SEM) experiments and primary wave (P-wave) velocity tests have been carried out on sandstone specimens heated to different temperature. The results showed that: (1) the mass loss rate increases exponentially with the increase of temperature and reaches 2.97% at 900 °C; (2) the P-wave velocity change rate increases exponentially with the increase of temperature while there is some fluctuation before 500 °C; (3) the damage threshold temperature of sandstone samples is 300 °C and the limit temperature is 900 °C; (4) there is a good linear relationship between the mass loss rate and the P-wave velocity change rate, and the correlation coefficient (R) of the fitting line is 0.989; (5) the damage caused by high temperature can be reflected better by the mass loss rate than P-wave velocity change rate. The results obtained in this paper will be good for predicting the properties of sandstone when exposed to high temperature.

  15. Assessment of the Water Quality of Jatiluhur Reservoir, the Downstream of Citarum Cascade River, Using Selected Physico-Chemical Parameters

    Directory of Open Access Journals (Sweden)

    Lieza Corsita

    2014-06-01

    Full Text Available Physico-chemistry and biological data were investigated  from  October 2010 until April 2011 of Jatiluhur reservoir. A total of six sampling stations were selected for this study. The discharge and hidrological data were obtained from Perum Jasa Tirta II Jatiluhur. The results showed that the hydrological regime in the reservoir Jatiluhur was affected by global phenomenon La Nina events in 2010 and early in 2011. Stream flows were determined during sampling to range from 78  to 482.5 m3/s. The water quality findings were as follows: pH (6.93-8.81, temperature (26.37-30.6°C, dissolved oxygen (0.733-5.2 mg/l, conductivity (2.45-233µmhos/cm, COD (7.36-96.9 mg/l, turbidity (4.063-65.6 NTU, total phosphate (0.002-0.324 mg/l, total nitrogen (0.99-5.96 mg/l, chlorophyl (2.237-43.37 mg/m3, visibility (30-160 cm. The eutrophication was pronounced at Jatiluhur reservoir. Canonical Correspendence Analysis found that some water quality parameters correlated positively with the discharge and the water level.

  16. Improving Oil Recovery (IOR) with Polymer Flooding in a Heavy-Oil River-Channel Sandstone Reservoir

    OpenAIRE

    Lu, Hongjiang

    2009-01-01

    Most of the old oil fields in China have reached high water cut stage, in order to meet the booming energy demanding, oil production rate must be kept in the near future with corresponding IOR (Improving Oil Recovery) methods. Z106 oilfield lies in Shengli Oilfields Area at the Yellow River delta. It was put into development in 1988. Since the oil belongs to heavy oil, the oil-water mobility ratio is so unfavourable that water cut increases very quickly. Especially for reservoir Ng21, the san...

  17. Desalination of salt damaged Obernkirchen sandstone by an applied DC field

    DEFF Research Database (Denmark)

    Matyščák, Ondřej; Ottosen, Lisbeth M.; Rörig-Dalgaard, Inge

    2014-01-01

    Soluble salts are considered as one of the most common causes for decay of building materials. In the present work, an electrokinetic method for desalination of sandstones from a historic warehouse was tested. The sandstones claddings were removed from the warehouse during a renovation action...... in the stones, i.e. the present investigation faces more challenges relevant to a real desalination action. Experiments were conducted with two Obernkirchen sandstones from the same warehouse, but with different levels of salt concentrations and porosity. The investigation includes removal of the most common...... salts: chlorides, nitrates, sulphates. In the experimental setup the electrodes were placed in a clay poultice: a mixture of kaolinite, calcite and distilled water. An electric direct current (DC) field was applied to the sandstone.By applying 2mA for 5–11days it was possible to reduce the chloride...

  18. Characteristics and model of sandstone type uranium deposit in south of Songliao basin

    International Nuclear Information System (INIS)

    Yu Wenbin; Yu Zhenqing

    2010-01-01

    Through analyzing the uranium deposit tectonic environment, upper cretaceous sequence stratigraphy, depositional system, evolutionary characteristics of sand bodies, the effect of subsequent transformation and the characteristic of uranium deposit, the sandstone type uranium deposit in southern basin is different from typical interlayer oxidation zone sandstone type uranium deposit. The formation and evolution of sandstone-type uranium deposit are controlled by structure fensters; the favorable sedimentary facies type is braided river facies, and the ore body is braided river sand body. The size of uranium deposits is controlled by the local oxidation zone with the characteristics of sandstone type uranium deposit in partial oxidation zone. Uranium ore bodies which distribute in the roof wings of structure fenstes, and occur in gray layers between the upper and lower oxidation zone, showing tabular, and the plate of uranium ore body is controlled by the local oxidation zone. Based on the geological features of sandstone-type uranium deposits, the metallogenic model of local oxidation zones sandstone-type uranium deposits has been set up in the south of Songliao Baisn. (authors)

  19. Assessment of water quality from water harvesting using small farm reservoir for irrigation

    Science.gov (United States)

    Dewi, W. S.; Komariah; Samsuri, I. Y.; Senge, M.

    2018-03-01

    This study aims to assess the quality of rainfall-runoff water harvesting using small farm reservoir (SFR) for irrigation. Water quality assessment criteria based on RI Government Regulation number 82 the year 2001 on Water Quality Management and Pollution Control, and FAO Irrigation Water Quality Guidelines 1985. The experiment was conducted in the dry land of Wonosari Village, Gondangrejo District, Karanganyar Regency. SFR size was 10 m x 3 m x 2 m. Water quality measurements are done every week, ten times. Water samples were taken at 6 points, namely: distance of 2.5 m, 5 m, and 7.5 m from the inlet, at depth 25 cm and 175 cm from surface water. In each sampling point replicated three times. Water quality parameters include dissolved oxygen (DO), Turbidity (TSS), water pH, Nitrate (NO3), and Phosphate. The results show that water harvesting that collected in SFR meets both standards quality used, so the water is feasible for agricultural irrigation. The average value of harvested water was DO 2.6 mg/l, TSS 62.7 mg/l, pH 6.6, P 5.3 mg/l and NO3 0.16 mg/l. Rainfall-runoff water harvesting using SFR prospectus for increasing save water availability for irrigation.

  20. 3-D description of fracture surfaces and stress-sensitivity analysis for naturally fractured reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, S.Q.; Jioa, D.; Meng, Y.F.; Fan, Y.

    1997-08-01

    Three kinds of reservoir cores (limestone, sandstone, and shale with natural fractures) were used to study the effect of morphology of fracture surfaces on stress sensitivity. The cores, obtained from the reservoirs with depths of 2170 to 2300 m, have fractures which are mated on a large scale, but unmated on a fine scale. A specially designed photoelectric scanner with a computer was used to describe the topography of the fracture surfaces. Then, theoretical analysis of the fracture closure was carried out based on the fracture topography generated. The scanning results show that the asperity has almost normal distributions for all three types of samples. For the tested samples, the fracture closure predicted by the elastic-contact theory is different from the laboratory measurements because plastic deformation of the aspirates plays an important role under the testing range of normal stresses. In this work, the traditionally used elastic-contact theory has been modified to better predict the stress sensitivity of reservoir fractures. Analysis shows that the standard deviation of the probability density function of asperity distribution has a great effect on the fracture closure rate.

  1. Gamma ray spectrometry logs as a hydrocarbon indicator for clastic reservoir rocks in Egypt

    International Nuclear Information System (INIS)

    Al-Alfy, I.M.; Nabih, M.A.; Eysa, E.A.

    2013-01-01

    Petroleum oil is an important source for the energy in the world. The Gulf of Suez, Nile Delta and South Valley are important regions for studying hydrocarbon potential in Egypt. A thorium normalization technique was applied on the sandstone reservoirs in the three regions to determine the hydrocarbon potentialities zones using the three spectrometric radioactive gamma ray-logs (eU, eTh and K% logs). The conventional well logs (gamma-ray, deep resistivity, shallow resistivity, neutron, density and sonic logs) are analyzed to determine the net pay zones in these wells. Indices derived from thorium normalized spectral logs indicate the hydrocarbon zones in petroleum reservoirs. The results of this technique in the three regions (Gulf of Suez, Nile Delta and South Valley) are in agreement with the results of the conventional well log analyses by ratios of 82%, 78% and 71% respectively. - Highlights: ► The positive DRAD values indicate the hydrocarbon zones in petroleum reservoirs. ► Thorium normalization was applied to determine the hydrocarbon potentialities. ► The conventional well logs are analyzed to determine the net pay zones in wells. ► Determining hydrocarbon potentialities zones using spectrometric gamma-ray logs

  2. Condições do movimento geostrófico das águas adjacentes a Cabo Frio (RJ On the conditions of the geostrophic circulation in waters off Cabo Frio (RJ

    Directory of Open Access Journals (Sweden)

    Luiz Bruner de Miranda

    1979-01-01

    Full Text Available A circulação geostrófica e as condições hidrográficas, na borda da plataforma continental adjacente ao Cabo Frio (RJ, são analisadas ao longo de duas secções verticais realizadas em julho de 1968. A principal característica resultante dessa análise é a ocorrência de movimentos para leste e oeste, com velocidades estimadas atingindo valores de até ± 2 cm.s-1 e -49 cm.s-1, respectivamente. Os movimentos para leste apresentam um fluxo de volume de 0,52 Sv (0,40 Sv e as maiores velocidades são atingidas abaixo da picnoclina e na região adjacente a borda da plataforma continental. O principal movimento para oeste, tem as maiores velocidades na camada de superfície, e os pequenos valores do transporte de volume, de -2,24 Sv (-2,68 Sv, sugerem que as observações hidrográficas foram realizadas na região de cisalhamento ciclonico da Corrente do Brasil. Detalhes da distribuição do fluxo de volume são apresentados sobre o diagrama T-S, em correspondência com classes delimitadas por intervalos de variação da anomalia termostérica e da temperatura.The geostrophic circulation and the hydrographic conditions on the edge of the continental shelf off Cabo Frio (RJ were investigated along two vertical sections sampled on July 1968. The main characteristics resulting from this analysis are the occurrences of east and west flows3 with speeds up to ± 2 cm.s-1 and -49 cm.s-1, respectively. The eastward motion presents a volume transport of 0.52 Sv (0.40 Sv and the highest speeds are reached under the pycnocline, near the edge of the continental shelf. The main flow westward, presents the highest speeds on the upper layer, and the low values of volume transport of -2.24 Sv (-2.68 Sv suggest that the hydrographic observations have been made in the cyclonic shear region of the Brazil Current. Details on the volume transport are presented, on the T-S diagram corresponding to classes bounded by intervals of thermosteric anomaly and

  3. Reservoir attributes of a hydrocarbon-prone sandstone complex: case of the Pab Formation (Late Cretaceous) of Southwest Pakistan

    DEFF Research Database (Denmark)

    Umar, Muhammad; Khan, Abdul Salam; Kelling, Gilbert

    2016-01-01

    Links between the architectural elements of major sand bodies and reservoir attributes have been explored in a field study of the hydrocarbon-yielding Late Cretaceous Pab Formation of southwest Pakistan. The lithofacies and facies associations represented in the Pab Formation are the main...... determinants of its reservoir properties. Thus, thick, vertically connected and laterally continuous sand packets have moderate-to-high mean porosities (10–13 %) in fluviodeltaic, shoreface, shelf delta, submarine channel, and fan-lobe facies associations while deeper shelf and basin floor sand bodies yield...... significantly lower porosities (4–6 %). Overall, in the Pab arenites, porosity values increase with increasing grain size and better sorting. The varying sand-shale ratios encountered in different sectors of the Pab outcrop are also petrophysically important: Sequences displaying high ratios yield higher bulk...

  4. Kansas environmental and resource study: A Great Plains model. Monitoring fresh water resources. [water quality of reservoirs

    Science.gov (United States)

    Yarger, H. L. (Principal Investigator); Mccauley, J. R.

    1974-01-01

    The author has identified the following significant results. Processing and analysis of CCT's for numerous ground truth supported passes over Kansas reservoirs has demonstrated that sun angle and atmospheric conditions are strong influences on water reflectance levels as detected by ERTS-1 and can suppress the contributions of true water quality factors. Band ratios, on the other hand, exhibit very little dependence on sun angle and sky conditions and thus are more directly related to water quality. Band ratio levels can be used to reliably determine suspended load. Other water quality indicators appear to have little or no affect on reflectance levels.

  5. Water quality of the reservoirs used for irrigation in São José dos Pinhais, Paraná State, Brazil

    Directory of Open Access Journals (Sweden)

    Tiago Miguel Jarek

    2016-04-01

    Full Text Available ABSTRACT: Land use outside its agricultural potential and low vegetation cover in the watershed impair the quality of water used for irrigation and may contribute to the spread of pathogenic coliform bacteria. The objective of this study was to relate the quality of irrigation water with the intensity and type of land use and the rainfall in a vegetable-producing region of São José dos Pinhais, Paraná. Water samples were collected monthly in 2013 from two reservoirs and one preserved source. After collection, the samples were chilled in Styrofoam boxes and transported to the laboratory for analyses of the total and thermotolerant coliforms. Effect of land use was analyzed by probability estimation trees. High land use and weekly above average rainfall increased the probability of thermo tolerant coliforms exceeding the limit allowed under legislation. In regards to thermo tolerant coliforms in the analyzed period, the water from only one reservoir was in accordance with the legislation for the quality of water to irrigate vegetables that are consumed raw. Results of this study are an alert to the local government for the necessity of environmental preservation to maintain the water quality of the county.

  6. Optimal spatio-temporal design of water quality monitoring networks for reservoirs: Application of the concept of value of information

    Science.gov (United States)

    Maymandi, Nahal; Kerachian, Reza; Nikoo, Mohammad Reza

    2018-03-01

    This paper presents a new methodology for optimizing Water Quality Monitoring (WQM) networks of reservoirs and lakes using the concept of the value of information (VOI) and utilizing results of a calibrated numerical water quality simulation model. With reference to the value of information theory, water quality of every checkpoint with a specific prior probability differs in time. After analyzing water quality samples taken from potential monitoring points, the posterior probabilities are updated using the Baye's theorem, and VOI of the samples is calculated. In the next step, the stations with maximum VOI is selected as optimal stations. This process is repeated for each sampling interval to obtain optimal monitoring network locations for each interval. The results of the proposed VOI-based methodology is compared with those obtained using an entropy theoretic approach. As the results of the two methodologies would be partially different, in the next step, the results are combined using a weighting method. Finally, the optimal sampling interval and location of WQM stations are chosen using the Evidential Reasoning (ER) decision making method. The efficiency and applicability of the methodology are evaluated using available water quantity and quality data of the Karkheh Reservoir in the southwestern part of Iran.

  7. Gamma ray spectrometry logs as a hydrocarbon indicator for clastic reservoir rocks in Egypt.

    Science.gov (United States)

    Al-Alfy, I M; Nabih, M A; Eysa, E A

    2013-03-01

    Petroleum oil is an important source for the energy in the world. The Gulf of Suez, Nile Delta and South Valley are important regions for studying hydrocarbon potential in Egypt. A thorium normalization technique was applied on the sandstone reservoirs in the three regions to determine the hydrocarbon potentialities zones using the three spectrometric radioactive gamma ray-logs (eU, eTh and K% logs). The conventional well logs (gamma-ray, deep resistivity, shallow resistivity, neutron, density and sonic logs) are analyzed to determine the net pay zones in these wells. Indices derived from thorium normalized spectral logs indicate the hydrocarbon zones in petroleum reservoirs. The results of this technique in the three regions (Gulf of Suez, Nile Delta and South Valley) are in agreement with the results of the conventional well log analyses by ratios of 82%, 78% and 71% respectively. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  8. Viga mista de aço e concreto constituída por perfil formado a frio preenchido

    OpenAIRE

    Igor Avelar Chaves

    2009-01-01

    As vigas mistas de aço e concreto têm sido amplamente empregadas em edifícios e pontes, havendo ampla investigação teórica e experimental a respeito da utilização de perfis laminados e soldados e conectores de cisalhamento compatíveis com esses perfis, como por exemplo, o conector tipo pino com cabeça (stud bolt) e perfil U laminado. No âmbito dos perfis formados a frio, a utilização do sistema misto ainda é incipiente, necessitando de investigações mais aprofundadas a respeito do comportamen...

  9. Multi-objective calibration of a reservoir water quality model in aggregation and non-dominated sorting approaches

    Science.gov (United States)

    Huang, Yongtai

    2014-03-01

    Numerical water quality models are developed to predict contaminant fate and transport in receiving waters such as reservoirs and lakes. They can be helpful tools for water resource management. The objective of this study is to calibrate a water quality model which was set up to simulate the water quality conditions of Pepacton Reservoir, Downsville, New York, USA, using an aggregation hybrid genetic algorithm (AHGA) and a non-dominated sorting hybrid genetic algorithm (NSHGA). Both AHGA and NSHGA use a hybrid genetic algorithm (HGA) as optimization engines but are different in fitness assignment. In the AHGA, a weighted sum of scaled simulation errors is designed as an overall objective function to measure the fitness of solutions (i.e., parameter values). In the NSHGA, a method based on non-dominated sorting and Euclidean distances is proposed to calculate the dummy fitness of solutions. In addition, this study also compares the AHGA and the NSHGA. The purpose of this comparison is to determine whether the objective function values (i.e., simulation errors) and simulated results obtained by the AHGA and the NSHGA are significantly different from each other. The results show that the objective function values from the two HGAs are good compromises between all objective functions, and the calibrated model results match the observed data reasonably well and are comparable to other studies, supporting and justifying the use of multi-objective calibration.

  10. CO2 geosequestration at the laboratory scale: Combined geophysical and hydromechanical assessment of weakly-cemented shallow Sleipner-like reservoirs

    Science.gov (United States)

    Falcon-Suarez, I.; North, L. J.; Best, A. I.

    2017-12-01

    To date, the most promising mitigation strategy for reducing global carbon emissions is Carbon Capture and Storage (CCS). The storage technology (i.e., CO2 geosequestration, CGS) consists of injecting CO2 into deep geological formations, specifically selected for such massive-scale storage. To guarantee the mechanical stability of the reservoir during and after injection, it is crucial to improve existing monitoring techniques for controlling CGS activities. We developed a comprehensive experimental program to investigate the integrity of the Sleipner CO2 storage site in the North Sea - the first commercial CCS project in history where 1 Mtn/y of CO2 has been injected since 1996. We assessed hydro-mechanical effects and the related geophysical signatures of three synthetic sandstones and samples from the Utsira Sand formation (main reservoir at Sleipner), at realistic pressure-temperature (PT) conditions and fluid compositions. Our experimental approach consists of brine-CO2 flow-through tests simulating variable inflation/depletion scenarios, performed in the CGS-rig (Fig. 1; Falcon-Suarez et al., 2017) at the National Oceanography Centre (NOC) in Southampton. The rig is designed for simultaneous monitoring of ultrasonic P- and S-wave velocities and attenuations, electrical resistivity, axial and radial strains, pore pressure and flow, during the co-injection of up to two fluids under controlled PT conditions. Our results show velocity-resistivity and seismic-geomechanical relations of practical importance for the distinction between pore pressure and pore fluid distribution during CGS activities. By combining geophysical and thermo-hydro-mechano-chemical coupled information, we can provide laboratory datasets that complement in situ seismic, geomechanical and electrical survey information, useful for the CO2 plume monitoring in Sleipner site and other shallow weakly-cemented sand CCS reservoirs. Falcon-Suarez, I., Marín-Moreno, H., Browning, F., Lichtschlag, A

  11. Streamflow, water quality and constituent loads and yields, Scituate Reservoir drainage area, Rhode Island, water year 2014

    Science.gov (United States)

    Smith, Kirk P.

    2016-05-03

    Streamflow and concentrations of sodium and chloride estimated from records of specific conductance were used to calculate loads of sodium and chloride during water year (WY) 2014 (October 1, 2013, through September 30, 2014) for tributaries to the Scituate Reservoir, Rhode Island. Streamflow and water-quality data used in the study were collected by the U.S. Geological Survey and the Providence Water Supply Board in the cooperative study. Streamflow was measured or estimated by the U.S. Geological Survey following standard methods at 23 streamgages; 14 of these streamgages are equipped with instrumentation capable of continuously monitoring water level, specific conductance, and water temperature. Water-quality samples were collected at 37 sampling stations by the Providence Water Supply Board and at 14 continuous-record streamgages by the U.S. Geological Survey during WY 2014 as part of a long-term sampling program; all stations are in the Scituate Reservoir drainage area. Water-quality data collected by the Providence Water Supply Board are summarized by using values of central tendency and are used, in combination with measured (or estimated) streamflows, to calculate loads and yields (loads per unit area) of selected water-quality constituents for WY 2014.The largest tributary to the reservoir (the Ponaganset River, which was monitored by the U.S. Geological Survey) contributed a mean streamflow of 23 cubic feet per second to the reservoir during WY 2014. For the same time period, annual mean streamflows measured (or estimated) for the other monitoring stations in this study ranged from about 0.35 to about 14 cubic feet per second. Together, tributaries (equipped with instrumentation capable of continuously monitoring specific conductance) transported about 1,200,000 kilograms of sodium and 2,100,000 kilograms of chloride to the Scituate Reservoir during WY 2014; sodium and chloride yields for the tributaries ranged from 7,700 to 45,000 kilograms per year per

  12. Streamflow, water quality, and constituent loads and yields, Scituate Reservoir drainage area, Rhode Island, water year 2012

    Science.gov (United States)

    Smith, Kirk P.

    2014-01-01

    Streamflow and concentrations of sodium and chloride estimated from records of specific conductance were used to calculate loads of sodium and chloride during water year (WY) 2012 (October 1, 2011, through September 30, 2012), for tributaries to the Scituate Reservoir, Rhode Island. Streamflow and water-quality data used in the study were collected by the U.S. Geological Survey (USGS) or the Providence Water Supply Board (PWSB). Streamflow was measured or estimated by the USGS following standard methods at 23 streamgages; 14 of these streamgages were equipped with instrumentation capable of continuously monitoring water level, specific conductance, and water temperature. Water-quality samples were collected at 37 sampling stations by the PWSB and at 14 continuous-record streamgages by the USGS during WY 2012 as part of a long-term sampling program; all stations were in the Scituate Reservoir drainage area. Water-quality data collected by the PWSB were summarized by using values of central tendency and used, in combination with measured (or estimated) streamflows, to calculate loads and yields (loads per unit area) of selected water-quality constituents for WY 2012. The largest tributary to the reservoir (the Ponaganset River, which was monitored by the USGS) contributed a mean streamflow of about 26 cubic feet per second (ft3/s) to the reservoir during WY 2012. For the same time period, annual mean1 streamflows measured (or estimated) for the other monitoring stations in this study ranged from about 0.40 to about 17 ft3/s. Together, tributaries (equipped with instrumentation capable of continuously monitoring specific conductance) transported about 1,100,000 kilograms (kg) of sodium and 1,900,000 kg of chloride to the Scituate Reservoir during WY 2012; sodium and chloride yields for the tributaries ranged from 8,700 to 51,000 kilograms per square mile (kg/mi2) and from 14,000 to 87,000 kg/mi2, respectively. At the stations where water-quality samples were collected

  13. Streamflow, water quality, and constituent loads and yields, Scituate Reservoir drainage area, Rhode Island, water year 2011

    Science.gov (United States)

    Smith, Kirk P.

    2013-01-01

    Streamflow and concentrations of sodium and chloride estimated from records of specific conductance were used to calculate loads of sodium and chloride during water year (WY) 2011 (October 1, 2010, to September 30, 2011), for tributaries to the Scituate Reservoir, Rhode Island. Streamflow and water-quality data used in the study were collected by the U.S. Geological Survey (USGS) or the Providence Water Supply Board (PWSB). Streamflow was measured or estimated by the USGS following standard methods at 23 streamgages; 14 of these streamgages were also equipped with instrumentation capable of continuously monitoring water level, specific conductance, and water temperature. Water-quality samples also were collected at 37 sampling stations by the PWSB and at 14 continuous-record streamgages by the USGS during WY 2011 as part of a long-term sampling program; all stations were in the Scituate Reservoir drainage area. Water-quality data collected by PWSB are summarized by using values of central tendency and are used, in combination with measured (or estimated) streamflows, to calculate loads and yields (loads per unit area) of selected water-quality constituents for WY 2011. The largest tributary to the reservoir (the Ponaganset River, which was monitored by the USGS) contributed a mean streamflow of about 37 cubic feet per second (ft3/s) to the reservoir during WY 2011. For the same time period, annual mean1 streamflows measured (or estimated) for the other monitoring stations in this study ranged from about 0.5 to about 21 ft3/s. Together, tributaries (equipped with instrumentation capable of continuously monitoring specific conductance) transported about 1,600,000 kg (kilograms) of sodium and 2,600,000 kg of chloride to the Scituate Reservoir during WY 2011; sodium and chloride yields for the tributaries ranged from 9,800 to 53,000 kilograms per square mile (kg/mi2) and from 15,000 to 90,000 kg/mi2, respectively. At the stations where water-quality samples were

  14. Impact of treated wastewater reuse and floods on water quality and fish health within a water reservoir in an arid climate.

    Science.gov (United States)

    Zaibel, Inbal; Zilberg, Dina; Groisman, Ludmila; Arnon, Shai

    2016-07-15

    Treated wastewater (TWW) reuse for agricultural irrigation is a well-established approach to coping with water shortages in semi-arid and arid environments. Recently, additional uses of TWW have emerged, including streamflow augmentation and aquatic ecosystem restoration. The purpose of the current study was to evaluate the water quality and fish health, in an artificial reservoir located in an arid climate (the Yeruham Reservoir, Israel), which regularly receives TWW and sporadic winter floods. The temporal distribution of water levels, nutrients and organic micropollutants (OMPs) were measured during the years 2013-2014. OMPs were also measured in sediment and fish tissues. Finally, the status of fish health was evaluated by histopathology. Water levels and quality were mainly influenced by seasonal processes such as floods and evaporation, and not by the discharge of TWW. Out of 16 tested OMPs, estrone, carbamazepine, diclofenac and bezafibrate were found in the reservoir water, but mostly at concentrations below the predicted no-effect concentration (PNEC) for fish. Concentrations of PCBs and dioxins in fish muscle and liver were much lower than the EU maximal permitted concentrations, and similar to concentrations that were found in food fish in Israel and Europe. In the histopathological analysis, there were no evident tissue abnormalities, and low to moderate infection levels of fish parasites were recorded. The results from the Yeruham Reservoir demonstrated a unique model for the mixture effect between TWW reuse and natural floods to support a unique stable and thriving ecosystem in a water reservoir located in an arid region. This type of reservoir can be widely used for recreation, education, and the social and economic development of a rural environment, such as has occurred in the Yeruham region. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Métodos alternativos do teste de frio para avaliação do vigor de sementes de milho Alternative methods of the cold test for evaluation of corn seed vigor

    Directory of Open Access Journals (Sweden)

    Roseli Fátima Caseiro

    2000-09-01

    Full Text Available O presente trabalho teve como objetivo básico estudar comparativamente quatro métodos para a condução do teste de frio, visando a avaliação do potencial fisiológico das sementes de milho. Para tanto, foram utilizados dois cultivares de milho (AG 3010 e AG 5011, cada um representado por 5 lotes com potenciais fisiológicos distintos. Amostras de sementes de todos os lotes foram submetidas a quatro procedimentos do teste de frio, a saber: "terra" (mistura de terra e areia em caixas empilhadas (método tradicional; "terra" em caixas dispostas lado a lado; bandeja com "terra"; bandeja com "terra" + papel toalha. Estes procedimentos foram comparados com os testes de germinação padrão, envelhecimento acelerado e emergência das plântulas em campo. O teste de frio em bandeja oferece maior facilidade para padronização e permite a obtenção de resultados mais consistentes do que o teste de frio utilizando-se "terra" em caixas, inclusive quanto à relação com a emergência das plântulas em campo.This research was conducted with the objective of comparing different procedures of the cold test to evaluate corn seed vigor. Two cultivars (AG 3010 and AG 5011 represented by 5 lots each were used. Seed samples of all lots were submitted to four procedures of the cold test: stacked deep-box (Brazilian traditional method, deep-box disposed side by side, tray with soil and tray with soil + paper towel, in cold chamber at 10°C for seven days followed by germination at 25°C. Those procedures were also compared with germination, accelerated aging and seedling field emergence tests. The cold test in tray exhibited a great level of standardization than the procedure known as deep-box, allowing for more consistent results and a closer relationship to seedling field emergence.

  16. Study on the enhancement of hydrocarbon recovery by characterization of the reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Young Hoon; Son, Jin Dam; Oh, Jae Ho [Korea Institute of Geology Mining and Materials, Taejon (Korea)] [and others

    1998-12-01

    Three year project is being carried out on the enhancement of hydrocarbon recovery by the reservoir characterization. This report describes the results of the second year's work. This project deals with characterization of fluids, bitumen ad rock matrix in the reservoir. New equipment and analytical solutions for naturally fractured reservoir were also included in this study. Main purpose of the reservoir geochemistry is to understand the origin of fluids (gas, petroleum and water) and distribution of the bitumens within the reservoir and to use them not only for exploration but development of the petroleum. For the theme of reservoir geochemistry, methods and principles of the reservoir gas and bitumen characterization, which is applicable to the petroleum development, are studied. and case study was carried out on the gas, water and bitumen samples in the reservoir taken form Haenam area and Ulleung Basin offshore Korea. Gases taken form the two different wells indicate the different origin. Formation water analyses show the absence of barrier within the tested interval. With the sidewall core samples from a well offshore Korea, the analysis using polarizing microscope, scanning electron microscope with EDX and cathodoluminoscope was performed for the study on sandstone diagenesis. The I/S changes were examined on the cuttings samples from a well, offshore Korea to estimate burial temperature. Oxygen stable isotope is used to study geothermal history in sedimentary basin. Study in the field is rare in Korea and basic data are urgently needed especially in continental basins to determine the value of formation water. In the test analyses, three samples from marine basins indicate final temperature from 55 deg.C to 83 deg.C and one marine sample indicate the initial temperature of 36 deg.C. One sample from continental basin represented the final temperature from 53 and 80 deg.C. These temperatures will be corrected because these values were based on assumed

  17. Numerical simulation of roadway support in a sandstone-type uranium mine

    International Nuclear Information System (INIS)

    Liu Huipeng; Li Yu; Song Lixia

    2009-01-01

    At present, the most surrounding rocks of sandstone-type uranium mines in China are mudstone, sandstone, pelitic siltstone, and so on. They show the characteristics of soft rock. Such uranium deposit is not fit for in-situ leaching. If the uranium ores are mined by conventional mining method, one of the problems to be solved is the support technique in the soft rock roadway. So, taking a uranium mine in Inner Mongolia as the research object, the support technique in the soft rock roadway of the sandstone-type uranium deposits is studied. Through on-site engineering geological investigation and laboratory test, the main reasons for roadway damage are analyzed. A technique of support in the soft rock roadway of sandstone-type uranium deposits is put forward by drawing on the expericnce of soft rock roadway support in coal mines. The roadway shape and support parameters are optimized by using a numerical simulation method. The results verified the feasibility of the supporting technique. (authors)

  18. Sediment transport direction in fluviatile Karharbari sandstone, Giridih Basin, Bihar

    Energy Technology Data Exchange (ETDEWEB)

    Tewari, R C; Casshyap, S M

    1978-01-01

    The sandstone is pebbly, very coarse grained in the lower part, and coarse to medium grained in the upper part. Shale and coal respectively constitute 9 and 5% of the strata Small and large erosional channels and successive sets of large scale cross-bedding characterize the sandstone. Palaeo- currents reveal that the paleodrainage and sediment transport were dominantly directed from SSW to NNE.

  19. Sensitivity of CO2 storage performance to varying rates and dynamic injectivity in the Bunter Sandstone, UK

    Science.gov (United States)

    Kolster, C.; Mac Dowell, N.; Krevor, S. C.; Agada, S.

    2016-12-01

    Carbon capture and storage (CCS) is needed for meeting legally binding greenhouse gas emissions targets in the UK (ECCC 2016). Energy systems models have been key to identifying the importance of CCS but they tend to impose few constraints on the availability and use of geologic CO2 storage reservoirs. Our aim is to develop simple models that use dynamic representations of limits on CO2 storage resources. This will allow for a first order representation of the storage reservoir for use in systems models with CCS. We use the ECLIPSE reservoir simulator and a model of the Southern North Sea Bunter Sandstone saline aquifer. We analyse reservoir performance sensitivities to scenarios of varying CO2 injection demand for a future UK low carbon energy market. With 12 injection sites, we compare the impact of injecting at a constant 2MtCO2/year per site and varying this rate by a factor of 1.8 and 0.2 cyclically every 5 and 2.5 years over 50 years of injection. The results show a maximum difference in average reservoir pressure of 3% amongst each case and a similar variation in plume migration extent. This suggests that simplified models can maintain accuracy by using average rates of injection over similar time periods. Meanwhile, by initiating injection at rates limited by pressurization at the wellhead we find that injectivity steadily increases. As a result, dynamic capacity increases. We find that instead of injecting into sites on a need basis, we can strategically inject the CO2 into 6 of the deepest sites increasing injectivity for the first 15 years by 13%. Our results show injectivity as highly dependent on reservoir heterogeneity near the injection site. Injecting 1MTCO2/year into a shallow, low permeability and porosity site instead of into a deep injection site with high permeability and porosity reduces injectivity in the first 5 years by 52%. ECCC. 2016. Future of Carbon Capture and Storage in the UK. UK Parliament House of Commons, Energy and Climate Change

  20. Traces of the heritage arising from the Macelj sandstone

    Science.gov (United States)

    Golež, Mateja

    2014-05-01

    The landscape of Southeast Slovenia and its stone heritage principally reveal itself through various Miocene sandstones. The most frequently found type on the borderline between Slovenia and Croatia, i.e. east of Rogatec, is the micaceous-quartz Macelj sandstone. This rock ranges in colour from greenish grey to bluish grey and yellowish, depending on the content of glauconite, which colours it green. In its composition, the rock is a heterogeneous mixture of grains of quartz, dolomite, muscovite, microcline, anorthite and glauconite. The average size of grains is 300μm. In cross-section, they are oblong, semi-rounded or round. The mechanical-physical and durability properties of the Macelj sandstone, which have been characterised pursuant to the applicable standards for natural stone, reveal that the rock exhibits poor resistance to active substances from the atmosphere, particularly in the presence of salt. In the surroundings of Rogatec, there are around 45 abandoned quarries of the Macelj sandstone, which are the result of the exploitation of this mineral resource from the 17th century on. The local quarrymen earned their bread until 1957, when the Kambrus quarry industry closed down. From the original use of this mineral resource as construction and decorative material, the useful value of the Macelj sandstone expanded during the development of the metals industry to the manufacture of large and small grindstones for the needs of the domestic and international market. Therefore, traces of quarrying can not only be seen in the disused quarries, but also in the rich architectural heritage of Rogatec and its surroundings, the stone furniture - from portals, window frames, wells, various troughs, pavements to stone walls - and other. The living quarrying heritage slowly passed into oblivion after World War II, although the analysis of the social image of the people residing in Rogatec and its surroundings revealed that there was an average of one stonemason in

  1. A simple fish-based approach to assess the ecological quality of freshwater reservoirs in Central Europe

    Directory of Open Access Journals (Sweden)

    Blabolil Petr

    2017-01-01

    Full Text Available The assessment of ecological quality in freshwater ecosystems is a key issue in many countries, but conditions for the development of assessment methodologies are often country-specific. This study proposes a simple methodology for the assessment of the ecological potential of reservoirs based on fish communities using a dataset covering major environmental and pressure gradients in reservoirs in the Czech Republic. Fish data obtained by gillnet sampling were correlated with a proxy of eutrophication as a key indicator of anthropogenic pressure for selecting appropriate fish-based indicators, establishing scoring criteria and developing the index of ecological quality. Expert judgement was also used to select potential fish indicators. Nine indicators were selected for the final fish-based index, fulfilling the criteria required by the Water Framework Directive. Two steps were used to validate the fish-based index quantification of its inter annual stability and sensitivity analysis of individual indicators. Finally, the index was compared to a previously developed general index for Central and Western Europe. Our study demonstrates that a combination of expert judgement and strict validation methods can result in an informative assessment of the ecological conditions, which can help identify conservation and restoration priorities.

  2. Monitoring programme of water reservoir Grliste

    International Nuclear Information System (INIS)

    Vuckovic, M; Milenkovic, P.; Lukic, D.

    2002-01-01

    The quality of surface waters is a very important problem incorporated in the environment protection, especially in water resources. The Timok border-land hasn't got sufficient underground and surface waters. This is certificated by the International Association for Water Resource. That was reason for building the water reservoir 'Grliste'. Drinking water from water reservoir 'Grliste' supplies Zajecar and the surroundings. (author)

  3. Middle Ordovician brachiopods from the Stairway Sandstone, Amadeus Basin, central Australia

    DEFF Research Database (Denmark)

    Jakobsen, Kristian Grube; Brock, Glenn A.; Nielsen, Arne Thorshøj

    2014-01-01

    -water palaeoenvironment along the margin of northeastern Gondwana. The brachiopods from the Stairway Sandstone are of low diversity and represent ca 9% of the entire shelly fauna. Five brachiopod taxa are described from the Stairway Sandstone; all are endemic to the Amadeus Basin at species level. Two new species...

  4. Analysis of the Temporal and Spatial Distribution of Lake and Reservoir Water Quality in China and Changes in Its Relationship with GDP from 2005 to 2010

    Directory of Open Access Journals (Sweden)

    Xiaojie Meng

    2015-02-01

    Full Text Available We analyzed the spatial distribution of lake and reservoir water quality in China, and the trends from 2005 to 2010, based on monitoring data from 28 large Chinese lakes and reservoirs. We used a comprehensive water pollution index (WPI to describe water quality and also identified the major pollutants. Using GDP data, we analyzed the relationships between economic factors and water quality. We found that although the water quality of large reservoirs is improving or remaining stable, despite economic growth, the water quality of most lakes either did not change or worsened. The outlook is pessimistic, as water quality in most lakes has decreased to Grade V or worse. The water quality was lowest for northern lakes and highest for southern lakes due to a combination of the local industrial structure and lower rainfall in the north. The primary pollutants generally remained stable during the study period. For some lakes, fluoride and volatile phenols became the primary pollutants, indicating more diverse sources of contamination. We divided the 28 bodies of water into four types based on the median WPI and GDP. The dominant combinations were low WPI with low GDP and high WPI with high GDP, as a result of the balance among economic development, the natural environment and environmental policy.

  5. Application potential of sequence stratigraphy to prospecting for sandstone-type uranium deposit in continental depositional basins

    International Nuclear Information System (INIS)

    Li Shengxiang; Chen Zhaobo; Chen Zuyi; Xiang Weidong; Cai Yuqi

    2001-01-01

    Sequence stratigraphy has been widely used in hydrocarbon exploration and development, and great achievements have been achieved. However, its application to the prospecting for sandstone-type uranium deposits is just beginning. The metallogenic characteristics of sandstone-type uranium deposits and those of oil and gas are compared, and the relationship between sandstone-type uranium metallogenesis and the system tracts of sequence stratigraphy is studied. The authors propose that highest and system tracts are the main targets for prospecting interlayer oxidation zone type sandstone uranium deposits, and the incised valleys of low stand system tracts are favourable places for phreatic oxidation zone type sandstone uranium deposits, and transgressive system tracts are generally unfavorable to the formation of in-situ leachable sandstone-type uranium deposits. Finally, the authors look ahead the application potential of sequence stratigraphy to the prospecting for sandstone-type uranium deposits in continental depositional basins

  6. Smart waterflooding in carbonate reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Zahid, A.

    2012-02-15

    During the last decade, smart waterflooding has been developed into an emerging EOR technology both for carbonate and sandstone reservoirs that does not require toxic or expensive chemicals. Although it is widely accepted that different salinity brines may increase the oil recovery for carbonate reservoirs, understanding of the mechanism of this increase is still developing. To understand this smart waterflooding process, an extensive research has been carried out covering a broad range of disciplines within surface chemistry, thermodynamics of crude oil and brine, as well as their behavior in porous media. The main conclusion of most previous studies was that it is the rock wettability alteration towards more water wetting condition that helps improving the oil recovery. In the first step of this project, we focused on verifying this conclusion. Coreflooding experiments were carried out using Stevens Klint outcrop chalk core plugs with brines without sulfate, as well as brines containing sulfate in different concentrations. The effects of temperature, injection rate, crude oil composition and different sulfate concentrations on the total oil recovery and the recovery rate were investigated. Experimental results clearly indicate improvement of the oil recovery without wettability alteration. At the second step of this project, we studied crude oil/brine interactions under different temperatures, pressures and salinity conditions in order to understand mechanisms behind the high salinity waterflooding. Our results show, in particular that sulfate ions may help decreasing the crude oil viscosity or formation of, seemingly, an emulsion phase between sulfate-enriched brine and oil at high temperature and pressure. Experimental results indicate that crude oils interact differently with the same brine solutions regarding phase behavior and viscosity measurements. This difference is attributed to the difference in composition of the different crude oils. More experiments

  7. Impacts of forest to urban land conversion and ENSO phase on water quality of a public water supply reservoir

    Science.gov (United States)

    We used coupled watershed and reservoir models to evaluate the impacts of deforestation and ENSO phase on drinking water quality. Source water total organic carbon (TOC) is especially important due to the potential for production of carcinogenic disinfection byproducts (DBPs). The Environmental Flui...

  8. Estimates of vertical hydraulic conductivity in the middle Dakota Sandstone, Monticello, Utah

    International Nuclear Information System (INIS)

    Kautsky, M.; Kearl, P.M.; Dexter, J.J.; Zinkl, R.J.

    1986-01-01

    There are about 2 million tons of uranium mill tailings which lie directly on top of an alluvial aquifer at the Monticello millsite, Utah. The aquifer is contaminated as a consequence of leachate percolating through the tailings. The Burro Canyon Formation which is the local culinary aquifer, underlies the site at depth, but is isolated from the alluvial aquifer by an aquitard composed primarily of middle Dakota Sandstone, and some Mancos Shale. Water quality monitoring of the Burro Canyon aquifer has indicated that it contains very low to no contamination by radionuclides. Tritium data have shown that the recharge to the aquifer predates 1953. Pump tests conducted on the system using the ratio method, have shown the vertical hydraulic conductivity of the aquitard is some 5.2 x 10/sup -7/ to 8.0 x 10/sup -9/ m/d (1.7 x 10/sup -6/ to 2.6 x 10/sup -8/ ft/d). Based upon the aquifer monitoring and test data, the middle Dakota Sandstone appears to be an effective aquitard impeding the downward migration of contaminants from the alluvial aquifer to the Burro Canyon aquifer

  9. Discussion on metallogenic prospect of sandstone-type uranium deposit in Yabulai basin

    International Nuclear Information System (INIS)

    Wang Lianshe; Li Xiangping

    2003-01-01

    Based on characteristics of initial basin type and tectonic reworking process, this article analyses the distribution features of depositional system and subsequent alteration of the target horizon of sandstone-type uranium deposits in Yabulai basin. Guided by prognostic criteria of sandstone-type uranium deposits, authors suggest that the post-depositional tectonic reworking in the basin was quite intense, and uranium metallogenic prospects are unfavorable. However, the Lower Cretaceous in the paleo-slope at the middle of the basin does show certain metallogenic prospects for sandstone-type uranium deposits

  10. Multidisciplinary studies on ancient sandstone quarries of Western Sardinia (Italy).

    Science.gov (United States)

    Grillo, Silvana Maria; Del Vais, Carla; Naitza, Stefano

    2013-04-01

    The ancient coastal quarries of Mediterranean are increasingly considered geosites of multidisciplinary relevance. They are sites of historical-archaeological interest that show ancient techniques of stone extraction; they are significant for cultural heritage conservation and restoration, as sources of the stones used in ancient buildings and monuments; they are sites of geological relevance, as often retain important stratigraphic sections; they are also useful markers of secular changes in the sea level. A multisciplinary study is in progress on the ancient quarries of the Sinis region (western Sardinia island), integrating archaeological, geological, minero-petrographical data. In Sardinia, coastal quarries have been established from Punic and Roman times. Many of them exploited Quaternary sediments along the southern and western coasts of the island. They consist of middle-late Pleistocene marine conglomerates and carbonate sandstones, and of coastal (aeolian) carbonate sandstones. Sandstone blocks of different sizes have been widely used in ancient cities for buildings, defensive works, harbours, etc. Three main areas of stone extraction (San Giovanni di Sinis, Punta Maimoni, Is Arutas) have been so far recognized in the Sinis. GIS-supported mapping and documentation of the sites includes their geology and stratigraphy, the extension and layout of the quarries, and an evaluation of volumes of extracted rocks. Documented archaeological evidences include ancient extraction fronts, spoil heaps, working areas, working traces in the old fronts, transport routes of blocks, and traces of loading facilities. The study is aimed at reconstructing the relationships of the quarries with the urban areas of Sinis, as the ancient Punic-Roman city of Tharros. Consequently, a minero-petrographical characterization (optical microscopy, XRD) is performed on sandstones sampled in each quarry, and in historical buildings in Tharros and other centres of the region (Cabras

  11. Impact of Catchment Area Activities on Water Quality in Small Retention Reservoirs

    Directory of Open Access Journals (Sweden)

    Oszczapińska Katarzyna

    2018-01-01

    Full Text Available The aim of the study was to evaluate catchment area impact on small water reservoirs condition in Podlasie. The researches were conducted in two different catchment areas. Topiło reservoir, located in Podlasie area in the south-east of Białowieża Forest, has typical sylvan catchment. Second reservoir, Dojlidy, is located also in Podlasie, in the south-east of Białystok as a part of Dojlidy Ponds. In contrast to Topiło, Dojlidy has agricultural catchment. Water samples collected from five sites along each reservoir were analysed for the presence of total nitrogen and phosphorus, chlorophyll “a”, reaction, turbidity and conductivity. Researches took place in spring, summer and autumn 2013 (Topiło Lake and 2014/2015 (Dojlidy. The lowest trophic state was observed in autumn and the highest in summer. Because of the high loads of phosphorus received by the reservoirs, this element did not limit primary production. Calculated TSI values based on total phosphorus were always markedly higher than calculated on chlorophyll-a and total nitrogen. Both reservoirs demonstrated TSI indexes specific to hypertrophic lakes due to large amount of total phosphorus.

  12. Impact of Catchment Area Activities on Water Quality in Small Retention Reservoirs

    Science.gov (United States)

    Oszczapińska, Katarzyna; Skoczko, Iwona; Szczykowska, Joanna

    2018-02-01

    The aim of the study was to evaluate catchment area impact on small water reservoirs condition in Podlasie. The researches were conducted in two different catchment areas. Topiło reservoir, located in Podlasie area in the south-east of Białowieża Forest, has typical sylvan catchment. Second reservoir, Dojlidy, is located also in Podlasie, in the south-east of Białystok as a part of Dojlidy Ponds. In contrast to Topiło, Dojlidy has agricultural catchment. Water samples collected from five sites along each reservoir were analysed for the presence of total nitrogen and phosphorus, chlorophyll "a", reaction, turbidity and conductivity. Researches took place in spring, summer and autumn 2013 (Topiło Lake) and 2014/2015 (Dojlidy). The lowest trophic state was observed in autumn and the highest in summer. Because of the high loads of phosphorus received by the reservoirs, this element did not limit primary production. Calculated TSI values based on total phosphorus were always markedly higher than calculated on chlorophyll-a and total nitrogen. Both reservoirs demonstrated TSI indexes specific to hypertrophic lakes due to large amount of total phosphorus.

  13. Absorption and fluorescence properties of chromophoric dissolved organic matter: implications for the monitoring of water quality in a large subtropical reservoir.

    Science.gov (United States)

    Liu, Xiaohan; Zhang, Yunlin; Shi, Kun; Zhu, Guangwei; Xu, Hai; Zhu, Mengyuan

    2014-12-01

    The development of techniques for real-time monitoring of water quality is of great importance for effectively managing inland water resources. In this study, we first analyzed the absorption and fluorescence properties in a large subtropical reservoir and then used a chromophoric dissolved organic matter (CDOM) fluorescence monitoring sensor to predict several water quality parameters including the total nitrogen (TN), total phosphorus (TP), chemical oxygen demand (COD), dissolved organic carbon (DOC), and CDOM fluorescence parallel factor analysis (PARAFAC) components in the reservoir. The CDOM absorption coefficient at 254 nm (a(254)), the humic-like component (C1), and the tryptophan-like component (C3) decreased significantly along a gradient from the northwest to the lake center, northeast, southwest, and southeast region in the reservoir. However, no significant spatial difference was found for the tyrosine-like component (C2), which contributed only four marked peaks. A highly significant linear correlation was found between the a(254) and CDOM concentration measured using the CDOM fluorescence sensor (r(2) = 0.865, n = 76, p CDOM concentrations could act as a proxy for the CDOM absorption coefficient measured in the laboratory. Significant correlations were also found between the CDOM concentration and TN, TP, COD, DOC, and the maximum fluorescence intensity of C1, suggesting that the real-time monitoring of CDOM concentrations could be used to predict these water quality parameters and trace the humic-like fluorescence substance in clear aquatic ecosystems with DOC CDOM fluorescence sensor is a useful tool for on-line water quality monitoring if the empirical relationship between the CDOM concentration measured using the CDOM fluorescence sensor and the water quality parameters is calibrated and validated.

  14. Reservoir characteristics and control factors of Carboniferous volcanic gas reservoirs in the Dixi area of Junggar Basin, China

    Directory of Open Access Journals (Sweden)

    Ji'an Shi

    2017-02-01

    Full Text Available Field outcrop observation, drilling core description, thin-section analysis, SEM analysis, and geochemistry, indicate that Dixi area of Carboniferous volcanic rock gas reservoir belongs to the volcanic rock oil reservoir of the authigenic gas reservoir. The source rocks make contact with volcanic rock reservoir directly or by fault, and having the characteristics of near source accumulation. The volcanic rock reservoir rocks mainly consist of acidic rhyolite and dacite, intermediate andesite, basic basalt and volcanic breccia: (1 Acidic rhyolite and dacite reservoirs are developed in the middle-lower part of the structure, have suffered strong denudation effect, and the secondary pores have formed in the weathering and tectonic burial stages, but primary pores are not developed within the early diagenesis stage. Average porosity is only at 8%, and the maximum porosity is at 13.5%, with oil and gas accumulation showing poor performance. (2 Intermediate andesite and basic basalt reservoirs are mainly distributed near the crater, which resembles the size of and suggests a volcanic eruption. Primary pores are formed in the early diagenetic stage, secondary pores developed in weathering and erosion transformation stage, and secondary fractures formed in the tectonic burial stage. The average porosity is at 9.2%, and the maximum porosity is at 21.9%: it is of the high-quality reservoir types in Dixi area. (3 The volcanic breccia reservoir has the same diagenetic features with sedimentary rocks, but also has the same mineral composition with volcanic rock; rigid components can keep the primary porosity without being affected by compaction during the burial process. At the same time, the brittleness of volcanic breccia reservoir makes it easily fracture under the stress; internal fracture was developmental. Volcanic breccia developed in the structural high part and suffered a long-term leaching effect. The original pore-fracture combination also made

  15. An index of reservoir habitat impairment

    Science.gov (United States)

    Miranda, L.E.; Hunt, K.M.

    2011-01-01

    Fish habitat impairment resulting from natural and anthropogenic watershed and in-lake processes has in many cases reduced the ability of reservoirs to sustain native fish assemblages and fisheries quality. Rehabilitation of impaired reservoirs is hindered by the lack of a method suitable for scoring impairment status. To address this limitation, an index of reservoir habitat impairment (IRHI) was developed by merging 14 metrics descriptive of common impairment sources, with each metric scored from 0 (no impairment) to 5 (high impairment) by fisheries scientists with local knowledge. With a plausible range of 5 to 25, distribution of the IRHI scores ranged from 5 to 23 over 482 randomly selected reservoirs dispersed throughout the USA. The IRHI reflected five impairment factors including siltation, structural habitat, eutrophication, water regime, and aquatic plants. The factors were weakly related to key reservoir characteristics including reservoir area, depth, age, and usetype, suggesting that common reservoir descriptors are poor predictors of fish habitat impairment. The IRHI is rapid and inexpensive to calculate, provides an easily understood measure of the overall habitat impairment, allows comparison of reservoirs and therefore prioritization of restoration activities, and may be used to track restoration progress. The major limitation of the IRHI is its reliance on unstandardized professional judgment rather than standardized empirical measurements. ?? 2010 US Government.

  16. Reservoir Models for Gas Hydrate Numerical Simulation

    Science.gov (United States)

    Boswell, R.

    2016-12-01

    Scientific and industrial drilling programs have now providing detailed information on gas hydrate systems that will increasingly be the subject of field experiments. The need to carefully plan these programs requires reliable prediction of reservoir response to hydrate dissociation. Currently, a major emphasis in gas hydrate modeling is the integration of thermodynamic/hydrologic phenomena with geomechanical response for both reservoir and bounding strata. However, also critical to the ultimate success of these efforts is the appropriate development of input geologic models, including several emerging issues, including (1) reservoir heterogeneity, (2) understanding of the initial petrophysical characteristics of the system (reservoirs and seals), the dynamic evolution of those characteristics during active dissociation, and the interdependency of petrophysical parameters and (3) the nature of reservoir boundaries. Heterogeneity is ubiquitous aspect of every natural reservoir, and appropriate characterization is vital. However, heterogeneity is not random. Vertical variation can be evaluated with core and well log data; however, core data often are challenged by incomplete recovery. Well logs also provide interpretation challenges, particularly where reservoirs are thinly-bedded due to limitation in vertical resolution. This imprecision will extend to any petrophysical measurements that are derived from evaluation of log data. Extrapolation of log data laterally is also complex, and should be supported by geologic mapping. Key petrophysical parameters include porosity, permeability and it many aspects, and water saturation. Field data collected to date suggest that the degree of hydrate saturation is strongly controlled by/dependant upon reservoir quality and that the ratio of free to bound water in the remaining pore space is likely also controlled by reservoir quality. Further, those parameters will also evolve during dissociation, and not necessary in a simple

  17. Characteristics of isotope geology of sandstone-type uranium deposit in Turpan-Hami Basin

    International Nuclear Information System (INIS)

    Liu Hanbin; Xia Yuliang; Lin Jinrong; Fan Guang

    2003-01-01

    This paper expounds the isotope characteristics of in-situ leachable sandstone-type uranium deposit of Shihongtan in the southwestern part of Turpan-Hami basin. The results suggest that uranium mineralization age of 48 ± 2 Ma and 28 ± 4 Ma are obtained. The ages of the porphyritic granite and gneissic granite from the southwestern area are 422 ± 5 Ma and 268 ± 23 Ma. The U-Pb age of clastic zircons from ore-bearing sandstone is 283 ± 67 Ma, which is corresponding to the age of gneissic granite of the provenance area indicating the material source of uraniferous sandstone.Based. The sources are uraniferous sandstone accumulated during the deposition and the uranium leached from provenance area rocks by weathering. (authors)

  18. Data Compression of Hydrocarbon Reservoir Simulation Grids

    KAUST Repository

    Chavez, Gustavo Ivan

    2015-05-28

    A dense volumetric grid coming from an oil/gas reservoir simulation output is translated into a compact representation that supports desired features such as interactive visualization, geometric continuity, color mapping and quad representation. A set of four control curves per layer results from processing the grid data, and a complete set of these 3-dimensional surfaces represents the complete volume data and can map reservoir properties of interest to analysts. The processing results yield a representation of reservoir simulation results which has reduced data storage requirements and permits quick performance interaction between reservoir analysts and the simulation data. The degree of reservoir grid compression can be selected according to the quality required, by adjusting for different thresholds, such as approximation error and level of detail. The processions results are of potential benefit in applications such as interactive rendering, data compression, and in-situ visualization of large-scale oil/gas reservoir simulations.

  19. Desenvolvimento de insertos sinterizados autolubrificantes para uso em matrizes de conformação a frio

    OpenAIRE

    Marcelo Salvador Cóser

    2016-01-01

    Este trabalho avalia o uso de insertos autolubrificantes de pó de aço ferramenta sinterizado para aplicação em ferramentas dos processos de Conformação a Frio. São apresentadas a preparação e a análise de diferentes composições de misturas de pós de aço ferramenta H 13. A Metalurgia do Pó convencional foi utilizada como processo para a obtenção dos insertos do estudo. Foram compactadas e sinterizadas misturas de pó de aço H13 com a adição de percentuais variados do lubrificante sólido Bissulf...

  20. Applying reaction condition index to predict sandstone type uranium deposit

    International Nuclear Information System (INIS)

    Chen Gongxin; Liu Jinhui; Cheng Hai

    2002-01-01

    On the basic of the explanation of reaction condition index, the deduction of reaction condition index calculation principle, the hydrogeological setting in Gongpoquan basin in Baishan, Gansu province and the study of reaction condition index of its water source point, the north Luotuoquan area in Gongpoquan basin seems to be a favourable place for sandstone type uranium deposit, and the prospect area for sandstone type uranium deposit is delimitated