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Sample records for reservoir saturation tool

  1. All-optical reservoir computer based on saturation of absorption.

    Science.gov (United States)

    Dejonckheere, Antoine; Duport, François; Smerieri, Anteo; Fang, Li; Oudar, Jean-Louis; Haelterman, Marc; Massar, Serge

    2014-05-05

    Reservoir computing is a new bio-inspired computation paradigm. It exploits a dynamical system driven by a time-dependent input to carry out computation. For efficient information processing, only a few parameters of the reservoir needs to be tuned, which makes it a promising framework for hardware implementation. Recently, electronic, opto-electronic and all-optical experimental reservoir computers were reported. In those implementations, the nonlinear response of the reservoir is provided by active devices such as optoelectronic modulators or optical amplifiers. By contrast, we propose here the first reservoir computer based on a fully passive nonlinearity, namely the saturable absorption of a semiconductor mirror. Our experimental setup constitutes an important step towards the development of ultrafast low-consumption analog computers.

  2. 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

  3. Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Michael Batzle

    2006-04-30

    During this last period of the ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342), we finalized integration of rock physics, well log analysis, seismic processing, and forward modeling techniques. Most of the last quarter was spent combining the results from the principal investigators and come to some final conclusions about the project. Also much of the effort was directed towards technology transfer through the Direct Hydrocarbon Indicators mini-symposium at UH and through publications. As a result we have: (1) Tested a new method to directly invert reservoir properties, water saturation, Sw, and porosity from seismic AVO attributes; (2) Constrained the seismic response based on fluid and rock property correlations; (3) Reprocessed seismic data from Ursa field; (4) Compared thin layer property distributions and averaging on AVO response; (5) Related pressures and sorting effects on porosity and their influence on DHI's; (6) Examined and compared gas saturation effects for deep and shallow reservoirs; (7) Performed forward modeling using geobodies from deepwater outcrops; (8) Documented velocities for deepwater sediments; (9) Continued incorporating outcrop descriptive models in seismic forward models; (10) Held an open DHI symposium to present the final results of the project; (11) Relations between Sw, porosity, and AVO attributes; (12) Models of Complex, Layered Reservoirs; and (14) Technology transfer Several factors can contribute to limit our ability to extract accurate hydrocarbon saturations in deep water environments. Rock and fluid properties are one factor, since, for example, hydrocarbon properties will be considerably different with great depths (high pressure) when compared to shallow properties. Significant over pressure, on the other hand will make the rocks behave as if they were shallower. In addition to the physical properties, the scale and

  4. Scale-dependent gas hydrate saturation estimates in sand reservoirs in the Ulleung Basin, East Sea of Korea

    Science.gov (United States)

    Lee, Myung Woong; Collett, Timothy S.

    2013-01-01

    Through the use of 2-D and 3-D seismic data, several gas hydrate prospects were identified in the Ulleung Basin, East Sea of Korea and thirteen drill sites were established and logging-while-drilling (LWD) data were acquired from each site in 2010. Sites UBGH2–6 and UBGH2–10 were selected to test a series of high amplitude seismic reflections, possibly from sand reservoirs. LWD logs from the UBGH2–6 well indicate that there are three significant sand reservoirs with varying thickness. Two upper sand reservoirs are water saturated and the lower thinly bedded sand reservoir contains gas hydrate with an average saturation of 13%, as estimated from the P-wave velocity. The well logs at the UBGH2–6 well clearly demonstrated the effect of scale-dependency on gas hydrate saturation estimates. Gas hydrate saturations estimated from the high resolution LWD acquired ring resistivity (vertical resolution of about 5–8 cm) reaches about 90% with an average saturation of 28%, whereas gas hydrate saturations estimated from the low resolution A40L resistivity (vertical resolution of about 120 cm) reaches about 25% with an average saturation of 11%. However, in the UBGH2–10 well, gas hydrate occupies a 5-m thick sand reservoir near 135 mbsf with a maximum saturation of about 60%. In the UBGH2–10 well, the average and a maximum saturation estimated from various well logging tools are comparable, because the bed thickness is larger than the vertical resolution of the various logging tools. High resolution wireline log data further document the role of scale-dependency on gas hydrate calculations.

  5. 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

  6. An innovative technique for estimating water saturation from capillary pressure in clastic reservoirs

    Science.gov (United States)

    Adeoti, Lukumon; Ayolabi, Elijah Adebowale; James, Logan

    2017-11-01

    A major drawback of old resistivity tools is the poor vertical resolution and estimation of hydrocarbon when applying water saturation (Sw) from historical resistivity method. In this study, we have provided an alternative method called saturation height function to estimate hydrocarbon in some clastic reservoirs in the Niger Delta. The saturation height function was derived from pseudo capillary pressure curves generated using modern wells with complete log data. Our method was based on the determination of rock type from log derived porosity-permeability relationship, supported by volume of shale for its classification into different zones. Leverette-J functions were derived for each rock type. Our results show good correlation between Sw from resistivity based method and Sw from pseudo capillary pressure curves in wells with modern log data. The resistivity based model overestimates Sw in some wells while Sw from the pseudo capillary pressure curves validates and predicts more accurate Sw. In addition, the result of Sw from pseudo capillary pressure curves replaces that of resistivity based model in a well where the resistivity equipment failed. The plot of hydrocarbon pore volume (HCPV) from J-function against HCPV from Archie shows that wells with high HCPV have high sand qualities and vice versa. This was further used to predict the geometry of stratigraphic units. The model presented here freshly addresses the gap in the estimation of Sw and is applicable to reservoirs of similar rock type in other frontier basins worldwide.

  7. 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

  8. Pressure and fluid saturation prediction in a multicomponent reservoir, using combined seismic and electromagnetic imaging

    International Nuclear Information System (INIS)

    Hoversten, G.M.; Gritto, Roland; Washbourne, John; Daley, Tom

    2002-01-01

    This paper presents a method for combining seismic and electromagnetic measurements to predict changes in water saturation, pressure, and CO 2 gas/oil ratio in a reservoir undergoing CO 2 flood. Crosswell seismic and electromagnetic data sets taken before and during CO 2 flooding of an oil reservoir are inverted to produce crosswell images of the change in compressional velocity, shear velocity, and electrical conductivity during a CO 2 injection pilot study. A rock properties model is developed using measured log porosity, fluid saturations, pressure, temperature, bulk density, sonic velocity, and electrical conductivity. The parameters of the rock properties model are found by an L1-norm simplex minimization of predicted and observed differences in compressional velocity and density. A separate minimization, using Archie's law, provides parameters for modeling the relations between water saturation, porosity, and the electrical conductivity. The rock-properties model is used to generate relationships between changes in geophysical parameters and changes in reservoir parameters. Electrical conductivity changes are directly mapped to changes in water saturation; estimated changes in water saturation are used along with the observed changes in shear wave velocity to predict changes in reservoir pressure. The estimation of the spatial extent and amount of CO 2 relies on first removing the effects of the water saturation and pressure changes from the observed compressional velocity changes, producing a residual compressional velocity change. This velocity change is then interpreted in terms of increases in the CO 2 /oil ratio. Resulting images of the CO 2 /oil ratio show CO 2 -rich zones that are well correlated to the location of injection perforations, with the size of these zones also correlating to the amount of injected CO 2 . The images produced by this process are better correlated to the location and amount of injected CO 2 than are any of the individual

  9. A new method for calculating gas saturation of low-resistivity shale gas reservoirs

    Directory of Open Access Journals (Sweden)

    Jinyan Zhang

    2017-09-01

    Full Text Available The Jiaoshiba shale gas field is located in the Fuling area of the Sichuan Basin, with the Upper Ordovician Wufeng–Lower Silurian Longmaxi Fm as the pay zone. At the bottom of the pay zone, a high-quality shale gas reservoir about 20 m thick is generally developed with high organic contents and gas abundance, but its resistivity is relatively low. Accordingly, the gas saturation calculated by formulas (e.g. Archie using electric logging data is often much lower than the experiment-derived value. In this paper, a new method was presented for calculating gas saturation more accurately based on non-electric logging data. Firstly, the causes for the low resistivity of shale gas reservoirs in this area were analyzed. Then, the limitation of traditional methods for calculating gas saturation based on electric logging data was diagnosed, and the feasibility of the neutron–density porosity overlay method was illustrated. According to the response characteristics of neutron, density and other porosity logging in shale gas reservoirs, a model for calculating gas saturation of shale gas was established by core experimental calibration based on the density logging value, the density porosity and the difference between density porosity and neutron porosity, by means of multiple methods (e.g. the dual-porosity overlay method by optimizing the best overlay coefficient. This new method avoids the effect of low resistivity, and thus can provide normal calculated gas saturation of high-quality shale gas reservoirs. It works well in practical application. This new method provides a technical support for the calculation of shale gas reserves in this area. Keywords: Shale gas, Gas saturation, Low resistivity, Non-electric logging, Volume density, Compensated neutron, Overlay method, Reserves calculation, Sichuan Basin, Jiaoshiba shale gas field

  10. 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.

  11. Impact of Reservoir Fluid Saturation on Seismic Parameters: Endrod Gas Field, Hungary

    Science.gov (United States)

    El Sayed, Abdel Moktader A.; El Sayed, Nahla A.

    2017-12-01

    Outlining the reservoir fluid types and saturation is the main object of the present research work. 37 core samples were collected from three different gas bearing zones in the Endrod gas field in Hungary. These samples are belonging to the Miocene and the Upper - Lower Pliocene. These samples were prepared and laboratory measurements were conducted. Compression and shear wave velocity were measured using the Sonic Viewer-170-OYO. The sonic velocities were measured at the frequencies of 63 and 33 kHz for compressional and shear wave respectively. All samples were subjected to complete petrophysical investigations. Sonic velocities and mechanical parameters such as young’s modulus, rigidity, and bulk modulus were measured when samples were saturated by 100%-75%-0% brine water. Several plots have been performed to show the relationship between seismic parameters and saturation percentages. Robust relationships were obtained, showing the impact of fluid saturation on seismic parameters. Seismic velocity, Poisson’s ratio, bulk modulus and rigidity prove to be applicable during hydrocarbon exploration or production stages. Relationships among the measured seismic parameters in gas/water fully and partially saturated samples are useful to outline the fluid type and saturation percentage especially in gas/water transitional zones.

  12. Integrated petrophysical and reservoir characterization workflow to enhance permeability and water saturation prediction

    Science.gov (United States)

    Al-Amri, Meshal; Mahmoud, Mohamed; Elkatatny, Salaheldin; Al-Yousef, Hasan; Al-Ghamdi, Tariq

    2017-07-01

    Accurate estimation of permeability is essential in reservoir characterization and in determining fluid flow in porous media which greatly assists optimize the production of a field. Some of the permeability prediction techniques such as Porosity-Permeability transforms and recently artificial intelligence and neural networks are encouraging but still show moderate to good match to core data. This could be due to limitation to homogenous media while the knowledge about geology and heterogeneity is indirectly related or absent. The use of geological information from core description as in Lithofacies which includes digenetic information show a link to permeability when categorized into rock types exposed to similar depositional environment. The objective of this paper is to develop a robust combined workflow integrating geology and petrophysics and wireline logs in an extremely heterogeneous carbonate reservoir to accurately predict permeability. Permeability prediction is carried out using pattern recognition algorithm called multi-resolution graph-based clustering (MRGC). We will bench mark the prediction results with hard data from core and well test analysis. As a result, we showed how much better improvements are achieved in the permeability prediction when geology is integrated within the analysis. Finally, we use the predicted permeability as an input parameter in J-function and correct for uncertainties in saturation calculation produced by wireline logs using the classical Archie equation. Eventually, high level of confidence in hydrocarbon volumes estimation is reached when robust permeability and saturation height functions are estimated in presence of important geological details that are petrophysically meaningful.

  13. Gas hydrate saturations estimated from fractured reservoir at Site NGHP-01-10, Krishna-Godavari Basin, India

    Science.gov (United States)

    Lee, M.W.; Collett, T.S.

    2009-01-01

    During the Indian National Gas Hydrate Program Expedition 01 (NGHP-Ol), one of the richest marine gas hydrate accumulations was discovered at Site NGHP-01-10 in the Krishna-Godavari Basin. The occurrence of concentrated gas hydrate at this site is primarily controlled by the presence of fractures. Assuming the resistivity of gas hydratebearing sediments is isotropic, th?? conventional Archie analysis using the logging while drilling resistivity log yields gas hydrate saturations greater than 50% (as high as ???80%) of the pore space for the depth interval between ???25 and ???160 m below seafloor. On the other hand, gas hydrate saturations estimated from pressure cores from nearby wells were less than ???26% of the pore space. Although intrasite variability may contribute to the difference, the primary cause of the saturation difference is attributed to the anisotropic nature of the reservoir due to gas hydrate in high-angle fractures. Archie's law can be used to estimate gas hydrate saturations in anisotropic reservoir, with additional information such as elastic velocities to constrain Archie cementation parameters m and the saturation exponent n. Theory indicates that m and n depend on the direction of the measurement relative to fracture orientation, as well as depending on gas hydrate saturation. By using higher values of m and n in the resistivity analysis for fractured reservoirs, the difference between saturation estimates is significantly reduced, although a sizable difference remains. To better understand the nature of fractured reservoirs, wireline P and S wave velocities were also incorporated into the analysis.

  14. Estimation of critical gas saturation during pressure depletion in virgin and waterflooded reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    McDougall, S.R.; Sorbie, K.S. [Heriot-Watt Univ., Dept. of Petroleum Engineering, Edinburgh (United Kingdom)

    1999-08-01

    An important issue in petroleum engineering is the prediction of gas production during reservoir depletion - either following conventional waterflooding operations or in the early stages of hydrocarbon production. The estimation of critical gas saturation for use in corresponding simulation studies is clearly a primary concern. To this end, a 3D, three-phase numerical pore-scale simulator has been developed that can be used to estimate critical gas saturations over a range of different lengthscales and for a wide range of fluid and rock properties. The model incorporates a great deal of the known physics observed in associated laboratory micromodel experiments, including embryonic nucleation, supersaturation effects, multiphase diffusion, bubble growth/migration/fragmentation, oil shrinkage, and three-phase spreading coefficients. These precise pore-scale mechanisms governing gas evolution have been found to be far more subtle than earlier models would suggest because of the large variation of gas/oil interfacial tension (IFT) with pressure. This has a profound effect upon the migration of gas structures during depletion. In models pertaining to reservoir rock, the process of gas migration is consequently much slower than predictions from more simplistic models would imply. This is the first time that bubble fragmentation and IFT variations have been included in a model of gas evolution at the pore-scale and the implications for production forecasting are expected to be significant. In addition, novel scaling groups have been derived for a number of different facies under both virgin and waterflooded conditions. One future application of these groups would be to scale S{sub gc} values obtained from high rate depressurization experiments to the low rate conditions more characteristic of field operations. (Author)

  15. Archie's Saturation Exponent for Natural Gas Hydrate in Coarse-Grained Reservoirs

    Science.gov (United States)

    Cook, Ann E.; Waite, William F.

    2018-03-01

    Accurately quantifying the amount of naturally occurring gas hydrate in marine and permafrost environments is important for assessing its resource potential and understanding the role of gas hydrate in the global carbon cycle. Electrical resistivity well logs are often used to calculate gas hydrate saturations, Sh, using Archie's equation. Archie's equation, in turn, relies on an empirical saturation parameter, n. Though n = 1.9 has been measured for ice-bearing sands and is widely used within the hydrate community, it is highly questionable if this n value is appropriate for hydrate-bearing sands. In this work, we calibrate n for hydrate-bearing sands from the Canadian permafrost gas hydrate research well, Mallik 5L-38, by establishing an independent downhole Sh profile based on compressional-wave velocity log data. Using the independently determined Sh profile and colocated electrical resistivity and bulk density logs, Archie's saturation equation is solved for n, and uncertainty is tracked throughout the iterative process. In addition to the Mallik 5L-38 well, we also apply this method to two marine, coarse-grained reservoirs from the northern Gulf of Mexico Gas Hydrate Joint Industry Project: Walker Ridge 313-H and Green Canyon 955-H. All locations yield similar results, each suggesting n ≈ 2.5 ± 0.5. Thus, for the coarse-grained hydrate bearing (Sh > 0.4) of greatest interest as potential energy resources, we suggest that n = 2.5 ± 0.5 should be applied in Archie's equation for either marine or permafrost gas hydrate settings if independent estimates of n are not available.

  16. Archie’s saturation exponent for natural gas hydrate in coarse-grained reservoirs

    Science.gov (United States)

    Cook, Ann E.; Waite, William F.

    2018-01-01

    Accurately quantifying the amount of naturally occurring gas hydrate in marine and permafrost environments is important for assessing its resource potential and understanding the role of gas hydrate in the global carbon cycle. Electrical resistivity well logs are often used to calculate gas hydrate saturations, Sh, using Archie's equation. Archie's equation, in turn, relies on an empirical saturation parameter, n. Though n = 1.9 has been measured for ice‐bearing sands and is widely used within the hydrate community, it is highly questionable if this n value is appropriate for hydrate‐bearing sands. In this work, we calibrate n for hydrate‐bearing sands from the Canadian permafrost gas hydrate research well, Mallik 5L‐38, by establishing an independent downhole Sh profile based on compressional‐wave velocity log data. Using the independently determined Sh profile and colocated electrical resistivity and bulk density logs, Archie's saturation equation is solved for n, and uncertainty is tracked throughout the iterative process. In addition to the Mallik 5L‐38 well, we also apply this method to two marine, coarse‐grained reservoirs from the northern Gulf of Mexico Gas Hydrate Joint Industry Project: Walker Ridge 313‐H and Green Canyon 955‐H. All locations yield similar results, each suggesting n ≈ 2.5 ± 0.5. Thus, for the coarse‐grained hydrate bearing (Sh > 0.4) of greatest interest as potential energy resources, we suggest that n = 2.5 ± 0.5 should be applied in Archie's equation for either marine or permafrost gas hydrate settings if independent estimates of n are not available.

  17. Kinetics of carbonate dissolution in CO2-saturated aqueous system at reservoir conditions

    Science.gov (United States)

    Peng, Cheng; Crawshaw, John P.; Maitland, Geoffrey; Trusler, J. P. Martin

    2014-05-01

    In recent years, carbon capture and storage (CCS) has emerged as a key technology for limiting anthropogenic CO2 emissions while allowing the continued utilisation of fossil fuels. The most promising geological storage sites are deep saline aquifers because the capacity, integrity and injection economics are most favourable, and the environmental impact can be minimal. Many rock-fluid chemical reactions are known to occur both during and after CO2 injection in saline aquifers. The importance of rock-fluid reactions in the (CO2 + H2O) system can be understood in terms of their impact on the integrity and stability of both the formation rocks and cap rocks. The chemical interactions between CO2-acidified brines and the reservoir minerals can influence the porosity and permeability of the formations, resulting in changes in the transport processes occurring during CO2 storage. Since carbonate minerals are abundant in sedimentary rocks, one of the requirements to safely implement CO2 storage in saline aquifers is to characterise the reactivity of carbonate minerals in aqueous solutions at reservoir conditions. In this work, we reported measurements of the intrinsic rate of carbonate dissolution in CO2-saturated water under high-temperature high-pressure reservoir conditions extending up to 373 K and 14 MPa. The rate of carbonate dissolution in CO2-free HCl(aq) was also measured at ambient pressure at temperatures up to 353 K. Various pure minerals and reservoir rocks were investigated in this study, including single-crystals of calcite and magnesite, and samples of dolomite, chalks and sandstones. A specially-designed batch reactor system, implementing the rotating disc technique, was used to obtain the intrinsic reaction rate at the solid/liquid interface, free of mass transfer effects. The effective area and mineralogy of the exposed surface was determined by a combination of surface characterisation techniques including XRD, SEM, EDX and optical microscopy. The

  18. Analytical solution to the diffusion, sorption and decay chain equation in a saturated porous medium between two reservoirs

    International Nuclear Information System (INIS)

    Guzman, Juan; Maximov, Serguei; Escarela-Perez, Rafael; López-García, Irvin; Moranchel, Mario

    2015-01-01

    The diffusion and distribution coefficients are important parameters in the design of barrier systems used in radioactive repositories. These coefficients can be determined using a two-reservoir configuration, where a saturated porous medium is allocated between two reservoirs filled by stagnant water. One of the reservoirs contains a high concentration of radioisotopes. The goal of this work is to obtain an analytical solution for the concentration of all radioisotopes in the decay chain of a two-reservoir configuration. The analytical solution must be obtained by taking into account the diffusion and sorption processes. Concepts such as overvalued concentration, diffusion and decay factors are employed to this end. It is analytically proven that a factor of the solution is identical for all chains (considering a time scaling factor), if certain parameters do not change. In addition, it is proven that the concentration sensitivity, due to the distribution coefficient variation, depends of the porous medium thickness, which is practically insensitive for small porous medium thicknesses. The analytical solution for the radioisotope concentration is compared with experimental and numerical results available in literature. - Highlights: • Saturated porous media allocated between two reservoirs. • Analytical solution of the isotope transport equation. • Transport considers diffusion, sorption and decay chain

  19. Low-Q structure related to partially saturated pores within the reservoir beneath The Geysers area in the northern California

    Science.gov (United States)

    Matsubara, M.

    2011-12-01

    with a high-Q zone. A vertical cross section shows the low-Q zone is consistent with the reservoir as it extends through the main greywacke and into the uppermost part of the felsite. Most of the felsite has high-Q, however, the portion of the reservoir that extends into the felsite has low-Q. The Geysers geothermal area is bounded by Collayomi fault zone to the northeast and the Mercuryville fault zone to the southwest. The Geysers Peak fault runs from northwest to southeast about 3 km southwest of the Mercuryville fault. The Mercuryville fault dips to northeast and the Geysers Peak fault dips to southwest. High-Q zone is located between these faults and the width of this zone broadens as the depth increases corresponding to the fault geometry. The presence of liquid water introduces high-Vp/Vs, however, steam rich zones become low-Vp/Vs. Near the transition zone between the water and steam, laboratory experiments indicate that the amplitude becomes extremely small (Ito et al., 1979). A partially saturated zone has lower Q than a fully saturated zone, and a dry zone has high-Q. A low-Q zone with low-Vp/Vs corresponding to the reservoir indicates that the reservoir is partially saturated with steam and water near transition zone.

  20. A Thermoelastic Hydraulic Fracture Design Tool for Geothermal Reservoir Development

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad Ghassemi

    2003-06-30

    Geothermal energy is recovered by circulating water through heat exchange areas within a hot rock mass. Geothermal reservoir rock masses generally consist of igneous and metamorphic rocks that have low matrix permeability. Therefore, cracks and fractures play a significant role in extraction of geothermal energy by providing the major pathways for fluid flow and heat exchange. Thus, knowledge of conditions leading to formation of fractures and fracture networks is of paramount importance. Furthermore, in the absence of natural fractures or adequate connectivity, artificial fracture are created in the reservoir using hydraulic fracturing. At times, the practice aims to create a number of parallel fractures connecting a pair of wells. Multiple fractures are preferred because of the large size necessary when using only a single fracture. Although the basic idea is rather simple, hydraulic fracturing is a complex process involving interactions of high pressure fluid injections with a stressed hot rock mass, mechanical interaction of induced fractures with existing natural fractures, and the spatial and temporal variations of in-situ stress. As a result it is necessary to develop tools that can be used to study these interactions as an integral part of a comprehensive approach to geothermal reservoir development, particularly enhanced geothermal systems. In response to this need we have set out to develop advanced thermo-mechanical models for design of artificial fractures and rock fracture research in geothermal reservoirs. These models consider the significant hydraulic and thermo-mechanical processes and their interaction with the in-situ stress state. Wellbore failure and fracture initiation is studied using a model that fully couples poro-mechanical and thermo-mechanical effects. The fracture propagation model is based on a complex variable and regular displacement discontinuity formulations. In the complex variable approach the displacement discontinuities are

  1. Rock Physics of Reservoir Rocks with Varying Pore Water Saturation and Pore Water Salinity

    DEFF Research Database (Denmark)

    Katika, Konstantina

    experiments, the rock is subjected to high external stresses that resemble the reservoir stresses; 2) the fluid distribution within the pore space changes during the flow through experiments and wettability alterations may occur; 3) different ions, present in the salt water injected in the core, interact......Advanced waterflooding (injection of water with selective ions in reservoirs) is a method of enhanced oil recovery (EOR) that has attracted the interest of oil and gas companies that exploit the Danish oil and gas reservoirs. This method has been applied successfully in oil reservoirs...... and in the Smart Water project performed in a laboratory scale in order to evaluate the EOR processes in selected core plugs. A major step towards this evaluation is to identify the composition of the injected water that leads to increased oil recovery in reservoirs and to define changes in the petrophysical...

  2. Reservoir characterization of the Upper Jurassic geothermal target formations (Molasse Basin, Germany): role of thermofacies as exploration tool

    Science.gov (United States)

    Homuth, S.; Götz, A. E.; Sass, I.

    2015-06-01

    The Upper Jurassic carbonates of the southern German Molasse Basin are the target of numerous geothermal combined heat and power production projects since the year 2000. A production-orientated reservoir characterization is therefore of high economic interest. Outcrop analogue studies enable reservoir property prediction by determination and correlation of lithofacies-related thermo- and petrophysical parameters. A thermofacies classification of the carbonate formations serves to identify heterogeneities and production zones. The hydraulic conductivity is mainly controlled by tectonic structures and karstification, whilst the type and grade of karstification is facies related. The rock permeability has only a minor effect on the reservoir's sustainability. Physical parameters determined on oven-dried samples have to be corrected, applying reservoir transfer models to water-saturated reservoir conditions. To validate these calculated parameters, a Thermo-Triaxial-Cell simulating the temperature and pressure conditions of the reservoir is used and calorimetric and thermal conductivity measurements under elevated temperature conditions are performed. Additionally, core and cutting material from a 1600 m deep research drilling and a 4850 m (total vertical depth, measured depth: 6020 m) deep well is used to validate the reservoir property predictions. Under reservoir conditions a decrease in permeability of 2-3 magnitudes is observed due to the thermal expansion of the rock matrix. For tight carbonates the matrix permeability is temperature-controlled; the thermophysical matrix parameters are density-controlled. Density increases typically with depth and especially with higher dolomite content. Therefore, thermal conductivity increases; however the dominant factor temperature also decreases the thermal conductivity. Specific heat capacity typically increases with increasing depth and temperature. The lithofacies-related characterization and prediction of reservoir

  3. 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

  4. CO2 storage in depleted gas reservoirs: A study on the effect of residual gas saturation

    Directory of Open Access Journals (Sweden)

    Arshad Raza

    2018-03-01

    Full Text Available Depleted gas reservoirs are recognized as the most promising candidate for carbon dioxide storage. Primary gas production followed by injection of carbon dioxide after depletion is the strategy adopted for secondary gas recovery and storage practices. This strategy, however, depends on the injection strategy, reservoir characteristics and operational parameters. There have been many studies to-date discussing critical factors influencing the storage performance in depleted gas reservoirs while little attention was given to the effect of residual gas. In this paper, an attempt was made to highlight the importance of residual gas on the capacity, injectivity, reservoir pressurization, and trapping mechanisms of storage sites through the use of numerical simulation. The results obtained indicated that the storage performance is proportionally linked to the amount of residual gas in the medium and reservoirs with low residual fluids are a better choice for storage purposes. Therefore, it would be wise to perform the secondary recovery before storage in order to have the least amount of residual gas in the medium. Although the results of this study are useful to screen depleted gas reservoirs for the storage purpose, more studies are required to confirm the finding presented in this paper.

  5. Modeling Tools for Drilling, Reservoir Navigation, and Formation Evaluation

    Directory of Open Access Journals (Sweden)

    Sushant Dutta

    2012-06-01

    successfully explains the unusual curve separations of an array laterolog tool in a shale-gas formation. The third example uses two-dimensional (2-D and 3-D modeling to prove the efficacy of a new borehole technology for reservoir monitoring.

  6. Water Saturation Relations and Their Diffusion-Limited Equilibration in Gas Shale: Implications for Gas Flow in Unconventional Reservoirs

    Science.gov (United States)

    Tokunaga, Tetsu K.; Shen, Weijun; Wan, Jiamin; Kim, Yongman; Cihan, Abdullah; Zhang, Yingqi; Finsterle, Stefan

    2017-11-01

    Large volumes of water are used for hydraulic fracturing of low permeability shale reservoirs to stimulate gas production, with most of the water remaining unrecovered and distributed in a poorly understood manner within stimulated regions. Because water partitioning into shale pores controls gas release, we measured the water saturation dependence on relative humidity (rh) and capillary pressure (Pc) for imbibition (adsorption) as well as drainage (desorption) on samples of Woodford Shale. Experiments and modeling of water vapor adsorption into shale laminae at rh = 0.31 demonstrated that long times are needed to characterize equilibrium in larger (5 mm thick) pieces of shales, and yielded effective diffusion coefficients from 9 × 10-9 to 3 × 10-8 m2 s-1, similar in magnitude to the literature values for typical low porosity and low permeability rocks. Most of the experiments, conducted at 50°C on crushed shale grains in order to facilitate rapid equilibration, showed significant saturation hysteresis, and that very large Pc (˜1 MPa) are required to drain the shales. These results quantify the severity of the water blocking problem, and suggest that gas production from unconventional reservoirs is largely associated with stimulated regions that have had little or no exposure to injected water. Gravity drainage of water from fractures residing above horizontal wells reconciles gas production in the presence of largely unrecovered injected water, and is discussed in the broader context of unsaturated flow in fractures.

  7. 3D seismic modeling in geothermal reservoirs with a distribution of steam patch sizes, permeabilities and saturations, including ductility of the rock frame

    Science.gov (United States)

    Carcione, José M.; Poletto, Flavio; Farina, Biancamaria; Bellezza, Cinzia

    2018-06-01

    method by the introduction of memory variables. The algorithm uses the Fourier pseudospectral method to compute the spatial derivatives. It is tested against an analytical solution obtained with the correspondence principle. We consider two main cases, namely the same rock frame (uniform porosity and permeability) saturated with water and a distribution of steam patches, and water-saturated background medium with thin layers of dissimilar permeability. Our model indicates how seismic properties change with the geothermal reservoir temperature and pressure, showing that both seismic velocity and attenuation can be used as a diagnostic tool to estimate the in situ conditions.

  8. 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.

  9. A Tool for Assessing Future Capacity Loss Due to Sedimentation in the United States' Reservoirs

    Science.gov (United States)

    Pinson, A. O.; Baker, B.; White, K. D.

    2017-12-01

    Federal reservoirs are critical components of the United States' water supply, flood risk management, hydropower and navigation infrastructure. These reservoirs included capacity for storage loss due to the deposition of sediment by inflowing streams in their original design. However, the actual rate of capacity loss experienced is controlled in part by climate, topography, soils, and land use/land cover, and may vary from the design. To assess the current and future vulnerability of its reservoirs to sedimentation. USACE has developed an online planning tool to identify USACE reservoirs where sedimentation is currently a problem (e.g., sedimentation rate exceeds design sedimentation rate, or zone losses disproportionately affect authorized purposes), and reservoirs where rates are expected to increase significantly in the future. The goal is to be able to prioritize operation and maintenance actions to minimize the effects of reservoir capacity loss on authorized purposes and help maximize reservoir use life.

  10. Mobility Effect on Poroelastic Seismic Signatures in Partially Saturated Rocks With Applications in Time-Lapse Monitoring of a Heavy Oil Reservoir

    Science.gov (United States)

    Zhao, Luanxiao; Yuan, Hemin; Yang, Jingkang; Han, De-hua; Geng, Jianhua; Zhou, Rui; Li, Hui; Yao, Qiuliang

    2017-11-01

    Conventional seismic analysis in partially saturated rocks normally lays emphasis on estimating pore fluid content and saturation, typically ignoring the effect of mobility, which decides the ability of fluids moving in the porous rocks. Deformation resulting from a seismic wave in heterogeneous partially saturated media can cause pore fluid pressure relaxation at mesoscopic scale, thereby making the fluid mobility inherently associated with poroelastic reflectivity. For two typical gas-brine reservoir models, with the given rock and fluid properties, the numerical analysis suggests that variations of patchy fluid saturation, fluid compressibility contrast, and acoustic stiffness of rock frame collectively affect the seismic reflection dependence on mobility. In particular, the realistic compressibility contrast of fluid patches in shallow and deep reservoir environments plays an important role in determining the reflection sensitivity to mobility. We also use a time-lapse seismic data set from a Steam-Assisted Gravity Drainage producing heavy oil reservoir to demonstrate that mobility change coupled with patchy saturation possibly leads to seismic spectral energy shifting from the baseline to monitor line. Our workflow starts from performing seismic spectral analysis on the targeted reflectivity interface. Then, on the basis of mesoscopic fluid pressure diffusion between patches of steam and heavy oil, poroelastic reflectivity modeling is conducted to understand the shift of the central frequency toward low frequencies after the steam injection. The presented results open the possibility of monitoring mobility change of a partially saturated geological formation from dissipation-related seismic attributes.

  11. 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

  12. Quantitative monitoring of gas flooding in oil-bearing reservoirs using a pulsed neutron tool

    International Nuclear Information System (INIS)

    Ruhovets, N.; Wyatt, D.F. Jr.

    1991-01-01

    This paper reports on quantitative monitoring of gas flooding in oil bearing reservoirs which is unique in that saturations of three fluids (gas, oil and water) in the effective pore space have to be determined, while in most other applications saturation behind casing is determined only for two fluids: hydrocarbons and water. A new method has been developed to monitor gas flooding of oil reservoirs. The method is based on computing two porosities: true effective (base) porosity determined before gas flooding, and apparent effective (monitor) porosity determined after gas flooding. The base porosity is determined from open and/or cased hole porosity logs run before the flooding. When open hole logs are available, the cased hole porosity logs are calibrated against open hole log. The monitor porosity is determined from one of the cased hole porosity logs, such as a neutron log or count rate ratio curve from a pulsed neutron log run after the gas flooding. The base and monitor porosities provide determination of the hydrogen index of the reservoir fluid after the flooding. This hydrogen index is then used to determine saturation of the flood agent after flooding. Water saturation after flooding can be determined from the equation which relates neutron total cross section (Σm) to volumetric constituent cross sections, using Σm values from a monitor run (after flooding)

  13. Nanosensors as Reservoir Engineering Tools to Map Insitu Temperature Distributions in Geothermal Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Morgan Ames

    2011-06-15

    The feasibility of using nanosensors to measure temperature distribution and predict thermal breakthrough in geothermal reservoirs is addressed in this report. Four candidate sensors were identified: melting tin-bismuth alloy nanoparticles, silica nanoparticles with covalently-attached dye, hollow silica nanoparticles with encapsulated dye and impermeable melting shells, and dye-polymer composite time-temperature indicators. Four main challenges associated with the successful implementation of temperature nanosensors were identified: nanoparticle mobility in porous and fractured media, the collection and detection of nanoparticles at the production well, engineering temperature sensing mechanisms that are both detectable and irreversible, and inferring the spatial geolocation of temperature measurements in order to map temperature distribution. Initial experiments were carried out to investigate each of these challenges. It was demonstrated in a slim-tube injection experiment that it is possible to transport silica nanoparticles over large distances through porous media. The feasibility of magnetic collection of nanoparticles from produced fluid was evaluated experimentally, and it was estimated that 3% of the injected nanoparticles were recovered in a prototype magnetic collection device. An analysis technique was tailored to nanosensors with a dye-release mechanism to estimate temperature measurement geolocation by analyzing the return curve of the released dye. This technique was used in a hypothetical example problem, and good estimates of geolocation were achieved. Tin-bismuth alloy nanoparticles were synthesized using a sonochemical method, and a bench heating experiment was performed using these nanoparticles. Particle growth due to melting was observed, indicating that tin-bismuth nanoparticles have potential as temperature nanosensors

  14. Increasing Waterflood Reserves in the Wilmington Oil Field through Improved Reservoir Characterization and Reservoir Management

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, D.; Koerner, R.; Moos D.; Nguyen, J.; Phillips, C.; Tagbor, K.; Walker, S.

    1999-04-05

    This project used advanced reservoir characterization tools, including the pulsed acoustic cased-hole logging tool, geologic three-dimensional (3-D) modeling software, and commercially available reservoir management software to identify sands with remaining high oil saturation following waterflood. Production from the identified high oil saturated sands was stimulated by recompleting existing production and injection wells in these sands using conventional means as well as a short radius redrill candidate.

  15. Development of a management tool for reservoirs in Mediterranean environments based on uncertainty analysis

    Science.gov (United States)

    Gómez-Beas, R.; Moñino, A.; Polo, M. J.

    2012-05-01

    In compliance with the development of the Water Framework Directive, there is a need for an integrated management of water resources, which involves the elaboration of reservoir management models. These models should include the operational and technical aspects which allow us to forecast an optimal management in the short term, besides the factors that may affect the volume of water stored in the medium and long term. The climate fluctuations of the water cycle that affect the reservoir watershed should be considered, as well as the social and economic aspects of the area. This paper shows the development of a management model for Rules reservoir (southern Spain), through which the water supply is regulated based on set criteria, in a sustainable way with existing commitments downstream, with the supply capacity being well established depending on demand, and the probability of failure when the operating requirements are not fulfilled. The results obtained allowed us: to find out the reservoir response at different time scales, to introduce an uncertainty analysis and to demonstrate the potential of the methodology proposed here as a tool for decision making.

  16. Assessment of water management tools for the geothermal reservoir Waiwera (New Zealand)

    Science.gov (United States)

    Kühn, Michael; Altmannsberger, Charlotte

    2016-04-01

    Water management tools are essential to ensure the conservation of natural resources. The geothermal hot water reservoir below the village of Waiwera, on the Northern Island of New Zealand is used commercially since 1863. The continuous production of 50 °C hot geothermal water, to supply hotels and spas, has a negative impact on the reservoir. Until the year 1969 from all wells drilled the warm water flow was artesian. Due to overproduction the water needs to be pumped up nowadays. Further, within the years 1975 to 1976 the warm water seeps on the beach of Waiwera ran dry. In order to protect the reservoir and the historical and tourist site in the early 1980s a Water Management Plan was deployed. The "Auckland Regional Water Board" today "Auckland Regional Council" established guidelines to enable a sustainable management [1]. The management plan demands that the water level in the official and appropriate observation well of the council is 0.5 m above sea level throughout the year in average. Almost four decades of data (since 1978 until today) are now available [2]. The minimum water level was observed beginning of the 1980s with -1.25 m and the maximum recently with 1.6 m. The higher the production rates from the field, the lower the water level in the observation well. Highest abstraction rates reached almost 1,500 m3/day and lowest were just above 500 m3/day. Several models of varying complexity where used from purely data driven statistical to fully coupled process simulation models. In all cases the available data were used for calibration and the models were then applied for predictive purposes. We used the Nash-Sutcliffe efficiency index to quantify their predictive ability. The recommendation for the full implementation of the water management plan is the regular revision of an existing multivariate regression model which is based on the Theis well equation. Further, we suggest improving the underlying geological model of the process simulations to

  17. Capillary pressure - saturation relations for supercritical CO2 and brine: Implications for capillary/residual trapping in carbonate reservoirs during geologic carbon sequestration

    Science.gov (United States)

    Wang, S.; Tokunaga, T. K.

    2014-12-01

    In geologic carbon sequestration (GCS), data on capillary pressure (Pc) - saturation (Sw) relations are routinely needed to appraise reservoir processes. Capillarity and its hysteresis have been often experimentally studied in oil-water, gas-water and three phase gas-oil-water systems, but fewer works have been reported on scCO2-water under in-situ reservoir conditions. Here, Pc-Sw relations of supercritical (sc) CO2 displacing brine, and brine rewetting the porous medium to trap scCO2 were studied to understand CO2 transport and trapping behavior in carbonate reservoirs under representative reservoir conditions. High-quality drainage and imbibition (and associated capillary pressure hysteresis) curves were measured under elevated temperature and pressure (45 ºC, 8.5 and 12 MPa) for scCO2-brine as well as at room temperature and pressure (23 ºC, 0.1 MPa) for air-brine in unconsolidated limestone and dolomite sand columns using newly developed semi-automated multistep outflow-inflow porous plate apparatus. Drainage and imbibition curves for scCO2-brine deviated from the universal scaling curves for hydrophilic interactions (with greater deviation under higher pressure) and shifted to lower Pc than predicted based on interfacial tension (IFT) changes. Augmented scaling incorporating differences in IFT and contact angle improved the scaling results but the scaled curves still did not converge onto the universal curves. Equilibrium residual trapping of the nonwetting phase was determined at Pc =0 during imbibition. The capillary-trapped amounts of scCO2 were significantly larger than for air. It is concluded that the deviations from the universal capillary scaling curves are caused by scCO2-induced wettability alteration, given the fact that pore geometry remained constant and IFT is well constrained. In-situ wettability alteration by reactive scCO2 is of critical importance and must be accounted for to achieve reliable predictions of CO2 behavior in GCS reservoirs.

  18. Tephrochronology as a tool to constrain radiocarbon reservoir age in the deglacial Bering Sea

    Science.gov (United States)

    Chapman, A. U.; White-Nockleby, C.; de Konkoly Thege, P. A.; Rubel, J. N.; Cook, M. S.; Mix, A. C.; Addison, J. A.

    2015-12-01

    In order to accurately calendar date marine carbon, it is necessary to constrain surface reservoir age, the apparent 14C age difference between the atmosphere and surface ocean that results from incomplete equilibration of 14C across the air-sea interface. Surface reservoir age is generally assumed to be constant at the preindustrial value, but evidence suggests it has varied through time by up to 1000 years. In this study we use tephrochronology, a method of correlating tephras across different environments, to identify equivalent strata, as a tool to quantify reservoir age in the Bering Sea during the transition between the Oldest Dryas and Bolling-Allerod (14.7 kcal BP). With frequent volcanic eruptions that allow for possibility of high-resolution reservoir age reconstructions, the Bering Sea/Aleutian Islands region is uniquely positioned to provide insight into the hypothesis that dense water formed in the North Pacific during the last deglaciation. We compare a massive tephra found in three deep-sea sediment cores from Umnak Plateau in the southeast Bering Sea (HLY02-02-55JPC, HLY-02-02-51JPC, and IODP Site U1339) to a tephra dated to 14.8 kcal BP from Deep Lake, Sanak Island in the Eastern Aleutians. For both the Umnak and Sanak tephras, volcanic glass shards are geochemically matched using major and trace elements from electron microprobe and laser-ablation inductively-coupled-plasma mass spectrometry. We compare 14C ages of foraminiferal species Uvigerina peregrina and Neogloboquadrina pachyderma (sinistral) from just above the tephra in HLY-02-02-51JPC (1467 m) to 14C age of the corresponding tephra at Sanak Island from terrestrial plant macrofossils. The surface reservoir age found (930 ± 160 14C y) is similar to the average preindustrial value in the region (790 ± 130 14C y). Benthic-atmosphere age difference (1860 ± 200 14C y) is also comparable to the preindustrial value (2030 ± 60 14C y). These results and future work on additional tephras from

  19. Neuro-Simulation Tool for Enhanced Oil Recovery Screening and Reservoir Performance Prediction

    Directory of Open Access Journals (Sweden)

    Soheil Bahrekazemi

    2017-09-01

    Full Text Available Assessment of the suitable enhanced oil recovery method in an oilfield is one of the decisions which are made prior to the natural drive production mechanism. In some cases, having in-depth knowledge about reservoir’s rock, fluid properties, and equipment is needed as well as economic evaluation. Both putting such data into simulation and its related consequent processes are generally very time consuming and costly.  In order to reduce study cases, an appropriate tool is required for primary screening prior to any operations being performed, to which leads reduction of time in design of ether pilot section or production under field condition. In this research, two different and useful screening tools are presented through a graphical user interface. The output of just over 900 simulations and verified screening criteria tables were employed to design the mentioned tools. Moreover, by means of gathered data and development of artificial neural networks, two dissimilar screening tools for proper assessment of suitable enhanced oil recovery method were finally introduced. The first tool is about the screening of enhanced oil recovery process based on published tables/charts and the second one which is Neuro-Simulation tool, concerns economical evaluation of miscible and immiscible injection of carbon dioxide, nitrogen and natural gas into the reservoir. Both of designed tools are provided in the form of a graphical user interface by which the user, can perceive suitable method through plot of oil recovery graph during 20 years of production, costs of gas injection per produced barrel, cumulative oil production, and finally, design the most efficient scenario.

  20. Climate modeling - a tool for the assessment of the paleodistribution of source and reservoir rocks

    Energy Technology Data Exchange (ETDEWEB)

    Roscher, M.; Schneider, J.W. [Technische Univ. Bergakademie Freiberg (Germany). Inst. fuer Geologie; Berner, U. [Bundesanstalt fuer Geowissenschaften und Rohstoffe, Hannover (Germany). Referat Organische Geochemie/Kohlenwasserstoff-Forschung

    2008-10-23

    In an on-going project of BGR and TU Bergakademie Freiberg, numeric paleo-climate modeling is used as a tool for the assessment of the paleo-distribution of organic rich deposits as well as of reservoir rocks. This modeling approach is based on new ideas concerning the formation of the Pangea supercontinent. The new plate tectonic concept is supported by paleo- magnetic data as it fits the 95% confidence interval of published data. Six Permocarboniferous time slices (340, 320, 300, 290, 270, 255 Ma) were chosen within a first paleo-climate modeling approach as they represent the most important changes of the Late Paleozoic climate development. The digital maps have a resolution of 2.8 x 2.8 (T42), suitable for high-resolution climate modeling, using the PLASIM model. CO{sub 2} concentrations of the paleo-atmosphere and paleo-insolation values have been estimated by published methods. For the purpose of validation, quantitative model output, had to be transformed into qualitative parameters in order to be able to compare digital data with qualitative data of geologic indicators. The model output of surface temperatures and precipitation was therefore converted into climate zones. The reconstructed occurrences of geological indicators like aeolian sands, evaporites, reefs, coals, oil source rocks, tillites, phosphorites and cherts were then compared to the computed paleo-climate zones. Examples of the Permian Pangea show a very good agreement between model results and geological indicators. From the modeling approach we are able to identify climatic processes which lead to the deposition of hydrocarbon source and reservoir rocks. The regional assessment of such atmospheric processes may be used for the identification of the paleo-distribution of organic rich deposits or rock types suitable to form hydrocarbon reservoirs. (orig.)

  1. 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

  2. Reservoir Modeling by Data Integration via Intermediate Spaces and Artificial Intelligence Tools in MPS Simulation Frameworks

    International Nuclear Information System (INIS)

    Ahmadi, Rouhollah; Khamehchi, Ehsan

    2013-01-01

    Conditioning stochastic simulations are very important in many geostatistical applications that call for the introduction of nonlinear and multiple-point data in reservoir modeling. Here, a new methodology is proposed for the incorporation of different data types into multiple-point statistics (MPS) simulation frameworks. Unlike the previous techniques that call for an approximate forward model (filter) for integration of secondary data into geologically constructed models, the proposed approach develops an intermediate space where all the primary and secondary data are easily mapped onto. Definition of the intermediate space, as may be achieved via application of artificial intelligence tools like neural networks and fuzzy inference systems, eliminates the need for using filters as in previous techniques. The applicability of the proposed approach in conditioning MPS simulations to static and geologic data is verified by modeling a real example of discrete fracture networks using conventional well-log data. The training patterns are well reproduced in the realizations, while the model is also consistent with the map of secondary data

  3. Reservoir Modeling by Data Integration via Intermediate Spaces and Artificial Intelligence Tools in MPS Simulation Frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Ahmadi, Rouhollah, E-mail: rouhollahahmadi@yahoo.com [Amirkabir University of Technology, PhD Student at Reservoir Engineering, Department of Petroleum Engineering (Iran, Islamic Republic of); Khamehchi, Ehsan [Amirkabir University of Technology, Faculty of Petroleum Engineering (Iran, Islamic Republic of)

    2013-12-15

    Conditioning stochastic simulations are very important in many geostatistical applications that call for the introduction of nonlinear and multiple-point data in reservoir modeling. Here, a new methodology is proposed for the incorporation of different data types into multiple-point statistics (MPS) simulation frameworks. Unlike the previous techniques that call for an approximate forward model (filter) for integration of secondary data into geologically constructed models, the proposed approach develops an intermediate space where all the primary and secondary data are easily mapped onto. Definition of the intermediate space, as may be achieved via application of artificial intelligence tools like neural networks and fuzzy inference systems, eliminates the need for using filters as in previous techniques. The applicability of the proposed approach in conditioning MPS simulations to static and geologic data is verified by modeling a real example of discrete fracture networks using conventional well-log data. The training patterns are well reproduced in the realizations, while the model is also consistent with the map of secondary data.

  4. Management of complex multi-reservoir water distribution systems using advanced control theoretic tools and techniques

    CERN Document Server

    Chmielowski, Wojciech Z

    2013-01-01

    This study discusses issues of optimal water management in a complex distribution system. The main elements of the water-management system under consideration are retention reservoirs, among which water transfers are possible, and a network of connections between these reservoirs and water treatment plants (WTPs). System operation optimisation involves determining the proper water transport routes and their flow volumes from the retention reservoirs to the WTPs, and the volumes of possible transfers among the reservoirs, taking into account transport-related delays for inflows, outflows and water transfers in the system. Total system operation costs defined by an assumed quality coefficient should be minimal. An analytical solution of the optimisation task so formulated has been obtained as a result of using Pontriagin’s maximum principle with reference to the quality coefficient assumed. Stable start and end conditions in reservoir state trajectories have been assumed. The researchers have taken into accou...

  5. INCREASING WATERFLOOD RESERVES IN THE WILMINGTON OIL FIELD THROUGH IMPROVED RESERVOIR CHARACTERIZATION AND RESERVOIR MANAGEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Scott Walker; Chris Phillips; Roy Koerner; Don Clarke; Dan Moos; Kwasi Tagbor

    2002-02-28

    This project increased recoverable waterflood reserves in slope and basin reservoirs through improved reservoir characterization and reservoir management. The particular application of this project is in portions of Fault Blocks IV and V of the Wilmington Oil Field, in Long Beach, California, but the approach is widely applicable in slope and basin reservoirs. Transferring technology so that it can be applied in other sections of the Wilmington Field and by operators in other slope and basin reservoirs is a primary component of the project. This project used advanced reservoir characterization tools, including the pulsed acoustic cased-hole logging tool, geologic three-dimensional (3-D) modeling software, and commercially available reservoir management software to identify sands with remaining high oil saturation following waterflood. Production from the identified high oil saturated sands was stimulated by recompleting existing production and injection wells in these sands using conventional means as well as a short radius redrill candidate. Although these reservoirs have been waterflooded over 40 years, researchers have found areas of remaining oil saturation. Areas such as the top sand in the Upper Terminal Zone Fault Block V, the western fault slivers of Upper Terminal Zone Fault Block V, the bottom sands of the Tar Zone Fault Block V, and the eastern edge of Fault Block IV in both the Upper Terminal and Lower Terminal Zones all show significant remaining oil saturation. Each area of interest was uncovered emphasizing a different type of reservoir characterization technique or practice. This was not the original strategy but was necessitated by the different levels of progress in each of the project activities.

  6. The reservoir engineering report in financial transactions: 'a useful tool - neither panacea nor placebo'

    International Nuclear Information System (INIS)

    Porter, T.W.

    1996-01-01

    The important role that independent reservoir engineering reports play in the oil and gas industry, was discussed. Among other things, such reports often form the basis upon which oil and gas properties are valued, bought and sold, and of course, they are necessary for the industry to gain access to sources of capital. However, interpretation plays a critical role in the process, and very different conclusions can be drawn by equally reputable and qualified engineers. Because of this, financial investors insist upon independent reservoir engineering reports (and then frequently ignore the limitations and qualifications which are stated in the report). Some of the important limitations stated in reservoir engineering reports were discussed, along with the risks inherent in reservoir engineering reports, and the strategies for minimizing those risks. The engineer's professional responsibilities and potential liabilities in the matter of reserves estimates, were re-stated

  7. Hydrologic modeling in a small mediterranean basin as a tool to assess the feasibility of a limno-reservoir.

    Science.gov (United States)

    Molina-Navarro, Eugenio; Martínez-Pérez, Silvia; Sastre-Merlín, Antonio; Bienes-Allas, Ramón

    2014-01-01

    The SWAT model was applied to the Ompólveda River Basin (Guadalajara, central Spain) to assess the hydrological feasibility of the Pareja Limno-reservoir. A limno-reservoir is a water management infrastructure designed to counteract some negative impacts caused by large reservoirs under Mediterranean climate. Highly detailed inputs were selected to set up the model. Its performance was evaluated by graphical and statistical techniques and compared with the previous knowledge of the basin. An overall good performance was obtained during the calibration and validation periods (monthly and annual NSE values of 0.67 and 0.60, respectively, for calibration and 0.70 and 0.83, respectively, for validation). Total discharge was well simulated, and flow components prediction was acceptable. However, the model is not accurate at predicting evapotranspiration. Once evaluated, the model was used to simulate the water discharge into the Pareja Limno-reservoir during 2008 and 2009, establishing a water balance and assessing its hydrologic feasibility. The water balance predicted the absence of surplus during summer (2008 and 2009) and autumn (2009), matching up with the decrease of water level and demonstrating the usefulness of SWAT as a tool to evaluate the hydrologic feasibility of the Pareja Limno-reservoir. Very low discharges from the Ompólveda River after a sequence of normal and dry years are the main factors responsible of this phenomenon, whereas the effect of the wastewater flow redirection in the Pareja village is negligible. These results question the usefulness of the Pareja Limno-reservoir during summer, the most favorable season for recreational activities. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  8. Reservoir management

    International Nuclear Information System (INIS)

    Satter, A.; Varnon, J.E.; Hoang, M.T.

    1992-01-01

    A reservoir's life begins with exploration leading to discovery followed by delineation of the reservoir, development of the field, production by primary, secondary and tertiary means, and finally to abandonment. Sound reservoir management is the key to maximizing economic operation of the reservoir throughout its entire life. Technological advances and rapidly increasing computer power are providing tools to better manage reservoirs and are increasing the gap between good and neural reservoir management. The modern reservoir management process involves goal setting, planning, implementing, monitoring, evaluating, and revising plans. Setting a reservoir management strategy requires knowledge of the reservoir, availability of technology, and knowledge of the business, political, and environmental climate. Formulating a comprehensive management plan involves depletion and development strategies, data acquisition and analyses, geological and numerical model studies, production and reserves forecasts, facilities requirements, economic optimization, and management approval. This paper provides management, engineers, geologists, geophysicists, and field operations staff with a better understanding of the practical approach to reservoir management using a multidisciplinary, integrated team approach

  9. Reservoir management

    International Nuclear Information System (INIS)

    Satter, A.; Varnon, J.E.; Hoang, M.T.

    1992-01-01

    A reservoir's life begins with exploration leading to discovery followed by delineation of the reservoir, development of the field, production by primary, secondary and tertiary means, and finally to abandonment. Sound reservoir management is the key to maximizing economic operation of the reservoir throughout its entire life. Technological advances and rapidly increasing computer power are providing tools to better manage reservoirs and are increasing the gap between good and neutral reservoir management. The modern reservoir management process involves goal setting, planning, implementing, monitoring, evaluating, and revising plans. Setting a reservoir management strategy requires knowledge of the reservoir, availability of technology, and knowledge of the business, political, and environmental climate. Formulating a comprehensive management plan involves depletion and development strategies, data acquisition and analyses, geological and numerical model studies, production and reserves forecasts, facilities requirements, economic optimization, and management approval. This paper provides management, engineers geologists, geophysicists, and field operations staff with a better understanding of the practical approach to reservoir management using a multidisciplinary, integrated team approach

  10. Heavy oil reservoir evaluation : performing an injection test using DST tools in the marine region of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Loaiza, J.; Ruiz, P. [Halliburton, Mexico City (Mexico); Barrera, D.; Gutierrez, F. [Pemex, Mexico City (Mexico)

    2010-07-01

    This paper described an injection test conducted to evaluate heavy oil reserves in an offshore area of Mexico. The drill-stem testing (DST) evaluation used a fluid injection technique in order to eliminate the need for artificial lift and coiled tubing. A pressure transient analysis method was used to determine the static pressure of the reservoir, effective hydrocarbon permeability, and formation damage. Boundary effects were also characterized. The total volume of the fluid injection was determined by analyzing various reservoir parameters. The timing of the shut-in procedure was determined by characterizing rock characteristics and fluids within the reservoir. The mobility and diffusivity relationships between the zones with the injection fluids and reservoir fluids were used to defined sweep fluids. A productivity analysis was used to predict various production scenarios. DST tools were then used to conduct a pressure-production assessment. Case histories were used to demonstrate the method. The studies showed that the method provides a cost-effective means of providing high quality data for productivity analyses. 4 refs., 2 tabs., 15 figs.

  11. Core Flooding Experiments Combined with X-rays and Micro-PET Imaging as a Tool to Calculate Fluid Saturations in a Fracture

    Science.gov (United States)

    Gran, M.; Zahasky, C.; Garing, C.; Pollyea, R. M.; Benson, S. M.

    2017-12-01

    One way to reduce CO2 emissions is to capture CO2 generated in power plants and other industrial sources to inject it into a geological formation. Sedimentary basins are the ones traditionally used to store CO2 but the emission sources are not always close to these type of basins. In this case, basalt rocks present a good storage alternative due their extent and also their potential for mineral trapping. Flow through basaltic rocks is governed by the permeable paths provided by rock fractures. Hence, knowing the behavior of the multiphase flow in these fractures becomes crucial. With the aim to describe how aperture and liquid-gas interface changes in the fracture affect relative permeability and what are the implications of permeability stress dependency, a series of core experiments were conducted. To calculate fracture apertures and fluid saturations, core flooding experiments combined with medical X-Ray CT scanner and micro-PET imaging (Micro Positron Emission Tomography) were performed. Capillary pressure and relative permeability drainage curves were simultaneously measured in a fractured basalt core under typical storage reservoir pressures and temperatures. The X-Ray scanner allows fracture apertures to be measured quite accurately even for fractures as small as 30 µ, but obtaining fluid saturations is not straightforward. The micro-PET imaging provides dynamic measurements of tracer distributions which can be used to calculate saturation. Here new experimental data is presented and the challenges associated with measuring fluid saturations using both X-Rays and micro-PET are discussed.

  12. Hepatitis B Virus Vaccination in HIV-1-Infected Young Adults: A Tool to Reduce the Size of HIV-1 Reservoirs?

    Science.gov (United States)

    Bekele, Yonas; Graham, Rebecka Lantto; Soeria-Atmadja, Sandra; Nasi, Aikaterini; Zazzi, Maurizio; Vicenti, Ilaria; Naver, Lars; Nilsson, Anna; Chiodi, Francesca

    2017-01-01

    activated CD4+ cells and an increase in central memory CD8+ T cells were associated with this finding. Further studies should assess whether vaccination is a possible tool to reduce HIV-1 reservoirs.

  13. Hepatitis B Virus Vaccination in HIV-1-Infected Young Adults: A Tool to Reduce the Size of HIV-1 Reservoirs?

    Directory of Open Access Journals (Sweden)

    Yonas Bekele

    2018-01-01

    frequency of activated CD4+ cells and an increase in central memory CD8+ T cells were associated with this finding. Further studies should assess whether vaccination is a possible tool to reduce HIV-1 reservoirs.

  14. Hepatitis B Virus Vaccination in HIV-1-Infected Young Adults: A Tool to Reduce the Size of HIV-1 Reservoirs?

    Science.gov (United States)

    Bekele, Yonas; Graham, Rebecka Lantto; Soeria-Atmadja, Sandra; Nasi, Aikaterini; Zazzi, Maurizio; Vicenti, Ilaria; Naver, Lars; Nilsson, Anna; Chiodi, Francesca

    2018-01-01

    activated CD4+ cells and an increase in central memory CD8+ T cells were associated with this finding. Further studies should assess whether vaccination is a possible tool to reduce HIV-1 reservoirs. PMID:29375579

  15. Application of PLT (Production Loggin Tool) surveys to select a vertical grid refinement in gas reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Pablo Julian [Petrosynergy Ltda., Sao Paulo, SP (Brazil); Schiozer, Denis Jose [Universidade Estadual de Campinas (UNISIM/UNICAMP), SP (Brazil). Dept. de Engenharia de Petroleo. Pesquisa em Simulacao e Gerenciamento de Reservatorios

    2012-07-01

    Most of the time, the fluid segregation in porous media between gas and water makes water breakthrough reach a well structurally from the bottom, even when coning effect is present. In this paper we describe a real case of a gas reservoir when water breakthrough reach the vertical well from the middle of the perforation, above gas phase. We also expose how to upgrade the geological model to represent the high permeability channels in the numerical simulation model. (author)

  16. Thermal infrared imagery as a tool for analysing the variability of surface saturated areas at various temporal and spatial scales

    Science.gov (United States)

    Glaser, Barbara; Antonelli, Marta; Pfister, Laurent; Klaus, Julian

    2017-04-01

    Surface saturated areas are important for the on- and offset of hydrological connectivity within the hillslope-riparian-stream continuum. This is reflected in concepts such as variable contributing areas or critical source areas. However, we still lack a standardized method for areal mapping of surface saturation and for observing its spatiotemporal variability. Proof-of-concept studies in recent years have shown the potential of thermal infrared (TIR) imagery to record surface saturation dynamics at various temporal and spatial scales. Thermal infrared imagery is thus a promising alternative to conventional approaches, such as the squishy boot method or the mapping of vegetation. In this study we use TIR images to investigate the variability of surface saturated areas at different temporal and spatial scales in the forested Weierbach catchment (0.45 km2) in western Luxembourg. We took TIR images of the riparian zone with a hand-held FLIR infrared camera at fortnightly intervals over 18 months at nine different locations distributed over the catchment. Not all of the acquired images were suitable for a derivation of the surface saturated areas, as various factors influence the usability of the TIR images (e.g. temperature contrasts, shadows, fog). Nonetheless, we obtained a large number of usable images that provided a good insight into the dynamic behaviour of surface saturated areas at different scales. The images revealed how diverse the evolution of surface saturated areas can be throughout the hydrologic year. For some locations with similar morphology or topography we identified diverging saturation dynamics, while other locations with different morphology / topography showed more similar behaviour. Moreover, we were able to assess the variability of the dynamics of expansion / contraction of saturated areas within the single locations, which can help to better understand the mechanisms behind surface saturation development.

  17. Chemical Exchange Saturation Transfer in Chemical Reactions: A Mechanistic Tool for NMR Detection and Characterization of Transient Intermediates.

    Science.gov (United States)

    Lokesh, N; Seegerer, Andreas; Hioe, Johnny; Gschwind, Ruth M

    2018-02-07

    The low sensitivity of NMR and transient key intermediates below detection limit are the central problems studying reaction mechanisms by NMR. Sensitivity can be enhanced by hyperpolarization techniques such as dynamic nuclear polarization or the incorporation/interaction of special hyperpolarized molecules. However, all of these techniques require special equipment, are restricted to selective reactions, or undesirably influence the reaction pathways. Here, we apply the chemical exchange saturation transfer (CEST) technique for the first time to NMR detect and characterize previously unobserved transient reaction intermediates in organocatalysis. The higher sensitivity of CEST and chemical equilibria present in the reaction pathway are exploited to access population and kinetics information on low populated intermediates. The potential of the method is demonstrated on the proline-catalyzed enamine formation for unprecedented in situ detection of a DPU stabilized zwitterionic iminium species, the elusive key intermediate between enamine and oxazolidinones. The quantitative analysis of CEST data at 250 K revealed the population ratio of [Z-iminium]/[exo-oxazolidinone] 0.02, relative free energy +8.1 kJ/mol (calculated +7.3 kJ/mol), and free energy barrier of +45.9 kJ/mol (ΔG ⧧ calc. (268 K) = +42.2 kJ/mol) for Z-iminium → exo-oxazolidinone. The findings underpin the iminium ion participation in enamine formation pathway corroborating our earlier theoretical prediction and help in better understanding. The reliability of CEST is validated using 1D EXSY-build-up techniques at low temperature (213 K). The CEST method thus serves as a new tool for mechanistic investigations in organocatalysis to access key information, such as chemical shifts, populations, and reaction kinetics of intermediates below the standard NMR detection limit.

  18. Efficient Data Assimilation Tool For Real Time CO2 Reservoir Monitoring and Characterization

    Science.gov (United States)

    Li, J. Y.; Ambikasaran, S.; Kokkinaki, A.; Darve, E. F.; Kitanidis, P. K.

    2014-12-01

    Reservoir forecasting and management are increasingly relying on a data-driven approach, which involves data assimilation to calibrate and keep up to date the complex model of multi-phase flow and transport in the geologic formation and to evaluate its uncertainty using monitoring data of different types and temporal resolution. The numbers of unknowns and measurements are usually very large, which represents a major computational challenge. Kalman filter (KF), the archetypical recursive filter, provides the framework to assimilate reservoir monitoring data into a dynamic system but the cost of implementing the original algorithm to large systems is computationally prohibitive. In our work, we have developed several Kalman-filter based approaches that reduce the computational and storage cost of standard KF from O (m2) to O (m), where m is the number of unknowns, and have the potential to be applied to field-scale problems. HiKF, a linear filter based on the hierarchical matrix approach, takes advantage of the informative high-frequency data acquired quasi-continuously and uses a random-walk model in the state forecast step when the a state evolution model is unavailable. A more general-purpose nonlinear filter CSKF achieves computational efficiency by exploiting the fact that the state covariance matrix for most dynamical systems can be approximated adequately through a low-rank matrix, and it allows using a forward simulator as a black-box for nonlinear error propagation. We will demonstrate both methods using synthetic CO2 injection cases and compare with the standard ensemble Kalman filter (EnKF).

  19. G-REALM: A lake/reservoir monitoring tool for drought monitoring and water resources management.

    Science.gov (United States)

    Birkett, C. M.; Ricko, M.; Beckley, B. D.; Yang, X.; Tetrault, R. L.

    2017-12-01

    G-REALM is a NASA/USDA funded operational program offering water-level products for lakes and reservoirs and these are currently derived from the NASA/CNES Topex/Jason series of satellite radar altimeters. The main stakeholder is the USDA/Foreign Agricultural Service (FAS) though many other end-users utilize the products for a variety of interdisciplinary science and operational programs. The FAS utilize the products within their CropExplorer Decision Support System (DSS) to help assess irrigation potential, and to monitor both short-term (agricultural) and longer-term (hydrological) drought conditions. There is increasing demand for a more global monitoring service that in particular, captures the variations in the smallest (1 to 100km2) reservoirs and water holdings in arid and semi-arid regions. Here, water resources are critical to both agriculture and regional security. A recent G-REALM 10-day resolution product upgrade and expansion has allowed for more accurate lake level products to be released and for a greater number of water bodies to be monitored. The next program phase focuses on the exploration of the enhanced radar altimeter data sets from the Cryosat-2 and Sentinel-3 missions with their improved spatial resolution, and the expansion of the system to the monitoring of 1,000 water bodies across the globe. In addition, a new element, the monitoring of surface water levels in wetland zones, is also being introduced. This aims to satisfy research and stakeholder requirements with respect to programs examining the links between inland fisheries catch potential and declining water levels, and to those monitoring the delicate balance between water resources, agriculture, and fisheries management in arid basins.

  20. Data Assimilation Tools for CO2 Reservoir Model Development – A Review of Key Data Types, Analyses, and Selected Software

    Energy Technology Data Exchange (ETDEWEB)

    Rockhold, Mark L.; Sullivan, E. C.; Murray, Christopher J.; Last, George V.; Black, Gary D.

    2009-09-30

    Pacific Northwest National Laboratory (PNNL) has embarked on an initiative to develop world-class capabilities for performing experimental and computational analyses associated with geologic sequestration of carbon dioxide. The ultimate goal of this initiative is to provide science-based solutions for helping to mitigate the adverse effects of greenhouse gas emissions. This Laboratory-Directed Research and Development (LDRD) initiative currently has two primary focus areas—advanced experimental methods and computational analysis. The experimental methods focus area involves the development of new experimental capabilities, supported in part by the U.S. Department of Energy’s (DOE) Environmental Molecular Science Laboratory (EMSL) housed at PNNL, for quantifying mineral reaction kinetics with CO2 under high temperature and pressure (supercritical) conditions. The computational analysis focus area involves numerical simulation of coupled, multi-scale processes associated with CO2 sequestration in geologic media, and the development of software to facilitate building and parameterizing conceptual and numerical models of subsurface reservoirs that represent geologic repositories for injected CO2. This report describes work in support of the computational analysis focus area. The computational analysis focus area currently consists of several collaborative research projects. These are all geared towards the development and application of conceptual and numerical models for geologic sequestration of CO2. The software being developed for this focus area is referred to as the Geologic Sequestration Software Suite or GS3. A wiki-based software framework is being developed to support GS3. This report summarizes work performed in FY09 on one of the LDRD projects in the computational analysis focus area. The title of this project is Data Assimilation Tools for CO2 Reservoir Model Development. Some key objectives of this project in FY09 were to assess the current state

  1. A new through-tubing oil-saturation measurement system

    International Nuclear Information System (INIS)

    Roscoe, B.A.; Adolph, R.A.; Bontemy, Y.; Cheeseborough, J.C. III; Hall, J.S.; McKeon, D.C.; Pittman, D.; Seeman, B.; Thomas, S.R. Jr.

    1991-01-01

    This paper reports on carbon-oxygen logging which is used primarily to estimate oil saturation in cased-hole conditions when the formation water is fresh or unknown. The drawbacks of current techniques are: slow logging speed, large tool diameter, and excessive sensitivity to borehole fluid composition. A new, slim, neutron-induced gamma ray spectroscopy logging system has been developed to overcome some of these limitations. The new logging service is called the Reservoir Saturation (RST) Tool. Initial field tests are being carried out in the Middle East. The RST tool uses multiple detectors to separate the signal contributions from the borehole and the formation. Therefore, even when the borehole fluid composition is unknown, oil saturation can be determined in addition to the borehole oil fraction. This presents the possibility of logging flowing wells, which ensures that reinvasion and crossflow will not affect the results, and eliminates the costs of well preparation

  2. Well-logging method using well-logging tools run through a drill stem test string for determining in-situ change in formation water saturation values

    International Nuclear Information System (INIS)

    Fertl, W.H.

    1975-01-01

    A logging tool (pulsed neutron or neutron-gamma ray) whose response indicates formation water saturation value, is run through an opening extending through a portion of a drill stem test string. A sample portion of the formation fluid in the zone of interest is removed and another logging run is made. The differences between the plots of the two logging runs indicate the formation potential productivity in the zone of interest

  3. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Joel Walls; M.T. Taner; Naum Derzhi; Gary Mavko; Jack Dvorkin

    2003-12-01

    We have developed and tested technology for a new type of direct hydrocarbon detection. The method uses inelastic rock properties to greatly enhance the sensitivity of surface seismic methods to the presence of oil and gas saturation. These methods include use of energy absorption, dispersion, and attenuation (Q) along with traditional seismic attributes like velocity, impedance, and AVO. Our approach is to combine three elements: (1) a synthesis of the latest rock physics understanding of how rock inelasticity is related to rock type, pore fluid types, and pore microstructure, (2) synthetic seismic modeling that will help identify the relative contributions of scattering and intrinsic inelasticity to apparent Q attributes, and (3) robust algorithms that extract relative wave attenuation attributes from seismic data. This project provides: (1) Additional petrophysical insight from acquired data; (2) Increased understanding of rock and fluid properties; (3) New techniques to measure reservoir properties that are not currently available; and (4) Provide tools to more accurately describe the reservoir and predict oil location and volumes. These methodologies will improve the industry's ability to predict and quantify oil and gas saturation distribution, and to apply this information through geologic models to enhance reservoir simulation. We have applied for two separate patents relating to work that was completed as part of this project.

  4. The equivalent pore aspect ratio as a tool for pore type prediction in carbonate reservoirs

    OpenAIRE

    FOURNIER , François; Pellerin , Matthieu; Villeneuve , Quentin; Teillet , Thomas; Hong , Fei; Poli , Emmanuelle; Borgomano , Jean; Léonide , Philippe; Hairabian , Alex

    2018-01-01

    International audience; The equivalent pore aspect ratios (EPAR) provide a tool to detect pore types by combining P-and S-wave velocities, porosity, bulk density and mineralogical composition of carbonate rocks. The integration of laboratory measurements, well log data and petrographic analysis of 468 carbonate samples from various depositional and diagenetic settings (Lower Cretaceous pre-salt non-marine carbonates from offshore Brazil, Lower Cretaceous shallow-water platform carbonates from...

  5. Application of MRIL-WD (Magnetic Resonance Imaging Logging While Drilling) for irreducible water saturation, total reservoir, free-fluid, bound-fluid porosity measurements and its value for the petrophysical analysis of RT/RM data from the Shah Deniz well

    Science.gov (United States)

    Amirov, Elnur

    2016-04-01

    , preferably while the drilling of the brand new wells (logging-while-drilling, LWD). The MRIL-WD Tool can accomplish any tasks reliably and in a timely manner thus saving drilling time and reducing the overall risk for the well. Control of water production and identification of pay zones with high irreducible water saturation are also very important for formation evaluation and petrophysical analysis in oil fields located in the Azerbaijan Republic and also other fields around the world. Sometimes above-mentioned problems can cause delay in completion decisions which will create additional expenses for field management. In many wells, breakthroughs in reservoir characterization have been achieved in directly determining hydrocarbon volumes, net permeability thickness, and hydrocarbon type, thus circumventing the problems associated with obtaining wireline data and the considerable amount of rig time required (so MRIL-WD can considerably reduce the NPT). Some reservoir zones with relatively low water saturation, which calculated from the other conventional logs, can produce with relatively high percentage of water cut, primarily because much of the water is movable. However, other zones with high calculated water saturation produce water free hydrocarbons. The difficulty in predicting water production can be related with the producing from the complex lithology, which can contain low-permeability, medium- to fine-grained shaly sands. Where grains are small, the formations have high surface to volume ratios that result in high irreducible water saturation and due to this we can see low resistivity values. As a result the use of resistivity logs as pay indicator, sometimes can cause low resistivity pay zones might be overlooked and consequently net field pay could be underestimated. In the last few years, nuclear magnetic resonance logs have shown great promise in solving problems of formation evaluation that could not be directly resolved with conventional logs. The capability

  6. Saturated Switching Systems

    CERN Document Server

    Benzaouia, Abdellah

    2012-01-01

    Saturated Switching Systems treats the problem of actuator saturation, inherent in all dynamical systems by using two approaches: positive invariance in which the controller is designed to work within a region of non-saturating linear behaviour; and saturation technique which allows saturation but guarantees asymptotic stability. The results obtained are extended from the linear systems in which they were first developed to switching systems with uncertainties, 2D switching systems, switching systems with Markovian jumping and switching systems of the Takagi-Sugeno type. The text represents a thoroughly referenced distillation of results obtained in this field during the last decade. The selected tool for analysis and design of stabilizing controllers is based on multiple Lyapunov functions and linear matrix inequalities. All the results are illustrated with numerical examples and figures many of them being modelled using MATLAB®. Saturated Switching Systems will be of interest to academic researchers in con...

  7. Development of a downhole tool measuring real-time concentration of ionic tracers and pH in geothermal reservoirs

    Science.gov (United States)

    Hess, Ryan F.; Boyle, Timothy J.; Limmer, Steven; Yelton, William G.; Bingham, Samuel; Stillman, Greg; Lindblom, Scott; Cieslewski, Grzegorz

    2014-06-01

    For enhanced or Engineered Geothermal Systems (EGS) geothermal brine is pumped to the surface via the production wells, the heat extracted to turn a turbine to generate electricity, and the spent brine re-injected via injection wells back underground. If designed properly, the subsurface rock formations will lead this water back to the extraction well as heated brine. Proper monitoring of these geothermal reservoirs is essential for developing and maintaining the necessary level of productivity of the field. Chemical tracers are commonly used to characterize the fracture network and determine the connectivity between the injection and production wells. Currently, most tracer experiments involve injecting the tracer at the injection well, manually collecting liquid samples at the wellhead of the production well, and sending the samples off for laboratory analysis. While this method provides accurate tracer concentration data at very low levels of detection, it does not provide information regarding the location of the fractures which were conducting the tracer between wellbores. Sandia is developing a high-temperature electrochemical sensor capable of measuring tracer concentrations and pH downhole on a wireline tool. The goal of this effort is to collect real-time pH and ionic tracer concentration data at temperatures up to 225 °C and pressures up to 3000 psi. In this paper, a prototype electrochemical sensor and the initial data obtained will be presented detailing the measurement of iodide tracer concentrations at high temperature and pressure in a newly developed laboratory scale autoclave.

  8. Application of Integrated Reservoir Management and Reservoir Characterization to Optimize Infill Drilling

    Energy Technology Data Exchange (ETDEWEB)

    P. K. Pande

    1998-10-29

    Initial drilling of wells on a uniform spacing, without regard to reservoir performance and characterization, must become a process of the past. Such efforts do not optimize reservoir development as they fail to account for the complex nature of reservoir heterogeneities present in many low permeability reservoirs, and carbonate reservoirs in particular. These reservoirs are typically characterized by: o Large, discontinuous pay intervals o Vertical and lateral changes in reservoir properties o Low reservoir energy o High residual oil saturation o Low recovery efficiency

  9. Isotopic and geochemical tools to assess the feasibility of methanogenesis as a way to enhance hydrocarbon recovery in oil reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, N.; Morris, B.E.L.; Richnow, H.H. [Helmholtz-Zentrum fuer Umweltforschung (UFZ), Leipzig (Germany). Abt. Isotopenbiogeochemie; Cai, M.; Yao, Jun [Helmholtz-Zentrum fuer Umweltforschung (UFZ), Leipzig (Germany). Abt. Isotopenbiogeochemie; University of Sicence and Technology, Beijing (China). School of Civil and Environment Engineering; Straaten, N.; Krueger, M. [Bundesanstalt fuer Geowissenschaften und Rohstoffe (BGR), Hannover (Germany). Fachbereich Geochemie

    2013-08-01

    In situ biotransformation of oil to methane was investigated in a thermophilic reservoir in Dagang, China using isotopic analyzes, chemical fingerprinting and molecular and biological methods. Our first results, which were already published, demonstrated that anaerobic oil degradation concomitant with methane production was occurring. The reservoir was highly methanogenic and the oil exhibited varying degrees of degradation between different parts of the reservoir, although it was mainly highly weathered, and nearly devoid of nalkanes, alkylbenzenes, alkyltoluenes, and light PAHs. In addition, the isotopic data from reservoir oil, water and gas was used to elucidate the origin of the methane. The average {delta}{sup 13}C for methane was around -47 permille and CO{sub 2} was highly enriched in {sup 13}C. The bulk isotopic discrimination ({Delta}{delta}{sup 13}C) between methane and CO{sub 2} was between 32 and 65 permille, in accordance with previously reported results for methane formation during hydrocarbon degradation. Subsequent microcosm experiments revealed that autochthonous microbiota are capable of degrading oil under methanogenic conditions and of producing methane and/or CO{sub 2} from {sup 13}C-labelled n-hexadecane, 2-methylnaphthalene or toluene ({delta}{sup 13}C values up to 550 permille). These results demonstrate that methanogenesis is linked to aliphatic and aromatic hydrocarbon degradation. Further experiments will elucidate the activation mechanisms for the different compounds. (orig.)

  10. All-optical reservoir computing.

    Science.gov (United States)

    Duport, François; Schneider, Bendix; Smerieri, Anteo; Haelterman, Marc; Massar, Serge

    2012-09-24

    Reservoir Computing is a novel computing paradigm that uses a nonlinear recurrent dynamical system to carry out information processing. Recent electronic and optoelectronic Reservoir Computers based on an architecture with a single nonlinear node and a delay loop have shown performance on standardized tasks comparable to state-of-the-art digital implementations. Here we report an all-optical implementation of a Reservoir Computer, made of off-the-shelf components for optical telecommunications. It uses the saturation of a semiconductor optical amplifier as nonlinearity. The present work shows that, within the Reservoir Computing paradigm, all-optical computing with state-of-the-art performance is possible.

  11. Reservoir resistivity characterization incorporating flow dynamics

    KAUST Repository

    Arango, Santiago; Sun, Shuyu; Hoteit, Ibrahim; Katterbauer, Klemens

    2016-01-01

    Systems and methods for reservoir resistivity characterization are provided, in various aspects, an integrated framework for the estimation of Archie's parameters for a strongly heterogeneous reservoir utilizing the dynamics of the reservoir are provided. The framework can encompass a Bayesian estimation/inversion method for estimating the reservoir parameters, integrating production and time lapse formation conductivity data to achieve a better understanding of the subsurface rock conductivity properties and hence improve water saturation imaging.

  12. Reservoir resistivity characterization incorporating flow dynamics

    KAUST Repository

    Arango, Santiago

    2016-04-07

    Systems and methods for reservoir resistivity characterization are provided, in various aspects, an integrated framework for the estimation of Archie\\'s parameters for a strongly heterogeneous reservoir utilizing the dynamics of the reservoir are provided. The framework can encompass a Bayesian estimation/inversion method for estimating the reservoir parameters, integrating production and time lapse formation conductivity data to achieve a better understanding of the subsurface rock conductivity properties and hence improve water saturation imaging.

  13. Gorilla gorilla gorilla gut: a potential reservoir of pathogenic bacteria as revealed using culturomics and molecular tools.

    Science.gov (United States)

    Bittar, Fadi; Keita, Mamadou B; Lagier, Jean-Christophe; Peeters, Martine; Delaporte, Eric; Raoult, Didier

    2014-11-24

    Wild apes are considered to be the most serious reservoir and source of zoonoses. However, little data are available about the gut microbiota and pathogenic bacteria in gorillas. For this propose, a total of 48 fecal samples obtained from 21 Gorilla gorilla gorilla individuals (as revealed via microsatellite analysis) were screened for human bacterial pathogens using culturomics and molecular techniques. By applying culturomics to one index gorilla and using specific media supplemented by plants, we tested 12,800 colonies and identified 147 different bacterial species, including 5 new species. Many opportunistic pathogens were isolated, including 8 frequently associated with human diseases; Mycobacterium bolletii, Proteus mirabilis, Acinetobacter baumannii, Klebsiella pneumoniae, Serratia marcescens, Escherichia coli, Staphylococcus aureus and Clostridium botulinum. The genus Treponema accounted for 27.4% of the total reads identified at the genus level via 454 pyrosequencing. Using specific real-time PCR on 48 gorilla fecal samples, in addition to classical human pathogens, we also observed the fastidious bacteria Bartonella spp. Borrelia spp., Coxiella burnetii and Tropheryma whipplei in the gorilla population. We estimated that the prevalence of these pathogens vary between 4.76% and 85.7%. Therefore, gorillas share many bacterial pathogens with humans suggesting that they could be a reservoir for their emergence.

  14. Recipe for residual oil saturation determination

    Energy Technology Data Exchange (ETDEWEB)

    Guillory, A.J.; Kidwell, C.M.

    1979-01-01

    In 1978, Shell Oil Co., in conjunction with the US Department of Energy, conducted a residual oil saturation study in a deep, hot high-pressured Gulf Coast Reservoir. The work was conducted prior to initiation of CO/sub 2/ tertiary recovery pilot. Many problems had to be resolved prior to and during the residual oil saturation determination. The problems confronted are outlined such that the procedure can be used much like a cookbook in designing future studies in similar reservoirs. Primary discussion centers around planning and results of a log-inject-log operation used as a prime method to determine the residual oil saturation. Several independent methods were used to calculate the residual oil saturation in the subject well in an interval between 12,910 ft (3935 m) and 12,020 ft (3938 m). In general, these numbers were in good agreement and indicated a residual oil saturation between 22% and 24%. 10 references.

  15. Reservoir Engineering Management Program

    Energy Technology Data Exchange (ETDEWEB)

    Howard, J.H.; Schwarz, W.J.

    1977-12-14

    The Reservoir Engineering Management Program being conducted at Lawrence Berkeley Laboratory includes two major tasks: 1) the continuation of support to geothermal reservoir engineering related work, started under the NSF-RANN program and transferred to ERDA at the time of its formation; 2) the development and subsequent implementation of a broad plan for support of research in topics related to the exploitation of geothermal reservoirs. This plan is now known as the GREMP plan. Both the NSF-RANN legacies and GREMP are in direct support of the DOE/DGE mission in general and the goals of the Resource and Technology/Resource Exploitation and Assessment Branch in particular. These goals are to determine the magnitude and distribution of geothermal resources and reduce risk in their exploitation through improved understanding of generically different reservoir types. These goals are to be accomplished by: 1) the creation of a large data base about geothermal reservoirs, 2) improved tools and methods for gathering data on geothermal reservoirs, and 3) modeling of reservoirs and utilization options. The NSF legacies are more research and training oriented, and the GREMP is geared primarily to the practical development of the geothermal reservoirs. 2 tabs., 3 figs.

  16. Application of fractal theory in refined reservoir description for EOR pilot area

    Energy Technology Data Exchange (ETDEWEB)

    Yue Li; Yonggang Duan; Yun Li; Yuan Lu

    1997-08-01

    A reliable reservoir description is essential to investigate scenarios for successful EOR pilot test. Reservoir characterization includes formation composition, permeability, porosity, reservoir fluids and other petrophysical parameters. In this study, various new tools have been applied to characterize Kilamayi conglomerate formation. This paper examines the merits of various statistical methods for recognizing rock property correlation in vertical columns and gives out methods to determine fractal dimension including R/S analysis and power spectral analysis. The paper also demonstrates that there is obvious fractal characteristics in conglomerate reservoirs of Kilamayi oil fields. Well log data in EOR pilot area are used to get distribution profile of parameters including permeability, porosity, water saturation and shale content.

  17. MAPPING OF RESERVOIR PROPERTIES AND FACIES THROUGH INTEGRATION OF STATIC AND DYNAMIC DATA

    Energy Technology Data Exchange (ETDEWEB)

    Albert C. Reynolds; Dean S. Oliver; Fengjun Zhang; Yannong Dong; Jan Arild Skjervheim; Ning Liu

    2003-01-01

    Knowledge of the distribution of permeability and porosity in a reservoir is necessary for the prediction of future oil production, estimation of the location of bypassed oil, and optimization of reservoir management. But while the volume of data that can potentially provide information on reservoir architecture and fluid distributions has increased enormously in the past decade, it is not yet possible to make use of all the available data in an integrated fashion. While it is relatively easy to generate plausible reservoir models that honor static data such as core, log, and seismic data, it is far more difficult to generate plausible reservoir models that honor dynamic data such as transient pressures, saturations, and flow rates. As a result, the uncertainty in reservoir properties is higher than it could be and reservoir management can not be optimized. The goal of this project is to develop computationally efficient automatic history matching techniques for generating geologically plausible reservoir models which honor both static and dynamic data. Solution of this problem is necessary for the quantification of uncertainty in future reservoir performance predictions and for the optimization of reservoir management. Facies (defined here as regions of relatively uniform petrophysical properties) are common features of all reservoirs. Because the flow properties of the various facies can vary greatly, knowledge of the location of facies boundaries is of utmost importance for the prediction of reservoir performance and for the optimization of reservoir management. When the boundaries between facies are fairly well known, but flow properties are poorly known, the average properties for all facies can be determined using traditional techniques. Traditional history matching honors dynamic data by adjusting petrophysical properties in large areas, but in the process of adjusting the reservoir model ignores the static data and often results in implausible reservoir

  18. 13C GIAO DFT calculation as a tool for configuration prediction of N-O group in saturated heterocyclic N-oxides

    Czech Academy of Sciences Publication Activity Database

    Pohl, Radek; Potmischil, F.; Dračínský, Martin; Vaněk, Václav; Slavětínská, Lenka; Buděšínský, Miloš

    2012-01-01

    Roč. 50, č. 6 (2012), s. 415-423 ISSN 0749-1581 R&D Projects: GA ČR GA203/09/1919 Institutional research plan: CEZ:AV0Z40550506 Keywords : NMR * 13C * 1H * saturated heterocyclic N-oxides * chemical shift calculations * DFT Subject RIV: CC - Organic Chemistry Impact factor: 1.528, year: 2012

  19. Massachusetts reservoir simulation tool—User’s manual

    Science.gov (United States)

    Levin, Sara B.

    2016-10-06

    IntroductionThe U.S. Geological Survey developed the Massachusetts Reservoir Simulation Tool to examine the effects of reservoirs on natural streamflows in Massachusetts by simulating the daily water balance of reservoirs. The simulation tool was developed to assist environmental managers to better manage water withdrawals in reservoirs and to preserve downstream aquatic habitats.

  20. Wave propagation in thermoelastic saturated porous medium

    Indian Academy of Sciences (India)

    the existence and propagation of four waves in the medium. Three of the waves are ... predicted infinite speed for propagation of ther- mal signals. Lord and ..... saturated reservoir rock (North-sea Sandstone) is chosen for the numerical model ...

  1. Noise and saturation properties of semiconductor quantum dot optical amplifiers

    DEFF Research Database (Denmark)

    Berg, Tommy Winther; Mørk, Jesper

    2002-01-01

    We present a detailed theoretical analysis of quantum dot optical amplifiers. Due to the presence of a reservoir of wetting layer states, the saturation and noise properties differ markedly from bulk or QW amplifiers and may be significantly improved.......We present a detailed theoretical analysis of quantum dot optical amplifiers. Due to the presence of a reservoir of wetting layer states, the saturation and noise properties differ markedly from bulk or QW amplifiers and may be significantly improved....

  2. Recombinant IFN-γ from the bank vole Myodes glareolus: a novel tool for research on rodent reservoirs of zoonotic pathogens.

    Science.gov (United States)

    Torelli, Francesca; Zander, Steffen; Ellerbrok, Heinz; Kochs, Georg; Ulrich, Rainer G; Klotz, Christian; Seeber, Frank

    2018-02-12

    Rodent species like Myodes glareolus and Microtus spp. are natural reservoirs for many zoonotic pathogens causing human diseases and are gaining increasing interest in the field of eco-immunology as candidate animal models. Despite their importance the lack of immunological reagents has hampered research in these animal species. Here we report the recombinant production and functional characterization of IFN-γ, a central mediator of host's innate and adaptive immune responses, from the bank vole M. glareolus. Soluble dimeric recMgIFN-γ was purified in high yield from Escherichia coli. Its activity on M. glareolus and Microtus arvalis kidney cell lines was assessed by immunofluorescent detection of nuclear translocation and phosphorylation of the transcription factor STAT1. RecMgIFN-γ also induced expression of an IFN-γ-regulated innate immunity gene. Inhibition of vesicular stomatitis virus replication in vole cells upon recMgIFN-γ treatment provided further evidence of its biological activity. Finally, we established a recMgIFN-γ-responsive bank vole reporter cell line that allows the sensitive titration of the cytokine activity via a bioluminescence reporter assay. Taken together, we report valuable tools for future investigations on the immune response against zoonotic pathogens in their natural animal hosts, which might foster the development of novel animal models.

  3. Improving reservoir history matching of EM heated heavy oil reservoirs via cross-well seismic tomography

    KAUST Repository

    Katterbauer, Klemens; Hoteit, Ibrahim

    2014-01-01

    process. While becoming a promising technology for heavy oil recovery, its effect on overall reservoir production and fluid displacements are poorly understood. Reservoir history matching has become a vital tool for the oil & gas industry to increase

  4. Future tools : from reservoir-embedded seismic to nanotechnological bitumen upgrading, scientists are unlocking new ways to extract and process fossil fuels

    Energy Technology Data Exchange (ETDEWEB)

    Collison, M.

    2006-10-15

    A review of reservoir monitoring tools and methods designed by research centres and high-tech firms in Alberta was presented. The National Centre for Upgrading Technology is currently examining the use of biological catalysts for partially upgrading bitumens at remote field production sites to lower the viscosity and density of heavy oil and reduce the environmental impacts associated with refining. Geo-scientists at the University of Calgary are using a combination of geophysical methods to improve coalbed methane and tight gas extraction processes. Research at the university has centred around multi-component seismic exploration, which uses a shear wave measurement to provide an image of the ground's rigidity and can discriminate between fluid types to produce different pictures of the subsurface. In addition to investigating the conversion of seismic waves to radio emissions, the university is also examining the integration of electromagnetic or electrical methods with seismic methods. Multi-component seismic is now being evaluated for the purpose of monitoring carbon dioxide (CO{sub 2}) enhanced recovery operations and sequestration at a demonstration project near Drayton Valley. Time-lapse monitoring will allow the research team to compare seismic surveys done months apart and identify changes caused by the growing pressure due to CO{sub 2} injection. It was suggested that a new nanotechnology fabrication facility created as part of the National Research Council (NRC) technology cluster will help scientists to discover new approaches in bitumen processing through a better understanding of the properties that cause bitumen to foul upgrading and transportation equipment. Many students are now using nanotechnology methods to understand how large bitumen molecules interact with catalyst surfaces. 4 figs.

  5. Shale gas reservoir characterization using LWD in real time

    Energy Technology Data Exchange (ETDEWEB)

    Han, S.Y.; Kok, J.C.L.; Tollefsen, E.M.; Baihly, J.D.; Malpani, R.; Alford, J. [Schlumberger Canada Ltd., Calgary, AB (Canada)

    2010-07-01

    Wireline logging programs are frequently used to evaluate vertical boreholes in shale gas plays. Data logged from the vertical hole are used to define reservoir profiles for the horizontal target window. The horizontal wells are then steered based on gamma ray measurements obtained using correlations against the vertical pilot wells. Logging-while-drilling tools are used in bottom hole assemblies (BHA) to ensure accurate well placement and to perform detailed reservoir characterizations across the target structure. The LWD measurements are also used to avoid hazards and enhance rates of penetration. LWD can also be used to enhance trajectory placement and provide an improved understanding of reservoirs. In this study, LWD measurements were conducted at a shale gas play in order to obtain accurate well placement, formation evaluation, and completion optimization processes. The study showed how LWD measurements can be used to optimize well completion and stimulation plans by considering well positions in relation to geological targets, reservoir property changes, hydrocarbon saturation disparity, and variations in geomechanical properties. 21 refs., 13 figs.

  6. Sensitivity analysis and economic optimization studies of inverted five-spot gas cycling in gas condensate reservoir

    OpenAIRE

    Shams Bilal; Yao Jun; Zhang Kai; Zhang Lei

    2017-01-01

    Gas condensate reservoirs usually exhibit complex flow behaviors because of propagation response of pressure drop from the wellbore into the reservoir. When reservoir pressure drops below the dew point in two phase flow of gas and condensate, the accumulation of large condensate amount occurs in the gas condensate reservoirs. Usually, the saturation of condensate accumulation in volumetric gas condensate reservoirs is lower than the critical condensate saturation that causes trapping of large...

  7. limnological study of the Guavio Reservoir (Colombia)

    International Nuclear Information System (INIS)

    Roldan, Gabriel; Bohorquez, Amparo; Catano, Ramiro; Ardila, Jorge I

    2000-01-01

    From September to December 1996, a limnological study of el Guavio reservoir from o to 100m deep was undertaken. Samples of plankton were taken and chlorophyll a determined. The study showed a well-mixed column of water. Dissolved oxygen remained 60% saturation at 100m deep. Values of phosphorus and nitrogen, as well chlorophyll was very low. Phytoplankton and zooplankton were diverse. The main problem of the reservoir is sediments coming from very erossionable surroundings

  8. Controls on Cementation in a Chalk Reservoir

    DEFF Research Database (Denmark)

    Meireles, Leonardo Teixeira Pinto; Hussein, A.; Welch, M.J.

    In this study, we identify different controls on cementation in a chalk reservoir. Biot’s coefficient, a measure of cementation, stiffness and strength in porous rocks, is calculated from logging data (bulk density and sonic Pwave velocity). We show that Biot’s coefficient is correlated...... to the water saturation of the Kraka reservoir and is partly controlled by its stratigraphic sub-units. While the direct causal relationship between Biot’s coefficient and water saturation cannot be extended for Biot’s coefficient and porosity, a correlation is also identified between the two, implying...

  9. Comparison of digital PCR platforms and semi-nested qPCR as a tool to determine the size of the HIV reservoir

    NARCIS (Netherlands)

    Bosman, K. J.; Nijhuis, M.; van Ham, P. M.; Wensing, A. M. J.; Vervisch, K.; Vandekerckhove, L.; De Spiegelaere, W.

    2015-01-01

    HIV persists in latently infected cells of patients on antiretroviral therapy (ART). This persistent proviral DNA reservoir is an important predictor of viral rebound upon therapy failure or interruption and forms a major obstacle towards cure. Accurate quantification of the low levels of persisting

  10. Reservoir engineering and hydrogeology

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    Summaries are included which show advances in the following areas: fractured porous media, flow in single fractures or networks of fractures, hydrothermal flow, hydromechanical effects, hydrochemical processes, unsaturated-saturated systems, and multiphase multicomponent flows. The main thrust of these efforts is to understand the movement of mass and energy through rocks. This has involved treating fracture rock masses in which the flow phenomena within both the fractures and the matrix must be investigated. Studies also address the complex coupling between aspects of thermal, hydraulic, and mechanical processes associated with a nuclear waste repository in a fractured rock medium. In all these projects, both numerical modeling and simulation, as well as field studies, were employed. In the theoretical area, a basic understanding of multiphase flow, nonisothermal unsaturated behavior, and new numerical methods have been developed. The field work has involved reservoir testing, data analysis, and case histories at a number of geothermal projects

  11. FRACTURED PETROLEUM RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Abbas Firoozabadi

    1999-06-11

    The four chapters that are described in this report cover a variety of subjects that not only give insight into the understanding of multiphase flow in fractured porous media, but they provide also major contribution towards the understanding of flow processes with in-situ phase formation. In the following, a summary of all the chapters will be provided. Chapter I addresses issues related to water injection in water-wet fractured porous media. There are two parts in this chapter. Part I covers extensive set of measurements for water injection in water-wet fractured porous media. Both single matrix block and multiple matrix blocks tests are covered. There are two major findings from these experiments: (1) co-current imbibition can be more efficient than counter-current imbibition due to lower residual oil saturation and higher oil mobility, and (2) tight fractured porous media can be more efficient than a permeable porous media when subjected to water injection. These findings are directly related to the type of tests one can perform in the laboratory and to decide on the fate of water injection in fractured reservoirs. Part II of Chapter I presents modeling of water injection in water-wet fractured media by modifying the Buckley-Leverett Theory. A major element of the new model is the multiplication of the transfer flux by the fractured saturation with a power of 1/2. This simple model can account for both co-current and counter-current imbibition and computationally it is very efficient. It can be orders of magnitude faster than a conventional dual-porosity model. Part II also presents the results of water injection tests in very tight rocks of some 0.01 md permeability. Oil recovery from water imbibition tests from such at tight rock can be as high as 25 percent. Chapter II discusses solution gas-drive for cold production from heavy-oil reservoirs. The impetus for this work is the study of new gas phase formation from in-situ process which can be significantly

  12. Sensitivity Analysis of Methane Hydrate Reservoirs: Effects of Reservoir Parameters on Gas Productivity and Economics

    Science.gov (United States)

    Anderson, B. J.; Gaddipati, M.; Nyayapathi, L.

    2008-12-01

    This paper presents a parametric study on production rates of natural gas from gas hydrates by the method of depressurization, using CMG STARS. Seven factors/parameters were considered as perturbations from a base-case hydrate reservoir description based on Problem 7 of the International Methane Hydrate Reservoir Simulator Code Comparison Study led by the Department of Energy and the USGS. This reservoir is modeled after the inferred properties of the hydrate deposit at the Prudhoe Bay L-106 site. The included sensitivity variables were hydrate saturation, pressure (depth), temperature, bottom-hole pressure of the production well, free water saturation, intrinsic rock permeability, and porosity. A two-level (L=2) Plackett-Burman experimental design was used to study the relative effects of these factors. The measured variable was the discounted cumulative gas production. The discount rate chosen was 15%, resulting in the gas contribution to the net present value of a reservoir. Eight different designs were developed for conducting sensitivity analysis and the effects of the parameters on the real and discounted production rates will be discussed. The breakeven price in various cases and the dependence of the breakeven price on the production parameters is given in the paper. As expected, initial reservoir temperature has the strongest positive effect on the productivity of a hydrate deposit and the bottom-hole pressure in the production well has the strongest negative dependence. Also resulting in a positive correlation is the intrinsic permeability and the initial free water of the formation. Negative effects were found for initial hydrate saturation (at saturations greater than 50% of the pore space) and the reservoir porosity. These negative effects are related to the available sensible heat of the reservoir, with decreasing productivity due to decreasing available sensible heat. Finally, we conclude that for the base case reservoir, the break-even price (BEP

  13. 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

  14. Gluon saturation in a saturated environment

    International Nuclear Information System (INIS)

    Kopeliovich, B. Z.; Potashnikova, I. K.; Schmidt, Ivan

    2011-01-01

    A bootstrap equation for self-quenched gluon shadowing leads to a reduced magnitude of broadening for partons propagating through a nucleus. Saturation of small-x gluons in a nucleus, which has the form of transverse momentum broadening of projectile gluons in pA collisions in the nuclear rest frame, leads to a modification of the parton distribution functions in the beam compared with pp collisions. In nucleus-nucleus collisions all participating nucleons acquire enhanced gluon density at small x, which boosts further the saturation scale. Solution of the reciprocity equations for central collisions of two heavy nuclei demonstrate a significant, up to several times, enhancement of Q sA 2 , in AA compared with pA collisions.

  15. An environmental data base for all Hydro-Quebec reservoirs

    International Nuclear Information System (INIS)

    Demers, C.

    1988-01-01

    Hydro-Quebec has created two management positions specifically for reservoirs, namely Reservoir Ecology Advisor and Reservoir Management Advisor. To assist management decisions, a means was required of bringing together all existing environmental information for each reservoir operated by Hydro-Quebec, including storage reservoirs, auxiliary reservoirs and forebays. A relational database using Reflex software was developed on a network of Macintosh computers. The database contains five blocks of information: general information, and physical, physiochemical, biologic and socioeconomic characteristics for each reservoir. Data will be collected on over 100 sites, and the tool will form the basis for developing a medium-range study program on reservoir ecology. The program must take into account the physical, biological and socioeconomic aspects of the environment, as well as the concerns of management personnel operating the reservoirs, the local population, reservoir users, and various government departments. 2 figs

  16. Metal and physico-chemical variations at a hydroelectric reservoir analyzed by Multivariate Analyses and Artificial Neural Networks: environmental management and policy/decision-making tools.

    Science.gov (United States)

    Cavalcante, Y L; Hauser-Davis, R A; Saraiva, A C F; Brandão, I L S; Oliveira, T F; Silveira, A M

    2013-01-01

    This paper compared and evaluated seasonal variations in physico-chemical parameters and metals at a hydroelectric power station reservoir by applying Multivariate Analyses and Artificial Neural Networks (ANN) statistical techniques. A Factor Analysis was used to reduce the number of variables: the first factor was composed of elements Ca, K, Mg and Na, and the second by Chemical Oxygen Demand. The ANN showed 100% correct classifications in training and validation samples. Physico-chemical analyses showed that water pH values were not statistically different between the dry and rainy seasons, while temperature, conductivity, alkalinity, ammonia and DO were higher in the dry period. TSS, hardness and COD, on the other hand, were higher during the rainy season. The statistical analyses showed that Ca, K, Mg and Na are directly connected to the Chemical Oxygen Demand, which indicates a possibility of their input into the reservoir system by domestic sewage and agricultural run-offs. These statistical applications, thus, are also relevant in cases of environmental management and policy decision-making processes, to identify which factors should be further studied and/or modified to recover degraded or contaminated water bodies. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Automatic NAA. Saturation activities

    International Nuclear Information System (INIS)

    Westphal, G.P.; Grass, F.; Kuhnert, M.

    2008-01-01

    A system for Automatic NAA is based on a list of specific saturation activities determined for one irradiation position at a given neutron flux and a single detector geometry. Originally compiled from measurements of standard reference materials, the list may be extended also by the calculation of saturation activities from k 0 and Q 0 factors, and f and α values of the irradiation position. A systematic improvement of the SRM approach is currently being performed by pseudo-cyclic activation analysis, to reduce counting errors. From these measurements, the list of saturation activities is recalculated in an automatic procedure. (author)

  18. Using reservoir engineering data to solve geological ambiguities : a case study of one of the Iranian carbonate reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Kord, S. [National Iranian South Oil Co. (Iran, Islamic Republic of)

    2006-07-01

    A fractured carbonate reservoir in southwest Iran was studied with reference to reserve estimation, risk analysis, material balance and recovery factor. The 40 km long and 4 km wide reservoir consists of 2 parts with crest depths of 3780 and 3749 mss respectively. The eastern part is smaller and more productive than the western part which has high water saturation and absolutely no production. Economic production from the reservoir began in 1977. By 2004, the cumulative production had reached 12.064 MMSTB. Of the 6 wells drilled, only 2 wells in the eastern part are productive. This study addressed the main uncertainty of whether the 2 parts of the reservoir are sealed or not. The reservoir is under-saturated but the current pressure is near saturation pressure. The reservoir is divided into the following 4 zones: zones 1 and 2 are productive and consist mainly of carbonate rocks; zone 3 has thin beds of sand and shale; and, zone 4 consists of layers of carbonate, shale, marn, and dolomite. Although there are no faults, mud loss suggests that the reservoir has hairline fractures. Oil in place and reserves were estimated for both parts based on calculated reservoir engineering parameters. Material balance calculations were then performed to analyze and simulate the reservoir. The communication between the 2 parts of the reservoir were examined according to core analysis, rock type, fluid characterization, pressure analysis, water-oil contacts, production history and petrophysical evaluations. The porosity was found to be the same in both parts, but the water saturation and net to gross ratios were different between the eastern and western parts. The petrophysical evaluation revealed that there is no communication between the two parts of the reservoir. 4 refs., 2 figs., 2 appendices.

  19. Refined reservoir description to maximize oil recovery

    International Nuclear Information System (INIS)

    Flewitt, W.E.

    1975-01-01

    To assure maximized oil recovery from older pools, reservoir description has been advanced by fully integrating original open-hole logs and the recently introduced interpretive techniques made available through cased-hole wireline saturation logs. A refined reservoir description utilizing normalized original wireline porosity logs has been completed in the Judy Creek Beaverhill Lake ''A'' Pool, a reefal carbonate pool with current potential productivity of 100,000 BOPD and 188 active wells. Continuous porosity was documented within a reef rim and cap while discontinuous porous lenses characterized an interior lagoon. With the use of pulsed neutron logs and production data a separate water front and pressure response was recognized within discrete environmental units. The refined reservoir description aided in reservoir simulation model studies and quantifying pool performance. A pattern water flood has now replaced the original peripheral bottom water drive to maximize oil recovery

  20. Minero-chemical composition as environmental quality assessment tool of an artificial water reservoir: the case of the "Pietra del Pertusillo" lake (Basilicata, Italia)

    Science.gov (United States)

    fortunato, elisabetta; mongelli, giovanni; paternoster, michele; sinisi, rosa

    2016-04-01

    The Pietra del Pertusillo fresh-water reservoir is an artificial lake located in the High Agri River Valley (Basilicata); its dam was completed in 1963 for producing hydroelectric energy and providing water for human use to Puglia and Basilicata southern Italian regions (approximately 2 million people). Pertusillo lake lies within a national park because of the presence of many special protected areas. This reservoir is a natural laboratory for assessing the sediment pollution from human activities, including: waste-water treatment plants, landfills, farms, treatment oil plant, plastics and other industrial activities. In addition, the Pertusillo reservoir is located in the area of the largest oil field of continental Europe. This anthropogenic pressure may thus represent an impact factor on the environmental equilibrium and consequently the knowledge and control on their quality represents a relevant environmental challenge. This study reports the preliminary results of a multidisciplinary (sedimentological, mineralogical, geochemical) PhD research focused on the analysis of the lacustrine sediments filling the Pietra del Pertusillo fresh-water reservoir. The lakes and its sediments represent the natural sink for nutrients and possible pollutants which tend to accumulate in relation to the nature and composition of the solid matrix but also the concentration and characteristics of the substances themselves. Moreover the deeper sediments, deposited under undisturbed condition, represent the "historical memory" of the ecosystem. Sub-aqueous lake sediments were investigated in May 2014, sampled using a small platform and a gravity corer (UWITEC, Austria) of 90 mm diameter which allowed to drill 19 cores up to 2 m long from the sediment/water interface. Successively cores were studied and described by using facies analysis techniques; a large number of core samples (147) were collected from the working half of each core, stored in HPDE containers, and frozen at -20

  1. Integration of rock typing methods for carbonate reservoir characterization

    International Nuclear Information System (INIS)

    Aliakbardoust, E; Rahimpour-Bonab, H

    2013-01-01

    Reservoir rock typing is the most important part of all reservoir modelling. For integrated reservoir rock typing, static and dynamic properties need to be combined, but sometimes these two are incompatible. The failure is due to the misunderstanding of the crucial parameters that control the dynamic behaviour of the reservoir rock and thus selecting inappropriate methods for defining static rock types. In this study, rock types were defined by combining the SCAL data with the rock properties, particularly rock fabric and pore types. First, air-displacing-water capillary pressure curues were classified because they are representative of fluid saturation and behaviour under capillary forces. Next the most important rock properties which control the fluid flow and saturation behaviour (rock fabric and pore types) were combined with defined classes. Corresponding petrophysical properties were also attributed to reservoir rock types and eventually, defined rock types were compared with relative permeability curves. This study focused on representing the importance of the pore system, specifically pore types in fluid saturation and entrapment in the reservoir rock. The most common tests in static rock typing, such as electrofacies analysis and porosity–permeability correlation, were carried out and the results indicate that these are not appropriate approaches for reservoir rock typing in carbonate reservoirs with a complicated pore system. (paper)

  2. Increasing Waterflooding Reservoirs in the Wilmington Oil Field through Improved Reservoir Characterization and Reservoir Management

    Energy Technology Data Exchange (ETDEWEB)

    Koerner, Roy; Clarke, Don; Walker, Scott

    1999-11-09

    The objectives of this quarterly report was to summarize the work conducted under each task during the reporting period April - June 1998 and to report all technical data and findings as specified in the ''Federal Assistance Reporting Checklist''. The main objective of this project is the transfer of technologies, methodologies, and findings developed and applied in this project to other operators of Slope and Basin Clastic Reservoirs. This project will study methods to identify sands with high remaining oil saturation and to recomplete existing wells using advanced completion technology.

  3. Reservoir Identification: Parameter Characterization or Feature Classification

    Science.gov (United States)

    Cao, J.

    2017-12-01

    The ultimate goal of oil and gas exploration is to find the oil or gas reservoirs with industrial mining value. Therefore, the core task of modern oil and gas exploration is to identify oil or gas reservoirs on the seismic profiles. Traditionally, the reservoir is identify by seismic inversion of a series of physical parameters such as porosity, saturation, permeability, formation pressure, and so on. Due to the heterogeneity of the geological medium, the approximation of the inversion model and the incompleteness and noisy of the data, the inversion results are highly uncertain and must be calibrated or corrected with well data. In areas where there are few wells or no well, reservoir identification based on seismic inversion is high-risk. Reservoir identification is essentially a classification issue. In the identification process, the underground rocks are divided into reservoirs with industrial mining value and host rocks with non-industrial mining value. In addition to the traditional physical parameters classification, the classification may be achieved using one or a few comprehensive features. By introducing the concept of seismic-print, we have developed a new reservoir identification method based on seismic-print analysis. Furthermore, we explore the possibility to use deep leaning to discover the seismic-print characteristics of oil and gas reservoirs. Preliminary experiments have shown that the deep learning of seismic data could distinguish gas reservoirs from host rocks. The combination of both seismic-print analysis and seismic deep learning is expected to be a more robust reservoir identification method. The work was supported by NSFC under grant No. 41430323 and No. U1562219, and the National Key Research and Development Program under Grant No. 2016YFC0601

  4. 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

  5. Reservoir Changes Derived from Seismic Observations at The Geysers Geothermal Field, CA, USA

    Science.gov (United States)

    Gritto, R.; Jarpre, S.

    2012-04-01

    Induced seismicity associated with the exploitation of geothermal fields is used as a tool to characterize and delineate changes associated with injection and production of fluids from the reservoir. At the same time public concern of felt seismicity has led to objections against the operation of geothermal reservoirs in close proximity to population centers. Production at the EGS sites in Basel (Switzerland) was stopped after renewed seismicity caused concern and objection from the public in the city. Operations in other geothermal reservoirs had to be scaled back or interrupted due to an unexpected increase in seismicity (Soultz-sous-forêt, France, Berlín, El Salvador). As a consequence of these concerns and in order to optimize the use of induced seismicity for reservoir engineering purposes, it becomes imperative to understand the relationship between seismic events and stress changes in the reservoir. We will address seismicity trends at The Geysers Geothermal Reservoir, CA USA, to understand the role of historical seismicity associated with past injection of water and/or production of steam. Our analysis makes use of a comprehensive database of earthquakes and associated phase arrivals from 2004 to 2011. A high-precision sub-set of the earthquake data was selected to analyze temporal changes in seismic velocities and Vp/Vs-ratio throughout the whole reservoir. We find relatively low Vp/Vs values in 2004 suggestive of a vapor dominated reservoir. With passing time, however, the observed temporal increase in Vp/Vs, coupled with a decrease in P- and S-wave velocities suggests the presence of fluid-filled fractured rock. Considering the start of a continuous water injection project in 2004, it can be concluded that the fluid saturation of the reservoir has successfully recovered. Preliminary results of 3-D velocity inversions of seismic data appear to corroborate earlier findings that the lowest Vp/Vs estimates are observed in the center of the reservoir

  6. Application of integrated reservoir management and reservoir characterization to optimize infill drilling, Class II

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-03-16

    The major purpose of this project was to demonstrate the use of cost effective reservoir characterization and management tools that will be helpful to both independent and major operators for the optimal development of heterogeneous, low permeability carbonate reservoirs such as the North Robertson (Clearfork) Unit.

  7. ADVANCED TECHNIQUES FOR RESERVOIR SIMULATION AND MODELING OF NONCONVENTIONAL WELLS

    Energy Technology Data Exchange (ETDEWEB)

    Louis J. Durlofsky; Khalid Aziz

    2004-08-20

    Nonconventional wells, which include horizontal, deviated, multilateral and ''smart'' wells, offer great potential for the efficient management of oil and gas reservoirs. These wells are able to contact larger regions of the reservoir than conventional wells and can also be used to target isolated hydrocarbon accumulations. The use of nonconventional wells instrumented with downhole inflow control devices allows for even greater flexibility in production. Because nonconventional wells can be very expensive to drill, complete and instrument, it is important to be able to optimize their deployment, which requires the accurate prediction of their performance. However, predictions of nonconventional well performance are often inaccurate. This is likely due to inadequacies in some of the reservoir engineering and reservoir simulation tools used to model and optimize nonconventional well performance. A number of new issues arise in the modeling and optimization of nonconventional wells. For example, the optimal use of downhole inflow control devices has not been addressed for practical problems. In addition, the impact of geological and engineering uncertainty (e.g., valve reliability) has not been previously considered. In order to model and optimize nonconventional wells in different settings, it is essential that the tools be implemented into a general reservoir simulator. This simulator must be sufficiently general and robust and must in addition be linked to a sophisticated well model. Our research under this five year project addressed all of the key areas indicated above. The overall project was divided into three main categories: (1) advanced reservoir simulation techniques for modeling nonconventional wells; (2) improved techniques for computing well productivity (for use in reservoir engineering calculations) and for coupling the well to the simulator (which includes the accurate calculation of well index and the modeling of multiphase flow

  8. Gluon Saturation and EIC

    Energy Technology Data Exchange (ETDEWEB)

    Sichtermann, Ernst

    2016-12-15

    The fundamental structure of nucleons and nuclear matter is described by the properties and dynamics of quarks and gluons in quantum chromodynamics. Electron-nucleon collisions are a powerful method to study this structure. As one increases the energy of the collisions, the interaction process probes regions of progressively higher gluon density. This density must eventually saturate. An high-energy polarized Electron-Ion Collider (EIC) has been proposed to observe and study the saturated gluon density regime. Selected measurements will be discussed, following a brief introduction.

  9. Exact expression for the effective acoustics of patchy-saturated rocks

    NARCIS (Netherlands)

    Vogelaar, B.; Smeulders, D.M.J.; Harris, J.

    2010-01-01

    Seismic effects of a partially gas-saturated subsurface have been known for many years. For example, patches of nonuniform saturation occur at the gas-oil and gas-water contacts in hydrocarbon reservoirs. Open-pore boundary conditions are applied to the quasi-static Biot equations of poroelasticity

  10. SILTATION IN RESERVOIRS

    African Journals Online (AJOL)

    Keywords: reservoir model, siltation, sediment, catchment, sediment transport. 1. Introduction. Sediment ... rendered water storage structures useless in less than 25 years. ... reservoir, thus reducing the space available for water storage and ...

  11. Reservoir fisheries of Asia

    International Nuclear Information System (INIS)

    Silva, S.S. De.

    1990-01-01

    At a workshop on reservoir fisheries research, papers were presented on the limnology of reservoirs, the changes that follow impoundment, fisheries management and modelling, and fish culture techniques. Separate abstracts have been prepared for three papers from this workshop

  12. The Larderello-Travale geothermal field (Tuscany, central Italy): seismic imaging as a tool for the analysis and assessment of the reservoir

    Science.gov (United States)

    Anselmi, M.; Piccinini, D.; Casini, M.; Spinelli, E.; Ciuffi, S.; De Gori, P.; Saccorotti, G.; chiarabba, C.

    2013-12-01

    The Larderello-Travale is a geothermal field with steam-dominated reservoirs (1300 kg/s of steam and running capacity of 700 MWatt), which is exploited by Enel Green Power, the electric company involved in the renewable energy and resources. The area is located in the pre-Apennine belt of southern Tuscany and has been characterized by extensional tectonics and sporadic events of compression. The result of these tectonic phases is a block-faulting structure with NW-SE trending horsts and basins. Small post-orogenic granitic stocks were emplaced along the main axes of the uplifted structures, causing the anomalous heat flow that marks the area. Results from seismic reflection lines crossing the study area show the presence of the top of a discontinuous reflector in the 3-8 km depth range and with thickness up to ~1 km, referred to as the ';K-horizon'. In this framework we present the results obtained by the processing of a high-quality local earthquake dataset, recorded during the 1977-2005 time interval by the seismic network managed by Enel Green Power. The geothermal target volume was parameterized using a 3-D grid for both Vp (P-wave velocities) and Qp (quality factor of P-waves). Grid nodes are spaced by 5 and 2 km along the two horizontal and vertical directions, respectively. The tomographic Vp images show an overall velocity increase with depth down to the K-horizon. Conversely, some characteristic features are observed in the distribution of Qp anomalies, with high Qp values in the 300-600 range located just below the K-horizon. The relationship between K-horizon and the seismicity distribution doesn't show a clear and homogeneous coupling: the bulk of re-located earthquakes are placed either above or below the top of the K-horizon in the shallower 8 km depth, with an abrupt cut-off at depth greater than 10 km. We then present the preliminary result from the G.A.P.S.S. (Geothermal Area Passive Seismic Sources) experiment, a project that the Istituto

  13. 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

  14. Large reservoirs: Chapter 17

    Science.gov (United States)

    Miranda, Leandro E.; Bettoli, Phillip William

    2010-01-01

    Large impoundments, defined as those with surface area of 200 ha or greater, are relatively new aquatic ecosystems in the global landscape. They represent important economic and environmental resources that provide benefits such as flood control, hydropower generation, navigation, water supply, commercial and recreational fisheries, and various other recreational and esthetic values. Construction of large impoundments was initially driven by economic needs, and ecological consequences received little consideration. However, in recent decades environmental issues have come to the forefront. In the closing decades of the 20th century societal values began to shift, especially in the developed world. Society is no longer willing to accept environmental damage as an inevitable consequence of human development, and it is now recognized that continued environmental degradation is unsustainable. Consequently, construction of large reservoirs has virtually stopped in North America. Nevertheless, in other parts of the world construction of large reservoirs continues. The emergence of systematic reservoir management in the early 20th century was guided by concepts developed for natural lakes (Miranda 1996). However, we now recognize that reservoirs are different and that reservoirs are not independent aquatic systems inasmuch as they are connected to upstream rivers and streams, the downstream river, other reservoirs in the basin, and the watershed. Reservoir systems exhibit longitudinal patterns both within and among reservoirs. Reservoirs are typically arranged sequentially as elements of an interacting network, filter water collected throughout their watersheds, and form a mosaic of predictable patterns. Traditional approaches to fisheries management such as stocking, regulating harvest, and in-lake habitat management do not always produce desired effects in reservoirs. As a result, managers may expend resources with little benefit to either fish or fishing. Some locally

  15. Diffuser Operations at Spring Hollow Reservoir

    OpenAIRE

    Gantzer, Paul Anthony

    2002-01-01

    Stratification is a natural occurrence in deep lakes and reservoirs. This phenomenon results in two distinct layers, the warmer, less dense epilimnion on top and the colder, denser, hypolimnion on the bottom. The epilimnion remains saturated with dissolved oxygen (DO) from mass transfer with the atmosphere, while the hypolimnion continues to undergo oxygen-depleting processes. During seasons of high oxygen demand the hypolimnion often becomes anoxic and results in the release of compounds,...

  16. Electrical anisotropy of gas hydrate-bearing sand reservoirs in the Gulf of Mexico

    Science.gov (United States)

    Cook, Anne E.; Anderson, Barbara I.; Rasmus, John; Sun, Keli; Li, Qiming; Collett, Timothy S.; Goldberg, David S.

    2012-01-01

    We present new results and interpretations of the electricalanisotropy and reservoir architecture in gashydrate-bearingsands using logging data collected during the Gulf of MexicoGasHydrate Joint Industry Project Leg II. We focus specifically on sandreservoirs in Hole Alaminos Canyon 21 A (AC21-A), Hole Green Canyon 955 H (GC955-H) and Hole Walker Ridge 313 H (WR313-H). Using a new logging-while-drilling directional resistivity tool and a one-dimensional inversion developed by Schlumberger, we resolve the resistivity of the current flowing parallel to the bedding, R| and the resistivity of the current flowing perpendicular to the bedding, R|. We find the sandreservoir in Hole AC21-A to be relatively isotropic, with R| and R| values close to 2 Ω m. In contrast, the gashydrate-bearingsandreservoirs in Holes GC955-H and WR313-H are highly anisotropic. In these reservoirs, R| is between 2 and 30 Ω m, and R| is generally an order of magnitude higher. Using Schlumberger's WebMI models, we were able to replicate multiple resistivity measurements and determine the formation resistivity the gashydrate-bearingsandreservoir in Hole WR313-H. The results showed that gashydrate saturations within a single reservoir unit are highly variable. For example, the sand units in Hole WR313-H contain thin layers (on the order of 10-100 cm) with varying gashydrate saturations between 15 and 95%. Our combined modeling results clearly indicate that the gashydrate-bearingsandreservoirs in Holes GC955-H and WR313-H are highly anisotropic due to varying saturations of gashydrate forming in thin layers within larger sand units.

  17. Low-cost but accurate radioactive logging for determining gas saturation in a reservior

    International Nuclear Information System (INIS)

    Neuman, C.H.

    1976-01-01

    A method is disclosed for determining gas saturation in a petroleum reservoir using logging signals indirectly related to the abundances of oxygen and carbon nuclei in the reservoir rock. The first step of the invention is to record first and second logs sensitive to the abundance of oxygen and carbon nuclei, respectively, after the region surrounding the well bore is caused to have fluid saturations representative of the bulk of the reservoir. A purposeful change is then made in the fluid saturations in the region surrounding the well bore by injecting a liquid capable of displacing substantially all of the original fluids. The logs are recorded a second time. The displacing fluid is then itself displaced by brine, and a third suite of logs is recorded. The total fluid and oil saturations are then determined from the differences between respective corresponding logs and from known fractional volume oxygen and carbon contents of the reservoir brine and oil and the first injected liquid. Gas saturation is then calculated from differences between total fluid and oil saturation values. It is not necessary that the log responses be independent of the material in the borehole, the casing, the casing cement, or the reservoir rock. It is only necessary that changes in formation fluids content cause proportional changes in log responses. 7 Claims, 4 Figures

  18. Designing a reservoir flow rate experiment for the GOM hydrate JIP leg 2 LWD drilling

    Energy Technology Data Exchange (ETDEWEB)

    Gullapalli, I.; Silpngarmlert, S.; Reik, B.; Kamal, M.; Jones, E. [Chevron Energy Technology Co., San Ramon, CA (United States); Moridis, G. [Lawrence Berkeley National Laboratories, CA (United States); Collett, T. [United States Geological Survey, Reston, VA (United States)

    2008-07-01

    Studies have indicated that the Gulf of Mexico may contain large deep sea hydrate deposits. This paper provided details of short-term production profiles obtained from a geological model of hydrate deposits located in the Gulf area. A well test analysis tool was used to obtain the production parameters. Pressure transients from numerical simulations of various well test designs were used to provide estimates of important flow parameters. The aim of the study was to determine the type and duration of a well test capable of providing data to support the accurate modeling of gas hydrate deposits. Parameters studied in the test included the effects of permeability and hydrate saturation as a function of the duration of the flow test. Results indicated that production using a constant bottom hole pressure is an appropriate method of impacting hydrate dissociation by depressurization. However, changes in transient pressure plots could not be characterized in order to identify regions of varying saturation levels. Results suggested that the rate of effective water to effective gas was higher than rates obtained from relative permeability relations due to low gas saturation levels. Fluid saturation regions were in areas of low confidence in relative permeability curves. However, it was not possible to calculate absolute permeability of the reservoir for systems with short production periods. Further studies are needed to determine effective permeability using history matching and a hydrate simulator. 8 refs., 4 tabs., 27 figs.

  19. Optimal Operation of Hydropower Reservoirs under Climate Change: The Case of Tekeze Reservoir, Eastern Nile

    Directory of Open Access Journals (Sweden)

    Fikru Fentaw Abera

    2018-03-01

    Full Text Available Optimal operation of reservoirs is very essential for water resource planning and management, but it is very challenging and complicated when dealing with climate change impacts. The objective of this paper was to assess existing and future hydropower operation at the Tekeze reservoir in the face of climate change. In this study, a calibrated and validated Soil and Water Assessment Tool (SWAT was used to model runoff inflow into the Tekeze hydropower reservoir under present and future climate scenarios. Inflow to the reservoir was simulated using hydro-climatic data from an ensemble of downscaled climate data based on the Coordinated Regional climate Downscaling Experiment over African domain (CORDEX-Africa with Coupled Intercomparison Project Phase 5 (CMIP5 simulations under Representative Concentration Pathway (RCP4.5 and RCP8.5 climate scenarios. Observed and projected inflows to Tekeze hydropower reservoir were used as input to the US Army Corps of Engineer’s Reservoir Evaluation System Perspective Reservoir Model (HEC-ResPRM, a reservoir operation model, to optimize hydropower reservoir release, storage and pool level. Results indicated that climate change has a clear impact on reservoir inflow and showed increase in annual and monthly inflow into the reservoir except in dry months from May to June under RCP4.5 and RCP8.5 climate scenarios. HEC-ResPRM optimal operation results showed an increase in Tekeze reservoir power storage potential up to 25% and 30% under RCP4.5 and RCP8.5 climate scenarios, respectively. This implies that Tekeze hydropower production will be affected by climate change. This analysis can be used by water resources planners and mangers to develop reservoir operation techniques considering climate change impact to increase power production.

  20. Improving reservoir history matching of EM heated heavy oil reservoirs via cross-well seismic tomography

    KAUST Repository

    Katterbauer, Klemens

    2014-01-01

    Enhanced recovery methods have become significant in the industry\\'s drive to increase recovery rates from oil and gas reservoirs. For heavy oil reservoirs, the immobility of the oil at reservoir temperatures, caused by its high viscosity, limits the recovery rates and strains the economic viability of these fields. While thermal recovery methods, such as steam injection or THAI, have extensively been applied in the field, their success has so far been limited due to prohibitive heat losses and the difficulty in controlling the combustion process. Electromagnetic (EM) heating via high-frequency EM radiation has attracted attention due to its wide applicability in different environments, its efficiency, and the improved controllability of the heating process. While becoming a promising technology for heavy oil recovery, its effect on overall reservoir production and fluid displacements are poorly understood. Reservoir history matching has become a vital tool for the oil & gas industry to increase recovery rates. Limited research has been undertaken so far to capture the nonlinear reservoir dynamics and significantly varying flow rates for thermally heated heavy oil reservoir that may notably change production rates and render conventional history matching frameworks more challenging. We present a new history matching framework for EM heated heavy oil reservoirs incorporating cross-well seismic imaging. Interfacing an EM heating solver to a reservoir simulator via Andrade’s equation, we couple the system to an ensemble Kalman filter based history matching framework incorporating a cross-well seismic survey module. With increasing power levels and heating applied to the heavy oil reservoirs, reservoir dynamics change considerably and may lead to widely differing production forecasts and increased uncertainty. We have shown that the incorporation of seismic observations into the EnKF framework can significantly enhance reservoir simulations, decrease forecasting

  1. Three types of gas hydrate reservoirs in the Gulf of Mexico identified in LWD data

    Science.gov (United States)

    Lee, Myung Woong; Collett, Timothy S.

    2011-01-01

    High quality logging-while-drilling (LWD) well logs were acquired in seven wells drilled during the Gulf of Mexico Gas Hydrate Joint Industry Project Leg II in the spring of 2009. These data help to identify three distinct types of gas hydrate reservoirs: isotropic reservoirs in sands, vertical fractured reservoirs in shale, and horizontally layered reservoirs in silty shale. In general, most gas hydratebearing sand reservoirs exhibit isotropic elastic velocities and formation resistivities, and gas hydrate saturations estimated from the P-wave velocity agree well with those from the resistivity. However, in highly gas hydrate-saturated sands, resistivity-derived gas hydrate-saturation estimates appear to be systematically higher by about 5% over those estimated by P-wave velocity, possibly because of the uncertainty associated with the consolidation state of gas hydrate-bearing sands. Small quantities of gas hydrate were observed in vertical fractures in shale. These occurrences are characterized by high formation resistivities with P-wave velocities close to those of water-saturated sediment. Because the formation factor varies significantly with respect to the gas hydrate saturation for vertical fractures at low saturations, an isotropic analysis of formation factor highly overestimates the gas hydrate saturation. Small quantities of gas hydrate in horizontal layers in shale are characterized by moderate increase in P-wave velocities and formation resistivities and either measurement can be used to estimate gas hydrate saturations.

  2. Static reservoir modeling of the Bahariya reservoirs for the oilfields development in South Umbarka area, Western Desert, Egypt

    Science.gov (United States)

    Abdel-Fattah, Mohamed I.; Metwalli, Farouk I.; Mesilhi, El Sayed I.

    2018-02-01

    3D static reservoir modeling of the Bahariya reservoirs using seismic and wells data can be a relevant part of an overall strategy for the oilfields development in South Umbarka area (Western Desert, Egypt). The seismic data is used to build the 3D grid, including fault sticks for the fault modeling, and horizon interpretations and surfaces for horizon modeling. The 3D grid is the digital representation of the structural geology of Bahariya Formation. When we got a reasonably accurate representation, we fill the 3D grid with facies and petrophysical properties to simulate it, to gain a more precise understanding of the reservoir properties behavior. Sequential Indicator Simulation (SIS) and Sequential Gaussian Simulation (SGS) techniques are the stochastic algorithms used to spatially distribute discrete reservoir properties (facies) and continuous reservoir properties (shale volume, porosity, and water saturation) respectively within the created 3D grid throughout property modeling. The structural model of Bahariya Formation exhibits the trapping mechanism which is a fault assisted anticlinal closure trending NW-SE. This major fault breaks the reservoirs into two major fault blocks (North Block and South Block). Petrophysical models classified Lower Bahariya reservoir as a moderate to good reservoir rather than Upper Bahariya reservoir in terms of facies, with good porosity and permeability, low water saturation, and moderate net to gross. The Original Oil In Place (OOIP) values of modeled Bahariya reservoirs show hydrocarbon accumulation in economic quantity, considering the high structural dips at the central part of South Umbarka area. The powerful of 3D static modeling technique has provided a considerable insight into the future prediction of Bahariya reservoirs performance and production behavior.

  3. On the propagation of a coupled saturation and pressure front

    Energy Technology Data Exchange (ETDEWEB)

    Vasco, D. W.

    2010-12-01

    Using an asymptotic technique, valid for a medium with smoothly varying heterogeneity, I derive an expression for the velocity of a propagating, coupled saturation and pressure front. Due to the nonlinearity of the governing equations, the velocity of the propagating front depends upon the magnitude of the saturation and pressure changes across the front in addition to the properties of the medium. Thus, the expression must be evaluated in conjunction with numerical reservoir simulation. The propagation of the two-phase front is governed by the background saturation distribution, the saturation-dependent component of the fluid mobility, the porosity, the permeability, the capillary pressure function, the medium compressibility, and the ratio of the slopes of the relative permeability curves. Numerical simulation of water injection into a porous layer saturated with a nonaqueous phase liquid indicates that two modes of propagation are important. The fastest mode of propagation is a pressure-dominated disturbance that travels through the saturated layer. This is followed, much later, by a coupled mode with a large saturation change. These two modes are also observed in a simulation using a heterogeneous porous layer. A comparison between the propagation times estimated from the results of the numerical simulation and predictions from the asymptotic expression indicates overall agreement.

  4. 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.

  5. Transport of reservoir fines

    DEFF Research Database (Denmark)

    Yuan, Hao; Shapiro, Alexander; Stenby, Erling Halfdan

    Modeling transport of reservoir fines is of great importance for evaluating the damage of production wells and infectivity decline. The conventional methodology accounts for neither the formation heterogeneity around the wells nor the reservoir fines’ heterogeneity. We have developed an integral...... dispersion equation in modeling the transport and the deposition of reservoir fines. It successfully predicts the unsymmetrical concentration profiles and the hyperexponential deposition in experiments....

  6. Saturated Zone Colloid Transport

    International Nuclear Information System (INIS)

    H. S. Viswanathan

    2004-01-01

    This scientific analysis provides retardation factors for colloids transporting in the saturated zone (SZ) and the unsaturated zone (UZ). These retardation factors represent the reversible chemical and physical filtration of colloids in the SZ. The value of the colloid retardation factor, R col is dependent on several factors, such as colloid size, colloid type, and geochemical conditions (e.g., pH, Eh, and ionic strength). These factors are folded into the distributions of R col that have been developed from field and experimental data collected under varying geochemical conditions with different colloid types and sizes. Attachment rate constants, k att , and detachment rate constants, k det , of colloids to the fracture surface have been measured for the fractured volcanics, and separate R col uncertainty distributions have been developed for attachment and detachment to clastic material and mineral grains in the alluvium. Radionuclides such as plutonium and americium sorb mostly (90 to 99 percent) irreversibly to colloids (BSC 2004 [DIRS 170025], Section 6.3.3.2). The colloid retardation factors developed in this analysis are needed to simulate the transport of radionuclides that are irreversibly sorbed onto colloids; this transport is discussed in the model report ''Site-Scale Saturated Zone Transport'' (BSC 2004 [DIRS 170036]). Although it is not exclusive to any particular radionuclide release scenario, this scientific analysis especially addresses those scenarios pertaining to evidence from waste-degradation experiments, which indicate that plutonium and americium may be irreversibly attached to colloids for the time scales of interest. A section of this report will also discuss the validity of using microspheres as analogs to colloids in some of the lab and field experiments used to obtain the colloid retardation factors. In addition, a small fraction of colloids travels with the groundwater without any significant retardation. Radionuclides irreversibly

  7. Stabilization of Neutral Systems with Saturating Actuators

    Directory of Open Access Journals (Sweden)

    F. El Haoussi

    2012-01-01

    to determine stabilizing state-feedback controllers with large domain of attraction, expressed as linear matrix inequalities, readily implementable using available numerical tools and with tuning parameters that make possible to select the most adequate solution. These conditions are derived by using a Lyapunov-Krasovskii functional on the vertices of the polytopic description of the actuator saturations. Numerical examples demonstrate the effectiveness of the proposed technique.

  8. Fractured reservoir discrete feature network technologies. Final report, March 7, 1996 to September 30, 1998

    Energy Technology Data Exchange (ETDEWEB)

    Dershowitz, William S.; Einstein, Herbert H.; LaPoint, Paul R.; Eiben, Thorsten; Wadleigh, Eugene; Ivanova, Violeta

    1998-12-01

    This report summarizes research conducted for the Fractured Reservoir Discrete Feature Network Technologies Project. The five areas studied are development of hierarchical fracture models; fractured reservoir compartmentalization, block size, and tributary volume analysis; development and demonstration of fractured reservoir discrete feature data analysis tools; development of tools for data integration and reservoir simulation through application of discrete feature network technologies for tertiary oil production; quantitative evaluation of the economic value of this analysis approach.

  9. Integrated reservoir assessment and characterization: Final report, October 1, 1985--September 30, 1988

    Energy Technology Data Exchange (ETDEWEB)

    Honarpour, M.; Szpakiewicz, M.; Sharma, B.; Chang, Ming-Ming; Schatzinger, R.; Jackson, S.; Tomutsa, L.; Maerefat, N.

    1989-05-01

    This report covers the development of a generic approach to reservoir characterization, the preliminary studies leading to the selection of an appropriate depositional system for detailed study, the application of outcrop studies to quantified reservoir characterization, and the construction of a quantified geological/engineering model used to screen the effects and scales of various geological heterogeneities within a reservoir. These heterogeneities result in large production/residual oil saturation contrasts over small distances. 36 refs., 124 figs., 38 tabs.

  10. 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.

  11. Lithological controls on gas hydrate saturation: Insights from signal classification of NMR downhole data

    Science.gov (United States)

    Bauer, Klaus; Kulenkampff, Johannes; Henninges, Jan; Spangenberg, Erik

    2016-04-01

    Nuclear magnetic resonance (NMR) downhole data are analyzed with a new strategy to study gas hydrate-bearing sediments in the Mackenzie Delta (NW Canada). NMR logging is a powerful tool to study geological reservoir formations. The measurements are based on interactions between the magnetic moments of protons in geological formation water and an external magnetic field. Inversion of the measured raw data provides so-called transverse relaxation time (T2) distribution curves or spectra. Different parts of the T2 curve are related with distinct pore radii and corresponding fluid components. A common practice in the analysis of T2 distribution curves is to extract single-valued parameters such as apparent total porosity. Moreover, the derived total NMR apparent porosity and the gamma-gamma density log apparent porosity can be combined to estimate gas hydrate saturation in hydrate-bearing sediments. To avoid potential loss of information, in our new approach we analyze the entire T2 distribution curves as quasi-continuous signals to characterize the rock formation. The approach is applied to NMR data measured in gas hydrate research well Mallik 5L-38. We use self-organizing maps, a neural network clustering technique, to subdivide the data set of NMR T2 distribution curves into classes with a similar and distinctive signal shape. The method includes (1) preparation of data vectors, (2) unsupervised learning, (3) cluster definition, and (4) classification and depth mapping of all NMR signals. Each signal class thus represents a specific pore size distribution which can be interpreted in terms of distinct lithologies and reservoir types. A key step in the interpretation strategy is to reconcile the NMR classes with other log data not considered in the clustering analysis, such as gamma ray, photo-electric factor, hydrate saturation, and other logs. Our results defined six main lithologies within the target zone. Gas hydrate layers were recognized by their low signal

  12. Saturated Zone Colloid Transport

    Energy Technology Data Exchange (ETDEWEB)

    H. S. Viswanathan

    2004-10-07

    This scientific analysis provides retardation factors for colloids transporting in the saturated zone (SZ) and the unsaturated zone (UZ). These retardation factors represent the reversible chemical and physical filtration of colloids in the SZ. The value of the colloid retardation factor, R{sub col} is dependent on several factors, such as colloid size, colloid type, and geochemical conditions (e.g., pH, Eh, and ionic strength). These factors are folded into the distributions of R{sub col} that have been developed from field and experimental data collected under varying geochemical conditions with different colloid types and sizes. Attachment rate constants, k{sub att}, and detachment rate constants, k{sub det}, of colloids to the fracture surface have been measured for the fractured volcanics, and separate R{sub col} uncertainty distributions have been developed for attachment and detachment to clastic material and mineral grains in the alluvium. Radionuclides such as plutonium and americium sorb mostly (90 to 99 percent) irreversibly to colloids (BSC 2004 [DIRS 170025], Section 6.3.3.2). The colloid retardation factors developed in this analysis are needed to simulate the transport of radionuclides that are irreversibly sorbed onto colloids; this transport is discussed in the model report ''Site-Scale Saturated Zone Transport'' (BSC 2004 [DIRS 170036]). Although it is not exclusive to any particular radionuclide release scenario, this scientific analysis especially addresses those scenarios pertaining to evidence from waste-degradation experiments, which indicate that plutonium and americium may be irreversibly attached to colloids for the time scales of interest. A section of this report will also discuss the validity of using microspheres as analogs to colloids in some of the lab and field experiments used to obtain the colloid retardation factors. In addition, a small fraction of colloids travels with the groundwater without any significant

  13. Simulation of California's Major Reservoirs Outflow Using Data Mining Technique

    Science.gov (United States)

    Yang, T.; Gao, X.; Sorooshian, S.

    2014-12-01

    The reservoir's outflow is controlled by reservoir operators, which is different from the upstream inflow. The outflow is more important than the reservoir's inflow for the downstream water users. In order to simulate the complicated reservoir operation and extract the outflow decision making patterns for California's 12 major reservoirs, we build a data-driven, computer-based ("artificial intelligent") reservoir decision making tool, using decision regression and classification tree approach. This is a well-developed statistical and graphical modeling methodology in the field of data mining. A shuffled cross validation approach is also employed to extract the outflow decision making patterns and rules based on the selected decision variables (inflow amount, precipitation, timing, water type year etc.). To show the accuracy of the model, a verification study is carried out comparing the model-generated outflow decisions ("artificial intelligent" decisions) with that made by reservoir operators (human decisions). The simulation results show that the machine-generated outflow decisions are very similar to the real reservoir operators' decisions. This conclusion is based on statistical evaluations using the Nash-Sutcliffe test. The proposed model is able to detect the most influential variables and their weights when the reservoir operators make an outflow decision. While the proposed approach was firstly applied and tested on California's 12 major reservoirs, the method is universally adaptable to other reservoir systems.

  14. Direct laboratory observation of fluid distribution and its influence on acoustic properties of patchy saturated rocks

    Science.gov (United States)

    Lebedev, M.; Clennell, B.; Pervukhina, M.; Shulakova, V.; Mueller, T.; Gurevich, B.

    2009-04-01

    Porous rocks in hydrocarbon reservoirs are often saturated with a mixture of two or more fluids. Interpretation of exploration seismograms requires understanding of the relationship between distribution of the fluids patches and acoustic properties of rocks. The sizes of patches as well as their distribution affect significantly the seismic response. If the size of the fluid patch is smaller than the diffusion wavelength then pressure equilibration is achieved and the bulk modulus of the rock saturated with a mixture is defined by the Gassmann equations (Gassmann, 1951) with the saturation-weighted average of the fluid bulk modulus given by Wood's law (Wood, 1955, Mavko et al., 1998). If the fluid patch size is much larger than the diffusion wavelength then there is no pressure communication between different patches. In this case, fluid-flow effects can be neglected and the overall rock may be considered equivalent to an elastic composite material consisting of homogeneous parts whose properties are given by Gassmann theory with Hill's equation for the bulk modulus (Hill, 1963, Mavko et al., 1998). At intermediate values of fluid saturation the velocity-saturation relationship is significantly affected by the fluid patch distribution. In order to get an improved understanding of factors influencing the patch distribution and the resulting seismic wave response we performed simultaneous measurements of P-wave velocities and rock sample CT imaging. The CT imaging allows us to map the fluid distribution inside rock sample during saturation (water imbibition). We compare the experimental results with theoretical predictions. In this paper we will present results of simultaneous measurements of longitudinal wave velocities and imaging mapping of fluid distribution inside rock sample during sample saturation. We will report results of two kinds of experiments: "dynamic" and "quasi static" saturation. In both experiments Casino Cores Otway Basin sandstone, Australia core

  15. Effect of paraffin saturation in a crude oil on operation of a field

    Energy Technology Data Exchange (ETDEWEB)

    Trebin, G F; Kapyrin, Yu V

    1968-11-01

    Both theoretical and practical studies in recent years have shown that in planning operational procedures for an oil field, the paraffin saturation of the crude oil must be considered. If the crude oil is essentially saturated with paraffin at reservoir condition, then paraffin deposition can occur around the well and in the well. Temperature in the reservoir can be lowered by 2 mechanisms: (1) by injection of water below reservoir temperature, and (2) by expansion of produced gas and consequent cooling of the produced oil. Possible application of these principles to several Soviet oil fields is discussed. In the Uzen field, a preliminary investigation is under way to test the feasibility of heating the injection water to prevent paraffin deposition in the reservoir.

  16. nitrogen saturation in stream ecosystems

    OpenAIRE

    Earl, S. R.; Valett, H. M.; Webster, J. R.

    2006-01-01

    The concept of nitrogen (N) saturation has organized the assessment of N loading in terrestrial ecosystems. Here we extend the concept to lotic ecosystems by coupling Michaelis-Menten kinetics and nutrient spiraling. We propose a series of saturation response types, which may be used to characterize the proximity of streams to N saturation. We conducted a series of short-term N releases using a tracer ((NO3)-N-15-N) to measure uptake. Experiments were conducted in streams spanning a gradient ...

  17. Sediment management for reservoir

    International Nuclear Information System (INIS)

    Rahman, A.

    2005-01-01

    All natural lakes and reservoirs whether on rivers, tributaries or off channel storages are doomed to be sited up. Pakistan has two major reservoirs of Tarbela and Managla and shallow lake created by Chashma Barrage. Tarbela and Mangla Lakes are losing their capacities ever since first impounding, Tarbela since 1974 and Mangla since 1967. Tarbela Reservoir receives average annual flow of about 62 MAF and sediment deposits of 0.11 MAF whereas Mangla gets about 23 MAF of average annual flows and is losing its storage at the rate of average 34,000 MAF annually. The loss of storage is a great concern and studies for Tarbela were carried out by TAMS and Wallingford to sustain its capacity whereas no study has been done for Mangla as yet except as part of study for Raised Mangla, which is only desk work. Delta of Tarbala reservoir has advanced to about 6.59 miles (Pivot Point) from power intakes. In case of liquefaction of delta by tremor as low as 0.12g peak ground acceleration the power tunnels I, 2 and 3 will be blocked. Minimum Pool of reservoir is being raised so as to check the advance of delta. Mangla delta will follow the trend of Tarbela. Tarbela has vast amount of data as reservoir is surveyed every year, whereas Mangla Reservoir survey was done at five-year interval, which has now been proposed .to be reduced to three-year interval. In addition suspended sediment sampling of inflow streams is being done by Surface Water Hydrology Project of WAPDA as also some bed load sampling. The problem of Chasma Reservoir has also been highlighted, as it is being indiscriminately being filled up and drawdown several times a year without regard to its reaction to this treatment. The Sediment Management of these reservoirs is essential and the paper discusses pros and cons of various alternatives. (author)

  18. 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

  19. Optimising reservoir operation

    DEFF Research Database (Denmark)

    Ngo, Long le

    Anvendelse af optimeringsteknik til drift af reservoirer er blevet et væsentligt element i vandressource-planlægning og -forvaltning. Traditionelt har reservoirer været styret af heuristiske procedurer for udtag af vand, suppleret i en vis udstrækning af subjektive beslutninger. Udnyttelse af...... reservoirer involverer en lang række interessenter med meget forskellige formål (f.eks. kunstig vanding, vandkraft, vandforsyning mv.), og optimeringsteknik kan langt bedre lede frem til afbalancerede løsninger af de ofte modstridende interesser. Afhandlingen foreslår en række tiltag, hvormed traditionelle...

  20. Enhanced characterization of reservoir hydrocarbon components using electromagnetic data attributes

    KAUST Repository

    Katterbauer, Klemens

    2015-12-23

    Advances in electromagnetic imaging techniques have led to the growing utilization of this technology for reservoir monitoring and exploration. These exploit the strong conductivity contrast between the hydrocarbon and water phases and have been used for mapping water front propagation in hydrocarbon reservoirs and enhancing the characterization of the reservoir formation. The conventional approach for the integration of electromagnetic data is to invert the data for saturation properties and then subsequently use the inverted properties as constraints in the history matching process. The non-uniqueness and measurement errors may however make this electromagnetic inversion problem strongly ill-posed, leading to potentially inaccurate saturation profiles. Another limitation of this approach is the uncertainty of Archie\\'s parameters in relating rock conductivity to water saturation, which may vary in the reservoir and are generally poorly known. We present an Ensemble Kalman Filter framework for efficiently integrating electromagnetic data into the history matching process and for simultaneously estimating the Archie\\'s parameters and the variance of the observation error of the electromagnetic data. We apply the proposed framework to a compositional reservoir model. We aim at assessing the relevance of EM data for estimating the different hydrocarbon components of the reservoir. The experimental results demonstrate that the individual hydrocarbon components are generally well matched, with nitrogen exhibiting the strongest improvement. The estimated observation error standard deviations are also within expected levels (between 5 and 10%), significantly contributing to the robustness of the proposed EM history matching framework. Archie\\'s parameter estimates approximate well the reference profile and assist in the accurate description of the electrical conductivity properties of the reservoir formation, hence leading to estimation accuracy improvements of around

  1. Enhanced characterization of reservoir hydrocarbon components using electromagnetic data attributes

    KAUST Repository

    Katterbauer, Klemens; Arango, Santiago; Sun, Shuyu; Hoteit, Ibrahim

    2015-01-01

    Advances in electromagnetic imaging techniques have led to the growing utilization of this technology for reservoir monitoring and exploration. These exploit the strong conductivity contrast between the hydrocarbon and water phases and have been used for mapping water front propagation in hydrocarbon reservoirs and enhancing the characterization of the reservoir formation. The conventional approach for the integration of electromagnetic data is to invert the data for saturation properties and then subsequently use the inverted properties as constraints in the history matching process. The non-uniqueness and measurement errors may however make this electromagnetic inversion problem strongly ill-posed, leading to potentially inaccurate saturation profiles. Another limitation of this approach is the uncertainty of Archie's parameters in relating rock conductivity to water saturation, which may vary in the reservoir and are generally poorly known. We present an Ensemble Kalman Filter framework for efficiently integrating electromagnetic data into the history matching process and for simultaneously estimating the Archie's parameters and the variance of the observation error of the electromagnetic data. We apply the proposed framework to a compositional reservoir model. We aim at assessing the relevance of EM data for estimating the different hydrocarbon components of the reservoir. The experimental results demonstrate that the individual hydrocarbon components are generally well matched, with nitrogen exhibiting the strongest improvement. The estimated observation error standard deviations are also within expected levels (between 5 and 10%), significantly contributing to the robustness of the proposed EM history matching framework. Archie's parameter estimates approximate well the reference profile and assist in the accurate description of the electrical conductivity properties of the reservoir formation, hence leading to estimation accuracy improvements of around 15%.

  2. A methodology to calibrate water saturation estimated from 4D seismic data

    International Nuclear Information System (INIS)

    Davolio, Alessandra; Maschio, Célio; José Schiozer, Denis

    2014-01-01

    Time-lapse seismic data can be used to estimate saturation changes within a reservoir, which is valuable information for reservoir management as it plays an important role in updating reservoir simulation models. The process of updating reservoir properties, history matching, can incorporate estimated saturation changes qualitatively or quantitatively. For quantitative approaches, reliable information from 4D seismic data is important. This work proposes a methodology to calibrate the volume of water in the estimated saturation maps, as these maps can be wrongly estimated due to problems with seismic signals (such as noise, errors associated with data processing and resolution issues). The idea is to condition the 4D seismic data to known information provided by engineering, in this case the known amount of injected and produced water in the field. The application of the proposed methodology in an inversion process (previously published) that estimates saturation from 4D seismic data is presented, followed by a discussion concerning the use of such data in a history matching process. The methodology is applied to a synthetic dataset to validate the results, the main of which are: (1) reduction of the effects of noise and errors in the estimated saturation, yielding more reliable data to be used quantitatively or qualitatively and (2) an improvement in the properties update after using this data in a history matching procedure. (paper)

  3. Integrating gravimetric and interferometric synthetic aperture radar data for enhancing reservoir history matching of carbonate gas and volatile oil reservoirs

    KAUST Repository

    Katterbauer, Klemens

    2016-08-25

    Reservoir history matching is assuming a critical role in understanding reservoir characteristics, tracking water fronts, and forecasting production. While production data have been incorporated for matching reservoir production levels and estimating critical reservoir parameters, the sparse spatial nature of this dataset limits the efficiency of the history matching process. Recently, gravimetry techniques have significantly advanced to the point of providing measurement accuracy in the microgal range and consequently can be used for the tracking of gas displacement caused by water influx. While gravity measurements provide information on subsurface density changes, i.e., the composition of the reservoir, these data do only yield marginal information about temporal displacements of oil and inflowing water. We propose to complement gravimetric data with interferometric synthetic aperture radar surface deformation data to exploit the strong pressure deformation relationship for enhancing fluid flow direction forecasts. We have developed an ensemble Kalman-filter-based history matching framework for gas, gas condensate, and volatile oil reservoirs, which synergizes time-lapse gravity and interferometric synthetic aperture radar data for improved reservoir management and reservoir forecasts. Based on a dual state-parameter estimation algorithm separating the estimation of static reservoir parameters from the dynamic reservoir parameters, our numerical experiments demonstrate that history matching gravity measurements allow monitoring the density changes caused by oil-gas phase transition and water influx to determine the saturation levels, whereas the interferometric synthetic aperture radar measurements help to improve the forecasts of hydrocarbon production and water displacement directions. The reservoir estimates resulting from the dual filtering scheme are on average 20%-40% better than those from the joint estimation scheme, but require about a 30% increase in

  4. Saturation and linear transport equation

    International Nuclear Information System (INIS)

    Kutak, K.

    2009-03-01

    We show that the GBW saturation model provides an exact solution to the one dimensional linear transport equation. We also show that it is motivated by the BK equation considered in the saturated regime when the diffusion and the splitting term in the diffusive approximation are balanced by the nonlinear term. (orig.)

  5. Misconceptions in Reporting Oxygen Saturation

    NARCIS (Netherlands)

    Toffaletti, John; Zijlstra, Willem G.

    2007-01-01

    BACKGROUND: We describe some misconceptions that have become common practice in reporting blood gas and cooximetry results. In 1980, oxygen saturation was incorrectly redefined in a report of a new instrument for analysis of hemoglobin (Hb) derivatives. Oxygen saturation (sO(2)) was redefined as the

  6. Effects of water-supply reservoirs on streamflow in Massachusetts

    Science.gov (United States)

    Levin, Sara B.

    2016-10-06

    State and local water-resource managers need modeling tools to help them manage and protect water-supply resources for both human consumption and ecological needs. The U.S. Geological Survey, in cooperation with the Massachusetts Department of Environmental Protection, has developed a decision-support tool to estimate the effects of reservoirs on natural streamflow. The Massachusetts Reservoir Simulation Tool is a model that simulates the daily water balance of a reservoir. The reservoir simulation tool provides estimates of daily outflows from reservoirs and compares the frequency, duration, and magnitude of the volume of outflows from reservoirs with estimates of the unaltered streamflow that would occur if no dam were present. This tool will help environmental managers understand the complex interactions and tradeoffs between water withdrawals, reservoir operational practices, and reservoir outflows needed for aquatic habitats.A sensitivity analysis of the daily water balance equation was performed to identify physical and operational features of reservoirs that could have the greatest effect on reservoir outflows. For the purpose of this report, uncontrolled releases of water (spills or spillage) over the reservoir spillway were considered to be a proxy for reservoir outflows directly below the dam. The ratio of average withdrawals to the average inflows had the largest effect on spillage patterns, with the highest withdrawals leading to the lowest spillage. The size of the surface area relative to the drainage area of the reservoir also had an effect on spillage; reservoirs with large surface areas have high evaporation rates during the summer, which can contribute to frequent and long periods without spillage, even in the absence of water withdrawals. Other reservoir characteristics, such as variability of inflows, groundwater interactions, and seasonal demand patterns, had low to moderate effects on the frequency, duration, and magnitude of spillage. The

  7. 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.

  8. Research on evaluation method for water saturation of tight sandstone in Suxi region

    Science.gov (United States)

    Lv, Hong; Lai, Fuqiang; Chen, Liang; Li, Chao; Li, Jie; Yi, Heping

    2017-05-01

    The evaluation of irreducible water saturation is important for qualitative and quantitative prediction of residual oil distribution. However, it is to be improved for the accuracy of experimental measuring the irreducible water saturation and logging evaluation. In this paper, firstly the multi-functional core flooding experiment and the nuclear magnetic resonance centrifugation experiment are carried out in the west of Sulige gas field. Then, the influence was discussed about particle size, porosity and permeability on the water saturation. Finally, the evaluation model was established about irreducible water saturation and the evaluation of irreducible water saturation was carried out. The results show that the results of two experiments are both reliable. It is inversely proportional to the median particle size, porosity and permeability, and is most affected by the median particle size. The water saturation of the dry layer is higher than that of the general reservoir. The worse the reservoir property, the greater the water saturation. The test results show that the irreducible water saturation model can be used to evaluate the water floor.

  9. Unconventional Tight Reservoirs Characterization with Nuclear Magnetic Resonance

    Science.gov (United States)

    Santiago, C. J. S.; Solatpour, R.; Kantzas, A.

    2017-12-01

    The increase in tight reservoir exploitation projects causes producing many papers each year on new, modern, and modified methods and techniques on estimating characteristics of these reservoirs. The most ambiguous of all basic reservoir property estimations deals with permeability. One of the logging methods that is advertised to predict permeability but is always met by skepticism is Nuclear Magnetic Resonance (NMR). The ability of NMR to differentiate between bound and movable fluids and providing porosity increased the capability of NMR as a permeability prediction technique. This leads to a multitude of publications and the motivation of a review paper on this subject by Babadagli et al. (2002). The first part of this presentation is dedicated to an extensive review of the existing correlation models for NMR based estimates of tight reservoir permeability to update this topic. On the second part, the collected literature information is used to analyze new experimental data. The data are collected from tight reservoirs from Canada, the Middle East, and China. A case study is created to apply NMR measurement in the prediction of reservoir characterization parameters such as porosity, permeability, cut-offs, irreducible saturations etc. Moreover, permeability correlations are utilized to predict permeability. NMR experiments were conducted on water saturated cores. NMR T2 relaxation times were measured. NMR porosity, the geometric mean relaxation time (T2gm), Irreducible Bulk Volume (BVI), and Movable Bulk Volume (BVM) were calculated. The correlation coefficients were computed based on multiple regression analysis. Results are cross plots of NMR permeability versus the independently measured Klinkenberg corrected permeability. More complicated equations are discussed. Error analysis of models is presented and compared. This presentation is beneficial in understanding existing tight reservoir permeability models. The results can be used as a guide for choosing

  10. APPLICATION OF WELL LOG ANALYSIS IN ASSESSMENT OF PETROPHYSICAL PARAMETERS AND RESERVOIR CHARACTERIZATION OF WELLS IN THE “OTH” FIELD, ANAMBRA BASIN, SOUTHERN NIGERIA

    Directory of Open Access Journals (Sweden)

    Eugene URORO

    2014-12-01

    Full Text Available Over the past years, the Anambra basin one of Nigeria’s inland basins has recorded significant level of hydrocarbon exploration activities. The basin has been confirmed by several authors from source rock analyses to have the potential for generating hydrocarbon. For the hydrocarbon to be exploited, it is imperative to have a thorough understanding of the reservoir. Computer-assisted log analyses were employed to effectively evaluate the petrophysical parameters such as the shale volume (Vsh, total porosity (TP, effective porosity (EP, water saturation (Sw, and hydrocarbon saturation (Sh. Cross-plots of the petrophysical parameters versus depth were illustrated. Five hydrocarbon bearing reservoirs were delineated in well 1, four in well 2. The reservoirs in well 3 do not contain hydrocarbon. The estimated reservoir porosity varies from 10% to 21% while their permeability values range from 20md to 1400md. The porosity and permeability values suggest that reservoirs are good enough to store and also permit free flow of fluid. The volume of shale (0.05% to 0.35% analysis reveals that the reservoirs range from shaly sand to slightly shaly sand to clean sand reservoir. On the basis of petrophysics data, the reservoirs are interpreted a good quality reservoir rocks which has been confirmed with high effective porosity range between 20% and high hydrocarbon saturation exceeding 55% water saturation in well 1 and well 2. Water saturation 3 is nearly 100% although the reservoir properties are good.  

  11. Nuclear register applications and pressure tests to foresee reservoirs exploitation with water drive

    International Nuclear Information System (INIS)

    Osorio F, X.; Redosado G, V.

    1994-01-01

    This paper illustrates how the pulsed neutron log and well test analysis aid proper reservoir management in strong water reservoirs. These techniques have been applied to Cetico reservoir which belongs to Corrientes Field which is located in the Peruvian Jungle. Corrientes is the most important field operated by PETROPERU S.A. As a result of the analysis we current know the present areal water saturation distribution and also have improve the reservoir characterization al of which is being used for increasing the oil production and reserves. (author). 4 refs, 7 figs, 3 tabs

  12. Advances in complex reservoir evaluation based on geophysical well logs

    Energy Technology Data Exchange (ETDEWEB)

    Fertl, W.H.; Sinha, A.K. (Western Atlas International, Inc., Houston, TX (USA)); McDougall, J.G. (Western Atlas Canada Ltd., Calgary, AB (Canada))

    1988-09-01

    The matrix of reservoirs having complex lithologies, cause different density, neutron, and acoustic responses. Therefore the lithologies and effective porosity of reservoirs can be determined by using various crossplot techniques on data collected from two of these logs. The Complex Reservoir Analysis program (CRA) computes lithology, porosity, water saturation and relative permeabilities in formations with interbedded limestone, dolomite, and anhydrite. Porosity options include crossplot and individual log response techniques. Corrections for light hydrocarbons were applied. In solving for porosity and mineral volumes, sand, limestone, dolomite, and anhydrite lines were defined on either density/neutron or neutron/acoustic crossplots. Four additional mineral lines were specified. Incorporation of Pe data from the Z-Densilog provided a significant advance in evaluating complex reservoirs via the Z-CRA analysis. The classic reservoir evaluation program CLASS, was used to perform both minerals and shaly evaluation based on density, neutron, resistivity, and natural gamma ray spectral measurements. Computations included total and effective porosities, fluid saturation distribution based on the Wasman-Smits model, productivity indices, and volume and distribution of clay minerals. Additional computed formation parameters included log-derived cation exchange capacity and hydrogen index of dry clay matrix to determine the type and amount of smectite, illite and chlorite/kaolinite present. Canadian field experiences was used to illustrate and support the techniques described. 11 refs., 11 figs., 6 tabs.

  13. Landsliding in partially saturated materials

    Science.gov (United States)

    Godt, J.W.; Baum, R.L.; Lu, N.

    2009-01-01

    [1] Rainfall-induced landslides are pervasive in hillslope environments around the world and among the most costly and deadly natural hazards. However, capturing their occurrence with scientific instrumentation in a natural setting is extremely rare. The prevailing thinking on landslide initiation, particularly for those landslides that occur under intense precipitation, is that the failure surface is saturated and has positive pore-water pressures acting on it. Most analytic methods used for landslide hazard assessment are based on the above perception and assume that the failure surface is located beneath a water table. By monitoring the pore water and soil suction response to rainfall, we observed shallow landslide occurrence under partially saturated conditions for the first time in a natural setting. We show that the partially saturated shallow landslide at this site is predictable using measured soil suction and water content and a novel unified effective stress concept for partially saturated earth materials. Copyright 2009 by the American Geophysical Union.

  14. Global Carbon Reservoir Oxidative Ratios

    Science.gov (United States)

    Masiello, C. A.; Gallagher, M. E.; Hockaday, W. C.

    2010-12-01

    Photosynthesis and respiration move carbon and oxygen between the atmosphere and the biosphere at a ratio that is characteristic of the biogeochemical processes involved. This ratio is called the oxidative ratio (OR) of photosynthesis and respiration, and is defined as the ratio of moles of O2 per moles of CO2. This O2/CO2 ratio is a characteristic of biosphere-atmosphere gas fluxes, much like the 13C signature of CO2 transferred between the biosphere and the atmosphere has a characteristic signature. OR values vary on a scale of 0 (CO2) to 2 (CH4), with most ecosystem values clustered between 0.9 and 1.2. Just as 13C can be measured for both carbon fluxes and carbon pools, OR can also be measured for fluxes and pools and can provide information about the processes involved in carbon and oxygen cycling. OR values also provide information about reservoir organic geochemistry because pool OR values are proportional to the oxidation state of carbon (Cox) in the reservoir. OR may prove to be a particularly valuable biogeochemical tracer because of its ability to couple information about ecosystem gas fluxes with ecosystem organic geochemistry. We have developed 3 methods to measure the OR of ecosystem carbon reservoirs and intercalibrated them to assure that they yield accurate, intercomparable data. Using these tools we have built a large enough database of biomass and soil OR values that it is now possible to consider the implications of global patterns in ecosystem OR values. Here we present a map of the natural range in ecosystem OR values and begin to consider its implications. One striking pattern is an apparent offset between soil and biospheric OR values: soil OR values are frequently higher than that of their source biomass. We discuss this trend in the context of soil organic geochemistry and gas fluxes.

  15. The Danish tax on saturated fat

    DEFF Research Database (Denmark)

    Vallgårda, Signild; Holm, Lotte; Jensen, Jørgen Dejgård

    2015-01-01

    arguments and themes involved in the debates surrounding the introduction and the repeal. SUBJECTS/METHODS: An analysis of parliamentary debates, expert reports and media coverage; key informant interviews; and a review of studies about the effects of the tax on consumer behaviour. RESULTS: A tax......BACKGROUND/OBJECTIVES: Health promoters have repeatedly proposed using economic policy tools, taxes and subsidies, as a means of changing consumer behaviour. As the first country in the world, Denmark introduced a tax on saturated fat in 2011. It was repealed in 2012. In this paper, we present...... indicates that the tax was effective in changing consumer behaviour....

  16. SEISMIC DETERMINATION OF RESERVOIR HETEROGENEITY: APPLICATION TO THE CHARACTERIZATION OF HEAVY OIL RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Matthias G. Imhof; James W. Castle

    2005-02-01

    The objective of the project was to examine how seismic and geologic data can be used to improve characterization of small-scale heterogeneity and their parameterization in reservoir models. The study focused on West Coalinga Field in California. The project initially attempted to build reservoir models based on different geologic and geophysical data independently using different tools, then to compare the results, and ultimately to integrate them all. We learned, however, that this strategy was impractical. The different data and tools need to be integrated from the beginning because they are all interrelated. This report describes a new approach to geostatistical modeling and presents an integration of geology and geophysics to explain the formation of the complex Coalinga reservoir.

  17. Nitrogen saturation in stream ecosystems.

    Science.gov (United States)

    Earl, Stevan R; Valett, H Maurice; Webster, Jackson R

    2006-12-01

    The concept of nitrogen (N) saturation has organized the assessment of N loading in terrestrial ecosystems. Here we extend the concept to lotic ecosystems by coupling Michaelis-Menten kinetics and nutrient spiraling. We propose a series of saturation response types, which may be used to characterize the proximity of streams to N saturation. We conducted a series of short-term N releases using a tracer (15NO3-N) to measure uptake. Experiments were conducted in streams spanning a gradient of background N concentration. Uptake increased in four of six streams as NO3-N was incrementally elevated, indicating that these streams were not saturated. Uptake generally corresponded to Michaelis-Menten kinetics but deviated from the model in two streams where some other growth-critical factor may have been limiting. Proximity to saturation was correlated to background N concentration but was better predicted by the ratio of dissolved inorganic N (DIN) to soluble reactive phosphorus (SRP), suggesting phosphorus limitation in several high-N streams. Uptake velocity, a reflection of uptake efficiency, declined nonlinearly with increasing N amendment in all streams. At the same time, uptake velocity was highest in the low-N streams. Our conceptual model of N transport, uptake, and uptake efficiency suggests that, while streams may be active sites of N uptake on the landscape, N saturation contributes to nonlinear changes in stream N dynamics that correspond to decreased uptake efficiency.

  18. Study of different factors affecting the electrical properties of natural gas reservoir rocks based on digital cores

    International Nuclear Information System (INIS)

    Jiang, Liming; Sun, Jianmeng; Wang, Haitao; Liu, Xuefeng

    2011-01-01

    The effects of the wettability and solubility of natural gas in formation water on the electrical properties of natural gas reservoir rocks are studied using the finite element method based on digital cores. The results show that the resistivity index of gas-wet reservoir rocks is significantly higher than that of water-wet reservoir rocks in the entire range of water saturation. The difference between them increases with decreasing water saturation. The resistivity index of natural gas reservoir rocks decreases with increasing additional conduction of water film. The solubility of natural gas in formation water has a dramatic effect on the electrical properties of reservoir rocks. The resistivity index of reservoir rocks increases as the solubility of natural gas increases. The effect of the solubility of natural gas on the resistivity index is very obvious under conditions of low water saturation, and it becomes weaker with increasing water saturation. Therefore, the reservoir wettability and the solubility of natural gas in formation water should be considered in defining the saturation exponent

  19. Sensitivity analysis and economic optimization studies of inverted five-spot gas cycling in gas condensate reservoir

    Directory of Open Access Journals (Sweden)

    Shams Bilal

    2017-08-01

    Full Text Available Gas condensate reservoirs usually exhibit complex flow behaviors because of propagation response of pressure drop from the wellbore into the reservoir. When reservoir pressure drops below the dew point in two phase flow of gas and condensate, the accumulation of large condensate amount occurs in the gas condensate reservoirs. Usually, the saturation of condensate accumulation in volumetric gas condensate reservoirs is lower than the critical condensate saturation that causes trapping of large amount of condensate in reservoir pores. Trapped condensate often is lost due to condensate accumulation-condensate blockage courtesy of high molecular weight, heavy condensate residue. Recovering lost condensate most economically and optimally has always been a challenging goal. Thus, gas cycling is applied to alleviate such a drastic loss in resources.

  20. Determination of the vertical distribution and areal of the composition in volatile oil and/or gas condensate reservoirs

    International Nuclear Information System (INIS)

    Santos Santos, Nicolas; Ortiz Cancino, Olga Patricia; Barrios Ortiz, Wilson

    2005-01-01

    The compositional variation in vertical and areal direction due to gravitational and thermal effects plays an important role in the determination of the original reserves in-situ and in the selection of the operation scheme for volatile oil and/or gas condensate reservoirs. In this work we presented the mathematical formulation of the thermodynamic behavior experienced by compositional fluids, such as volatile oil and/or gas condensate, under the influence of the mentioned effects (gravitational and thermal), which was implemented in a software tool, this tool determine the compositional variation in vertical direction and, in addition, it allows to know the saturation pressure variation in the hydrocarbon column and the location of the gas-oil contact. With the obtained results, product of the use of this tool, was developed a methodology to obtain one first approach of the compositional variation in areal direction to obtain compositional spatial distribution (iso composition maps) in the reservoir, for components like the methane, which experiences the greater variations. These iso composition maps allow to determine the location of the hydrocarbon deposits, in such a way that the production strategies can be selected and be applied to maximize the recovery, such as in fill wells, perforation of new zones, EOR processes, etc

  1. A combination of streamtube and geostatical simulation methodologies for the study of large oil reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Chakravarty, A.; Emanuel, A.S.; Bernath, J.A. [Chevron Petroleum Technology Company, LaHabra, CA (United States)

    1997-08-01

    The application of streamtube models for reservoir simulation has an extensive history in the oil industry. Although these models are strictly applicable only to fields under voidage balance, they have proved to be useful in a large number of fields provided that there is no solution gas evolution and production. These models combine the benefit of very fast computational time with the practical ability to model a large reservoir over the course of its history. These models do not, however, directly incorporate the detailed geological information that recent experience has taught is important. This paper presents a technique for mapping the saturation information contained in a history matched streamtube model onto a detailed geostatistically derived finite difference grid. With this technique, the saturation information in a streamtube model, data that is actually statistical in nature, can be identified with actual physical locations in a field and a picture of the remaining oil saturation can be determined. Alternatively, the streamtube model can be used to simulate the early development history of a field and the saturation data then used to initialize detailed late time finite difference models. The proposed method is presented through an example application to the Ninian reservoir. This reservoir, located in the North Sea (UK), is a heterogeneous sandstone characterized by a line drive waterflood, with about 160 wells, and a 16 year history. The reservoir was satisfactorily history matched and mapped for remaining oil saturation. A comparison to 3-D seismic survey and recently drilled wells have provided preliminary verification.

  2. Geothermal reservoir engineering

    CERN Document Server

    Grant, Malcolm Alister

    2011-01-01

    As nations alike struggle to diversify and secure their power portfolios, geothermal energy, the essentially limitless heat emanating from the earth itself, is being harnessed at an unprecedented rate.  For the last 25 years, engineers around the world tasked with taming this raw power have used Geothermal Reservoir Engineering as both a training manual and a professional reference.  This long-awaited second edition of Geothermal Reservoir Engineering is a practical guide to the issues and tasks geothermal engineers encounter in the course of their daily jobs. The bo

  3. 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.

  4. Nagylengyel: an interesting reservoir. [Yugoslovia

    Energy Technology Data Exchange (ETDEWEB)

    Dedinszky, J

    1971-04-01

    The Nagylengyel oil field, discovered in 1951, has oil-producing formations mostly in the Upper-Triassic dolomites, in the Norian-Ractian transition formations, in the Upper-Cretaceous limestones and shales, and in the Miocene. The formation of the reservoir space occurred in many stages. A porous, cavernous fractured reservoir is developed in the Norian principal dolomite. A cavernous fractured reservoir exists in the Cretaceous limestone and in the Cretaceous shale and porous fractured reservoir is developed in the Miocene. The derivation of the model of the reservoir, and the conservative evaluation of the volume of the reservoir made it possible to use secondary recovery.

  5. Gain dynamics and saturation in semiconductor quantum dot amplifiers

    DEFF Research Database (Denmark)

    Berg, Tommy Winther; Mørk, Jesper; Hvam, Jørn Märcher

    2004-01-01

    Quantum dot (QD)-based semiconductor optical amplifiers offer unique properties compared with conventional devices based on bulk or quantum well material. Due to the bandfilling properties of QDs and the existence of a nearby reservoir of carriers in the form of a wetting layer, QD semiconductor...... optical amplifiers may be operated in regimes of high linearity, i.e. with a high saturation power, but can also show strong and fast nonlinearities by breaking the equilibrium between discrete dot states and the continuum of wetting layer states. In this paper, we analyse the interplay of these two...

  6. Reservoirs talk to pressure recorders

    Energy Technology Data Exchange (ETDEWEB)

    Pamenter, C B

    1968-02-01

    Keeping pace with increased demand for efficiency in secondary recovery schemes is the widening use of downhole tools charged with supplying data before and during the operation of the projects. One of the most important of these is the pressure recorder. This highly sensitive instrument, housed in a tough, slim steel case and lowered by drill pipe or cable, accurately measures the pressure of its downhole environment. This information is instantly available at the surface whenever a pressure reading is required. Typical applications of surface recorders often contribute are: (1) production practices such as checking surface and subsurface equipment, and special lifting problems; (2) well conditions including regular productivity indices, data observations and for interference studies; (3) secondary recovery projects, in both producing and injection wells; and (4) reservoir conditions where oil-water contacts and damaged zones need close attention.

  7. Reviving Abandoned Reservoirs with High-Pressure Air Injection: Application in a Fractured and Karsted Dolomite Reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Robert Loucks; Stephen C. Ruppel; Dembla Dhiraj; Julia Gale; Jon Holder; Jeff Kane; Jon Olson; John A. Jackson; Katherine G. Jackson

    2006-09-30

    Engineering (both at The University of Texas at Austin) to define the controls on fluid flow in the reservoir as a basis for developing a reservoir model. The successful development of HPAI technology has tremendous potential for increasing the flow of oil from deep carbonate reservoirs in the Permian Basin, a target resource that can be conservatively estimated at more than 1.5 billion barrels. Successful implementation in the field chosen for demonstration, for example, could result in the recovery of more than 34 million barrels of oil that will not otherwise be produced. Geological and petrophysical analysis of available data at Barnhart field reveals the following important observations: (1) the Barnhart Ellenburger reservoir is similar to most other Ellenburger reservoirs in terms of depositional facies, diagenesis, and petrophysical attributes; (2) the reservoir is characterized by low to moderate matrix porosity much like most other Ellenburger reservoirs in the Permian Basin; (3) karst processes (cave formation, infill, and collapse) have substantially altered stratigraphic architecture and reservoir properties; (4) porosity and permeability increase with depth and may be associated with the degree of karst-related diagenesis; (5) tectonic fractures overprint the reservoir, improving overall connectivity; (6) oil-saturation profiles show that the oil-water contact (OWC) is as much as 125 ft lower than previous estimations; (7) production history and trends suggest that this reservoir is very similar to other solution-gas-drive reservoirs in the Permian Basin; and (8) reservoir simulation study showed that the Barnhart reservoir is a good candidate for HPAI and that application of horizontal-well technology can improve ultimate resource recovery from the reservoir.

  8. Parallel reservoir simulator computations

    International Nuclear Information System (INIS)

    Hemanth-Kumar, K.; Young, L.C.

    1995-01-01

    The adaptation of a reservoir simulator for parallel computations is described. The simulator was originally designed for vector processors. It performs approximately 99% of its calculations in vector/parallel mode and relative to scalar calculations it achieves speedups of 65 and 81 for black oil and EOS simulations, respectively on the CRAY C-90

  9. unconventional natural gas reservoirs

    International Nuclear Information System (INIS)

    Correa G, Tomas F; Osorio, Nelson; Restrepo R, Dora P

    2009-01-01

    This work is an exploration about different unconventional gas reservoirs worldwide: coal bed methane, tight gas, shale gas and gas hydrate? describing aspects such as definition, reserves, production methods, environmental issues and economics. The overview also mentioned preliminary studies about these sources in Colombia.

  10. Small Reservoir Impact on Simulated Watershed-Scale Nutrient Yield

    Directory of Open Access Journals (Sweden)

    Shane J. Prochnow

    2007-01-01

    Full Text Available The soil and water assessment tool (SWAT is used to assess the influence of small upland reservoirs (PL566 on watershed nutrient yield. SWAT simulates the impact of collectively increasing and decreasing PL566 magnitudes (size parameters on the watershed. Totally removing PL566 reservoirs results in a 100% increase in total phosphorus and an 82% increase in total nitrogen, while a total maximum daily load (TMDL calling for a 50% reduction in total phosphorus can be achieved with a 500% increase in the magnitude of PL566s in the watershed. PL566 reservoirs capture agriculture pollution in surface flow, providing long-term storage of these constituents when they settle to the reservoir beds. A potential strategy to reduce future downstream nutrient loading is to enhance or construct new PL566 reservoirs in the upper basin to better capture agricultural runoff.

  11. Modeling Study of High Pressure and High Temperature Reservoir Fluids

    DEFF Research Database (Denmark)

    Varzandeh, Farhad

    properties like saturation pressures, densities at reservoir temperature and Stock TankviOil (STO) densities, while keeping the n-alkane limit of the correlations unchanged. Apart from applying this general approach to PC-SAFT, we have also shown that the approach can be applied to classical cubic models...... approach to characterizing reservoir fluids for any EoS. The approach consists in developing correlations of model parameters first with a database for well-defined components and then adjusting the correlations with a large PVT database. The adjustment is made to minimize the deviation in key PVT...... method to SRK and PR improved the saturation pressure calculation in comparisonto the original characterization method for SRK and PR. Using volume translationtogether with the new characterization approach for SRK and PR gives comparable results for density and STO density to that of original...

  12. Sampling from stochastic reservoir models constrained by production data

    Energy Technology Data Exchange (ETDEWEB)

    Hegstad, Bjoern Kaare

    1997-12-31

    When a petroleum reservoir is evaluated, it is important to forecast future production of oil and gas and to assess forecast uncertainty. This is done by defining a stochastic model for the reservoir characteristics, generating realizations from this model and applying a fluid flow simulator to the realizations. The reservoir characteristics define the geometry of the reservoir, initial saturation, petrophysical properties etc. This thesis discusses how to generate realizations constrained by production data, that is to say, the realizations should reproduce the observed production history of the petroleum reservoir within the uncertainty of these data. The topics discussed are: (1) Theoretical framework, (2) History matching, forecasting and forecasting uncertainty, (3) A three-dimensional test case, (4) Modelling transmissibility multipliers by Markov random fields, (5) Up scaling, (6) The link between model parameters, well observations and production history in a simple test case, (7) Sampling the posterior using optimization in a hierarchical model, (8) A comparison of Rejection Sampling and Metropolis-Hastings algorithm, (9) Stochastic simulation and conditioning by annealing in reservoir description, and (10) Uncertainty assessment in history matching and forecasting. 139 refs., 85 figs., 1 tab.

  13. CO2/ brine substitution experiments at simulated reservoir conditions

    Science.gov (United States)

    Kummerow, Juliane; Spangenberg, Erik

    2015-04-01

    Capillary properties of rocks affect the mobility of fluids in a reservoir. Therefore, the understanding of the capillary pressure behaviour is essential to assess the long-term behaviour of CO2 reservoirs. Beyond this, a calibration of the petrophysical properties on water saturation of reservoir rocks at simulated in situ conditions is crucial for a proper interpretation of field monitoring data. We present a set-up, which allows for the combined measurements of capillary pressure, electric resistivity, and elastic wave velocities under controlled reservoir conditions (pconf = 400 bar, ppore = 180 bar, T = 65 ° C) at different brine-CO2 saturations. The capillary properties of the samples are measured using the micropore membrane technique. The sample is jacketed with a Viton tube (thickness = 4 mm) and placed between two current electrode endcaps, which as well contain pore fluid ports and ultrasonic P and S wave transducers. Between the sample and the lower endcap the hydrophilic semi-permeable micro-pore membrane (pore size = 100 nm) is integrated. It is embedded into filter papers to establish a good capillary contact and to protect the highly sensitive membrane against mechanical damage under load. Two high-precision syringe pumps are used to displace a quantified volume of brine by CO2 and determine the corresponding sample saturation. The fluid displacement induces a pressure gradient along the sample, which corresponds to the capillary pressure at a particular sample saturation. It is measured with a differential pressure sensor in the range between 0 - 0.2 MPa. Drainage and imbibition cycles are performed to provide information on the efficiency of capillary trapping and to get a calibration of the petrophysical parameters of the sample.

  14. Development and linearization of generalized material balance equation for coal bed methane reservoirs

    International Nuclear Information System (INIS)

    Penuela, G; Ordonez R, A; Bejarano, A

    1998-01-01

    A generalized material balance equation was presented at the Escuela de Petroleos de la Universidad Industrial de Santander for coal seam gas reservoirs based on Walsh's method, who worked in an analogous approach for oil and gas conventional reservoirs (Walsh, 1995). Our equation was based on twelve similar assumptions itemized by Walsh for his generalized expression for conventional reservoirs it was started from the same volume balance consideration and was finally reorganized like Walsh (1994) did. Because it is not expressed in terms of traditional (P/Z) plots, as proposed by King (1990), it allows to perform a lot of quantitative and qualitative analyses. It was also demonstrated that the existent equations are only particular cases of the generalized expression evaluated under certain restrictions. This equation is applicable to coal seam gas reservoirs in saturated, equilibrium and under saturated conditions, and to any type of coal beds without restriction on especial values of the constant diffusion

  15. Interpreting isotopic analyses of microbial sulfate reduction in oil reservoirs

    Science.gov (United States)

    Hubbard, C. G.; Engelbrektson, A. L.; Druhan, J. L.; Cheng, Y.; Li, L.; Ajo Franklin, J. B.; Coates, J. D.; Conrad, M. E.

    2013-12-01

    Microbial sulfate reduction in oil reservoirs is often associated with secondary production of oil where seawater (28 mM sulfate) is commonly injected to maintain reservoir pressure and displace oil. The hydrogen sulfide produced can cause a suite of operating problems including corrosion of infrastructure, health exposure risks and additional processing costs. We propose that monitoring of the sulfur and oxygen isotopes of sulfate can be used as early indicators that microbial sulfate reduction is occurring, as this process is well known to cause substantial isotopic fractionation. This approach relies on the idea that reactions with reservoir (iron) minerals can remove dissolved sulfide, thereby delaying the transport of the sulfide through the reservoir relative to the sulfate in the injected water. Changes in the sulfate isotopes due to microbial sulfate reduction may therefore be measurable in the produced water before sulfide is detected. However, turning this approach into a predictive tool requires (i) an understanding of appropriate fractionation factors for oil reservoirs, (ii) incorporation of isotopic data into reservoir flow and reactive transport models. We present here the results of preliminary batch experiments aimed at determining fractionation factors using relevant electron donors (e.g. crude oil and volatile fatty acids), reservoir microbial communities and reservoir environmental conditions (pressure, temperature). We further explore modeling options for integrating isotope data and discuss whether single fractionation factors are appropriate to model complex environments with dynamic hydrology, geochemistry, temperature and microbiology gradients.

  16. Chalk as a reservoir

    DEFF Research Database (Denmark)

    Fabricius, Ida Lykke

    , and the best reservoir properties are typically found in mudstone intervals. Chalk mudstones vary a lot though. The best mudstones are purely calcitic, well sorted and may have been redeposited by traction currents. Other mudstones are rich in very fine grained silica, which takes up pore space and thus...... basin, so stylolite formation in the chalk is controlled by effective burial stress. The stylolites are zones of calcite dissolution and probably are the source of calcite for porefilling cementation which is typical in water zone chalk and also affect the reservoirs to different extent. The relatively...... have hardly any stylolites and can have porosity above 40% or even 50% and thus also have relatively high permeability. Such intervals have the problem though, that increasing effective stress caused by hydrocarbon production results in mechanical compaction and overall subsidence. Most other chalk...

  17. Work reservoirs in thermodynamics

    International Nuclear Information System (INIS)

    Anacleto, Joaquim

    2010-01-01

    We stress the usefulness of the work reservoir in the formalism of thermodynamics, in particular in the context of the first law. To elucidate its usefulness, the formalism is then applied to the Joule expansion and other peculiar and instructive experimental situations, clarifying the concepts of configuration and dissipative work. The ideas and discussions presented in this study are primarily intended for undergraduate students, but they might also be useful to graduate students, researchers and teachers.

  18. Work reservoirs in thermodynamics

    Science.gov (United States)

    Anacleto, Joaquim

    2010-05-01

    We stress the usefulness of the work reservoir in the formalism of thermodynamics, in particular in the context of the first law. To elucidate its usefulness, the formalism is then applied to the Joule expansion and other peculiar and instructive experimental situations, clarifying the concepts of configuration and dissipative work. The ideas and discussions presented in this study are primarily intended for undergraduate students, but they might also be useful to graduate students, researchers and teachers.

  19. Transformation of seismic velocity data to extract porosity and saturation values for rocks

    International Nuclear Information System (INIS)

    Berryman, James G.; Berge, Patricia A.; Bonner, Brian P.

    2000-01-01

    For wave propagation at low frequencies in a porous medium, the Gassmann-Domenico relations are well-established for homogeneous partial saturation by a liquid. They provide the correct relations for seismic velocities in terms of constituent bulk and shear moduli, solid and fluid densities, porosity and saturation. It has not been possible, however, to invert these relations easily to determine porosity and saturation when the seismic velocities are known. Also, the state (or distribution) of saturation, i.e., whether or not liquid and gas are homogeneously mixed in the pore space, is another important variable for reservoir evaluation. A reliable ability to determine the state of saturation from velocity data continues to be problematic. It is shown how transforming compressional and shear wave velocity data to the (ρ/λ,μ/λ)-plane (where λ and μ are the Lame parameters and ρ is the total density) results in a set of quasi-orthogonal coordinates for porosity and liquid saturation that greatly aids in the interpretation of seismic data for the physical parameters of most interest. A second transformation of the same data then permits isolation of the liquid saturation value, and also provides some direct information about the state of saturation. By thus replotting the data in the (λ/μ, ρ/μ)-plane, inferences can be made concerning the degree of patchy (inhomogeneous) versus homogeneous saturation that is present in the region of the medium sampled by the data. Our examples include igneous and sedimentary rocks, as well as man-made porous materials. These results have potential applications in various areas of interest, including petroleum exploration and reservoir characterization, geothermal resource evaluation, environmental restoration monitoring, and geotechnical site characterization. (c) 2000 Acoustical Society of America

  20. Modeling Reservoir-River Networks in Support of Optimizing Seasonal-Scale Reservoir Operations

    Science.gov (United States)

    Villa, D. L.; Lowry, T. S.; Bier, A.; Barco, J.; Sun, A.

    2011-12-01

    HydroSCOPE (Hydropower Seasonal Concurrent Optimization of Power and the Environment) is a seasonal time-scale tool for scenario analysis and optimization of reservoir-river networks. Developed in MATLAB, HydroSCOPE is an object-oriented model that simulates basin-scale dynamics with an objective of optimizing reservoir operations to maximize revenue from power generation, reliability in the water supply, environmental performance, and flood control. HydroSCOPE is part of a larger toolset that is being developed through a Department of Energy multi-laboratory project. This project's goal is to provide conventional hydropower decision makers with better information to execute their day-ahead and seasonal operations and planning activities by integrating water balance and operational dynamics across a wide range of spatial and temporal scales. This presentation details the modeling approach and functionality of HydroSCOPE. HydroSCOPE consists of a river-reservoir network model and an optimization routine. The river-reservoir network model simulates the heat and water balance of river-reservoir networks for time-scales up to one year. The optimization routine software, DAKOTA (Design Analysis Kit for Optimization and Terascale Applications - dakota.sandia.gov), is seamlessly linked to the network model and is used to optimize daily volumetric releases from the reservoirs to best meet a set of user-defined constraints, such as maximizing revenue while minimizing environmental violations. The network model uses 1-D approximations for both the reservoirs and river reaches and is able to account for surface and sediment heat exchange as well as ice dynamics for both models. The reservoir model also accounts for inflow, density, and withdrawal zone mixing, and diffusive heat exchange. Routing for the river reaches is accomplished using a modified Muskingum-Cunge approach that automatically calculates the internal timestep and sub-reach lengths to match the conditions of

  1. Advantageous Reservoir Characterization Technology in Extra Low Permeability Oil Reservoirs

    Directory of Open Access Journals (Sweden)

    Yutian Luo

    2017-01-01

    Full Text Available This paper took extra low permeability reservoirs in Dagang Liujianfang Oilfield as an example and analyzed different types of microscopic pore structures by SEM, casting thin sections fluorescence microscope, and so on. With adoption of rate-controlled mercury penetration, NMR, and some other advanced techniques, based on evaluation parameters, namely, throat radius, volume percentage of mobile fluid, start-up pressure gradient, and clay content, the classification and assessment method of extra low permeability reservoirs was improved and the parameter boundaries of the advantageous reservoirs were established. The physical properties of reservoirs with different depth are different. Clay mineral variation range is 7.0%, and throat radius variation range is 1.81 μm, and start pressure gradient range is 0.23 MPa/m, and movable fluid percentage change range is 17.4%. The class IV reservoirs account for 9.56%, class II reservoirs account for 12.16%, and class III reservoirs account for 78.29%. According to the comparison of different development methods, class II reservoir is most suitable for waterflooding development, and class IV reservoir is most suitable for gas injection development. Taking into account the gas injection in the upper section of the reservoir, the next section of water injection development will achieve the best results.

  2. Comparison of static and dynamic resilience for a multipurpose reservoir operation

    Science.gov (United States)

    Simonovic, Slobodan P.; Arunkumar, R.

    2016-11-01

    dynamics simulation approach, a feedback-based object-oriented method, very effective for modeling complex systems. The results of dynamic resilience are compared with the traditional performance measures in order to identify advantages of the proposed measure. The results confirm that the dynamic resilience is a powerful tool for selecting proactive and reactive adaptive response of a multipurpose reservoir to a disturbing event that cannot be achieved using traditional measures. The generic quantification approach proposed in the paper allows for easy use of dynamic resilience for planning and operations of various civil infrastructure systems.

  3. Rapid determination of oxygen saturation and vascularity for cancer detection.

    Directory of Open Access Journals (Sweden)

    Fangyao Hu

    Full Text Available A rapid heuristic ratiometric analysis for estimating tissue hemoglobin concentration and oxygen saturation from measured tissue diffuse reflectance spectra is presented. The analysis was validated in tissue-mimicking phantoms and applied to clinical measurements in head and neck, cervical and breast tissues. The analysis works in two steps. First, a linear equation that translates the ratio of the diffuse reflectance at 584 nm and 545 nm to estimate the tissue hemoglobin concentration using a Monte Carlo-based lookup table was developed. This equation is independent of tissue scattering and oxygen saturation. Second, the oxygen saturation was estimated using non-linear logistic equations that translate the ratio of the diffuse reflectance spectra at 539 nm to 545 nm into the tissue oxygen saturation. Correlations coefficients of 0.89 (0.86, 0.77 (0.71 and 0.69 (0.43 were obtained for the tissue hemoglobin concentration (oxygen saturation values extracted using the full spectral Monte Carlo and the ratiometric analysis, for clinical measurements in head and neck, breast and cervical tissues, respectively. The ratiometric analysis was more than 4000 times faster than the inverse Monte Carlo analysis for estimating tissue hemoglobin concentration and oxygen saturation in simulated phantom experiments. In addition, the discriminatory power of the two analyses was similar. These results show the potential of such empirical tools to rapidly estimate tissue hemoglobin in real-time spectral imaging applications.

  4. Optimizing withdrawal from drinking water reservoirs to reduce downstream temperature pollution and reservoir hypoxia.

    Science.gov (United States)

    Weber, M; Rinke, K; Hipsey, M R; Boehrer, B

    2017-07-15

    Sustainable management of drinking water reservoirs requires balancing the demands of water supply whilst minimizing environmental impact. This study numerically simulates the effect of an improved withdrawal scheme designed to alleviate the temperature pollution downstream of a reservoir. The aim was to identify an optimal withdrawal strategy such that water of a desirable discharge temperature can be supplied downstream without leading to unacceptably low oxygen concentrations within the reservoir. First, we calibrated a one-dimensional numerical model for hydrodynamics and oxygen dynamics (GLM-AED2), verifying that the model reproduced water temperatures and hypolimnetic dissolved oxygen concentrations accurately over a 5 year period. Second, the model was extended to include an adaptive withdrawal functionality, allowing for a prescribed withdrawal temperature to be found, with the potential constraint of hypolimnetic oxygen concentration. Scenario simulations on epi-/metalimnetic withdrawal demonstrate that the model is able to autonomously determine the best withdrawal height depending on the thermal structure and the hypolimnetic oxygen concentration thereby optimizing the ability to supply a desirable discharge temperature to the downstream river during summer. This new withdrawal strategy also increased the hypolimnetic raw water volume to be used for drinking water supply, but reduced the dissolved oxygen concentrations in the deep and cold water layers (hypolimnion). Implications of the results for reservoir management are discussed and the numerical model is provided for operators as a simple and efficient tool for optimizing the withdrawal strategy within different reservoir contexts. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Development of infill drilling recovery models for carbonates reservoirs using neural networks and multivariate statistical as a novel method

    International Nuclear Information System (INIS)

    Soto, R; Wu, Ch. H; Bubela, A M

    1999-01-01

    This work introduces a novel methodology to improve reservoir characterization models. In this methodology we integrated multivariate statistical analyses, and neural network models for forecasting the infill drilling ultimate oil recovery from reservoirs in San Andres and Clearfork carbonate formations in west Texas. Development of the oil recovery forecast models help us to understand the relative importance of dominant reservoir characteristics and operational variables, reproduce recoveries for units included in the database, forecast recoveries for possible new units in similar geological setting, and make operational (infill drilling) decisions. The variety of applications demands the creation of multiple recovery forecast models. We have developed intelligent software (Soto, 1998), oilfield intelligence (01), as an engineering tool to improve the characterization of oil and gas reservoirs. 01 integrates neural networks and multivariate statistical analysis. It is composed of five main subsystems: data input, preprocessing, architecture design, graphic design, and inference engine modules. One of the challenges in this research was to identify the dominant and the optimum number of independent variables. The variables include porosity, permeability, water saturation, depth, area, net thickness, gross thickness, formation volume factor, pressure, viscosity, API gravity, number of wells in initial water flooding, number of wells for primary recovery, number of infill wells over the initial water flooding, PRUR, IWUR, and IDUR. Multivariate principal component analysis is used to identify the dominant and the optimum number of independent variables. We compared the results from neural network models with the non-parametric approach. The advantage of the non-parametric regression is that it is easy to use. The disadvantage is that it retains a large variance of forecast results for a particular data set. We also used neural network concepts to develop recovery

  6. Prototyping and Testing a New Volumetric Curvature Tool for Modeling Reservoir Compartments and Leakage Pathways in the Arbuckle Saline Aquifer: Reducing Uncertainty in CO2 Storage and Permanence

    Energy Technology Data Exchange (ETDEWEB)

    Rush, Jason [Univ. of Kansas and Kansas Geological Survey, Lawrence, KS (United States); Holubnyak, Yevhen [Univ. of Kansas and Kansas Geological Survey, Lawrence, KS (United States); Watney, Willard [Univ. of Kansas and Kansas Geological Survey, Lawrence, KS (United States)

    2016-12-09

    This DOE-funded project evaluates the utility of seismic volumetric curvature (VC) for predicting stratal and structural architecture diagnostic of paleokarst reservoirs. Of special interest are applications geared toward carbon capture, utilization, and storage (CCUS). VC has been championed for identifying faults (offset <¼ λ) that cannot be imaged by conventional 3-D seismic attributes such as coherence. The objective of this research was to evaluate VC-techniques for reducing uncertainties in reservoir compartmentalization studies and seal risk assessments especially for saline aquifers. A 2000-ft horizontal lateral was purposefully drilled across VC-imaged lineaments—interpreted to record a fractured and a fault-bounded doline—to physically confirm their presence. The 15-mi² study area is located in southeastern Bemis-Shutts Field, which is situated along the crest of the Central Kansas Uplift (CKU) in Ellis County, Kansas. The uppermost Arbuckle (200+ ft) has extensive paleokarst including collapsed paleocaverns and dolines related to exceedingly prolonged pre-Simpson (Sauk–Tippecanoe) and/or pre-Pennsylvanian subaerial exposure. A lateral borehole was successfully drilled across the full extent (~1100 ft) of a VC-inferred paleokarst doline. Triple combo (GR-neutron/density-resistivity), full-wave sonic, and borehole micro-imager logs were successfully run to TD on drill-pipe. Results from the formation evaluation reveal breccias (e.g., crackle, mosaic, chaotic), fractures, faults, vugs (1-6"), and unaffected host strata consistent with the pre-spud interpretation. Well-rounded pebbles were also observed on the image log. VC-inferred lineaments coincide with 20–80-ft wide intervals of high GR values (100+ API), matrix-rich breccias, and faults. To further demonstrate their utility, VC attributes are integrated into a geocellular modeling workflow: 1) to constrain the structural model; 2) to generate facies probability grids, and; 3) to collocate

  7. Saturation of the turbulent dynamo.

    Science.gov (United States)

    Schober, J; Schleicher, D R G; Federrath, C; Bovino, S; Klessen, R S

    2015-08-01

    The origin of strong magnetic fields in the Universe can be explained by amplifying weak seed fields via turbulent motions on small spatial scales and subsequently transporting the magnetic energy to larger scales. This process is known as the turbulent dynamo and depends on the properties of turbulence, i.e., on the hydrodynamical Reynolds number and the compressibility of the gas, and on the magnetic diffusivity. While we know the growth rate of the magnetic energy in the linear regime, the saturation level, i.e., the ratio of magnetic energy to turbulent kinetic energy that can be reached, is not known from analytical calculations. In this paper we present a scale-dependent saturation model based on an effective turbulent resistivity which is determined by the turnover time scale of turbulent eddies and the magnetic energy density. The magnetic resistivity increases compared to the Spitzer value and the effective scale on which the magnetic energy spectrum is at its maximum moves to larger spatial scales. This process ends when the peak reaches a characteristic wave number k☆ which is determined by the critical magnetic Reynolds number. The saturation level of the dynamo also depends on the type of turbulence and differs for the limits of large and small magnetic Prandtl numbers Pm. With our model we find saturation levels between 43.8% and 1.3% for Pm≫1 and between 2.43% and 0.135% for Pm≪1, where the higher values refer to incompressible turbulence and the lower ones to highly compressible turbulence.

  8. Criteria for saturated magnetization loop

    International Nuclear Information System (INIS)

    Harres, A.; Mikhov, M.; Skumryev, V.; Andrade, A.M.H. de; Schmidt, J.E.; Geshev, J.

    2016-01-01

    Proper estimation of magnetization curve parameters is vital in studying magnetic systems. In the present article, criteria for discrimination non-saturated (minor) from saturated (major) hysteresis loops are proposed. These employ the analysis of (i) derivatives of both ascending and descending branches of the loop, (ii) remanent magnetization curves, and (iii) thermomagnetic curves. Computational simulations are used in order to demonstrate their validity. Examples illustrating the applicability of these criteria to well-known real systems, namely Fe_3O_4 and Ni fine particles, are provided. We demonstrate that the anisotropy-field value estimated from a visual examination of an only apparently major hysteresis loop could be more than two times lower than the real one. - Highlights: • Proper estimation of hysteresis-loop parameters is vital in magnetic studies. • We propose criteria for discrimination minor from major hysteresis loops. • The criteria analyze magnetization, remanence and ZFC/FC curves and/or their derivatives. • Examples of their application on real nanoparticles systems are given. • Using the criteria could avoid twofold or bigger saturation-field underestimation errors.

  9. Criteria for saturated magnetization loop

    Energy Technology Data Exchange (ETDEWEB)

    Harres, A. [Departamento de Física, UFSM, Santa Maria, 97105-900 Rio Grande do Sul (Brazil); Mikhov, M. [Faculty of Physics, University of Sofia, 1164 Sofia (Bulgaria); Skumryev, V. [Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona (Spain); Departament de Física, Universitat Autònoma de Barcelona, 08193 Barcelona (Spain); Andrade, A.M.H. de; Schmidt, J.E. [Instituto de Física, UFRGS, Porto Alegre, 91501-970 Rio Grande do Sul (Brazil); Geshev, J., E-mail: julian@if.ufrgs.br [Departament de Física, Universitat Autònoma de Barcelona, 08193 Barcelona (Spain); Instituto de Física, UFRGS, Porto Alegre, 91501-970 Rio Grande do Sul (Brazil)

    2016-03-15

    Proper estimation of magnetization curve parameters is vital in studying magnetic systems. In the present article, criteria for discrimination non-saturated (minor) from saturated (major) hysteresis loops are proposed. These employ the analysis of (i) derivatives of both ascending and descending branches of the loop, (ii) remanent magnetization curves, and (iii) thermomagnetic curves. Computational simulations are used in order to demonstrate their validity. Examples illustrating the applicability of these criteria to well-known real systems, namely Fe{sub 3}O{sub 4} and Ni fine particles, are provided. We demonstrate that the anisotropy-field value estimated from a visual examination of an only apparently major hysteresis loop could be more than two times lower than the real one. - Highlights: • Proper estimation of hysteresis-loop parameters is vital in magnetic studies. • We propose criteria for discrimination minor from major hysteresis loops. • The criteria analyze magnetization, remanence and ZFC/FC curves and/or their derivatives. • Examples of their application on real nanoparticles systems are given. • Using the criteria could avoid twofold or bigger saturation-field underestimation errors.

  10. 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.

  11. Three dimensional heat transport modeling in Vossoroca reservoir

    Science.gov (United States)

    Arcie Polli, Bruna; Yoshioka Bernardo, Julio Werner; Hilgert, Stephan; Bleninger, Tobias

    2017-04-01

    Freshwater reservoirs are used for many purposes as hydropower generation, water supply and irrigation. In Brazil, according to the National Energy Balance of 2013, hydropower energy corresponds to 70.1% of the Brazilian demand. Superficial waters (which include rivers, lakes and reservoirs) are the most used source for drinking water supply - 56% of the municipalities use superficial waters as a source of water. The last two years have shown that the Brazilian water and electricity supply is highly vulnerable and that improved management is urgently needed. The construction of reservoirs affects physical, chemical and biological characteristics of the water body, e.g. stratification, temperature, residence time and turbulence reduction. Some water quality issues related to reservoirs are eutrophication, greenhouse gas emission to the atmosphere and dissolved oxygen depletion in the hypolimnion. The understanding of the physical processes in the water body is fundamental to reservoir management. Lakes and reservoirs may present a seasonal behavior and stratify due to hydrological and meteorological conditions, and especially its vertical distribution may be related to water quality. Stratification can control heat and dissolved substances transport. It has been also reported the importance of horizontal temperature gradients, e.g. inflows and its density and processes of mass transfer from shallow to deeper regions of the reservoir, that also may impact water quality. Three dimensional modeling of the heat transport in lakes and reservoirs is an important tool to the understanding and management of these systems. It is possible to estimate periods of large vertical temperature gradients, inhibiting vertical transport and horizontal gradients, which could be responsible for horizontal transport of heat and substances (e.g. differential cooling or inflows). Vossoroca reservoir was constructed in 1949 by the impoundment of São João River and is located near to

  12. Direct hydrocarbon exploration and gas reservoir development technology

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Young Hoon; Oh, Jae Ho; Jeong, Tae Jin [Korea Inst. of Geology Mining and Materials, Taejon (Korea, Republic of); and others

    1995-12-01

    In order to enhance the capability of petroleum exploration and development techniques, three year project (1994 - 1997) was initiated on the research of direct hydrocarbon exploration and gas reservoir development. This project consists of four sub-projects. (1) Oil(Gas) - source rock correlation technique: The overview of bio-marker parameters which are applicable to hydrocarbon exploration has been illustrated. Experimental analysis of saturated hydrocarbon and bio-markers of the Pohang E and F core samples has been carried out. (2) Study on surface geochemistry and microbiology for hydrocarbon exploration: the test results of the experimental device for extraction of dissolved gases from water show that the device can be utilized for the gas geochemistry of water. (3) Development of gas and gas condensate reservoirs: There are two types of reservoir characterization. For the reservoir formation characterization, calculation of conditional simulation was compared with that of unconditional simulation. In the reservoir fluid characterization, phase behavior calculations revealed that the component grouping is more important than the increase of number of components. (4) Numerical modeling of seismic wave propagation and full waveform inversion: Three individual sections are presented. The first one is devoted to the inversion theory in general sense. The second and the third sections deal with the frequency domain pseudo waveform inversion of seismic reflection data and refraction data respectively. (author). 180 refs., 91 figs., 60 tabs.

  13. Overspill avalanching in a dense reservoir network

    Science.gov (United States)

    Mamede, George L.; Araújo, Nuno A. M.; Schneider, Christian M.; de Araújo, José Carlos; Herrmann, Hans J.

    2012-01-01

    Sustainability of communities, agriculture, and industry is strongly dependent on an effective storage and supply of water resources. In some regions the economic growth has led to a level of water demand that can only be accomplished through efficient reservoir networks. Such infrastructures are not always planned at larger scale but rather made by farmers according to their local needs of irrigation during droughts. Based on extensive data from the upper Jaguaribe basin, one of the world’s largest system of reservoirs, located in the Brazilian semiarid northeast, we reveal that surprisingly it self-organizes into a scale-free network exhibiting also a power-law in the distribution of the lakes and avalanches of discharges. With a new self-organized-criticality-type model we manage to explain the novel critical exponents. Implementing a flow model we are able to reproduce the measured overspill evolution providing a tool for catastrophe mitigation and future planning. PMID:22529343

  14. Advances in photonic reservoir computing

    Science.gov (United States)

    Van der Sande, Guy; Brunner, Daniel; Soriano, Miguel C.

    2017-05-01

    We review a novel paradigm that has emerged in analogue neuromorphic optical computing. The goal is to implement a reservoir computer in optics, where information is encoded in the intensity and phase of the optical field. Reservoir computing is a bio-inspired approach especially suited for processing time-dependent information. The reservoir's complex and high-dimensional transient response to the input signal is capable of universal computation. The reservoir does not need to be trained, which makes it very well suited for optics. As such, much of the promise of photonic reservoirs lies in their minimal hardware requirements, a tremendous advantage over other hardware-intensive neural network models. We review the two main approaches to optical reservoir computing: networks implemented with multiple discrete optical nodes and the continuous system of a single nonlinear device coupled to delayed feedback.

  15. The time-lapse AVO difference inversion for changes in reservoir parameters

    Science.gov (United States)

    Longxiao, Zhi; Hanming, Gu; Yan, Li

    2016-12-01

    The result of conventional time-lapse seismic processing is the difference between the amplitude and the post-stack seismic data. Although stack processing can improve the signal-to-noise ratio (SNR) of seismic data, it also causes a considerable loss of important information about the amplitude changes and only gives the qualitative interpretation. To predict the changes in reservoir fluid more precisely and accurately, we also need the quantitative information of the reservoir. To achieve this aim, we develop the method of time-lapse AVO (amplitude versus offset) difference inversion. For the inversion of reservoir changes in elastic parameters, we apply the Gardner equation as the constraint and convert the three-parameter inversion of elastic parameter changes into a two-parameter inversion to make the inversion more stable. For the inversion of variations in the reservoir parameters, we infer the relation between the difference of the reflection coefficient and variations in the reservoir parameters, and then invert reservoir parameter changes directly. The results of the theoretical modeling computation and practical application show that our method can estimate the relative variations in reservoir density, P-wave and S-wave velocity, calculate reservoir changes in water saturation and effective pressure accurately, and then provide reference for the rational exploitation of the reservoir.

  16. Encapsulated microsensors for reservoir interrogation

    Science.gov (United States)

    Scott, Eddie Elmer; Aines, Roger D.; Spadaccini, Christopher M.

    2016-03-08

    In one general embodiment, a system includes at least one microsensor configured to detect one or more conditions of a fluidic medium of a reservoir; and a receptacle, wherein the receptacle encapsulates the at least one microsensor. In another general embodiment, a method include injecting the encapsulated at least one microsensor as recited above into a fluidic medium of a reservoir; and detecting one or more conditions of the fluidic medium of the reservoir.

  17. An Analysis and Design for Nonlinear Quadratic Systems Subject to Nested Saturation

    Directory of Open Access Journals (Sweden)

    Minsong Zhang

    2013-01-01

    Full Text Available This paper considers the stability problem for nonlinear quadratic systems with nested saturation input. The interesting treatment method proposed to nested saturation here is put into use a well-established linear differential control tool. And the new conclusions include the existing conclusion on this issue and have less conservatism than before. Simulation example illustrates the effectiveness of the established methodologies.

  18. Observability of linear systems with saturated outputs

    NARCIS (Netherlands)

    Koplon, R.; Sontag, E.D.; Hautus, M.L.J.

    1994-01-01

    We present necessary and sufficient conditions for observability of the class of output-saturated systems. These are linear systems whose output passes through a saturation function before it can be measured.

  19. Fault tolerant control of systems with saturations

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik

    2013-01-01

    This paper presents framework for fault tolerant controllers (FTC) that includes input saturation. The controller architecture known from FTC is based on the Youla-Jabr-Bongiorno-Kucera (YJBK) parameterization is extended to handle input saturation. Applying this controller architecture in connec......This paper presents framework for fault tolerant controllers (FTC) that includes input saturation. The controller architecture known from FTC is based on the Youla-Jabr-Bongiorno-Kucera (YJBK) parameterization is extended to handle input saturation. Applying this controller architecture...... in connection with faulty systems including input saturation gives an additional YJBK transfer function related to the input saturation. In the fault free case, this additional YJBK transfer function can be applied directly for optimizing the feedback loop around the input saturation. In the faulty case......, the design problem is a mixed design problem involved both parametric faults and input saturation....

  20. Control Systems with Saturating Inputs Analysis Tools and Advanced Design

    CERN Document Server

    Corradini, Maria Letizia; Giannoni, Fabio; Orlando, Giuseppe

    2012-01-01

    This series aims to report new developments in the fields of control and information sciences - quickly, informally and at a high level. The type of material considered for publication includes: 1. Preliminary drafts of monographs and advanced textbooks 2. Lectures on a new field, or presenting a new angle on a classical field 3. Research reports 4. Reports of meetings, provided they are a) of exceptional interest and b) devoted to a specific topic. The timeliness of subject material is very important.

  1. Cesium reservoir and interconnective components

    International Nuclear Information System (INIS)

    1994-03-01

    The program objective is to demonstrate the technology readiness of a TFE (thermionic fuel element) suitable for use as the basic element in a thermionic reactor with electric power output in the 0.5 to 5.0 MW range. A thermionic converter must be supplied with cesium vapor for two reasons. Cesium atoms adsorbed on the surface of the emitter cause a reduction of the emitter work function to permit high current densities without excessive heating of the emitter. The second purpose of the cesium vapor is to provide space-charge neutralization in the emitter-collector gap so that the high current densities may flow across the gap unattenuated. The function of the cesium reservoir is to provide a source of cesium atoms, and to provide a reserve in the event that cesium is lost from the plasma by any mechanism. This can be done with a liquid cesium metal reservoir in which case it is heated to the desired temperature with auxiliary heaters. In a TFE, however, it is desirable to have the reservoir passively heated by the nuclear fuel. In this case, the reservoir must operate at a temperature intermediate between the emitter and the collector, ruling out the use of liquid reservoirs. Integral reservoirs contained within the TFE will produce cesium vapor pressures in the desired range at typical electrode temperatures. The reservoir material that appears to be the best able to meet requirements is graphite. Cesium intercalates easily into graphite, and the cesium pressure is insensitive to loading for a given intercalation stage. The goals of the cesium reservoir test program were to verify the performance of Cs-graphite reservoirs in the temperature-pressure range of interest to TFE operation, and to test the operation of these reservoirs after exposure to a fast neutron fluence corresponding to seven year mission lifetime. In addition, other materials were evaluated for possible use in the integral reservoir

  2. Receptor saturation in roentgen films

    Energy Technology Data Exchange (ETDEWEB)

    Strid, K G; Reichmann, S [Sahlgrenska Sjukhuset, Goeteborg (Sweden)

    1980-01-01

    Roentgen-film recording of small object details of low attenuation differences (e.g. pulmonary vessels) is regularly seen to be impaired when the film is exposed to yield high values of optical density (D). This high-density failure is due to receptor saturation, which implies that at high exposure values most silver halide grains of the film are made developable, leaving few grains available to receive additional informative photons. The receptor saturation is analysed by means of a mathematical model of a non-screen film yielding Dsub(max) = 2.0. Optimum recording, defined by maximum signal-to-noise ratio in the image, is found at D approximately 0.64, corresponding to, on an average, 1.6 photons absorbed per grain. On the other hand, maximum contrast occurs at D approximately 1.4, where, on the average, 3.6 photons are absorbed per grain. The detective quantum efficiency of the film, i.e. the fraction of the photons actually contributing to the information content of the image, drops from 41 per cent at maximum signal-to-noise ratio to a mere 10 per cent at maximum contrast.

  3. Reservoir sedimentation; a literature survey

    NARCIS (Netherlands)

    Sloff, C.J.

    1991-01-01

    A survey of literature is made on reservoir sedimentation, one of the most threatening processes for world-wide reservoir performance. The sedimentation processes, their impacts, and their controlling factors are assessed from a hydraulic engineering point of view with special emphasis on

  4. Adaptive implicit method for thermal compositional reservoir simulation

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, A.; Tchelepi, H.A. [Society of Petroleum Engineers, Richardson, TX (United States)]|[Stanford Univ., Palo Alto (United States)

    2008-10-15

    As the global demand for oil increases, thermal enhanced oil recovery techniques are becoming increasingly important. Numerical reservoir simulation of thermal methods such as steam assisted gravity drainage (SAGD) is complex and requires a solution of nonlinear mass and energy conservation equations on a fine reservoir grid. The most currently used technique for solving these equations is the fully IMplicit (FIM) method which is unconditionally stable, allowing for large timesteps in simulation. However, it is computationally expensive. On the other hand, the method known as IMplicit pressure explicit saturations, temperature and compositions (IMPEST) is computationally inexpensive, but it is only conditionally stable and restricts the timestep size. To improve the balance between the timestep size and computational cost, the thermal adaptive IMplicit (TAIM) method uses stability criteria and a switching algorithm, where some simulation variables such as pressure, saturations, temperature, compositions are treated implicitly while others are treated with explicit schemes. This presentation described ongoing research on TAIM with particular reference to thermal displacement processes such as the stability criteria that dictate the maximum allowed timestep size for simulation based on the von Neumann linear stability analysis method; the switching algorithm that adapts labeling of reservoir variables as implicit or explicit as a function of space and time; and, complex physical behaviors such as heat and fluid convection, thermal conduction and compressibility. Key numerical results obtained by enhancing Stanford's General Purpose Research Simulator (GPRS) were also presented along with a list of research challenges. 14 refs., 2 tabs., 11 figs., 1 appendix.

  5. Data Integration for the Generation of High Resolution Reservoir Models

    Energy Technology Data Exchange (ETDEWEB)

    Albert Reynolds; Dean Oliver; Gaoming Li; Yong Zhao; Chaohui Che; Kai Zhang; Yannong Dong; Chinedu Abgalaka; Mei Han

    2009-01-07

    The goal of this three-year project was to develop a theoretical basis and practical technology for the integration of geologic, production and time-lapse seismic data in a way that makes best use of the information for reservoir description and reservoir performance predictions. The methodology and practical tools for data integration that were developed in this research project have been incorporated into computational algorithms that are feasible for large scale reservoir simulation models. As the integration of production and seismic data require calibrating geological/geostatistical models to these data sets, the main computational tool is an automatic history matching algorithm. The following specific goals were accomplished during this research. (1) We developed algorithms for calibrating the location of the boundaries of geologic facies and the distribution of rock properties so that production and time-lapse seismic data are honored. (2) We developed and implemented specific procedures for conditioning reservoir models to time-lapse seismic data. (3) We developed and implemented algorithms for the characterization of measurement errors which are needed to determine the relative weights of data when conditioning reservoir models to production and time-lapse seismic data by automatic history matching. (4) We developed and implemented algorithms for the adjustment of relative permeability curves during the history matching process. (5) We developed algorithms for production optimization which accounts for geological uncertainty within the context of closed-loop reservoir management. (6) To ensure the research results will lead to practical public tools for independent oil companies, as part of the project we built a graphical user interface for the reservoir simulator and history matching software using Visual Basic.

  6. Geometric and Hydrodynamic Characteristics of Three-dimensional Saturated Prefractal Porous Media Determined with Lattice Boltzmann Modeling

    Science.gov (United States)

    Fractal and prefractal geometric models have substantial potential of contributing to the analysis of flow and transport in porous media such as soils and reservoir rocks. In this study, geometric and hydrodynamic parameters of saturated 3D mass and pore-solid prefractal porous media were characteri...

  7. Estimation of changes in saturation and pressure from 4D seismic AVO and time-shift analysis

    NARCIS (Netherlands)

    Trani, M.; Arts, R.; Leeuwenburgh, O.; Brouwer, J.

    2011-01-01

    A reliable estimate of reservoir pressure and fluid saturation changes from time-lapse seismic data is difficult to obtain. Existing methods generally suffer from leakage between the estimated parameters. We propose a new method using different combinations of time-lapse seismic attributes based on

  8. Explicit Singly Diagonally Implicit Runge-Kutta Methods and Adaptive Stepsize Control for Reservoir Simulation

    DEFF Research Database (Denmark)

    Völcker, Carsten; Jørgensen, John Bagterp; Thomsen, Per Grove

    2010-01-01

    The implicit Euler method, normally refered to as the fully implicit (FIM) method, and the implicit pressure explicit saturation (IMPES) method are the traditional choices for temporal discretization in reservoir simulation. The FIM method offers unconditionally stability in the sense of discrete......-Kutta methods, ESDIRK, Newton-Raphson, convergence control, error control, stepsize selection....

  9. Advances in photonic reservoir computing

    Directory of Open Access Journals (Sweden)

    Van der Sande Guy

    2017-05-01

    Full Text Available We review a novel paradigm that has emerged in analogue neuromorphic optical computing. The goal is to implement a reservoir computer in optics, where information is encoded in the intensity and phase of the optical field. Reservoir computing is a bio-inspired approach especially suited for processing time-dependent information. The reservoir’s complex and high-dimensional transient response to the input signal is capable of universal computation. The reservoir does not need to be trained, which makes it very well suited for optics. As such, much of the promise of photonic reservoirs lies in their minimal hardware requirements, a tremendous advantage over other hardware-intensive neural network models. We review the two main approaches to optical reservoir computing: networks implemented with multiple discrete optical nodes and the continuous system of a single nonlinear device coupled to delayed feedback.

  10. Semiconductor saturable absorbers for ultrafast terahertz signals

    DEFF Research Database (Denmark)

    Hoffmann, Matthias C.; Turchinovich, Dmitry

    2010-01-01

    states, due to conduction band onparabolicity and scattering into satellite valleys in strong THz fields. Saturable absorber parameters, such as linear and nonsaturable transmission, and saturation fluence, are extracted by fits to a classic saturable absorber model. Further, we observe THz pulse......We demonstrate saturable absorber behavior of n-type semiconductors GaAs, GaP, and Ge in the terahertz THz frequency range at room temperature using nonlinear THz spectroscopy. The saturation mechanism is based on a decrease in electron conductivity of semiconductors at high electron momentum...

  11. Mechanics of non-saturated soils

    International Nuclear Information System (INIS)

    Coussy, O.; Fleureau, J.M.

    2002-01-01

    This book presents the different ways to approach the mechanics of non saturated soils, from the physico-chemical aspect to the mechanical aspect, from the experiment to the theoretical modeling, from the laboratory to the workmanship, and from the microscopic scale to the macroscopic one. Content: water and its representation; experimental bases of the behaviour of non-saturated soils; transfer laws in non-saturated environment; energy approach of the behaviour of non-saturated soils; homogenization for the non-saturated soils; plasticity and hysteresis; dams and backfilling; elaborated barriers. (J.S.)

  12. The impact of rock and fluid uncertainties in the estimation of saturation and pressure from a 4D petro elastic inversion

    International Nuclear Information System (INIS)

    Pazetti, Bruno; Davolio, Alessandra; Schiozer, Denis J

    2015-01-01

    The integration of 4D seismic (4DS) attributes and reservoir simulation is used to reduce risks in the management of petroleum fields. One possible alternative is the saturation and pressure domain. In this case, we use estimations of saturation and pressure changes from 4D seismic data as input in history matching processes to yield more reliable production predictions in simulation models. The estimation of dynamic changes from 4DS depends on the knowledge of reservoir rock and fluid properties that are uncertain in the process of estimation. This paper presents a study of the impact of rock and fluid uncertainties on the estimation of saturation and pressure changes achieved through a 4D petro-elastic inversion. The term impact means that the saturation and pressure estimation can be perturbed by the rock and fluid uncertainties. The motivation for this study comes from the necessity to estimate uncertainties in saturation and pressure variation to incorporate them in the history matching procedures, avoiding the use of deterministic values from 4DS, which may not be reliable. The study is performed using a synthetic case with known response from where it is possible to show that the errors of estimated saturation and pressure depend on the magnitude of rock and fluid uncertainties jointly with the reservoir dynamic changes. The main contribution of this paper is to show how uncertain reservoir properties can affect the reliability of pressure and saturation estimation from 4DS and how it depends on reservoir changes induced by production. This information can be used in future projects which use quantitative inversion to integrate reservoir simulation and 4D seismic data. (paper)

  13. Investigating leaks in dams and reservoirs

    International Nuclear Information System (INIS)

    2003-01-01

    Millions of people throughout the world depend on dams and reservoirs for electricity, water and flood protection. Dams require significant investment to build and maintain, and yet their usefulness and integrity are constantly threatened by leakage and sedimentation. Isotope hydrology techniques, combined with conventional analytical methods, are a cost-effective tool to reduce such threats. The International Atomic Energy Agency is promoting their use to protect these investments and improve management, particularly by supporting specialized teams of scientists and engineers to investigate dam leakage in African countries on request. (IAEA)

  14. An experimental study of tracers for labelling of injection gas in oil reservoirs

    International Nuclear Information System (INIS)

    Dugstad, Oe.

    1992-01-01

    This work demonstrates the feasibility of the PMCP and PMCH as tracers in field experiments. These compounds have properties which make them as well suited for well to well studies as the more common tracers CH 3 T and 85 Kr. In an injection project carried out at the Gullfaks field in the North Sea the two PFCs verified communication between wells. This implies communication between different geological layers in the reservoir and also communication across faults within the same layers. Laboratory studies carried out have focused on the retention of the tracers in dynamic flooding experiments under conditions comparable with those in the petroleum reservoirs. Simultaneous injection of a variety of tracers has shown individual variations in tracer retention which are caused by important reservoir parameters as fluid saturation and rock properties. By proper design of field injection programs the tracers response may therefore be used to estimate fluid saturation if actual rock properties are known. 45 refs., 20 figs., 13 tabs

  15. Effective teamwork and communication mitigate task saturation in simulated critical care air transport team missions.

    Science.gov (United States)

    Davis, Bradley; Welch, Katherine; Walsh-Hart, Sharon; Hanseman, Dennis; Petro, Michael; Gerlach, Travis; Dorlac, Warren; Collins, Jocelyn; Pritts, Timothy

    2014-08-01

    Critical Care Air Transport Teams (CCATTs) are a critical component of the United States Air Force evacuation paradigm. This study was conducted to assess the incidence of task saturation in simulated CCATT missions and to determine if there are predictable performance domains. Sixteen CCATTs were studied over a 6-month period. Performance was scored using a tool assessing eight domains of performance. Teams were also assessed during critical events to determine the presence or absence of task saturation and its impact on patient care. Sixteen simulated missions were reviewed and 45 crisis events identified. Task saturation was present in 22/45 (49%) of crisis events. Scoring demonstrated that task saturation was associated with poor performance in teamwork (odds ratio [OR] = 1.96), communication (OR = 2.08), and mutual performance monitoring (OR = 1.9), but not maintenance of guidelines, task management, procedural skill, and equipment management. We analyzed the effect of task saturation on adverse patient outcomes during crisis events. Adverse outcomes occurred more often when teams were task saturated as compared to non-task-saturated teams (91% vs. 23%; RR 4.1, p < 0.0001). Task saturation is observed in simulated CCATT missions. Nontechnical skills correlate with task saturation. Task saturation is associated with worsening physiologic derangements in simulated patients. Reprint & Copyright © 2014 Association of Military Surgeons of the U.S.

  16. Analysis of real-time reservoir monitoring : reservoirs, strategies, & modeling.

    Energy Technology Data Exchange (ETDEWEB)

    Mani, Seethambal S.; van Bloemen Waanders, Bart Gustaaf; Cooper, Scott Patrick; Jakaboski, Blake Elaine; Normann, Randy Allen; Jennings, Jim (University of Texas at Austin, Austin, TX); Gilbert, Bob (University of Texas at Austin, Austin, TX); Lake, Larry W. (University of Texas at Austin, Austin, TX); Weiss, Chester Joseph; Lorenz, John Clay; Elbring, Gregory Jay; Wheeler, Mary Fanett (University of Texas at Austin, Austin, TX); Thomas, Sunil G. (University of Texas at Austin, Austin, TX); Rightley, Michael J.; Rodriguez, Adolfo (University of Texas at Austin, Austin, TX); Klie, Hector (University of Texas at Austin, Austin, TX); Banchs, Rafael (University of Texas at Austin, Austin, TX); Nunez, Emilio J. (University of Texas at Austin, Austin, TX); Jablonowski, Chris (University of Texas at Austin, Austin, TX)

    2006-11-01

    The project objective was to detail better ways to assess and exploit intelligent oil and gas field information through improved modeling, sensor technology, and process control to increase ultimate recovery of domestic hydrocarbons. To meet this objective we investigated the use of permanent downhole sensors systems (Smart Wells) whose data is fed real-time into computational reservoir models that are integrated with optimized production control systems. The project utilized a three-pronged approach (1) a value of information analysis to address the economic advantages, (2) reservoir simulation modeling and control optimization to prove the capability, and (3) evaluation of new generation sensor packaging to survive the borehole environment for long periods of time. The Value of Information (VOI) decision tree method was developed and used to assess the economic advantage of using the proposed technology; the VOI demonstrated the increased subsurface resolution through additional sensor data. Our findings show that the VOI studies are a practical means of ascertaining the value associated with a technology, in this case application of sensors to production. The procedure acknowledges the uncertainty in predictions but nevertheless assigns monetary value to the predictions. The best aspect of the procedure is that it builds consensus within interdisciplinary teams The reservoir simulation and modeling aspect of the project was developed to show the capability of exploiting sensor information both for reservoir characterization and to optimize control of the production system. Our findings indicate history matching is improved as more information is added to the objective function, clearly indicating that sensor information can help in reducing the uncertainty associated with reservoir characterization. Additional findings and approaches used are described in detail within the report. The next generation sensors aspect of the project evaluated sensors and packaging

  17. Saturation in dual radiation action

    International Nuclear Information System (INIS)

    Rossi, H.H.; Zaider, M.

    1988-01-01

    The theory of dual radiation action (TDRA) was developed with the aim of applying microdosimetry to radiobiology. It therefore can deal only with the first phases in a long chain of events that results in patent effects. It is, however, clear that the initial spatial and temporal pattern of energy deposition has a profound influence on the ultimate outcome. As often happens, the early formulation of the theory contained a number of simplifying assumptions. Although most of these were explicitly stated when the first version of the TDRA was published experimental data obtained when the limitations are important were cited as contrary evidence causing considerable confusion. A more advanced version eliminated some of the restrictions but there remain others, one of which relates to certain aspects of saturation which are addressed here

  18. [Determination of the redox potential of water saturated with hydrogen].

    Science.gov (United States)

    Piskarev, I M; Ushkanov, V A; Aristova, N A; Likhachev, P P; Myslivets, T C

    2010-01-01

    It has been shown that the redox potential of water saturated with hydrogen is -500--700 mV. The time of the establishment of the potential is 24 h. The potential somewhat increases with increasing volume of hydrogen introduced to a reservoir with water and practically does not depend on the presence of additions in water, provided these additions are not reduced by hydrogen. The pH value of water does not change after the addition of water. In a glass vessel with a metallic cover resting on the side, no decrease in potential during the 2.5-month storage was observed. In plastic bottles, the content of hydrogen decreased; on storage for more than two weeks, it disappeared almost completely, and as a result, the potential increased after storage for three to four weeks to a level near zero. In an open vessel, the potential remained negative for two days.

  19. MAPPING OF RESERVOIR PROPERTIES AND FACIES THROUGH INTEGRATION OF STATIC AND DYNAMIC DATA

    Energy Technology Data Exchange (ETDEWEB)

    Albert C. Reynolds; Dean S. Oliver; Yannong Dong; Ning Liu; Guohua Gao; Fengjun Zhang; Ruijian Li

    2004-12-01

    Knowledge of the distribution of permeability and porosity in a reservoir is necessary for the prediction of future oil production, estimation of the location of bypassed oil, and optimization of reservoir management. The volume of data that can potentially provide information on reservoir architecture and fluid distributions has increased enormously in the past decade. The techniques developed in this research will make it easier to use all the available data in an integrated fashion. While it is relatively easy to generate plausible reservoir models that honor static data such as core, log, and seismic data, it is far more difficult to generate plausible reservoir models that honor dynamic data such as transient pressures, saturations, and flow rates. As a result, the uncertainty in reservoir properties is higher than it could be and reservoir management can not be optimized. In this project, we have developed computationally efficient automatic history matching techniques for generating geologically plausible reservoir models which honor both static and dynamic data. Specifically, we have developed methods for adjusting porosity and permeability fields to match both production and time-lapse seismic data and have also developed a procedure to adjust the locations of boundaries between facies to match production data. In all cases, the history matched rock property fields are consistent with a prior model based on static data and geologic information. Our work also indicates that it is possible to adjust relative permeability curves when history matching production data.

  20. 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.

  1. Experimental investigation of wettability alteration on residual oil saturation using nonionic surfactants: Capillary pressure measurement

    Directory of Open Access Journals (Sweden)

    Masoud Amirpour

    2015-12-01

    Full Text Available Introducing the novel technique for enhancing oil recovery from available petroleum reservoirs is one of the important issues in future energy demands. Among of all operative factors, wettability may be the foremost parameter affecting residual oil saturation in all stage of oil recovery. Although wettability alteration is one of the methods which enhance oil recovery from the petroleum reservoir. Recently, the studies which focused on this subject were more than the past and many contributions have been made on this area. The main objective of the current study is experimentally investigation of the two nonionic surfactants effects on altering wettability of reservoir rocks. Purpose of this work is to change the wettability to preferentially the water-wet condition. Also reducing the residual oil saturation (Sor is the other purpose of this work. The wettability alteration of reservoir rock is measured by two main quantitative methods namely contact angle and the USBM methods. Results of this study showed that surfactant flooding is more effective in oil-wet rocks to change their wettability and consequently reducing Sor to a low value. Cedar (Zizyphus Spina Christi is low priced, absolutely natural, and abundantly accessible in the Middle East and Central Asia. Based on the results, this material can be used as a chemical surfactant in field for enhancing oil recovery.

  2. Towards an integrated petrophysical tool for multiphase flow properties of core samples

    Energy Technology Data Exchange (ETDEWEB)

    Lenormand, R. [Institut Francais du Petrole, Rueil Malmaison (France)

    1997-08-01

    This paper describes the first use of an Integrated Petrophysical Tool (IPT) on reservoir rock samples. The IPT simultaneously measures the following petrophysical properties: (1) Complete capillary pressure cycle: primary drainage, spontaneous and forced imbibitions, secondary drainage (the cycle leads to the wettability of the core by using the USBM index); End-points and parts of the relative permeability curves; Formation factor and resistivity index. The IPT is based on the steady-state injection of one fluid through the sample placed in a Hassler cell. The experiment leading to the whole Pc cycle on two reservoir sandstones consists of about 30 steps at various oil or water flow rates. It takes about four weeks and is operated at room conditions. Relative permeabilities are in line with standard steady-state measurements. Capillary pressures are in accordance with standard centrifuge measurements. There is no comparison for the resistivity index, but the results are in agreement with literature data. However, the accurate determination of saturation remains the main difficulty and some improvements are proposed. In conclusion, the Integrated Petrophysical Tool is as accurate as standard methods and has the advantage of providing the various parameters on the same sample and during a single experiment. The FIT is easy to use and can be automated. In addition, it can be operated in reservoir conditions.

  3. Value of information in closed-loop reservoir managment

    NARCIS (Netherlands)

    Barros, E.G.D.; Van den Hof, P.M.J.; Jansen, J.D.

    This paper proposes a new methodology to perform value of information (VOI) analysis within a closed-loop reservoir management (CLRM) framework. The workflow combines tools such as robust optimization and history matching in an environment of uncertainty characterization. The approach is illustrated

  4. Reservoir souring: it is all about risk mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Kuijvenhoven, Cor [Shell (Canada)

    2011-07-01

    The presence of H2S in produced fluid can be due to various sources, among which are heat/rock interaction and leaks from other reservoirs. This paper discusses the reasons, risk assessment and tools for mitigating reservoir souring. Uncontrolled microorganism activity can cause a sweet reservoir (without H2S) to become sour (production of H2S). The development of bacteria is one of the main causes of reservoir souring in unconventional gas fields. It is difficult to predict souring in seawater due to produced water re-injection (PWRI). Risk assessment and modeling techniques for reservoir souring are discussed. Some of the factors controlling H2S production include injection location, presence of scavenging minerals and biogenic souring. Mitigation methods such as biocide treatment of injection water, sulphate removal from seawater, microbial monitoring techniques such as the molecular microbiology method (MMM), and enumeration by serial dilution are explained. In summary, it can be concluded that reservoir souring is a long-term problem and should be assessed at the beginning of operations.

  5. A Time Domain Update Method for Reservoir History Matching of Electromagnetic Data

    KAUST Repository

    Katterbauer, Klemens

    2014-03-25

    The oil & gas industry has been the backbone of the world\\'s economy in the last century and will continue to be in the decades to come. With increasing demand and conventional reservoirs depleting, new oil industry projects have become more complex and expensive, operating in areas that were previously considered impossible and uneconomical. Therefore, good reservoir management is key for the economical success of complex projects requiring the incorporation of reliable uncertainty estimates for reliable production forecasts and optimizing reservoir exploitation. Reservoir history matching has played here a key role incorporating production, seismic, electromagnetic and logging data for forecasting the development of reservoirs and its depletion. With the advances in the last decade, electromagnetic techniques, such as crosswell electromagnetic tomography, have enabled engineers to more precisely map the reservoirs and understand their evolution. Incorporating the large amount of data efficiently and reducing uncertainty in the forecasts has been one of the key challenges for reservoir management. Computing the conductivity distribution for the field for adjusting parameters in the forecasting process via solving the inverse problem has been a challenge, due to the strong ill-posedness of the inversion problem and the extensive manual calibration required, making it impossible to be included into an efficient reservoir history matching forecasting algorithm. In the presented research, we have developed a novel Finite Difference Time Domain (FDTD) based method for incorporating electromagnetic data directly into the reservoir simulator. Based on an extended Archie relationship, EM simulations are performed for both forecasted and Porosity-Saturation retrieved conductivity parameters being incorporated directly into an update step for the reservoir parameters. This novel direct update method has significant advantages such as that it overcomes the expensive and ill

  6. Understanding the True Stimulated Reservoir Volume in Shale Reservoirs

    KAUST Repository

    Hussain, Maaruf; Saad, Bilal; Negara, Ardiansyah; Sun, Shuyu

    2017-01-01

    Successful exploitation of shale reservoirs largely depends on the effectiveness of hydraulic fracturing stimulation program. Favorable results have been attributed to intersection and reactivation of pre-existing fractures by hydraulically

  7. Experimental Characterization of Dielectric Properties in Fluid Saturated Artificial Shales

    Directory of Open Access Journals (Sweden)

    Roman Beloborodov

    2017-01-01

    Full Text Available High dielectric contrast between water and hydrocarbons provides a useful method for distinguishing between producible layers of reservoir rocks and surrounding media. Dielectric response at high frequencies is related to the moisture content of rocks. Correlations between the dielectric permittivity and specific surface area can be used for the estimation of elastic and geomechanical properties of rocks. Knowledge of dielectric loss-factor and relaxation frequency in shales is critical for the design of techniques for effective hydrocarbon extraction and production from unconventional reservoirs. Although applicability of dielectric measurements is intriguing, the data interpretation is very challenging due to many factors influencing the dielectric response. For instance, dielectric permittivity is determined by mineralogical composition of solid fraction, volumetric content and composition of saturating fluid, rock microstructure and geometrical features of its solid components and pore space, temperature, and pressure. In this experimental study, we investigate the frequency dependent dielectric properties of artificial shale rocks prepared from silt-clay mixtures via mechanical compaction. Samples are prepared with various clay contents and pore fluids of different salinity and cation compositions. Measurements of dielectric properties are conducted in two orientations to investigate the dielectric anisotropy as the samples acquire strongly oriented microstructures during the compaction process.

  8. Simulation study of huff-n-puff air injection for enhanced oil recovery in shale oil reservoirs

    Directory of Open Access Journals (Sweden)

    Hu Jia

    2018-03-01

    Full Text Available This paper is the first attempt to evaluate huff-n-puff air injection in a shale oil reservoir using a simulation approach. Recovery mechanisms and physical processes of huff-n-puff air injection in a shale oil reservoir are investigated through investigating production performance, thermal behavior, reservoir pressure and fluid saturation features. Air flooding is used as the basic case for a comparative study. The simulation study suggests that thermal drive is the main recovery mechanism for huff-n-puff air injection in the shale oil reservoir, but not for simple air flooding. The synergic recovery mechanism of air flooding in conventional light oil reservoirs can be replicated in shale oil reservoirs by using air huff-n-puff injection strategy. Reducing huff-n-puff time is better for performing the synergic recovery mechanism of air injection. O2 diffusion plays an important role in huff-n-puff air injection in shale oil reservoirs. Pressure transmissibility as well as reservoir pressure maintenance ability in huff-n-puff air injection is more pronounced than the simple air flooding after primary depletion stage. No obvious gas override is exhibited in both air flooding and air huff-n-puff injection scenarios in shale reservoirs. Huff-n-puff air injection has great potential to develop shale oil reservoirs. The results from this work may stimulate further investigations.

  9. [Hematophagous bats as reservoirs of rabies].

    Science.gov (United States)

    Scheffer, Karin Corrêa; Iamamoto, Keila; Asano, Karen Miyuki; Mori, Enio; Estevez Garcia, Andrea Isabel; Achkar, Samira M; Fahl, Williande Oliveira

    2014-04-01

    Rabies continues to be a challenge for public health authorities and a constraint to the livestock industry in Latin America. Wild and domestic canines and vampire bats are the main transmitter species and reservoirs of the disease. Currently, variations observed in the epidemiological profile of rabies, where the species of hematophagous bat Desmodus rotundus constitutes the main transmitting species. Over the years, knowledge has accumulated about the ecology, biology and behavior of this species and the natural history of rabies, which should lead to continuous development of methods of population control of d. Rotundus as well as prevention and diagnostic tools for rabies. Ecological relationships of this species with other hematophagous and non-hematophagous bats is unknown, and there is much room for improvement in reporting systems and surveillance, as well as creating greater awareness among the farming community. Understanding the impact of human-induced environmental changes on the rabies virus in bats should be cause for further investigation. This will require a combination of field studies with mathematical models and new diagnostic tools. This review aims to present the most relevant issues on the role of hematophagous bats as reservoirs and transmitters of the rabies virus.

  10. Evaluating the Influence of Pore Architecture and Initial Saturation on Wettability and Relative Permeability in Heterogeneous, Shallow-Shelf Carbonates

    Energy Technology Data Exchange (ETDEWEB)

    Byrnes, Alan P.; Bhattacharya, Saibal; Victorine, John; Stalder, Ken

    2007-09-30

    Thin (3-40 ft thick), heterogeneous, limestone and dolomite reservoirs, deposited in shallow-shelf environments, represent a significant fraction of the reservoirs in the U.S. midcontinent and worldwide. In Kansas, reservoirs of the Arbuckle, Mississippian, and Lansing-Kansas City formations account for over 73% of the 6.3 BBO cumulative oil produced over the last century. For these reservoirs basic petrophysical properties (e.g., porosity, absolute permeability, capillary pressure, residual oil saturation to waterflood, resistivity, and relative permeability) vary significantly horizontally, vertically, and with scale of measurement. Many of these reservoirs produce from structures of less than 30-60 ft, and being located in the capillary pressure transition zone, exhibit vertically variable initial saturations and relative permeability properties. Rather than being simpler to model because of their small size, these reservoirs challenge characterization and simulation methodology and illustrate issues that are less apparent in larger reservoirs where transition zone effects are minor and most of the reservoir is at saturations near S{sub wirr}. These issues are further augmented by the presence of variable moldic porosity and possible intermediate to mixed wettability and the influence of these on capillary pressure and relative permeability. Understanding how capillary-pressure properties change with rock lithology and, in turn, within transition zones, and how relative permeability and residual oil saturation to waterflood change through the transition zone is critical to successful reservoir management and as advanced waterflood and improved and enhanced recovery methods are planned and implemented. Major aspects of the proposed study involve a series of tasks to measure data to reveal the nature of how wettability and drainage and imbibition oil-water relative permeability change with pore architecture and initial water saturation. Focus is placed on

  11. Design Techniques and Reservoir Simulation

    Directory of Open Access Journals (Sweden)

    Ahad Fereidooni

    2012-11-01

    Full Text Available Enhanced oil recovery using nitrogen injection is a commonly applied method for pressure maintenance in conventional reservoirs. Numerical simulations can be practiced for the prediction of a reservoir performance in the course of injection process; however, a detailed simulation might take up enormous computer processing time. In such cases, a simple statistical model may be a good approach to the preliminary prediction of the process without any application of numerical simulation. In the current work, seven rock/fluid reservoir properties are considered as screening parameters and those parameters having the most considerable effect on the process are determined using the combination of experimental design techniques and reservoir simulations. Therefore, the statistical significance of the main effects and interactions of screening parameters are analyzed utilizing statistical inference approaches. Finally, the influential parameters are employed to create a simple statistical model which allows the preliminary prediction of nitrogen injection in terms of a recovery factor without resorting to numerical simulations.

  12. The Characteristics of Spanish Reservoirs

    National Research Council Canada - National Science Library

    Armengol, J; Merce, R

    2003-01-01

    Sau Reservoir was first filled in 1963 in a middle stretch of the Ter River, as part of a multi-use scheme, including hydroelectric power, agricultural irrigation, domestic and industrial water supply...

  13. A sensitivity analysis on seismic tomography data with respect to CO2 saturation of a CO2 geological sequestration field

    Science.gov (United States)

    Park, Chanho; Nguyen, Phung K. T.; Nam, Myung Jin; Kim, Jongwook

    2013-04-01

    Monitoring CO2 migration and storage in geological formations is important not only for the stability of geological sequestration of CO2 but also for efficient management of CO2 injection. Especially, geophysical methods can make in situ observation of CO2 to assess the potential leakage of CO2 and to improve reservoir description as well to monitor development of geologic discontinuity (i.e., fault, crack, joint, etc.). Geophysical monitoring can be based on wireline logging or surface surveys for well-scale monitoring (high resolution and nallow area of investigation) or basin-scale monitoring (low resolution and wide area of investigation). In the meantime, crosswell tomography can make reservoir-scale monitoring to bridge the resolution gap between well logs and surface measurements. This study focuses on reservoir-scale monitoring based on crosswell seismic tomography aiming describe details of reservoir structure and monitoring migration of reservoir fluid (water and CO2). For the monitoring, we first make a sensitivity analysis on crosswell seismic tomography data with respect to CO2 saturation. For the sensitivity analysis, Rock Physics Models (RPMs) are constructed by calculating the values of density and P and S-wave velocities of a virtual CO2 injection reservoir. Since the seismic velocity of the reservoir accordingly changes as CO2 saturation changes when the CO2 saturation is less than about 20%, while when the CO2 saturation is larger than 20%, the seismic velocity is insensitive to the change, sensitivity analysis is mainly made when CO2 saturation is less than 20%. For precise simulation of seismic tomography responses for constructed RPMs, we developed a time-domain 2D elastic modeling based on finite difference method with a staggered grid employing a boundary condition of a convolutional perfectly matched layer. We further make comparison between sensitivities of seismic tomography and surface measurements for RPMs to analysis resolution

  14. Understanding the True Stimulated Reservoir Volume in Shale Reservoirs

    KAUST Repository

    Hussain, Maaruf

    2017-06-06

    Successful exploitation of shale reservoirs largely depends on the effectiveness of hydraulic fracturing stimulation program. Favorable results have been attributed to intersection and reactivation of pre-existing fractures by hydraulically-induced fractures that connect the wellbore to a larger fracture surface area within the reservoir rock volume. Thus, accurate estimation of the stimulated reservoir volume (SRV) becomes critical for the reservoir performance simulation and production analysis. Micro-seismic events (MS) have been commonly used as a proxy to map out the SRV geometry, which could be erroneous because not all MS events are related to hydraulic fracture propagation. The case studies discussed here utilized a fully 3-D simulation approach to estimate the SRV. The simulation approach presented in this paper takes into account the real-time changes in the reservoir\\'s geomechanics as a function of fluid pressures. It is consisted of four separate coupled modules: geomechanics, hydrodynamics, a geomechanical joint model for interfacial resolution, and an adaptive re-meshing. Reservoir stress condition, rock mechanical properties, and injected fluid pressure dictate how fracture elements could open or slide. Critical stress intensity factor was used as a fracture criterion governing the generation of new fractures or propagation of existing fractures and their directions. Our simulations were run on a Cray XC-40 HPC system. The studies outcomes proved the approach of using MS data as a proxy for SRV to be significantly flawed. Many of the observed stimulated natural fractures are stress related and very few that are closer to the injection field are connected. The situation is worsened in a highly laminated shale reservoir as the hydraulic fracture propagation is significantly hampered. High contrast in the in-situ stresses related strike-slip developed thereby shortens the extent of SRV. However, far field nature fractures that were not connected to

  15. Patterning via optical saturable transitions

    Science.gov (United States)

    Cantu, Precious

    For the past 40 years, optical lithography has been the patterning workhorse for the semiconductor industry. However, as integrated circuits have become more and more complex, and as device geometries shrink, more innovative methods are required to meet these needs. In the far-field, the smallest feature that can be generated with light is limited to approximately half the wavelength. This, so called far-field diffraction limit or the Abbe limit (after Prof. Ernst Abbe who first recognized this), effectively prevents the use of long-wavelength photons >300nm from patterning nanostructures barrier is developed and experimentally verified. This approach, which I refer to as Patterning via Optical Saturable Transitions (POST) has the potential for massive parallelism, enabling the creation of nanostructures and devices at a speed far surpassing what is currently possible with conventional optical lithographic techniques. The fundamental understanding of this technique goes beyond optical lithography in the semiconductor industry and is applicable to any area that requires the rapid patterning of large-area two or three-dimensional complex geometries. At a basic level, this research intertwines the fields of electrochemistry, material science, electrical engineering, optics, physics, and mechanical engineering with the goal of developing a novel super-resolution lithographic technique.

  16. Sensorial saturation for infants' pain.

    Science.gov (United States)

    Bellieni, Carlo Valerio; Tei, Monica; Coccina, Francesca; Buonocore, Giuseppe

    2012-04-01

    Sensorial saturation (SS) is a multisensorial stimulation consisting of delicate tactile, gustative, auditory and visual stimuli. This procedure consists of simultaneously: attracting the infant's attention by massaging the infant's face; speaking to the infant gently, but firmly, and instilling a sweet solution on the infant's tongue. We performed a systematic Medline search of for articles focusing on human neonatal studies related to SS. The search was performed within the last 10 years and was current as of January 2012. We retrieved 8 articles that used a complete form of SS and 2 articles with an incomplete SS. Data show that the use of SS is effective in relieving newborns' pain. Oral solution alone are less effective than SS, but the stimuli without oral sweet solution are ineffective. the partial forms of SS have some effectiveness, but minor than the complete SS. Only one article showed lack of SS as analgesic method, after endotracheal suctioning. SS can be used for all newborns undergoing blood samples or other minor painful procedures. It is more effective than oral sugar alone. SS also promotes interaction between nurse and infant and is a simple effective form of analgesia for the neonatal intensive care unit.

  17. Δ isobars and nuclear saturation

    Science.gov (United States)

    Ekström, A.; Hagen, G.; Morris, T. D.; Papenbrock, T.; Schwartz, P. D.

    2018-02-01

    We construct a nuclear interaction in chiral effective field theory with explicit inclusion of the Δ -isobar Δ (1232 ) degree of freedom at all orders up to next-to-next-to-leading order (NNLO). We use pion-nucleon (π N ) low-energy constants (LECs) from a Roy-Steiner analysis of π N scattering data, optimize the LECs in the contact potentials up to NNLO to reproduce low-energy nucleon-nucleon scattering phase shifts, and constrain the three-nucleon interaction at NNLO to reproduce the binding energy and point-proton radius of 4He. For heavier nuclei we use the coupled-cluster method to compute binding energies, radii, and neutron skins. We find that radii and binding energies are much improved for interactions with explicit inclusion of Δ (1232 ) , while Δ -less interactions produce nuclei that are not bound with respect to breakup into α particles. The saturation of nuclear matter is significantly improved, and its symmetry energy is consistent with empirical estimates.

  18. Well log and seismic data analysis for complex pore-structure carbonate reservoir using 3D rock physics templates

    Science.gov (United States)

    Li, Hongbing; Zhang, Jiajia

    2018-04-01

    The pore structure in heterogeneous carbonate rock is usually very complex. This complex pore system makes the relationship between the velocity and porosity of the rock highly scattered, so that for the classical two-dimensional rock physics template (2D RPT) it is not enough to accurately describe the quantitative relationship between the rock elastic parameters of this kind of reservoir and its porosity and water saturation. Therefore it is possible to attribute the effect of pore type to that of the porosity or water saturation, and leads to great deviations when applying such a 2D RPT to predict the porosity and water saturation in seismic reservoir prediction and hydrocarbon detection. This paper first presents a method to establish a new three-dimensional rock physics template (3D RPT) by integrating the Gassmann equations and the porous rock physics model, and use it to characterize the quantitative relation between rock elastic properties and the reservoir parameters including the pore aspect ratio, porosity and water saturation, and to predict these parameters from the known elastic properties. The test results on the real logging and seismic inversion data show that the 3D RPT can accurately describe the variations of elastic properties with the porosity, water saturation and pore-structure parameters, and effectively improve the accuracy of reservoir parameters prediction.

  19. 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.

  20. 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.

  1. Surface and Subsurface Geodesy Combined with Active Borehole Experimentation for the Advanced Characterization of EGS Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Elsworth, Derek [Pennsylvania State Univ., University Park, PA (United States); Im, Kyungjae [Pennsylvania State Univ., University Park, PA (United States); Guglielmi, Yves [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mattioli, Glen [Univ. of Texas, Arlington, TX (United States). UNAVCO

    2016-11-14

    We explore the utility of combining active downhole experimentation with borehole and surface geodesy to determine both the characteristics and evolving state of EGS reservoirs during stimulation through production. The study is divided into two parts. We demonstrate the feasibility of determining in situ reservoir characteristics of reservoir size, strain and fracture permeability and their dependence on feedbacks of stress and temperature using surface and borehole geodetic measurements (Part I). We then define the opportunity to apply the unique hydraulic pulse protocol (HPP) borehole tool to evaluate reservoir state. This can be accomplished by monitoring and co-inverting measured reservoir characteristics (from the HPP tool) with surface geodetic measurements of deformation, tilt and strain with continuous measurements of borehole-wall strain (via optical fiber and fiber Bragg gratings) and measured flow rates (Part II).

  2. A rationale for reservoir management economics

    International Nuclear Information System (INIS)

    Hickman, T.S.

    1995-01-01

    Significant economic benefits can be derived from the application f reservoir management. The key elements in economical reservoir management are the efficient use of available resources and optimization of reservoir exploitation through a multidisciplined approach. This paper describes various aspects of and approaches to reservoir management and provides case histories that support the findings

  3. Local Refinement of the Super Element Model of Oil Reservoir

    Directory of Open Access Journals (Sweden)

    A.B. Mazo

    2017-12-01

    Full Text Available In this paper, we propose a two-stage method for petroleum reservoir simulation. The method uses two models with different degrees of detailing to describe hydrodynamic processes of different space-time scales. At the first stage, the global dynamics of the energy state of the deposit and reserves is modeled (characteristic scale of such changes is km / year. The two-phase flow equations in the model of global dynamics operate with smooth averaged pressure and saturation fields, and they are solved numerically on a large computational grid of super-elements with a characteristic cell size of 200-500 m. The tensor coefficients of the super-element model are calculated using special procedures of upscaling of absolute and relative phase permeabilities. At the second stage, a local refinement of the super-element model is constructed for calculating small-scale processes (with a scale of m / day, which take place, for example, during various geological and technical measures aimed at increasing the oil recovery of a reservoir. Then we solve the two-phase flow problem in the selected area of the measure exposure on a detailed three-dimensional grid, which resolves the geological structure of the reservoir, and with a time step sufficient for describing fast-flowing processes. The initial and boundary conditions of the local problem are formulated on the basis of the super-element solution. This approach allows us to reduce the computational costs in order to solve the problems of designing and monitoring the oil reservoir. To demonstrate the proposed approach, we give an example of the two-stage modeling of the development of a layered reservoir with a local refinement of the model during the isolation of a water-saturated high-permeability interlayer. We show a good compliance between the locally refined solution of the super-element model in the area of measure exposure and the results of numerical modeling of the whole history of reservoir

  4. Estimation of oil reservoir thermal properties through temperature log data using inversion method

    International Nuclear Information System (INIS)

    Cheng, Wen-Long; Nian, Yong-Le; Li, Tong-Tong; Wang, Chang-Long

    2013-01-01

    Oil reservoir thermal properties not only play an important role in steam injection well heat transfer, but also are the basic parameters for evaluating the oil saturation in reservoir. In this study, for estimating reservoir thermal properties, a novel heat and mass transfer model of steam injection well was established at first, this model made full analysis on the wellbore-reservoir heat and mass transfer as well as the wellbore-formation, and the simulated results by the model were quite consistent with the log data. Then this study presented an effective inversion method for estimating the reservoir thermal properties through temperature log data. This method is based on the heat transfer model in steam injection wells, and can be used to predict the thermal properties as a stochastic approximation method. The inversion method was applied to estimate the reservoir thermal properties of two steam injection wells, it was found that the relative error of thermal conductivity for the two wells were 2.9% and 6.5%, and the relative error of volumetric specific heat capacity were 6.7% and 7.0%,which demonstrated the feasibility of the proposed method for estimating the reservoir thermal properties. - Highlights: • An effective inversion method for predicting the oil reservoir thermal properties was presented. • A novel model for steam injection well made full study on the wellbore-reservoir heat and mass transfer. • The wellbore temperature field and steam parameters can be simulated by the model efficiently. • Both reservoirs and formation thermal properties could be estimated simultaneously by the proposed method. • The estimated steam temperature was quite consistent with the field data

  5. Integration of Seismic and Petrophysics to Characterize Reservoirs in “ALA” Oil Field, Niger Delta

    Directory of Open Access Journals (Sweden)

    P. A. Alao

    2013-01-01

    Full Text Available In the exploration and production business, by far the largest component of geophysical spending is driven by the need to characterize (potential reservoirs. The simple reason is that better reservoir characterization means higher success rates and fewer wells for reservoir exploitation. In this research work, seismic and well log data were integrated in characterizing the reservoirs on “ALA” field in Niger Delta. Three-dimensional seismic data was used to identify the faults and map the horizons. Petrophysical parameters and time-depth structure maps were obtained. Seismic attributes was also employed in characterizing the reservoirs. Seven hydrocarbon-bearing reservoirs with thickness ranging from 9.9 to 71.6 m were delineated. Structural maps of horizons in six wells containing hydrocarbon-bearing zones with tops and bottoms at range of −2,453 to −3,950 m were generated; this portrayed the trapping mechanism to be mainly fault-assisted anticlinal closures. The identified prospective zones have good porosity, permeability, and hydrocarbon saturation. The environments of deposition were identified from log shapes which indicate a transitional-to-deltaic depositional environment. In this research work, new prospects have been recommended for drilling and further research work. Geochemical and biostratigraphic studies should be done to better characterize the reservoirs and reliably interpret the depositional environments.

  6. Integration of seismic and petrophysics to characterize reservoirs in "ALA" oil field, Niger Delta.

    Science.gov (United States)

    Alao, P A; Olabode, S O; Opeloye, S A

    2013-01-01

    In the exploration and production business, by far the largest component of geophysical spending is driven by the need to characterize (potential) reservoirs. The simple reason is that better reservoir characterization means higher success rates and fewer wells for reservoir exploitation. In this research work, seismic and well log data were integrated in characterizing the reservoirs on "ALA" field in Niger Delta. Three-dimensional seismic data was used to identify the faults and map the horizons. Petrophysical parameters and time-depth structure maps were obtained. Seismic attributes was also employed in characterizing the reservoirs. Seven hydrocarbon-bearing reservoirs with thickness ranging from 9.9 to 71.6 m were delineated. Structural maps of horizons in six wells containing hydrocarbon-bearing zones with tops and bottoms at range of -2,453 to -3,950 m were generated; this portrayed the trapping mechanism to be mainly fault-assisted anticlinal closures. The identified prospective zones have good porosity, permeability, and hydrocarbon saturation. The environments of deposition were identified from log shapes which indicate a transitional-to-deltaic depositional environment. In this research work, new prospects have been recommended for drilling and further research work. Geochemical and biostratigraphic studies should be done to better characterize the reservoirs and reliably interpret the depositional environments.

  7. Femoral venous oxygen saturation is no surrogate for central venous oxygen saturation

    NARCIS (Netherlands)

    van Beest, Paul A.; van der Schors, Alice; Liefers, Henriëtte; Coenen, Ludo G. J.; Braam, Richard L.; Habib, Najib; Braber, Annemarije; Scheeren, Thomas W. L.; Kuiper, Michaël A.; Spronk, Peter E.

    2012-01-01

    Objective: The purpose of our study was to determine if central venous oxygen saturation and femoral venous oxygen saturation can be used interchangeably during surgery and in critically ill patients. Design: Prospective observational controlled study. Setting: Nonacademic university-affiliated

  8. Ultrafast THz Saturable Absorption in Semiconductors

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hoffmann, Matthias C.

    2011-01-01

    We demonstrate THz saturable absorption in n-doped semiconductors GaAs, GaP, and Ge in a nonlinear THz time-domain spectroscopy experiment. Saturable absorption is caused by sample conductivity modulation due to electron heating and satellite valley scattering in the field of a strong THz pulse....

  9. Determination of saturation functions and wettability for chalk based on measured fluid saturations

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, D.; Bech, N.; Moeller Nielsen, C.

    1998-08-01

    The end effect of displacement experiments on low permeable porous media is used for determination of relative permeability functions and capillary pressure functions. Saturation functions for a drainage process are determined from a primary drainage experiment. A reversal of the flooding direction creates an intrinsic imbibition process in the sample, which enables determination if imbibition saturation functions. The saturation functions are determined by a parameter estimation technique. Scanning effects are modelled by the method of Killough. Saturation profiles are determined by NMR. (au)

  10. Full Waveform Inversion for Reservoir Characterization - A Synthetic Study

    KAUST Repository

    Zabihi Naeini, E.

    2017-05-26

    Most current reservoir-characterization workflows are based on classic amplitude-variation-with-offset (AVO) inversion techniques. Although these methods have generally served us well over the years, here we examine full-waveform inversion (FWI) as an alternative tool for higher-resolution reservoir characterization. An important step in developing reservoir-oriented FWI is the implementation of facies-based rock physics constraints adapted from the classic methods. We show that such constraints can be incorporated into FWI by adding appropriately designed regularization terms to the objective function. The advantages of the proposed algorithm are demonstrated on both isotropic and VTI (transversely isotropic with a vertical symmetry axis) models with pronounced lateral and vertical heterogeneity. The inversion results are explained using the theoretical radiation patterns produced by perturbations in the medium parameters.

  11. Real-time optimisation of the Hoa Binh reservoir, Vietnam

    DEFF Research Database (Denmark)

    Richaud, Bertrand; Madsen, Henrik; Rosbjerg, Dan

    2011-01-01

    -time optimisation. First, the simulation-optimisation framework is applied for optimising reservoir operating rules. Secondly, real-time and forecast information is used for on-line optimisation that focuses on short-term goals, such as flood control or hydropower generation, without compromising the deviation...... in the downstream part of the Red River, and at the same time to increase hydropower generation and to save water for the dry season. The real-time optimisation procedure further improves the efficiency of the reservoir operation and enhances the flexibility for the decision-making. Finally, the quality......Multi-purpose reservoirs often have to be managed according to conflicting objectives, which requires efficient tools for trading-off the objectives. This paper proposes a multi-objective simulation-optimisation approach that couples off-line rule curve optimisation with on-line real...

  12. Time-lapse cased hole reservoir evaluation based on the dual-detector neutron lifetime log: the CHES II approach

    International Nuclear Information System (INIS)

    DeVries, M.R.; Fertl, W.

    1977-01-01

    A newly developed cased hole analysis technique provides detailed information on (1) reservoir rock properties, such as porosity, shaliness, and formation permeability, (2) reservoir fluid saturation, (3) distinction of oil and gas pays, (4) state of reservoir depletion, such as cumulative hydrocarbon-feet at present time and cumulative hydrocarbon-feet already depleted (e.g., the sum of both values then giving the cumulative hydrocarbon-feet originally present), and (5) monitoring of hydrocarbon/water and gas/oil contacts behind pipe. The basic well log data required for this type of analysis include the Dual-Detector Neutron Lifetime Log, run in casing at any particular time in the life of a reservoir, and the initial open-hole resistivity log. In addition, porosity information from open-hole porosity log(s) or core data is necessary. Field examples from several areas are presented and discussed in the light of formation reservoir and hydrocarbon production characteristics

  13. Two-phase flow in volatile oil reservoir using two-phase pseudo-pressure well test method

    Energy Technology Data Exchange (ETDEWEB)

    Sharifi, M.; Ahmadi, M. [Calgary Univ., AB (Canada)

    2009-09-15

    A study was conducted to better understand the behaviour of volatile oil reservoirs. Retrograde condensation occurs in gas-condensate reservoirs when the flowing bottomhole pressure (BHP) lowers below the dewpoint pressure, thus creating 4 regions in the reservoir with different liquid saturations. Similarly, when the BHP of volatile oil reservoirs falls below the bubblepoint pressure, two phases are created in the region around the wellbore, and a single phase (oil) appears in regions away from the well. In turn, higher gas saturation causes the oil relative permeability to decrease towards the near-wellbore region. Reservoir compositional simulations were used in this study to predict the fluid behaviour below the bubblepoint. The flowing bottomhole pressure was then exported to a well test package to diagnose the occurrence of different mobility regions. The study also investigated the use of a two-phase pseudo-pressure method on volatile and highly volatile oil reservoirs. It was concluded that this method can successfully predict the true permeability and mechanical skin. It can also distinguish between mechanical skin and condensate bank skin. As such, the two-phase pseudo-pressure method is particularly useful for developing after-drilling well treatment and enhanced oil recovery process designs. However, accurate relative permeability and PVT data must be available for reliable interpretation of the well test in volatile oil reservoirs. 18 refs., 3 tabs., 9 figs.

  14. A Parallel Saturation Algorithm on Shared Memory Architectures

    Science.gov (United States)

    Ezekiel, Jonathan; Siminiceanu

    2007-01-01

    Symbolic state-space generators are notoriously hard to parallelize. However, the Saturation algorithm implemented in the SMART verification tool differs from other sequential symbolic state-space generators in that it exploits the locality of ring events in asynchronous system models. This paper explores whether event locality can be utilized to efficiently parallelize Saturation on shared-memory architectures. Conceptually, we propose to parallelize the ring of events within a decision diagram node, which is technically realized via a thread pool. We discuss the challenges involved in our parallel design and conduct experimental studies on its prototypical implementation. On a dual-processor dual core PC, our studies show speed-ups for several example models, e.g., of up to 50% for a Kanban model, when compared to running our algorithm only on a single core.

  15. Modelling suction instabilities in soils at varying degrees of saturation

    Directory of Open Access Journals (Sweden)

    Buscarnera Giuseppe

    2016-01-01

    Full Text Available Wetting paths imparted by the natural environment and/or human activities affect the state of soils in the near-surface, promoting transitions across different regimes of saturation. This paper discusses a set of techniques aimed at quantifying the role of hydrologic processes on the hydro-mechanical stability of soil specimens subjected to saturation events. Emphasis is given to the mechanical conditions leading to coupled flow/deformation instabilities. For this purpose, energy balance arguments for three-phase systems are used to derive second-order work expressions applicable to various regimes of saturation. Controllability analyses are then performed to relate such work input with constitutive singularities that reflect the loss of strength under coupled and/or uncoupled hydro-mechanical forcing. A suction-dependent plastic model is finally used to track the evolution of stability conditions in samples subjected to wetting, thus quantifying the growth of the potential for coupled failure modes upon increasing degree of saturation. These findings are eventually linked with the properties of the field equations that govern pore pressure transients, thus disclosing a conceptual link between the onset of coupled hydro-mechanical failures and the evolution of suction with time. Such results point out that mathematical instabilities caused by a non-linear suction dependent behaviour play an important role in the advanced constitutive and/or numerical tools that are commonly used for the analysis of geomechanical problems in the unsaturated zone, and further stress that the relation between suction transients and soil deformations is a key factor for the interpretation of runaway failures caused by intense saturation events.

  16. In-situ gas hydrate hydrate saturation estimated from various well logs at the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope

    Science.gov (United States)

    Lee, M.W.; Collett, T.S.

    2011-01-01

    In 2006, the U.S. Geological Survey (USGS) completed detailed analysis and interpretation of available 2-D and 3-D seismic data and proposed a viable method for identifying sub-permafrost gas hydrate prospects within the gas hydrate stability zone in the Milne Point area of northern Alaska. To validate the predictions of the USGS and to acquire critical reservoir data needed to develop a long-term production testing program, a well was drilled at the Mount Elbert prospect in February, 2007. Numerous well log data and cores were acquired to estimate in-situ gas hydrate saturations and reservoir properties.Gas hydrate saturations were estimated from various well logs such as nuclear magnetic resonance (NMR), P- and S-wave velocity, and electrical resistivity logs along with pore-water salinity. Gas hydrate saturations from the NMR log agree well with those estimated from P- and S-wave velocity data. Because of the low salinity of the connate water and the low formation temperature, the resistivity of connate water is comparable to that of shale. Therefore, the effect of clay should be accounted for to accurately estimate gas hydrate saturations from the resistivity data. Two highly gas hydrate-saturated intervals are identified - an upper ???43 ft zone with an average gas hydrate saturation of 54% and a lower ???53 ft zone with an average gas hydrate saturation of 50%; both zones reach a maximum of about 75% saturation. ?? 2009.

  17. Cengklik Reservoir Performance and Its Role for Drought Mitigation

    Directory of Open Access Journals (Sweden)

    Yovi Hardiyanto

    2015-05-01

    Full Text Available Water availability problem is encountered by Cengklik Reservoir due to drought disaster in the current year. It causes irrigation water crisis over 850 hectares crop field which of 350 hectares were not cultivated. The risk that must be faced by farmers is decrease in potential productivity, losses about more than 2.5 billion. Therefore, it needs technical solution to reduce this drought disaster risk. To obtain an alternative solution against water availability problem for drought disaster mitigation, this research used optimization of reservoir standard operating simulation. It applies field area of rice or Palawija at the second and/or the third cultivation season as decision variable, maximum productivity value as objective function, irrigation water demand as parameter depending on specified alternative crop pattern and schedule, and several constraints comprising 100% of reservoir reliability, all field is irrigated at the first and second season in which maximum non-irrigated crop field at the third cultivation season are 300 hectares. The tool used to conduct optimization was Microsoft Excel software. The result showed that crop pattern considered as an alternative solution against water availability problem in Cengklik reservoir is paddy-paddy-maize at the early of November II cultivated over 433 hectares and 1524 hectares. Risk reduction reached 9.33% in term of reservoir reliability, 23.61% in term of irrigated area, and 27.29% in term of vulnerability towards water availability crisis.

  18. Decision Support System for Reservoir Management and Operation in Africa

    Science.gov (United States)

    Navar, D. A.

    2016-12-01

    Africa is currently experiencing a surge in dam construction for flood control, water supply and hydropower production, but ineffective reservoir management has caused problems in the region, such as water shortages, flooding and loss of potential hydropower generation. Our research aims to remedy ineffective reservoir management by developing a novel Decision Support System(DSS) to equip water managers with a technical planning tool based on the state of the art in hydrological sciences. The DSS incorporates a climate forecast model, a hydraulic model of the watershed, and an optimization model to effectively plan for the operation of a system of cascade large-scale reservoirs for hydropower production, while treating water supply and flood control as constraints. Our team will use the newly constructed hydropower plants in the Omo Gibe basin of Ethiopia as the test case. Using the basic HIDROTERM software developed in Brazil, the General Algebraic Modeling System (GAMS) utilizes a combination of linear programing (LP) and non-linear programming (NLP) in conjunction with real time hydrologic and energy demand data to optimize the monthly and daily operations of the reservoir system. We compare the DSS model results with the current reservoir operating policy used by the water managers of that region. We also hope the DSS will eliminate the current dangers associated with the mismanagement of large scale water resources projects in Africa.

  19. Cloud computing and Reservoir project

    International Nuclear Information System (INIS)

    Beco, S.; Maraschini, A.; Pacini, F.; Biran, O.

    2009-01-01

    The support for complex services delivery is becoming a key point in current internet technology. Current trends in internet applications are characterized by on demand delivery of ever growing amounts of content. The future internet of services will have to deliver content intensive applications to users with quality of service and security guarantees. This paper describes the Reservoir project and the challenge of a reliable and effective delivery of services as utilities in a commercial scenario. It starts by analyzing the needs of a future infrastructure provider and introducing the key concept of a service oriented architecture that combines virtualisation-aware grid with grid-aware virtualisation, while being driven by business service management. This article will then focus on the benefits and the innovations derived from the Reservoir approach. Eventually, a high level view of Reservoir general architecture is illustrated.

  20. Multilevel techniques for Reservoir Simulation

    DEFF Research Database (Denmark)

    Christensen, Max la Cour

    The subject of this thesis is the development, application and study of novel multilevel methods for the acceleration and improvement of reservoir simulation techniques. The motivation for addressing this topic is a need for more accurate predictions of porous media flow and the ability to carry...... Full Approximation Scheme) • Variational (Galerkin) upscaling • Linear solvers and preconditioners First, a nonlinear multigrid scheme in the form of the Full Approximation Scheme (FAS) is implemented and studied for a 3D three-phase compressible rock/fluids immiscible reservoir simulator...... is extended to include a hybrid strategy, where FAS is combined with Newton’s method to construct a multilevel nonlinear preconditioner. This method demonstrates high efficiency and robustness. Second, an improved IMPES formulated reservoir simulator is implemented using a novel variational upscaling approach...

  1. A sampling-based Bayesian model for gas saturation estimationusing seismic AVA and marine CSEM data

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jinsong; Hoversten, Michael; Vasco, Don; Rubin, Yoram; Hou,Zhangshuan

    2006-04-04

    We develop a sampling-based Bayesian model to jointly invertseismic amplitude versus angles (AVA) and marine controlled-sourceelectromagnetic (CSEM) data for layered reservoir models. The porosityand fluid saturation in each layer of the reservoir, the seismic P- andS-wave velocity and density in the layers below and above the reservoir,and the electrical conductivity of the overburden are considered asrandom variables. Pre-stack seismic AVA data in a selected time windowand real and quadrature components of the recorded electrical field areconsidered as data. We use Markov chain Monte Carlo (MCMC) samplingmethods to obtain a large number of samples from the joint posteriordistribution function. Using those samples, we obtain not only estimatesof each unknown variable, but also its uncertainty information. Thedeveloped method is applied to both synthetic and field data to explorethe combined use of seismic AVA and EM data for gas saturationestimation. Results show that the developed method is effective for jointinversion, and the incorporation of CSEM data reduces uncertainty influid saturation estimation, when compared to results from inversion ofAVA data only.

  2. Assessing species saturation: conceptual and methodological challenges.

    Science.gov (United States)

    Olivares, Ingrid; Karger, Dirk N; Kessler, Michael

    2018-05-07

    Is there a maximum number of species that can coexist? Intuitively, we assume an upper limit to the number of species in a given assemblage, or that a lineage can produce, but defining and testing this limit has proven problematic. Herein, we first outline seven general challenges of studies on species saturation, most of which are independent of the actual method used to assess saturation. Among these are the challenge of defining saturation conceptually and operationally, the importance of setting an appropriate referential system, and the need to discriminate among patterns, processes and mechanisms. Second, we list and discuss the methodological approaches that have been used to study species saturation. These approaches vary in time and spatial scales, and in the variables and assumptions needed to assess saturation. We argue that assessing species saturation is possible, but that many studies conducted to date have conceptual and methodological flaws that prevent us from currently attaining a good idea of the occurrence of species saturation. © 2018 Cambridge Philosophical Society.

  3. Reservoir effects in radiocarbon dating

    International Nuclear Information System (INIS)

    Head, M.J.

    1997-01-01

    Full text: The radiocarbon dating technique depends essentially on the assumption that atmospheric carbon dioxide containing the cosmogenic radioisotope 14 C enters into a state of equilibrium with all living material (plants and animals) as part of the terrestrial carbon cycle. Terrestrial reservoir effects occur when the atmospheric 14 C signal is diluted by local effects where systems depleted in 14 C mix with systems that are in equilibrium with the atmosphere. Naturally, this can occur with plant material growing close to an active volcano adding very old CO 2 to the atmosphere (the original 14 C has completely decayed). It can also occur in highly industrialised areas where fossil fuel derived CO 2 dilutes the atmospheric signal. A terrestrial reservoir effect can occur in the case of fresh water shells living in rivers or lakes where there is an input of ground water from springs or a raising of the water table. Soluble bicarbonate derived from the dissolution of very old limestone produces a 14 C dilution effect. Land snail shells and stream carbonate depositions (tufas and travertines) can be affected by a similar mechanism. Alternatively, in specific cases, these reservoir effects may not occur. This means that general interpretations assuming quantitative values for these terrestrial effects are not possible. Each microenvironment associated with samples being analysed needs to be evaluated independently. Similarly, the marine environment produces reservoir effects. With respect to marine shells and corals, the water depth at which carbonate growth occurs can significantly affect quantitative 14 C dilution, especially in areas where very old water is uplifted, mixing with top layers of water that undergo significant exchange with atmospheric CO 2 . Hence, generalisations with respect to the marine reservoir effect also pose problems. These can be exacerbated by the mixing of sea water with either terrestrial water in estuaries, or ground water where

  4. Predicting Formation Damage in Aquifer Thermal Energy Storage Systems Utilizing a Coupled Hydraulic-Thermal-Chemical Reservoir Model

    Science.gov (United States)

    Müller, Daniel; Regenspurg, Simona; Milsch, Harald; Blöcher, Guido; Kranz, Stefan; Saadat, Ali

    2014-05-01

    formation damage in ATES systems. We would like to present preliminary results of the structural reservoir model and the hydraulic-thermal-chemical coupling for the demonstration site. Literature: Wissmeier, L. and Barry, D.A., 2011. Simulation tool for variably saturated flow with comprehensive geochemical reactions in two- and three-dimensional domains. Environmental Modelling & Software 26, 210-218.

  5. Assessment of oxygen saturation in dental pulp of permanent teeth with periodontal disease.

    Science.gov (United States)

    Giovanella, Larissa Bergesch; Barletta, Fernando Branco; Felippe, Wilson Tadeu; Bruno, Kely Firmino; de Alencar, Ana Helena Gonçalves; Estrela, Carlos

    2014-12-01

    In individuals with periodontal disease, dental pulp status should be determined before a treatment plan is made. Pulse oximeters are promising diagnostic tools to evaluate pulp vascularization. This study used pulse oximetry to determine the level of oxygen saturation in dental pulp of intact permanent teeth with periodontal attachment loss (PAL) and gingival recession (GR) and to evaluate the correlation between periodontal disease and level of oxygen saturation in the pulp. This study included 67 anterior teeth of 35 patients; all teeth showed intact crowns, PAL, a periodontal pocket (PP), and GR. The teeth underwent periodontal examination, cold and electric pulp testing, and pulse oximetry measurements. The Pearson correlation coefficient and a linear regression coefficient were calculated to evaluate the degree of correlation between periodontal disease markers (PAL, PP, and GR) and the level of oxygen saturation in dental pulp. These tests also evaluated possible associations between oxygen saturation and cold and electric pulp testing. PAL, PP, and GR had negative correlations with oxygen saturation in dental pulp. Conversely, no statistically significant association was found between oxygen saturation in dental pulp and the response to electric sensibility testing. Oxygen saturation was lower in the pulp of permanent teeth with PAL, PP, and GR, indicating that periodontal disease correlates with the level of oxygen saturation in the pulp. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  6. Sedimentological and Geomorphological Effects of Reservoir Flushing: The Cachi Reservoir, Costa Rica, 1996

    DEFF Research Database (Denmark)

    Brandt, Anders; Swenning, Joar

    1999-01-01

    Physical geography, hydrology, geomorphology, sediment transport, erosion, sedimentation, dams, reservoirs......Physical geography, hydrology, geomorphology, sediment transport, erosion, sedimentation, dams, reservoirs...

  7. Saturation and forward jets at HERA

    International Nuclear Information System (INIS)

    Marquet, C.; Peschanski, R.; Royon, C.

    2004-01-01

    We analyse forward-jet production at HERA in the framework of the Golec-Biernat and Wusthoff saturation models. We obtain a good description of the forward-jet cross-sections measured by the H1 and ZEUS Collaborations in the two-hard-scale region (k T∼ Q >> Λ QCD ) with two different parametrizations with either significant or weak saturation effects. The weak saturation parametrization gives a scale compatible with the one found for the proton structure function F2. We argue that Mueller-Navelet jets at the Tevatron and the LHC could help distinguishing between both options

  8. Scintillation probe with photomultiplier tube saturation indicator

    International Nuclear Information System (INIS)

    Ruch, J.F.; Urban, D.J.

    1996-01-01

    A photomultiplier tube saturation indicator is formed by supplying a supplemental light source, typically an light emitting diode (LED), adjacent to the photomultiplier tube. A switch allows the light source to be activated. The light is forwarded to the photomultiplier tube by an optical fiber. If the probe is properly light tight, then a meter attached to the indicator will register the light from the LED. If the probe is no longer light tight, and the saturation indicator is saturated, no signal will be registered when the LED is activated. 2 figs

  9. Avo analysis in the high impedance reservoir of Chuchupa Field

    International Nuclear Information System (INIS)

    Cediel Mauricio; Almanza Ovidio; Montes Luis

    2012-01-01

    The technique of bright spot as a direct indicator of hydrocarbons has been widely used since the work of Ostrander (1984), particularly in gas fields. Located at north of Colombia, the Chuchupa field has produced gas continuously during 30 years, but despite the coverage with 2D seismic, amplitude anomalies associated with gas accumulation have not been observed. In order to find the relationships between the amplitude information and the gas accumulation, an AVO analysis was performed to describe the seismic reservoir response. The raw data of a 2D seismic line that crosses the field from East to West and a well log data set were used. In a first approach the seismic response was modeled using well logs, so a comparative analysis between the furnished synthetic seismograms and the real CDP gathers was done. The results indicated that the reservoirs top is represented by a low amplitude peak which decreases when the offset increases but whose phase remains unchanged. In the well, where the reservoir has 100% gas saturation, a high correlation between the synthetic and real CDP gathers was observed. In a second approach, anomalous clustered points in the IV quadrant were discriminated through intercept versus gradient cross plot analysis. A weak Class-I anomaly was identified, which could not be observed in stacked sections and hence it should be analyzed using pre-stack data.

  10. Prevention of Reservoir Interior Discoloration

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, K.F.

    2001-04-03

    Contamination is anathema in reservoir production. Some of the contamination is a result of welding and some appears after welding but existed before. Oxygen was documented to be a major contributor to discoloration in welding. This study demonstrates that it can be controlled and that some of the informal cleaning processes contribute to contamination.

  11. Nonlinear Multigrid for Reservoir Simulation

    DEFF Research Database (Denmark)

    Christensen, Max la Cour; Eskildsen, Klaus Langgren; Engsig-Karup, Allan Peter

    2016-01-01

    efficiency for a black-oil model. Furthermore, the use of the FAS method enables a significant reduction in memory usage compared with conventional techniques, which suggests new possibilities for improved large-scale reservoir simulation and numerical efficiency. Last, nonlinear multilevel preconditioning...

  12. Minimum K_2,3-saturated Graphs

    OpenAIRE

    Chen, Ya-Chen

    2010-01-01

    A graph is K_{2,3}-saturated if it has no subgraph isomorphic to K_{2,3}, but does contain a K_{2,3} after the addition of any new edge. We prove that the minimum number of edges in a K_{2,3}-saturated graph on n >= 5 vertices is sat(n, K_{2,3}) = 2n - 3.

  13. Semiconductor saturable absorbers for ultrafast THz signals

    DEFF Research Database (Denmark)

    Hoffmann, Matthias C.; Turchinovich, Dmitry

    We demonstrate saturable absorber behavior of n-type semiconductors in the THz frequency range using nonlinear THz spectroscopy. Further, we observe THz pulse shortening and increase of the group refractive index at high field strengths.......We demonstrate saturable absorber behavior of n-type semiconductors in the THz frequency range using nonlinear THz spectroscopy. Further, we observe THz pulse shortening and increase of the group refractive index at high field strengths....

  14. Ultrafast THz Saturable Absorption in Doped Semiconductors

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hoffmann, Matthias C.

    2011-01-01

    We demonstrate ultrafast THz saturable absorption in n-doped semiconductors by nonlinear THz time-domain spectroscopy. This effect is caused by the semiconductor conductivity modulation due to electron heating and satellite-valley scattering in strong THz fields.......We demonstrate ultrafast THz saturable absorption in n-doped semiconductors by nonlinear THz time-domain spectroscopy. This effect is caused by the semiconductor conductivity modulation due to electron heating and satellite-valley scattering in strong THz fields....

  15. Simulation and optimisation modelling approach for operation of the Hoa Binh Reservoir, Vietnam

    DEFF Research Database (Denmark)

    Ngo, Long le; Madsen, Henrik; Rosbjerg, Dan

    2007-01-01

    Hoa Binh, the largest reservoir in Vietnam, plays an important role in flood control for the Red River delta and hydropower generation. Due to its multi-purpose character, conflicts and disputes in operating the reservoir have been ongoing since its construction, particularly in the flood season....... This paper proposes to optimise the control strategies for the Hoa Binh reservoir operation by applying a combination of simulation and optimisation models. The control strategies are set up in the MIKE 11 simulation model to guide the releases of the reservoir system according to the current storage level......, the hydro-meteorological conditions, and the time of the year. A heuristic global optimisation tool, the shuffled complex evolution (SCE) algorithm, is adopted for optimising the reservoir operation. The optimisation puts focus on the trade-off between flood control and hydropower generation for the Hoa...

  16. Cased-hole log analysis and reservoir performance monitoring

    CERN Document Server

    Bateman, Richard M

    2015-01-01

    This book addresses vital issues, such as the evaluation of shale gas reservoirs and their production. Topics include the cased-hole logging environment, reservoir fluid properties; flow regimes; temperature, noise, cement bond, and pulsed neutron logging; and casing inspection. Production logging charts and tables are included in the appendices. The work serves as a comprehensive reference for production engineers with upstream E&P companies, well logging service company employees, university students, and petroleum industry training professionals. This book also: ·       Provides methods of conveying production logging tools along horizontal well segments as well as measurements of formation electrical resistivity through casing ·       Covers new information on fluid flow characteristics in inclined pipe and provides new and improved nuclear tool measurements in cased wells ·       Includes updates on cased-hole wireline formation testing  

  17. 49 CFR 236.792 - Reservoir, equalizing.

    Science.gov (United States)

    2010-10-01

    ... Reservoir, equalizing. An air reservoir connected with and adding volume to the top portion of the equalizing piston chamber of the automatic brake valve, to provide uniform service reductions in brake pipe...

  18. Impact of Petrophysical Properties on Hydraulic Fracturing and Development in Tight Volcanic Gas Reservoirs

    Directory of Open Access Journals (Sweden)

    Yinghao Shen

    2017-01-01

    Full Text Available The volcanic reservoir is an important kind of unconventional reservoir. The aqueous phase trapping (APT appears because of fracturing fluids filtration. However, APT can be autoremoved for some wells after certain shut-in time. But there is significant distinction for different reservoirs. Experiments were performed to study the petrophysical properties of a volcanic reservoir and the spontaneous imbibition is monitored by nuclear magnetic resonance (NMR and pulse-decay permeability. Results showed that natural cracks appear in the samples as well as high irreducible water saturation. There is a quick decrease of rock permeability once the rock contacts water. The pores filled during spontaneous imbibition are mainly the nanopores from NMR spectra. Full understanding of the mineralogical effect and sample heterogeneity benefits the selection of segments to fracturing. The fast flow-back scheme is applicable in this reservoir to minimize the damage. Because lots of water imbibed into the nanopores, the main flow channels become larger, which are beneficial to the permeability recovery after flow-back of hydraulic fracturing. This is helpful in understanding the APT autoremoval after certain shut-in time. Also, Keeping the appropriate production differential pressure is very important in achieving the long term efficient development of volcanic gas reservoirs.

  19. Seismic modeling of acid-gas injection in a deep saline reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Ursenbach, C.P.; Lawton, D.C. [Calgary Univ., AB (Canada). Dept. of Geoscience, Consortium for Research in Elastic Wave Exploration Seismology

    2008-07-01

    Carbon dioxide (CO{sub 2}) and hydrogen sulfide (H{sub 2}S) are common byproducts of the energy industry. As such, remediation studies are underway to determine the feasibility of sequestering these byproducts in subsurface reservoirs, including deep saline reservoirs. Acid gas injection at smaller gas wells holds promise. However, in order for such injection programs to work, the progress of the injection plume must be tracked. A modeling study of fluid substitution was carried out to gain insight into the ability of seismic monitoring to distinguish pre- and post-injection states of the reservoir medium. The purpose of this study was to carry out fluid substitution calculations for the modeling of an injection process. A methodology that may be applied or adapted to a variety of acid-gas injection scenarios was also developed. The general approach involved determining acoustic properties at reservoir temperature and pressure of relevant fluids; obtaining elastic properties of the reservoir rock for some reference saturated state, and the elastic properties of the mineral comprising it; and, determining the change in reservoir elastic properties due to fluid substitution via Gassmann's equation. Water, brine and non-aqueous acid gas were the 3 fluids of interest in this case. The feasibility of monitoring was judged by the sensitivity of travel times and reflection coefficients to fluid substitution. 4 refs., 2 figs.

  20. Strength and Biot's coefficient for high-porosity oil- or water-saturated chalk

    DEFF Research Database (Denmark)

    Andreassen, Katrine Alling

    . The Biot coefficient states the degree of cementation or how the pore pressure contributes to the strain resulting from an external load for a porous material. It is here calculated from dynamic measurements and correlated with the strength of outcrop chalk characterized by the onset of pore collapse...... during hydrostatic loading. The hypothesis is that the Biot coefficient and the theory of poroelasticity may cover the fluid effect by including the increased fluid bulk modulus from oil to water. A high number of test results for both oil- and water-saturated high-porosity outcrop chalk show correlation......In the petroleum industry it is relevant to know the Biot coefficient for establishing the effective stresses present in both the overburden and for the reservoir interval. When depleting a reservoir it is important to estimate the settlement through the strain imposed by the effective stress. Also...

  1. RECENT ADVANCES IN NATURALLY FRACTURED RESERVOIR MODELING

    OpenAIRE

    ORDOÑEZ, A; PEÑUELA, G; IDROBO, E. A; MEDINA, C. E

    2001-01-01

    Large amounts of oil reserves are contained in naturally fractured reservoirs. Most of these hydrocarbon volumes have been left behind because of the poor knowledge and/or description methodology of those reservoirs. This lack of knowledge has lead to the nonexistence of good quantitative models for this complicated type of reservoirs. The complexity of naturally fractured reservoirs causes the need for integration of all existing information at all scales (drilling, well logging, seismic, we...

  2. 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

  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. SATURATED ZONE IN-SITU TESTING

    Energy Technology Data Exchange (ETDEWEB)

    P.W. REIMUS

    2004-11-08

    The purpose of this scientific analysis is to document the results and interpretations of field experiments that test and validate conceptual flow and radionuclide transport models in the saturated zone (SZ) near Yucca Mountain, Nevada. The test interpretations provide estimates of flow and transport parameters used in the development of parameter distributions for total system performance assessment (TSPA) calculations. These parameter distributions are documented in ''Site-Scale Saturated Zone Flow Model (BSC 2004 [DIRS 170037]), Site-Scale Saturated Zone Transport'' (BSC 2004 [DIRS 170036]), Saturated Zone Colloid Transport (BSC 2004 [DIRS 170006]), and ''Saturated Zone Flow and Transport Model Abstraction'' (BSC 2004 [DIRS 170042]). Specifically, this scientific analysis contributes the following to the assessment of the capability of the SZ to serve as part of a natural barrier for waste isolation for the Yucca Mountain repository system: (1) The bases for selection of conceptual flow and transport models in the saturated volcanics and the saturated alluvium located near Yucca Mountain. (2) Results and interpretations of hydraulic and tracer tests conducted in saturated fractured volcanics at the C-wells complex near Yucca Mountain. The test interpretations include estimates of hydraulic conductivities, anisotropy in hydraulic conductivity, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass transfer coefficients, matrix diffusion coefficients, fracture apertures, and colloid transport parameters. (3) Results and interpretations of hydraulic and tracer tests conducted in saturated alluvium at the Alluvial Testing Complex (ATC) located at the southwestern corner of the Nevada Test Site (NTS). The test interpretations include estimates of hydraulic conductivities, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass

  5. SATURATED ZONE IN-SITU TESTING

    International Nuclear Information System (INIS)

    REIMUS, P.W.

    2004-01-01

    The purpose of this scientific analysis is to document the results and interpretations of field experiments that test and validate conceptual flow and radionuclide transport models in the saturated zone (SZ) near Yucca Mountain, Nevada. The test interpretations provide estimates of flow and transport parameters used in the development of parameter distributions for total system performance assessment (TSPA) calculations. These parameter distributions are documented in ''Site-Scale Saturated Zone Flow Model (BSC 2004 [DIRS 170037]), Site-Scale Saturated Zone Transport'' (BSC 2004 [DIRS 170036]), Saturated Zone Colloid Transport (BSC 2004 [DIRS 170006]), and ''Saturated Zone Flow and Transport Model Abstraction'' (BSC 2004 [DIRS 170042]). Specifically, this scientific analysis contributes the following to the assessment of the capability of the SZ to serve as part of a natural barrier for waste isolation for the Yucca Mountain repository system: (1) The bases for selection of conceptual flow and transport models in the saturated volcanics and the saturated alluvium located near Yucca Mountain. (2) Results and interpretations of hydraulic and tracer tests conducted in saturated fractured volcanics at the C-wells complex near Yucca Mountain. The test interpretations include estimates of hydraulic conductivities, anisotropy in hydraulic conductivity, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass transfer coefficients, matrix diffusion coefficients, fracture apertures, and colloid transport parameters. (3) Results and interpretations of hydraulic and tracer tests conducted in saturated alluvium at the Alluvial Testing Complex (ATC) located at the southwestern corner of the Nevada Test Site (NTS). The test interpretations include estimates of hydraulic conductivities, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass transfer coefficients, and colloid

  6. Approaches to identifying reservoir heterogeneity and reserve growth opportunities from subsurface data: The Oficina Formation, Budare field, Venezuela

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, D.S.; Raeuchle, S.K.; Holtz, M.H. [Bureau of Economic Geology, Austin, TX (United States)] [and others

    1997-08-01

    We applied an integrated geologic, geophysical, and engineering approach devised to identify heterogeneities in the subsurface that might lead to reserve growth opportunities in our analysis of the Oficina Formation at Budare field, Venezuela. The approach involves 4 key steps: (1) Determine geologic reservoir architecture; (2) Investigate trends in reservoir fluid flow; (3) Integrate fluid flow trends with reservoir architecture; and (4) Estimate original oil-in-place, residual oil saturation, and remaining mobile oil, to identify opportunities for reserve growth. There are three main oil-producing reservoirs in the Oficina Formation that were deposited in a bed-load fluvial system, an incised valley-fill, and a barrier-strandplain system. Reservoir continuity is complex because, in addition to lateral facies variability, the major Oficina depositional systems were internally subdivided by high-frequency stratigraphic surfaces. These surfaces define times of intermittent lacustrine and marine flooding events that punctuated the fluvial and marginal marine sedimentation, respectively. Syn and post depositional faulting further disrupted reservoir continuity. Trends in fluid flow established from initial fluid levels, response to recompletion workovers, and pressure depletion data demonstrated barriers to lateral and vertical fluid flow caused by a combination of reservoir facies pinchout, flooding shale markers, and the faults. Considerable reserve growth potential exists at Budare field because the reservoir units are highly compartment by the depositional heterogeneity and structural complexity. Numerous reserve growth opportunities were identified in attics updip of existing production, in untapped or incompletely drained compartments, and in field extensions.

  7. Sleeving-back of horizontal wells to control downstream oil saturation and improve oil recovery

    Energy Technology Data Exchange (ETDEWEB)

    Greaves, M.; Saghr, A. M. [Bath Univ (United Kingdom)

    1998-12-31

    Air injection has become popular as an enhanced recovery technology, applicable over a wide variety of reservoir conditions including heavy, medium and light oils. One problem observed in light oil reservoirs is the tendency to desaturate the oil layer downstream of the moving front. This is particularly common in the case of thermal recovery processes. In this experiment designed to study ways to restrict the de-saturation of the oil layer, a modified horizontal producer well, incorporating a `sleeve-back` principal was used. The objective was to replicate the `toe-to-heel` displacement process occurring during heavy oil recovery, wherein downstream oil is essentially immobile due to its high viscosity. The `sleeve-back` of the well was achieved using a co-aligned, two-well assembly, so that the upstream section of the horizontal producer well was active, and continuously adjusted during propagation of the combustion front. The use of this continuous `sleeve-back` operation to control the level of de-saturation in the downstream section of a sand pack was successful as confirmed by the very high oil recovery achieved, equivalent to 93.5 per cent of oil in place. The level of CO{sub 2} production was also very high. The `sleeve-back` of the horizontal producer well made the light oil in-situ combustion more efficient compared to what would be expected in a fully-open well. The `sleeve-back` of the well also produced thermal contours in the sand pack that closely resembled those observed with heavy, highly viscous oil. By sealing-off the otherwise open well in the downstream part of the reservoir, the de-saturation of the oil layer was prevented. 9 refs., 4 tabs., 9 figs.

  8. Pinpointing water entries using pulsed neutron and Production logging tools

    International Nuclear Information System (INIS)

    Mukerji, P.; Oluwa, J.

    2003-01-01

    A successful work over requires a comprehensive understanding of fluid entries into the wellbore and fluid contact movement in the reservoir. Such information can be obtained by a combination of production logs and saturation-monitoring measurements. The ability to combine pulsed neutron and production logging tools provides the operator with better diagnostics for identifying candidates for remedial actions and greatly increases the possibility of a successful well intervention. Advances in pulsed neutron spectroscopy tools have improved the accuracy and precision of measured carbon/oxygen ratios. Some of the improvements in accuracy and precision have resulted from better tool characterization in a wider variety of logging environments in the calibration facility and new spectral standards. Coincident with the advances in pulsed neutron spectroscopy has been the development of production logging measurements run on a platform common. We will show how the application of pulsed neutron and production logs can optimize subsequent well intervention to reduce water production and/or increase oil production

  9. Tenth workshop on geothermal reservoir engineering: proceedings

    Energy Technology Data Exchange (ETDEWEB)

    1985-01-22

    The workshop contains presentations in the following areas: (1) reservoir engineering research; (2) field development; (3) vapor-dominated systems; (4) the Geysers thermal area; (5) well test analysis; (6) production engineering; (7) reservoir evaluation; (8) geochemistry and injection; (9) numerical simulation; and (10) reservoir physics. (ACR)

  10. Amplitude various angles (AVA) phenomena in thin layer reservoir: Case study of various reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Nurhandoko, Bagus Endar B., E-mail: bagusnur@bdg.centrin.net.id, E-mail: bagusnur@rock-fluid.com [Wave Inversion and Subsurface Fluid Imaging Research Laboratory (WISFIR), Basic Science Center A 4" t" hfloor, Physics Dept., FMIPA, Institut Teknologi Bandung (Indonesia); Rock Fluid Imaging Lab., Bandung (Indonesia); Susilowati, E-mail: bagusnur@bdg.centrin.net.id, E-mail: bagusnur@rock-fluid.com [Rock Fluid Imaging Lab., Bandung (Indonesia)

    2015-04-16

    Amplitude various offset is widely used in petroleum exploration as well as in petroleum development field. Generally, phenomenon of amplitude in various angles assumes reservoir’s layer is quite thick. It also means that the wave is assumed as a very high frequency. But, in natural condition, the seismic wave is band limited and has quite low frequency. Therefore, topic about amplitude various angles in thin layer reservoir as well as low frequency assumption is important to be considered. Thin layer reservoir means the thickness of reservoir is about or less than quarter of wavelength. In this paper, I studied about the reflection phenomena in elastic wave which considering interference from thin layer reservoir and transmission wave. I applied Zoeppritz equation for modeling reflected wave of top reservoir, reflected wave of bottom reservoir, and also transmission elastic wave of reservoir. Results show that the phenomena of AVA in thin layer reservoir are frequency dependent. Thin layer reservoir causes interference between reflected wave of top reservoir and reflected wave of bottom reservoir. These phenomena are frequently neglected, however, in real practices. Even though, the impact of inattention in interference phenomena caused by thin layer in AVA may cause inaccurate reservoir characterization. The relation between classes of AVA reservoir and reservoir’s character are different when effect of ones in thin reservoir and ones in thick reservoir are compared. In this paper, I present some AVA phenomena including its cross plot in various thin reservoir types based on some rock physics data of Indonesia.

  11. Amplitude various angles (AVA) phenomena in thin layer reservoir: Case study of various reservoirs

    International Nuclear Information System (INIS)

    thfloor, Physics Dept., FMIPA, Institut Teknologi Bandung (Indonesia); Rock Fluid Imaging Lab., Bandung (Indonesia))" data-affiliation=" (Wave Inversion and Subsurface Fluid Imaging Research Laboratory (WISFIR), Basic Science Center A 4thfloor, Physics Dept., FMIPA, Institut Teknologi Bandung (Indonesia); Rock Fluid Imaging Lab., Bandung (Indonesia))" >Nurhandoko, Bagus Endar B.; Susilowati

    2015-01-01

    Amplitude various offset is widely used in petroleum exploration as well as in petroleum development field. Generally, phenomenon of amplitude in various angles assumes reservoir’s layer is quite thick. It also means that the wave is assumed as a very high frequency. But, in natural condition, the seismic wave is band limited and has quite low frequency. Therefore, topic about amplitude various angles in thin layer reservoir as well as low frequency assumption is important to be considered. Thin layer reservoir means the thickness of reservoir is about or less than quarter of wavelength. In this paper, I studied about the reflection phenomena in elastic wave which considering interference from thin layer reservoir and transmission wave. I applied Zoeppritz equation for modeling reflected wave of top reservoir, reflected wave of bottom reservoir, and also transmission elastic wave of reservoir. Results show that the phenomena of AVA in thin layer reservoir are frequency dependent. Thin layer reservoir causes interference between reflected wave of top reservoir and reflected wave of bottom reservoir. These phenomena are frequently neglected, however, in real practices. Even though, the impact of inattention in interference phenomena caused by thin layer in AVA may cause inaccurate reservoir characterization. The relation between classes of AVA reservoir and reservoir’s character are different when effect of ones in thin reservoir and ones in thick reservoir are compared. In this paper, I present some AVA phenomena including its cross plot in various thin reservoir types based on some rock physics data of Indonesia

  12. Nuclear magnetic resonance and sound velocity measurements of chalk saturated with magnesium rich brine

    DEFF Research Database (Denmark)

    Katika, Konstantina; Alam, Mohammad Monzurul; Fabricius, Ida Lykke

    2013-01-01

    The use of low field Nuclear Magnetic Resonance (NMR) to determine petrophysical properties of reservoirs has proved to be a good technique. Together with sonic and electrical resistivity measurements, NMR can contribute to illustrate the changes on chalk elasticity due to different pore water...... solutions of the same ionic strength. Saturation with a solution that contained divalent ions caused a major shift on the distribution of the relaxation time. The changes were probably due to precipitats forming extra internal surface in the sample. Sonic velocities were relatively low in the MgCl2 solution...

  13. 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.

  14. On-farm irrigation reservoirs for surface water storage in eastern Arkansas: Trends in construction in response to aquifer depletion

    Science.gov (United States)

    Yaeger, M. A.; Reba, M. L.; Massey, J. H.; Adviento-Borbe, A.

    2017-12-01

    On-farm surface water storage reservoirs have been constructed to address declines in the Mississippi River Valley Alluvial aquifer, the primary source of irrigation for most of the row crops grown in eastern Arkansas. These reservoirs and their associated infrastructure represent significant investments in financial and natural resources, and may cause producers to incur costs associated with foregone crop production and long-term maintenance. Thus, an analysis of reservoir construction trends in the Grand Prairie Critical Groundwater Area (GPCGA) and Cache River Critical Groundwater Area (CRCGA) was conducted to assist future water management decisions. Between 1996 and 2015, on average, 16 and 4 reservoirs were constructed per year, corresponding to cumulative new reservoir surface areas of 161 and 60 ha yr-1, for the GPCGA and the CRCGA, respectively. In terms of reservoir locations relative to aquifer status, after 1996, 84.5% of 309 total reservoirs constructed in the GPCGA and 91.0% of 78 in the CRCGA were located in areas with remaining saturated aquifer thicknesses of 50% or less. The majority of new reservoirs (74% in the GPCGA and 63% in the CRCGA) were constructed on previously productive cropland. The next most common land use, representing 11% and 15% of new reservoirs constructed in the GPCGA and CRCGA, respectively, was the combination of a field edge and a ditch, stream, or other low-lying area. Less than 10% of post-1996 reservoirs were constructed on predominately low-lying land, and the use of such lands decreased in both critical groundwater areas during the past 20 years. These disparities in reservoir construction rates, locations, and prior land uses is likely due to groundwater declines being first observed in the GPCGA as well as the existence of two large-scale river diversion projects under construction in the GPCGA that feature on-farm storage as a means to offset groundwater use.

  15. Generation of dense plume fingers in saturated-unsaturated homogeneous porous media

    Science.gov (United States)

    Cremer, Clemens J. M.; Graf, Thomas

    2015-02-01

    Flow under variable-density conditions is widespread, occurring in geothermal reservoirs, at waste disposal sites or due to saltwater intrusion. The migration of dense plumes typically results in the formation of vertical plume fingers which are known to be triggered by material heterogeneity or by variations in source concentration that causes the density variation. Using a numerical groundwater model, six perturbation methods are tested under saturated and unsaturated flow conditions to mimic heterogeneity and concentration variations on the pore scale in order to realistically generate dense fingers. A laboratory-scale sand tank experiment is numerically simulated, and the perturbation methods are evaluated by comparing plume fingers obtained from the laboratory experiment with numerically simulated fingers. Dense plume fingering for saturated flow can best be reproduced with a spatially random, time-constant perturbation of the solute source. For unsaturated flow, a spatially and temporally random noise of solute concentration or a random conductivity field adequately simulate plume fingering.

  16. In-Situ X-ray Tomography Study of Cement Exposed to CO2 Saturated Brine

    DEFF Research Database (Denmark)

    Chavez Panduro, E. A.; Torsæter, M.; Gawel, K.

    2017-01-01

    For successful CO2 storage in underground reservoirs, the potential problem of CO2 leakage needs to be addressed. A profoundly improved understanding of the behavior of fractured cement under realistic subsurface conditions including elevated temperature, high pressure and the presence of CO2...... saturated brine is required. Here, we report in situ X-ray micro computed tomography (μ-CT) studies visualizing the microstructural changes upon exposure of cured Portland cement with an artificially engineered leakage path (cavity) to CO2 saturated brine at high pressure. Carbonation of the bulk cement......, self-healing of the leakage path in the cement specimen, and leaching of CaCO3 were thus directly observed. The precipitation of CaCO3, which is of key importance as a possible healing mechanism of fractured cement, was found to be enhanced in confined regions having limited access to CO2...

  17. Comparison of an impec and a semi-implicit formulation for compositional reservoir simulation

    Directory of Open Access Journals (Sweden)

    B. R. B. Fernandes

    2014-12-01

    Full Text Available In compositional reservoir simulation, a set of non-linear partial differential equations must be solved. In this work, two numerical formulations are compared. The first formulation is based on an implicit pressure and explicit composition (IMPEC procedure, and the second formulation uses an implicit pressure and implicit saturation (IMPSAT. The main goal of this work is to compare the formulations in terms of computational times for solving 2D and 3D compositional reservoir simulation case studies. In the comparison, both UDS (Upwind difference scheme and third order TVD schemes were used. The computational results for the aforementioned formulations and the two interpolation functions are presented for several case studies involving homogeneous and heterogeneous reservoirs. Based on our comparison of IMPEC and IMPSAT formulations using several case studies presented in this work, the IMPSAT formulation was faster than the IMPEC formulation.

  18. 4. International reservoir characterization technical conference

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-04-01

    This volume contains the Proceedings of the Fourth International Reservoir Characterization Technical Conference held March 2-4, 1997 in Houston, Texas. The theme for the conference was Advances in Reservoir Characterization for Effective Reservoir Management. On March 2, 1997, the DOE Class Workshop kicked off with tutorials by Dr. Steve Begg (BP Exploration) and Dr. Ganesh Thakur (Chevron). Tutorial presentations are not included in these Proceedings but may be available from the authors. The conference consisted of the following topics: data acquisition; reservoir modeling; scaling reservoir properties; and managing uncertainty. Selected papers have been processed separately for inclusion in the Energy Science and Technology database.

  19. Lipid order, saturation and surface property relationships: a study of human meibum saturation.

    Science.gov (United States)

    Mudgil, Poonam; Borchman, Douglas; Yappert, Marta C; Duran, Diana; Cox, Gregory W; Smith, Ryan J; Bhola, Rahul; Dennis, Gary R; Whitehall, John S

    2013-11-01

    Tear film stability decreases with age however the cause(s) of the instability are speculative. Perhaps the more saturated meibum from infants may contribute to tear film stability. The meibum lipid phase transition temperature and lipid hydrocarbon chain order at physiological temperature (33 °C) decrease with increasing age. It is reasonable that stronger lipid-lipid interactions could stabilize the tear film since these interactions must be broken for tear break up to occur. In this study, meibum from a pool of adult donors was saturated catalytically. The influence of saturation on meibum hydrocarbon chain order was determined by infrared spectroscopy. Meibum is in an anhydrous state in the meibomian glands and on the surface of the eyelid. The influence of saturation on the surface properties of meibum was determined using Langmuir trough technology. Saturation of native human meibum did not change the minimum or maximum values of hydrocarbon chain order so at temperatures far above or below the phase transition of human meibum, saturation does not play a role in ordering or disordering the lipid hydrocarbon chains. Saturation did increase the phase transition temperature in human meibum by over 20 °C, a relatively high amount. Surface pressure-area studies showing the late take off and higher maximum surface pressure of saturated meibum compared to native meibum suggest that the saturated meibum film is quite molecularly ordered (stiff molecular arrangement) and elastic (molecules are able to rearrange during compression and expansion) compared with native meibum films which are more fluid agreeing with the infrared spectroscopic results of this study. In saturated meibum, the formation of compacted ordered islands of lipids above the surfactant layer would be expected to decrease the rate of evaporation compared to fluid and more loosely packed native meibum. Higher surface pressure observed with films of saturated meibum compared to native meibum

  20. MIKROMITSETY- MIGRANTS IN MINGECHEVIR RESERVOIR

    Directory of Open Access Journals (Sweden)

    M. A. Salmanov

    2017-01-01

    Full Text Available Aim. It is hardly possible to predict the continued stability of the watercourse ecosystems without the study of biological characteristics and composition of organisms inhabiting them. In the last 35-40 years, environmental conditions of the Mingachevir reservoir are determined by the stationary anthropogenic pressure. It was found that such components of plankton as algae, bacteria and fungi play a leading role in the transformation and migration of pollutants. The role of the three groups of organisms is very important in maintaining the water quality by elimination of pollutants. Among the organisms inhabiting the Mingachevir Reservoir, micromycetes have not yet been studied. Therefore, the study of the species composition and seasonal dynamics, peculiarities of their growth and development in the environment with the presence of some of the pollutants should be considered to date.Methods. In order to determine the role of micromycetes-migrants in the mineralization of organic substrates, as an active participant of self-purification process, we used water samples from the bottom sediments as well as decaying and skeletonized stalks of cane, reeds, algae, macrophytes, exuvia of insects and fish remains submerged in water.Findings. For the first time, we obtained the data on the quality and quantity of microscopic mycelial fungi in freshwater bodies on the example of the Mingachevir water reservoir; we also studied the possibilities for oxygenating the autochthonous organic matter of allochthonous origin with micromycetes-migrants.Conclusions. It was found that the seasonal development of micromycetes-migrants within the Mingachevir reservoir is characterized by an increase in the number of species in the summer and a gradual reduction in species diversity in the fall. 

  1. 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.

  2. Williston Reservoir raising - environmental overview

    Energy Technology Data Exchange (ETDEWEB)

    1988-07-01

    This preliminary environmental overview report was prepared by B.C. Hydro in June 1987 and revised in July 1988 as an initial assessment of a possible 1.5 m (5 ft.) raise in the Williston Reservoir maximum normal level. The enviromental overview study and the associated engineering and property studies were undertaken to provide information for a decision on whether to initiate more detailed studies. Overview studies are based mainly on available reports, mapping and field data, supplemented by limited site reconnaissance and, in this case, input from key agencies and groups. The lack of adequate mapping of areas which could be affected by reservoir raising did not permit definitive conclusion to be reached. This mapping will be done over the next year to complete the overview assessment. This document covers the impact assessment of socio-economic factors, forestry, reservoir clearing, heritage, recreation, aquatic resources, and wilflife. Further studies in each of these areas are also included. 54 refs., 11 figs., 8 tabs.

  3. Reservoir floodplains support distinct fish assemblages

    Science.gov (United States)

    Miranda, Leandro E.; Wigen, S. L.; Dagel, Jonah D.

    2014-01-01

    Reservoirs constructed on floodplain rivers are unique because the upper reaches of the impoundment may include extensive floodplain environments. Moreover, reservoirs that experience large periodic water level fluctuations as part of their operational objectives seasonally inundate and dewater floodplains in their upper reaches, partly mimicking natural inundations of river floodplains. In four flood control reservoirs in Mississippi, USA, we explored the dynamics of connectivity between reservoirs and adjacent floodplains and the characteristics of fish assemblages that develop in reservoir floodplains relative to those that develop in reservoir bays. Although fish species richness in floodplains and bays were similar, species composition differed. Floodplains emphasized fish species largely associated with backwater shallow environments, often resistant to harsh environmental conditions. Conversely, dominant species in bays represented mainly generalists that benefit from the continuous connectivity between the bay and the main reservoir. Floodplains in the study reservoirs provided desirable vegetated habitats at lower water level elevations, earlier in the year, and more frequently than in bays. Inundating dense vegetation in bays requires raising reservoir water levels above the levels required to reach floodplains. Therefore, aside from promoting distinct fish assemblages within reservoirs and helping promote diversity in regulated rivers, reservoir floodplains are valued because they can provide suitable vegetated habitats for fish species at elevations below the normal pool, precluding the need to annually flood upland vegetation that would inevitably be impaired by regular flooding. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

  4. Evaluation of field development plans using 3-D reservoir modelling

    Energy Technology Data Exchange (ETDEWEB)

    Seifert, D.; Lewis, J.J.M. [Heriot-Watt Univ., Edinburgh (United Kingdom); Newbery, J.D.H. [Conoco, UK Ltd., Aberdeen (United Kingdom)] [and others

    1997-08-01

    Three-dimensional reservoir modelling has become an accepted tool in reservoir description and is used for various purposes, such as reservoir performance prediction or integration and visualisation of data. In this case study, a small Northern North Sea turbiditic reservoir was to be developed with a line drive strategy utilising a series of horizontal producer and injector pairs, oriented north-south. This development plan was to be evaluated and the expected outcome of the wells was to be assessed and risked. Detailed analyses of core, well log and analogue data has led to the development of two geological {open_quotes}end member{close_quotes} scenarios. Both scenarios have been stochastically modelled using the Sequential Indicator Simulation method. The resulting equiprobable realisations have been subjected to detailed statistical well placement optimisation techniques. Based upon bivariate statistical evaluation of more than 1000 numerical well trajectories for each of the two scenarios, it was found that the wells inclinations and lengths had a great impact on the wells success, whereas the azimuth was found to have only a minor impact. After integration of the above results, the actual well paths were redesigned to meet external drilling constraints, resulting in substantial reductions in drilling time and costs.

  5. The role of reservoir characterization in the reservoir management process (as reflected in the Department of Energy`s reservoir management demonstration program)

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, M.L. [BDM-Petroleum Technologies, Bartlesville, OK (United States); Young, M.A.; Madden, M.P. [BDM-Oklahoma, Bartlesville, OK (United States)] [and others

    1997-08-01

    Optimum reservoir recovery and profitability result from guidance of reservoir practices provided by an effective reservoir management plan. Success in developing the best, most appropriate reservoir management plan requires knowledge and consideration of (1) the reservoir system including rocks, and rock-fluid interactions (i.e., a characterization of the reservoir) as well as wellbores and associated equipment and surface facilities; (2) the technologies available to describe, analyze, and exploit the reservoir; and (3) the business environment under which the plan will be developed and implemented. Reservoir characterization is the essential to gain needed knowledge of the reservoir for reservoir management plan building. Reservoir characterization efforts can be appropriately scaled by considering the reservoir management context under which the plan is being built. Reservoir management plans de-optimize with time as technology and the business environment change or as new reservoir information indicates the reservoir characterization models on which the current plan is based are inadequate. BDM-Oklahoma and the Department of Energy have implemented a program of reservoir management demonstrations to encourage operators with limited resources and experience to learn, implement, and disperse sound reservoir management techniques through cooperative research and development projects whose objectives are to develop reservoir management plans. In each of the three projects currently underway, careful attention to reservoir management context assures a reservoir characterization approach that is sufficient, but not in excess of what is necessary, to devise and implement an effective reservoir management plan.

  6. Interger multiplication with overflow detection or saturation

    Energy Technology Data Exchange (ETDEWEB)

    Schulte, M.J.; Balzola, P.I.; Akkas, A.; Brocato, R.W.

    2000-01-11

    High-speed multiplication is frequently used in general-purpose and application-specific computer systems. These systems often support integer multiplication, where two n-bit integers are multiplied to produce a 2n-bit product. To prevent growth in word length, processors typically return the n least significant bits of the product and a flag that indicates whether or not overflow has occurred. Alternatively, some processors saturate results that overflow to the most positive or most negative representable number. This paper presents efficient methods for performing unsigned or two's complement integer multiplication with overflow detection or saturation. These methods have significantly less area and delay than conventional methods for integer multiplication with overflow detection and saturation.

  7. Tracking Controller for Intrinsic Output Saturated Systems in Presence of Amplitude and Rate Input Saturations

    DEFF Research Database (Denmark)

    Chater, E.; Giri, F.; Guerrero, Josep M.

    2014-01-01

    We consider the problem of controlling plants that are subject to multiple saturation constraints. Especially, we are interested in linear systems whose input is subject to amplitude and rate constraints of saturation type. Furthermore, the considered systems output is also subject to an intrinsi...

  8. Studies of non-isothermal flow in saturated and partially saturated porous media

    International Nuclear Information System (INIS)

    Ho, C.K.; Maki, K.S.; Glass, R.J.

    1993-01-01

    Physical and numerical experiments have been performed to investigate the behavior of nonisothermal flow in two-dimensional saturated and partially saturated porous media. The physical experiments were performed to identify non-isothermal flow fields and temperature distributions in fully saturated, half-saturated, and residually saturated two-dimensional porous media with bottom heating and top cooling. Two counter-rotating liquid-phase convective cells were observed to develop in the saturated regions of all three cases. Gas-phase convection was also evidenced in the unsaturated regions of the partially saturated experiments. TOUGH2 numerical simulations of the saturated case were found to be strongly dependent on the assumed boundary conditions of the physical system. Models including heat losses through the boundaries of the test cell produced temperature and flow fields that were in better agreement with the observed temperature and flow fields than models that assumed insulated boundary conditions. A sensitivity analysis also showed that a reduction of the bulk permeability of the porous media in the numerical simulations depressed the effects of convection, flattening the temperature profiles across the test cell

  9. Femoral venous oxygen saturation is no surrogate for central venous oxygen saturation

    NARCIS (Netherlands)

    van Beest, Paul A.; van der Schors, Alice; Liefers, Henriette; Coenen, Ludo G. J.; Braam, Richard L.; Habib, Najib; Braber, Annemarije; Scheeren, Thomas W. L.; Kuiper, Michael A.; Spronk, Peter E.

    2012-01-01

    Objective:  The purpose of our study was to determine if central venous oxygen saturation and femoral venous oxygen saturation can be used interchangeably during surgery and in critically ill patients. Design:  Prospective observational controlled study. Setting:  Nonacademic university-affiliated

  10. Saturated poroelastic actuators generated by topology optimization

    DEFF Research Database (Denmark)

    Andreasen, Casper Schousboe; Sigmund, Ole

    2011-01-01

    the coupling of internal fluid pressure and elastic shear stresses a slab of the optimized porous material deflects/deforms when a pressure is imposed and an actuator is created. Several phenomenologically based constraints are imposed in order to get a stable force transmitting actuator.......In this paper the fluid-structure interaction problem of a saturated porous media is considered. The pressure coupling properties of porous saturated materials change with the microstructure and this is utilized in the design of an actuator using a topology optimized porous material. By maximizing...

  11. High speed drying of saturated steam

    International Nuclear Information System (INIS)

    Marty, C.; Peyrelongue, J.P.

    1993-01-01

    This paper describes the development of the drying process for the saturated steam used in the PWR nuclear plant turbines in order to prevent negative effects of water on turbine efficiency, maintenance costs and equipment lifetime. The high speed drying concept is based on rotating the incoming saturated steam in order to separate water which is more denser than the steam; the water film is then extracted through an annular slot. A multicellular modular equipment has been tested. Applications on high and low pressure extraction of various PWR plants are described (Bugey, Loviisa)

  12. Site-Scale Saturated Zone Flow Model

    International Nuclear Information System (INIS)

    G. Zyvoloski

    2003-01-01

    The purpose of this model report is to document the components of the site-scale saturated-zone flow model at Yucca Mountain, Nevada, in accordance with administrative procedure (AP)-SIII.lOQ, ''Models''. This report provides validation and confidence in the flow model that was developed for site recommendation (SR) and will be used to provide flow fields in support of the Total Systems Performance Assessment (TSPA) for the License Application. The output from this report provides the flow model used in the ''Site-Scale Saturated Zone Transport'', MDL-NBS-HS-000010 Rev 01 (BSC 2003 [162419]). The Site-Scale Saturated Zone Transport model then provides output to the SZ Transport Abstraction Model (BSC 2003 [164870]). In particular, the output from the SZ site-scale flow model is used to simulate the groundwater flow pathways and radionuclide transport to the accessible environment for use in the TSPA calculations. Since the development and calibration of the saturated-zone flow model, more data have been gathered for use in model validation and confidence building, including new water-level data from Nye County wells, single- and multiple-well hydraulic testing data, and new hydrochemistry data. In addition, a new hydrogeologic framework model (HFM), which incorporates Nye County wells lithology, also provides geologic data for corroboration and confidence in the flow model. The intended use of this work is to provide a flow model that generates flow fields to simulate radionuclide transport in saturated porous rock and alluvium under natural or forced gradient flow conditions. The flow model simulations are completed using the three-dimensional (3-D), finite-element, flow, heat, and transport computer code, FEHM Version (V) 2.20 (software tracking number (STN): 10086-2.20-00; LANL 2003 [161725]). Concurrently, process-level transport model and methodology for calculating radionuclide transport in the saturated zone at Yucca Mountain using FEHM V 2.20 are being

  13. Saturated Zone Colloid-Facilitated Transport

    International Nuclear Information System (INIS)

    Wolfsberg, A.; Reimus, P.

    2001-01-01

    The purpose of the Saturated Zone Colloid-Facilitated Transport Analysis and Modeling Report (AMR), as outlined in its Work Direction and Planning Document (CRWMS MandO 1999a), is to provide retardation factors for colloids with irreversibly-attached radionuclides, such as plutonium, in the saturated zone (SZ) between their point of entrance from the unsaturated zone (UZ) and downgradient compliance points. Although it is not exclusive to any particular radionuclide release scenario, this AMR especially addresses those scenarios pertaining to evidence from waste degradation experiments, which indicate that plutonium and perhaps other radionuclides may be irreversibly attached to colloids. This report establishes the requirements and elements of the design of a methodology for calculating colloid transport in the saturated zone at Yucca Mountain. In previous Total Systems Performance Assessment (TSPA) analyses, radionuclide-bearing colloids were assumed to be unretarded in their migration. Field experiments in fractured tuff at Yucca Mountain and in porous media at other sites indicate that colloids may, in fact, experience retardation relative to the mean pore-water velocity, suggesting that contaminants associated with colloids should also experience some retardation. Therefore, this analysis incorporates field data where available and a theoretical framework when site-specific data are not available for estimating plausible ranges of retardation factors in both saturated fractured tuff and saturated alluvium. The distribution of retardation factors for tuff and alluvium are developed in a form consistent with the Performance Assessment (PA) analysis framework for simulating radionuclide transport in the saturated zone. To improve on the work performed so far for the saturated-zone flow and transport modeling, concerted effort has been made in quantifying colloid retardation factors in both fractured tuff and alluvium. The fractured tuff analysis used recent data

  14. On the saturation of astrophysical dynamos

    DEFF Research Database (Denmark)

    Dorch, Bertil; Archontis, Vasilis

    2004-01-01

    In the context of astrophysical dynamos we illustrate that the no-cosines flow, with zero mean helicity, can drive fast dynamo action and we study the dynamo's mode of operation during both the linear and non-linear saturation regimes. It turns out that in addition to a high growth rate in the li......In the context of astrophysical dynamos we illustrate that the no-cosines flow, with zero mean helicity, can drive fast dynamo action and we study the dynamo's mode of operation during both the linear and non-linear saturation regimes. It turns out that in addition to a high growth rate...

  15. Nonlinear saturation of the Rayleigh Taylor instability

    International Nuclear Information System (INIS)

    Das, A.; Mahajan, S.; Kaw, P.; Sen, A.; Benkadda, S.; Verga, A.

    1997-01-01

    The problem of the nonlinear saturation of the 2 dimensional Rayleigh Taylor instability is re-examined to put various earlier results in a proper perspective. The existence of a variety of final states can be attributed to the differences in the choice of boundary conditions and initial conditions in earlier numerical modeling studies. Our own numerical simulations indicate that the RT instability saturates by the self consistent generation of shear flow even in situations (with periodic boundaries) where, in principle, an infinite amount of gravitational energy can be tapped. Such final states can be achieved for suitable values of the Prandtl number. (author)

  16. Saturable absorption in detonation nanodiamond dispersions

    Science.gov (United States)

    Vanyukov, Viatcheslav; Mikheev, Gennady; Mogileva, Tatyana; Puzyr, Alexey; Bondar, Vladimir; Lyashenko, Dmitry; Chuvilin, Andrey

    2017-07-01

    We report on a saturable absorption in aqueous dispersions of nanodiamonds with femtosecond laser pulse excitation at a wavelength of 795 nm. The open aperture Z-scan experiments reveal that in a wide range of nanodiamond particle sizes and concentrations, a light-induced increase of transmittance occurs. The transmittance increase originates from the saturation of light absorption and is associated with a light absorption at 1.5 eV by graphite and dimer chains (Pandey dimer chains). The obtained key nonlinear parameters of nanodiamond dispersions are compared with those of graphene and carbon nanotubes, which are widely used for the mode-locking.

  17. Oxygen general saturation after bronchography under general ...

    African Journals Online (AJOL)

    Thirty-six patients undergoing bronchography or bronchoscopy under general anaesthesia were continuously monitored by pulse oximetry for 5 hours after these procedures. Significant falls in oxygen saturation were observed in the first hour and were of most clinical relevance in patients with preexisting pulmonary ...

  18. Iron saturation control in RHIC dipole magnets

    International Nuclear Information System (INIS)

    Thompson, P.A.; Gupta, R.C.; Kahn, S.A.; Hahn, H.; Morgan, G.H.; Wanderer, P.J.; Willen, E.

    1991-01-01

    The Relativistic Heavy Ion Collider (RHIC) will require 360 dipoles of 80 mm bore. This paper discusses the field perturbations produced by the saturation of the yoke iron. Changes have been made to the yoke to reduce these perturbations, in particular, decapole -4 . Measurements and calculations for 6 series of dipole magnets are presented. 2 refs., 2 figs., 1 tab

  19. Saturated fat, carbohydrates and cardiovascular disease

    NARCIS (Netherlands)

    Kuipers, R. S.; de Graaf, D. J.; Luxwolda, M. F.; Muskiet, M. H. A.; Dijck-Brouwer, D. A. J.; Muskiet, F. A. J.

    The dietary intake of saturated fatty acids (SAFA) is associated with a modest increase in serum total cholesterol, but not with cardiovascular disease (CVD). Replacing dietary SAFA with carbohydrates (CHO), notably those with a high glycaemic index, is associated with an increase in CVD risk in

  20. Saturation at Low X and Nonlinear Evolution

    International Nuclear Information System (INIS)

    Stasto, A.M.

    2002-01-01

    In this talk the results of the analytical and numerical analysis of the nonlinear Balitsky-Kovchegov equation are presented. The characteristic BFKL diffusion into infrared regime is suppressed by the generation of the saturation scale Q s . We identify the scaling and linear regimes for the solution. We also study the impact of subleading corrections onto the nonlinear evolution. (author)

  1. Saturation of bentonite dependent upon temperature

    International Nuclear Information System (INIS)

    Hausmannova, Lucie; Vasicek, Radek

    2010-01-01

    Document available in extended abstract form only. The fundamental idea behind the long-term safe operation of a deep repository is the use of the Multi-barrier system principle. Barriers may well differ according to the type of host rock in which the repository is located. It is assumed that the buffer in the granitic host rock environment will consist of swelling clays which boast the ideal properties for such a function i.e. low permeability, high swelling pressure, self-healing ability etc. all of which are affected primarily by mineralogy and dry density. Water content plays a crucial role in the activation of swelling pressure as well as, subsequently, in the potential self healing of the various contact areas of the numerous buffer components made from bentonite. In the case of a deep repository, a change in water content is not only connected with the possible intake of water from the host rock, but also with its redistribution owing to changes in temperature after the insertion of the heat source (disposal waste package containing spent fuel) into the repository 'nest'. The principal reason for the experimental testing of this high dry density material is the uncertainty with regard to its saturation ability (final water content or the degree of saturation) at higher temperatures. The results of the Mock-Up-CZ experiment showed that when the barrier is constantly supplied with a saturation medium over a long time period the water content in the barrier as well as the degree of saturation settle independently of temperature. The Mock-Up-CZ experiment was performed at temperatures of 30 deg. - 90 deg. C in the barrier; therefore it was decided to experimentally verify this behaviour by means of targeted laboratory tests. A temperature of 110 deg. C was added to the set of experimental temperatures resulting in samples being tested at 25 deg. C, 95 deg. C and 110 deg. C. The degree of saturation is defined as the ratio of pore water volume to pore

  2. Two-beam interaction in saturable media

    DEFF Research Database (Denmark)

    Schjødt-Eriksen, Jens; Schmidt, Michel R.; Juul Rasmussen, Jens

    1998-01-01

    The dynamics of two coupled soliton solutions of the nonlinear Schrodinger equation with a saturable nonlinearity is investigated It is shown by means of a variational method and by direct numerical calculations that two well-separated solitons can orbit around each other, if their initial velocity...

  3. Oxygenation of saturated and unsaturated hydrocarbons with ...

    Indian Academy of Sciences (India)

    Unknown

    Oxygenation of saturated and unsaturated hydrocarbons with sodium periodate. 431. Table 1. Competitive oxygenation of tetralin and cyclooctene with sodium periodate catalyzed by different manga- .... Teacher Education University. My grateful thanks also extend to Dr D Mohajer for his useful sugges- tions. References. 1.

  4. Multiscale optimization of saturated poroelastic actuators

    DEFF Research Database (Denmark)

    Andreasen, Casper Schousboe; Sigmund, Ole

    A multiscale method for optimizing the material micro structure in a macroscopically heterogeneous saturated poroelastic media with respect to macro properties is presented. The method is based on topology optimization using the homogenization technique, here applied to the optimization of a bi...

  5. Synthesis and characterization of saturated polyester and ...

    Indian Academy of Sciences (India)

    but which can actually be used for processes, which pro- duce interesting ... ing the synthesis of saturated polyester (from GPET waste). This has been done for the .... The solid product obtained from the glycolysis of PET was bis(hydroxy ethyl ...

  6. Geophysical assessments of renewable gas energy compressed in geologic pore storage reservoirs.

    Science.gov (United States)

    Al Hagrey, Said Attia; Köhn, Daniel; Rabbel, Wolfgang

    2014-01-01

    Renewable energy resources can indisputably minimize the threat of global warming and climate change. However, they are intermittent and need buffer storage to bridge the time-gap between production (off peak) and demand peaks. Based on geologic and geochemical reasons, the North German Basin has a very large capacity for compressed air/gas energy storage CAES in porous saltwater aquifers and salt cavities. Replacing pore reservoir brine with CAES causes changes in physical properties (elastic moduli, density and electrical properties) and justify applications of integrative geophysical methods for monitoring this energy storage. Here we apply techniques of the elastic full waveform inversion FWI, electric resistivity tomography ERT and gravity to map and quantify a gradually saturated gas plume injected in a thin deep saline aquifer within the North German Basin. For this subsurface model scenario we generated different synthetic data sets without and with adding random noise in order to robust the applied techniques for the real field applications. Datasets are inverted by posing different constraints on the initial model. Results reveal principally the capability of the applied integrative geophysical approach to resolve the CAES targets (plume, host reservoir, and cap rock). Constrained inversion models of elastic FWI and ERT are even able to recover well the gradual gas desaturation with depth. The spatial parameters accurately recovered from each technique are applied in the adequate petrophysical equations to yield precise quantifications of gas saturations. Resulting models of gas saturations independently determined from elastic FWI and ERT techniques are in accordance with each other and with the input (true) saturation model. Moreover, the gravity technique show high sensitivity to the mass deficit resulting from the gas storage and can resolve saturations and temporal saturation changes down to ±3% after reducing any shallow fluctuation such as that of

  7. Nuclear register applications and pressure tests to foresee reservoirs exploitation with water drive; Aplicaciones de registros nucleares y pruebas de presion para predecir el grado de explotacion de reservorios con impulsion de agua

    Energy Technology Data Exchange (ETDEWEB)

    Osorio F, X.; Redosado G, V. [PETROPERU S.A., Lima (Peru)

    1994-12-31

    This paper illustrates how the pulsed neutron log and well test analysis aid proper reservoir management in strong water reservoirs. These techniques have been applied to Cetico reservoir which belongs to Corrientes Field which is located in the Peruvian Jungle. Corrientes is the most important field operated by PETROPERU S.A. As a result of the analysis we current know the present areal water saturation distribution and also have improve the reservoir characterization al of which is being used for increasing the oil production and reserves. (author). 4 refs, 7 figs, 3 tabs.

  8. 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

  9. Assessment of nutrient loadings of a large multipurpose prairie reservoir

    Science.gov (United States)

    Morales-Marín, L. A.; Wheater, H. S.; Lindenschmidt, K. E.

    2017-07-01

    The relatively low water flow velocities in reservoirs cause them to have high capacities for retaining sediments and pollutants, which can lead to a reduction in downstream nutrient loading. Hence, nutrients can progressively accumulate in reservoirs, resulting in the deterioration of aquatic ecosystems and water quality. Lake Diefenbaker (LD) is a large multipurpose reservoir, located on the South Saskatchewan River (SSR), that serves as a major source of freshwater in Saskatchewan, Canada. Over the past several years, changes in land use (e.g. expansion of urban areas and industrial developments) in the reservoir's catchment have heightened concerns about future water quality in the catchment and in the reservoir. Intensification of agricultural activities has led to an increase in augmented the application of manure and fertilizer for crops and pasture. Although previous research has attempted to quantify nutrient retention in LD, there is a knowledge gap related to the identification of major nutrient sources and quantification of nutrient export from the catchment at different spatial scales. Using the SPAtially Referenced Regression On Watershed (SPARROW) model, this gap has been addressed by assessing water quality regionally, and identifying spatial patterns of factors and processes that affect water quality in the LD catchment. Model results indicate that LD retains about 70% of the inflowing total nitrogen (TN) and 90% of the inflowing total phosphorus (TP) loads, of which fertilizer and manure applied to agricultural fields contribute the greatest proportion. The SPARROW model will be useful as a tool to guide the optimal implementation of nutrient management plans to reduce nutrient inputs to LD.

  10. Microscopic analysis of saturable absorbers: Semiconductor saturable absorber mirrors versus graphene

    Energy Technology Data Exchange (ETDEWEB)

    Hader, J.; Moloney, J. V. [Nonlinear Control Strategies, Inc., 3542 N. Geronimo Ave., Tucson, Arizona 85705 (United States); College of Optical Sciences, University of Arizona, Tucson, Arizona 85721 (United States); Yang, H.-J.; Scheller, M. [College of Optical Sciences, University of Arizona, Tucson, Arizona 85721 (United States); Koch, S. W. [Department of Physics and Materials Sciences Center, Philipps Universität Marburg, Renthof 5, 35032 Marburg (Germany)

    2016-02-07

    Fully microscopic many-body calculations are used to study the influence of strong sub-picosecond pulses on the carrier distributions and corresponding optical response in saturable absorbers used for mode-locking—semiconductor (quantum well) saturable absorber mirrors (SESAMs) and single layer graphene based saturable absorber mirrors (GSAMs). Unlike in GSAMs, the saturation fluence and recovery time in SESAMs show a strong spectral dependence. While the saturation fluence in the SESAM is minimal at the excitonic bandgap, the optimal recovery time and least pulse distortion due to group delay dispersion are found for excitation higher in the first subband. For excitation near the SESAM bandgap, the saturation fluence is about one tenth of that in the GSAM. At energies above the bandgap, the fluences in both systems become similar. A strong dependence of the saturation fluence on the pulse width in both systems is caused by carrier relaxation during the pulse. The recovery time in graphene is found to be about two to four times faster than that in the SESAMs. The occurrence of negative differential transmission in graphene is shown to be caused by dopant related carriers. In SESAMs, a negative differential transmission is found when exciting below the excitonic resonance where excitation induced dephasing leads to an enhancement of the absorption. Comparisons of the simulation data to the experiment show a very good quantitative agreement.

  11. Are Geotehrmal Reservoirs Stressed Out?

    Science.gov (United States)

    Davatzes, N. C.; Laboso, R. C.; Layland-Bachmann, C. E.; Feigl, K. L.; Foxall, W.; Tabrez, A. R.; Mellors, R. J.; Templeton, D. C.; Akerley, J.

    2017-12-01

    Crustal permeability can be strongly influenced by developing connected networks of open fractures. However, the detailed evolution of a fracture network, its extent, and the persistence of fracture porosity are difficult to analyze. Even in fault-hosted geothermal systems, where heat is brought to the surface from depth along a fault, hydrothermal flow is heterogeneously distributed. This is presumably due to variations in fracture density, connectivity, and attitude, as well as variations in fracture permeability caused by sealing of fractures by precipitated cements or compaction. At the Brady Geothermal field in Nevada, we test the relationship between the modeled local stress state perturbed by dislocations representing fault slip or volume changes in the geothermal reservoir inferred from surface deformation measured by InSAR and the location of successful geothermal wells, hydrothermal activity, and seismicity. We postulate that permeability is favored in volumes that experience positive Coulomb stress changes and reduced compression, which together promote high densities of dilatant fractures. Conversely, permeability can be inhibited in locations where Coulomb stress is reduced, compression promotes compaction, or where the faults are poorly oriented in the stress field and consequently slip infrequently. Over geologic time scales spanning the development of the fault system, these local stress states are strongly influenced by the geometry of the fault network relative to the remote stress driving slip. At shorter time scales, changes in fluid pressure within the fracture network constituting the reservoir cause elastic dilations and contractions. We integrate: (1) direct observations of stress state and fractures in boreholes and the mapped geometry of the fault network; (2) evidence of permeability from surface hydrothermal features, production/injection wells and surface deformations related to pumping history; and (3) seismicity to test the

  12. Constant rate natural gas production from a well in a hydrate reservoir

    International Nuclear Information System (INIS)

    Ji Chuang; Ahmadi, Goodarz; Smith, Duane H.

    2003-01-01

    Using a computational model, production of natural gas at a constant rate from a well that is drilled into a confined methane hydrate reservoir is studied. It is assumed that the pores in the reservoir are partially saturated with hydrate. A linearized model for an axisymmetric condition with a fixed well output is used in the analysis. For different reservoir temperatures and various well outputs, time evolutions of temperature and pressure profiles, as well as the gas flow rate in the hydrate zone and the gas region, are evaluated. The distance of the decomposition front from the well as a function of time is also computed. It is shown that to maintain a constant natural gas production rate, the well pressure must be decreased with time. A constant low production rate can be sustained for a long duration of time, but a high production rate demands unrealistically low pressure at the well after a relatively short production time. The simulation results show that the process of natural gas production in a hydrate reservoir is a sensitive function of reservoir temperature and hydrate zone permeability

  13. A reservoir trap for antiprotons

    CERN Document Server

    Smorra, Christian; Franke, Kurt; Nagahama, Hiroki; Schneider, Georg; Higuchi, Takashi; Van Gorp, Simon; Blaum, Klaus; Matsuda, Yasuyuki; Quint, Wolfgang; Walz, Jochen; Yamazaki, Yasunori; Ulmer, Stefan

    2015-01-01

    We have developed techniques to extract arbitrary fractions of antiprotons from an accumulated reservoir, and to inject them into a Penning-trap system for high-precision measurements. In our trap-system antiproton storage times > 1.08 years are estimated. The device is fail-safe against power-cuts of up to 10 hours. This makes our planned comparisons of the fundamental properties of protons and antiprotons independent from accelerator cycles, and will enable us to perform experiments during long accelerator shutdown periods when background magnetic noise is low. The demonstrated scheme has the potential to be applied in many other precision Penning trap experiments dealing with exotic particles.

  14. Effect of reservoir heterogeneity on air injection performance in a light oil reservoir

    Directory of Open Access Journals (Sweden)

    Hu Jia

    2018-03-01

    Full Text Available Air injection is a good option to development light oil reservoir. As well-known that, reservoir heterogeneity has great effect for various EOR processes. This also applies to air injection. However, oil recovery mechanisms and physical processes for air injection in heterogeneous reservoir with dip angle are still not well understood. The reported setting of reservoir heterogeneous for physical model or simulation model of air injection only simply uses different-layer permeability of porous media. In practice, reservoir heterogeneity follows the principle of geostatistics. How much of contrast in permeability actually challenges the air injection in light oil reservoir? This should be investigated by using layered porous medial settings of the classical Dykstra-Parsons style. Unfortunately, there has been no work addressing this issue for air injection in light oil reservoir. In this paper, Reservoir heterogeneity is quantified based on the use of different reservoir permeability distribution according to classical Dykstra-Parsons coefficients method. The aim of this work is to investigate the effect of reservoir heterogeneity on physical process and production performance of air injection in light oil reservoir through numerical reservoir simulation approach. The basic model is calibrated based on previous study. Total eleven pseudo compounders are included in this model and ten complexity of reactions are proposed to achieve the reaction scheme. Results show that oil recovery factor is decreased with the increasing of reservoir heterogeneity both for air and N2 injection from updip location, which is against the working behavior of air injection from updip location. Reservoir heterogeneity sometimes can act as positive effect to improve sweep efficiency as well as enhance production performance for air injection. High O2 content air injection can benefit oil recovery factor, also lead to early O2 breakthrough in heterogeneous reservoir. Well

  15. 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.

  16. Visualization of viscous coupling effects in heavy oil reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz-Arango, J.D. [Calgary Univ., AB (Canada). Tomographic Imaging and Porous Media Laboratory; Kantzas, A. [Society of Petroleum Engineers, Canadian Section, Calgary, AB (Canada)]|[Calgary Univ., AB (Canada). Tomographic Imaging and Porous Media Laboratory

    2008-10-15

    Some heavy oil reservoirs in Venezuela and Canada have shown higher than expected production rates attributed to the effects of foamy oil or enhanced solution gas drive. However, foamy oil 2-phase flow does not fully explain oil rate enhancement in heavy oil reservoirs. In this study, flow visualization experiments were conducted in a 2-D etched network micromodel in order to determine the effect of the viscosity ratio on oil mobility at the pore scale. The micromodel's pattern was characterized by macroscopic heterogeneities with a random network of larger pore bodies interconnected with a random network of smaller pore throats. Displacement tests were conducted with green-dyed distilled water as a wetting phase. N-octane, bromododecane and mineral oil were used as non-wetting phases. An unsteady-state method was used to obtain displacement data, and the Alternate method was used to calculate relative permeabilities. Results of the study showed that relative permeabilities depended on the viscosity ratio of the fluids flowing through the porous medium. Channel and annular flows co-existed, and water lubrication was stronger at higher water saturations. The results of the study explained the abnormally high production rates in heavier oil fields. 19 refs., 3 tabs., 14 figs.

  17. Carbon dioxide sequestration induced mineral precipitation healing of fractured reservoir seals

    Science.gov (United States)

    Welch, N.; Crawshaw, J.

    2017-12-01

    Initial experiments and the thermodynaic basis for carbon dioxide sequestration induced mineral precipitation healing of fractures through reservoir seals will be presented. The basis of this work is the potential exists for the dissolution of reservoir host rock formation carbonate minerals in the acidified injection front of CO2 during sequestration or EOR. This enriched brine and the bulk CO2 phase will then flow through the reservoir until contact with the reservoir seal. At this point any fractures present in the reservoir seal will be the preferential flow path for the bulk CO2 phase as well as the acidified brine front. These fractures would currently be filled with non-acidified brine saturated in seal formation brine. When the acidifeid brine from the host formation and the cap rock brine mix there is the potential for minerals to fall out of solution, and for these precipitated minerals to decrease or entirely cut off the fluid flow through the fractures present in a reservoir seal. Initial equilibrium simulations performed using the PHREEQC1 database drived from the PHREEQE2 database are used to show the favorable conditions under which this mineral precipitation can occurs. Bench scale fluid mixing experiments were then performed to determine the kinetics of the mineral precipitation process, and determine the progress of future experiemnts involving fluid flow within fractured anhydrite reservoir seal samples. 1Parkhurst, D.L., and Appelo, C.A.J., 2013, Description of input and examples for PHREEQC version 3—A computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations: U.S. Geological Survey Techniques and Methods, book 6, chap. A43, 497 p., available only at https://pubs.usgs.gov/tm/06/a43/. 2Parkhurst, David L., Donald C. Thorstenson, and L. Niel Plummer. PHREEQE: a computer program for geochemical calculations. No. 80-96. US Geological Survey, Water Resources Division,, 1980.

  18. Metallothionein and heavy metals in daphnia pulex from Jose Antonio Alzate reservoir

    International Nuclear Information System (INIS)

    Avila Perez, P.; Zarazua Ortega, G.; Barcelo Quintal, D.; Rosas, I.; Diazdelgado, C.

    2001-01-01

    Water and specimens of the freshwater cladoceran Dhapnia pulex were collected at 4 different sites located in an area influenced by industrial, agricultural and urban activities in the Jose Antonio Alzate Reservoir in two different seasons. The Jose Antonio Alzate Reservoir fed by the Lerma river is the first significant water reservoir downstream of the main industrial areas in the State of Mexico. There are about 2,500 industrial discharges between the river source and the Alzate Reservoir which makes the Lerma river and the Jose Antonio Alzate Reservoir the most contaminated water bodies in the State of Mexico. The Monitoring National Network recognises these waters as highly contaminated, especially in the zone located between the Mexico-Toluca highway and the Alzate Reservoir. Water samples and freshwater cladoceran were analysed for Cu and Zn by Energy Dispersive X-Ray Fluorescence (EDXRF) and for Hg and Cd by Neutron Activation Analysis (NAA). As a general feature, the heavy metal concentrations of the water were found to decrease in the sequence: Cu > Zn > Hg > Cd. Metallothioneins (MT) were determined by silver saturation method. Tissue concentrations of MT in Dhapnia pulex varied between 5.69 and 8.96 (mg MT/ g wet wt) in rain season and between 48.87 and 74.00 (mg MT/ g wet wt) in dry season. Metallothioneins levels in Dhapnia pulex were significantly correlated (P < 0.01) with tissue Hg concentrations. In contrast, correlations between MT and tissue levels of Cu and Zn were weak. These observations suggest that Hg2+ activity is the key environmental factor to which metallothionein levels in Daphnia pulex are responding in the studied reservoir

  19. Oil recovery from naturally fractured reservoirs by steam injection methods. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Reis, J.C.; Miller, M.A.

    1995-05-01

    Oil recovery by steam injection is a proven, successful technology for nonfractured reservoirs, but has received only limited study for fractured reservoirs. Preliminary studies suggest recovery efficiencies in fractured reservoirs may be increased by as much as 50% with the application of steam relative to that of low temperature processes. The key mechanisms enhancing oil production at high temperature are the differential thermal expansion between oil and the pore volume, and the generation of gases within matrix blocks. Other mechanisms may also contribute to increased production. These mechanisms are relatively independent of oil gravity, making steam injection into naturally fractured reservoirs equally attractive to light and heavy oil deposits. The objectives of this research program are to quantify the amount of oil expelled by these recovery mechanisms and to develop a numerical model for predicting oil recovery in naturally fractured reservoirs during steam injection. The experimental study consists of constructing and operating several apparatuses to isolate each of these mechanisms. The first measures thermal expansion and capillary imbibition rates at relatively low temperature, but for various lithologies and matrix block shapes. The second apparatus measures the same parameters, but at high temperatures and for only one shape. A third experimental apparatus measures the maximum gas saturations that could build up within a matrix block. A fourth apparatus measures thermal conductivity and diffusivity of porous media. The numerical study consists of developing transfer functions for oil expulsion from matrix blocks to fractures at high temperatures and incorporating them, along with the energy equation, into a dual porosity thermal reservoir simulator. This simulator can be utilized to make predictions for steam injection processes in naturally-fractured reservoirs. Analytical models for capillary imbibition have also been developed.

  20. Integrated Reflection Seismic Monitoring and Reservoir Modeling for Geologic CO2 Sequestration

    Energy Technology Data Exchange (ETDEWEB)

    John Rogers

    2011-12-31

    developed from this injection was observed migrating due to gravity to the apexes of the double anticline in the Crow Mountain reservoir of the Teapot dome. Four models were generated from the reservoir simulation task of the project which included three saturation models representing snapshots at different times during and after simulated CO{sub 2} injection and a fully saturated CO{sub 2} fluid substitution model. The saturation models were used along with a Gassmann fluid substitution model for CO{sub 2} to perform fluid volumetric substitution in the Crow Mountain formation. The fluid substitution resulted in a velocity and density model for the 3D volume at each saturation condition that was used to generate a synthetic seismic survey. FPTI's (Fusion Petroleum Technologies Inc.) proprietary SeisModelPRO{trademark} full acoustic wave equation software was used to simulate acquisition of a 3D seismic survey on the four models over a subset of the field area. The simulated acquisition area included the injection wells and the majority of the simulated plume area.

  1. Assessing geotechnical centrifuge modelling in addressing variably saturated flow in soil and fractured rock.

    Science.gov (United States)

    Jones, Brendon R; Brouwers, Luke B; Van Tonder, Warren D; Dippenaar, Matthys A

    2017-05-01

    The vadose zone typically comprises soil underlain by fractured rock. Often, surface water and groundwater parameters are readily available, but variably saturated flow through soil and rock are oversimplified or estimated as input for hydrological models. In this paper, a series of geotechnical centrifuge experiments are conducted to contribute to the knowledge gaps in: (i) variably saturated flow and dispersion in soil and (ii) variably saturated flow in discrete vertical and horizontal fractures. Findings from the research show that the hydraulic gradient, and not the hydraulic conductivity, is scaled for seepage flow in the geotechnical centrifuge. Furthermore, geotechnical centrifuge modelling has been proven as a viable experimental tool for the modelling of hydrodynamic dispersion as well as the replication of similar flow mechanisms for unsaturated fracture flow, as previously observed in literature. Despite the imminent challenges of modelling variable saturation in the vadose zone, the geotechnical centrifuge offers a powerful experimental tool to physically model and observe variably saturated flow. This can be used to give valuable insight into mechanisms associated with solid-fluid interaction problems under these conditions. Findings from future research can be used to validate current numerical modelling techniques and address the subsequent influence on aquifer recharge and vulnerability, contaminant transport, waste disposal, dam construction, slope stability and seepage into subsurface excavations.

  2. Saturated Zone In-Situ Testing

    International Nuclear Information System (INIS)

    Reimus, P. W.; Umari, M. J.

    2003-01-01

    The purpose of this scientific analysis is to document the results and interpretations of field experiments that have been conducted to test and validate conceptual flow and radionuclide transport models in the saturated zone (SZ) near Yucca Mountain. The test interpretations provide estimates of flow and transport parameters that are used in the development of parameter distributions for Total System Performance Assessment (TSPA) calculations. These parameter distributions are documented in the revisions to the SZ flow model report (BSC 2003 [ 162649]), the SZ transport model report (BSC 2003 [ 162419]), the SZ colloid transport report (BSC 2003 [162729]), and the SZ transport model abstraction report (BSC 2003 [1648701]). Specifically, this scientific analysis report provides the following information that contributes to the assessment of the capability of the SZ to serve as a barrier for waste isolation for the Yucca Mountain repository system: (1) The bases for selection of conceptual flow and transport models in the saturated volcanics and the saturated alluvium located near Yucca Mountain. (2) Results and interpretations of hydraulic and tracer tests conducted in saturated fractured volcanics at the C-wells complex near Yucca Mountain. The test interpretations include estimates of hydraulic conductivities, anisotropy in hydraulic conductivity, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass transfer coefficients, matrix diffusion coefficients, fracture apertures, and colloid transport parameters. (3) Results and interpretations of hydraulic and tracer tests conducted in saturated alluvium at the Alluvium Testing Complex (ATC), which is located at the southwestern corner of the Nevada Test Site (NTS). The test interpretations include estimates of hydraulic conductivities, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass transfer coefficients, and

  3. Saturated Zone In-Situ Testing

    Energy Technology Data Exchange (ETDEWEB)

    P. W. Reimus; M. J. Umari

    2003-12-23

    The purpose of this scientific analysis is to document the results and interpretations of field experiments that have been conducted to test and validate conceptual flow and radionuclide transport models in the saturated zone (SZ) near Yucca Mountain. The test interpretations provide estimates of flow and transport parameters that are used in the development of parameter distributions for Total System Performance Assessment (TSPA) calculations. These parameter distributions are documented in the revisions to the SZ flow model report (BSC 2003 [ 162649]), the SZ transport model report (BSC 2003 [ 162419]), the SZ colloid transport report (BSC 2003 [162729]), and the SZ transport model abstraction report (BSC 2003 [1648701]). Specifically, this scientific analysis report provides the following information that contributes to the assessment of the capability of the SZ to serve as a barrier for waste isolation for the Yucca Mountain repository system: (1) The bases for selection of conceptual flow and transport models in the saturated volcanics and the saturated alluvium located near Yucca Mountain. (2) Results and interpretations of hydraulic and tracer tests conducted in saturated fractured volcanics at the C-wells complex near Yucca Mountain. The test interpretations include estimates of hydraulic conductivities, anisotropy in hydraulic conductivity, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass transfer coefficients, matrix diffusion coefficients, fracture apertures, and colloid transport parameters. (3) Results and interpretations of hydraulic and tracer tests conducted in saturated alluvium at the Alluvium Testing Complex (ATC), which is located at the southwestern corner of the Nevada Test Site (NTS). The test interpretations include estimates of hydraulic conductivities, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass transfer coefficients, and

  4. Muon Tomography of Deep Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Bonneville, Alain H.; Kouzes, Richard T.

    2016-12-31

    Imaging subsurface geological formations, oil and gas reservoirs, mineral deposits, cavities or magma chambers under active volcanoes has been for many years a major quest of geophysicists and geologists. Since these objects cannot be observed directly, different indirect geophysical methods have been developed. They are all based on variations of certain physical properties of the subsurface that can be detected from the ground surface or from boreholes. Electrical resistivity, seismic wave’s velocities and density are certainly the most used properties. If we look at density, indirect estimates of density distributions are performed currently by seismic reflection methods - since the velocity of seismic waves depend also on density - but they are expensive and discontinuous in time. Direct estimates of density are performed using gravimetric data looking at variations of the gravity field induced by the density variations at depth but this is not sufficiently accurate. A new imaging technique using cosmic-ray muon detectors has emerged during the last decade and muon tomography - or muography - promises to provide, for the first time, a complete and precise image of the density distribution in the subsurface. Further, this novel approach has the potential to become a direct, real-time, and low-cost method for monitoring fluid displacement in subsurface reservoirs.

  5. 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

  6. Development of gas and gas condensate reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-01

    In the study of gas reservoir development, the first year topics are restricted on reservoir characterization. There are two types of reservoir characterization. One is the reservoir formation characterization and the other is the reservoir fluid characterization. For the reservoir formation characterization, calculation of conditional simulation was compared with that of unconditional simulation. The results of conditional simulation has higher confidence level than the unconditional simulation because conditional simulation considers the sample location as well as distance correlation. In the reservoir fluid characterization, phase behavior calculations revealed that the component grouping is more important than the increase of number of components. From the liquid volume fraction with pressure drop, the phase behavior of reservoir fluid can be estimated. The calculation results of fluid recombination, constant composition expansion, and constant volume depletion are matched very well with the experimental data. In swelling test of the reservoir fluid with lean gas, the accuracy of dew point pressure forecast depends on the component characterization. (author). 28 figs., 10 tabs.

  7. Stretch due to Penile Prosthesis Reservoir Migration

    Directory of Open Access Journals (Sweden)

    E. Baten

    2016-03-01

    Full Text Available A 43-year old patient presented to the emergency department with stretch, due to impossible deflation of the penile prosthesis, 4 years after successful implant. A CT-scan showed migration of the reservoir to the left rectus abdominis muscle. Refilling of the reservoir was inhibited by muscular compression, causing stretch. Removal and replacement of the reservoir was performed, after which the prosthesis was well-functioning again. Migration of the penile prosthesis reservoir is extremely rare but can cause several complications, such as stretch.

  8. Multi-data reservoir history matching for enhanced reservoir forecasting and uncertainty quantification

    KAUST Repository

    Katterbauer, Klemens; Arango, Santiago; Sun, Shuyu; Hoteit, Ibrahim

    2015-01-01

    Reservoir simulations and history matching are critical for fine-tuning reservoir production strategies, improving understanding of the subsurface formation, and forecasting remaining reserves. Production data have long been incorporated

  9. FLASH: A finite element computer code for variably saturated flow

    International Nuclear Information System (INIS)

    Baca, R.G.; Magnuson, S.O.

    1992-05-01

    A numerical model was developed for use in performance assessment studies at the INEL. The numerical model, referred to as the FLASH computer code, is designed to simulate two-dimensional fluid flow in fractured-porous media. The code is specifically designed to model variably saturated flow in an arid site vadose zone and saturated flow in an unconfined aquifer. In addition, the code also has the capability to simulate heat conduction in the vadose zone. This report presents the following: description of the conceptual frame-work and mathematical theory; derivations of the finite element techniques and algorithms; computational examples that illustrate the capability of the code; and input instructions for the general use of the code. The FLASH computer code is aimed at providing environmental scientists at the INEL with a predictive tool for the subsurface water pathway. This numerical model is expected to be widely used in performance assessments for: (1) the Remedial Investigation/Feasibility Study process and (2) compliance studies required by the US Department of Energy Order 5820.2A

  10. Super-resolution fluorescence microscopy by stepwise optical saturation

    Science.gov (United States)

    Zhang, Yide; Nallathamby, Prakash D.; Vigil, Genevieve D.; Khan, Aamir A.; Mason, Devon E.; Boerckel, Joel D.; Roeder, Ryan K.; Howard, Scott S.

    2018-01-01

    Super-resolution fluorescence microscopy is an important tool in biomedical research for its ability to discern features smaller than the diffraction limit. However, due to its difficult implementation and high cost, the super-resolution microscopy is not feasible in many applications. In this paper, we propose and demonstrate a saturation-based super-resolution fluorescence microscopy technique that can be easily implemented and requires neither additional hardware nor complex post-processing. The method is based on the principle of stepwise optical saturation (SOS), where M steps of raw fluorescence images are linearly combined to generate an image with a M-fold increase in resolution compared with conventional diffraction-limited images. For example, linearly combining (scaling and subtracting) two images obtained at regular powers extends the resolution by a factor of 1.4 beyond the diffraction limit. The resolution improvement in SOS microscopy is theoretically infinite but practically is limited by the signal-to-noise ratio. We perform simulations and experimentally demonstrate super-resolution microscopy with both one-photon (confocal) and multiphoton excitation fluorescence. We show that with the multiphoton modality, the SOS microscopy can provide super-resolution imaging deep in scattering samples. PMID:29675306

  11. Validation of the Nonin 8600V Pulse Oximeter for heart rate and oxygen saturation measurements in rats.

    Science.gov (United States)

    Bernard, Susan L; An, Dowon; Glenny, Robb W

    2004-05-01

    This report validates the use and limitations of the Nonin Pulse Oximeter for measuring heart rate and oxygen saturation in rats. Eight anesthetized Sprague-Dawley rats were intubated and catheterized. Oxygen saturation was directly measured from arterial blood by using a Radiometer OSM3 Hemoximeter adjusted for rat blood as well as indirectly by using the Nonin Pulse Oximeter. Oxygen saturation was changed by varying the level of inhaled oxygen. Heart rate was measured in two ways: 1) by using the signal from the Nonin Pulse Oximeter and 2) by counting the pressure pulses from the transduced blood pressure. There was excellent agreement between heart rate values measured by the Nonin Pulse Oximeter and that measured by counting the pulses from the arterial blood pressure recording. The Nonin Pulse Oximeter underestimated oxygen saturations by about 3% to 5% compared to the Hemoximeter. Overall, the pulse oximeter reflected important trends in oxygen saturations, making it a useful tool for laboratory animal medicine.

  12. Appraisal of transport and deformation in shale reservoirs using natural noble gas tracers

    Energy Technology Data Exchange (ETDEWEB)

    Heath, Jason E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kuhlman, Kristopher L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Robinson, David G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bauer, Stephen J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gardner, William Payton [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Univ. of Montana, Missoula, MT (United States)

    2015-09-01

    This report presents efforts to develop the use of in situ naturally-occurring noble gas tracers to evaluate transport mechanisms and deformation in shale hydrocarbon reservoirs. Noble gases are promising as shale reservoir diagnostic tools due to their sensitivity of transport to: shale pore structure; phase partitioning between groundwater, liquid, and gaseous hydrocarbons; and deformation from hydraulic fracturing. Approximately 1.5-year time-series of wellhead fluid samples were collected from two hydraulically-fractured wells. The noble gas compositions and isotopes suggest a strong signature of atmospheric contribution to the noble gases that mix with deep, old reservoir fluids. Complex mixing and transport of fracturing fluid and reservoir fluids occurs during production. Real-time laboratory measurements were performed on triaxially-deforming shale samples to link deformation behavior, transport, and gas tracer signatures. Finally, we present improved methods for production forecasts that borrow statistical strength from production data of nearby wells to reduce uncertainty in the forecasts.

  13. Microbial conversion of higher hydrocarbons to methane in oil and coal reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, Martin; Beckmaann, Sabrina; Siegert, Michael; Grundger, Friederike; Richnow, Hans [Geomicrobiology Group, Federal Institute for Geosciences and Natural Resources (Germany)

    2011-07-01

    In recent years, oil production has increased enormously but almost half of the oil now remaining is heavy/biodegraded and cannot be put into production. There is therefore a need for new technology and for diversification of energy sources. This paper discusses the microbial conversion of higher hydrocarbons to methane in oil and coal reservoirs. The objective of the study is to identify microbial and geochemical controls on methanogenesis in reservoirs. A graph shows the utilization of methane for various purposes in Germany from 1998 to 2007. A degradation process to convert coal to methane is shown using a flow chart. The process for converting oil to methane is also given. Controlling factors include elements such as Fe, nitrogen and sulfur. Atmospheric temperature and reservoir pressure and temperature also play an important role. From the study it can be concluded that isotopes of methane provide exploration tools for reservoir selection and alkanes and aromatic compounds provide enrichment cultures.

  14. Space Charge Saturated Sheath Regime and Electron Temperature Saturation in Hall Thrusters

    International Nuclear Information System (INIS)

    Raitses, Y.; Staack, D.; Smirnov, A.; Fisch, N.J.

    2005-01-01

    Secondary electron emission in Hall thrusters is predicted to lead to space charge saturated wall sheaths resulting in enhanced power losses in the thruster channel. Analysis of experimentally obtained electron-wall collision frequency suggests that the electron temperature saturation, which occurs at high discharge voltages, appears to be caused by a decrease of the Joule heating rather than by the enhancement of the electron energy loss at the walls due to a strong secondary electron emission

  15. Comparison of pulseoximetry oxygen saturation and arterial oxygen saturation in open heart intensive care unit

    Directory of Open Access Journals (Sweden)

    Alireza Mahoori

    2013-08-01

    Full Text Available Background: Pulseoximetry is widely used in the critical care setting, currently used to guide therapeutic interventions. Few studies have evaluated the accuracy of SPO2 (puls-eoximetry oxygen saturation in intensive care unit after cardiac surgery. Our objective was to compare pulseoximetry with arterial oxygen saturation (SaO2 during clinical routine in such patients, and to examine the effect of mild acidosis on this relationship.Methods: In an observational prospective study 80 patients were evaluated in intensive care unit after cardiac surgery. SPO2 was recorded and compared with SaO2 obtained by blood gas analysis. One or serial arterial blood gas analyses (ABGs were performed via a radial artery line while a reliable pulseoximeter signal was present. One hundred thirty seven samples were collected and for each blood gas analyses, SaO2 and SPO2 we recorded.Results: O2 saturation as a marker of peripheral perfusion was measured by Pulseoxim-etry (SPO2. The mean difference between arterial oxygen saturation and pulseoximetry oxygen saturation was 0.12%±1.6%. A total of 137 paired readings demonstrated good correlation (r=0.754; P<0.0001 between changes in SPO2 and those in SaO2 in samples with normal hemoglobin. Also in forty seven samples with mild acidosis, paired readings demonstrated good correlation (r=0.799; P<0.0001 and the mean difference between SaO2 and SPO2 was 0.05%±1.5%.Conclusion: Data showed that in patients with stable hemodynamic and good signal quality, changes in pulseoximetry oxygen saturation reliably predict equivalent changes in arterial oxygen saturation. Mild acidosis doesn’t alter the relation between SPO2 and SaO2 to any clinically important extent. In conclusion, the pulse oximeter is useful to monitor oxygen saturation in patients with stable hemodynamic.

  16. Scaling of saturation amplitudes in baroclinic instability

    International Nuclear Information System (INIS)

    Shepherd, T.G.

    1994-01-01

    By using finite-amplitude conservation laws for pseudomomentum and pseudoenergy, rigorous upper bounds have been derived on the saturation amplitudes in baroclinic instability for layered and continuously-stratified quasi-geostrophic models. Bounds have been obtained for both the eddy energy and the eddy potential enstrophy. The bounds apply to conservative (inviscid, unforced) flow, as well as to forced-dissipative flow when the dissipation is proportional to the potential vorticity. This approach provides an efficient way of extracting an analytical estimate of the dynamical scalings of the saturation amplitudes in terms of crucial non-dimensional parameters. A possible use is in constructing eddy parameterization schemes for zonally-averaged climate models. The scaling dependences are summarized, and compared with those derived from weakly-nonlinear theory and from baroclinic-adjustment estimates

  17. Effective stress principle for partially saturated media

    International Nuclear Information System (INIS)

    McTigue, D.F.; Wilson, R.K.; Nunziato, J.W.

    1984-04-01

    In support of the Nevada Nuclear Waste Storage Investigation (NNWSI) Project, we have undertaken a fundamental study of water migration in partially saturated media. One aspect of that study, on which we report here, has been to use the continuum theory of mixtures to extend the classical notion of effective stress to partially saturated media. Our analysis recovers previously proposed phenomenological representations for the effective stress in terms of the capillary pressure. The theory is illustrated by specializing to the case of linear poroelasticity, for which we calculate the deformation due to the fluid pressure in a static capillary fringe. We then examine the transient consolidation associated with liquid flow induced by an applied surface load. Settlement accompanies this flow as the liquid is redistributed by a nonlinear diffusion process. For material properties characteristic of tuff from the Nevada Test Site, these effects are found to be vanishingly small. 14 references, 7 figures, 1 table

  18. Saturated tearing modes in tokamaks with divertors

    International Nuclear Information System (INIS)

    Bateman, G.

    1982-12-01

    We have developed a self-consistent theory of saturated tearing modes capable of predicting multiple magnetic island widths in tokamaks with no assumptions on the cross-sectional shape, aspect ratio, or plasma pressure. We are in the process of implementing this algorithm in the form of a computer code. We propose: (1) to complete, refine, document and publish this computer code; (2) to carry out a survey in which we vary the current profile, aspect ratio, cross-sectional shape, and pressure profile in order to determine their effect on saturated tearing mode magnetic island widths; and (3) to determine the effect of some externally applied magnetic perturbation harmonics on these magnetic island widths. Particular attention will be paid to the coupling between different helical harmonics, the effect of multiple magnetic islands on the profiles of temperature, pressure and current, and the potential of magnetic island overlap leading to a disruptive instability

  19. Tearing mode saturation with finite pressure

    International Nuclear Information System (INIS)

    Lee, J.K.

    1988-01-01

    With finite pressure, the saturation of the current-driven tearing mode is obtained in three-dimensional nonlinear resistive magnetohydrodynamic simulations for Tokamak plasmas. To effectively focus on the tearing modes, the perturbed pressure effects are excluded while the finite equilibrium pressure effects are retained. With this model, the linear growth rates of the tearing modes are found to be very insensitive to the equilibrium pressure increase. The nonlinear aspects of the tearing modes, however, are found to be very sensitive to the pressure increase in that the saturation level of the nonlinear harmonics of the tearing modes increases monotonically with the pressure rise. The increased level is associated with enhanced tearing island sizes or increased stochastic magnetic field region. (author)

  20. The danish tax on saturated fat

    DEFF Research Database (Denmark)

    Jensen, Jørgen Dejgård; Smed, Sinne

    Denmark introduced a new tax on saturated fat in food products with effect from October 2011. The objective of this paper is to make an effect assessment of this tax for some of the product categories most significantly affected by the new tax, namely fats such as butter, butter-blends, margarine...... on saturated fat in food products has had some effects on the market for the considered products, in that the level of consumption of fats dropped by 10 – 20%. Furthermore, the analysis points at shifts in demand from high-price supermarkets towards low-price discount stores – a shift that seems to have been...... utilized by discount chains to raise the prices of butter and margarine by more than the pure tax increase. Due to the relatively short data period with the tax being active, interpretation of these findings from a long-run perspective should be done with considerable care. It is thus recommended to repeat...

  1. Advanced Oil Recovery Technologies for Improved Recovery from Slope Basin Clastic Reservoirs, Nash Draw Brushy Canyon Pool, Eddy County, NM

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, Mark B.

    1999-02-24

    The Nash Draw Brushy Canyon Pool in Eddy County New Mexico is a cost-shared field demonstration project in the US Department of Energy Class II Program. A major goal of the Class III Program is to stimulate the use of advanced technologies to increase ultimate recovery from slope-basin clastic reservoirs. Advanced characterization techniques are being used at the Nash Draw project to develop reservoir management strategies for optimizing oil recovery from this Delaware reservoir. Analysis, interpretation, and integration of recently acquired geologic, geophysical, and engineering data revealed that the initial reservoir characterization was too simplistic to capture the critical features of this complex formation. Contrary to the initial characterization, a new reservoir description evolved that provided sufficient detail regarding the complexity of the Brushy Canyon interval at Nash Draw. This new reservoir description is being used as a risk reduction tool to identify ''sweet spots'' for a development drilling program as well as to evaluate pressure maintenance strategies. The reservoir characterization, geological modeling, 3-D seismic interpretation, and simulation studies have provided a detailed model of the Brushy Canyon zones. This model was used to predict the success of different reservoir management scenarios and to aid in determining the most favorable combination of targeted drilling, pressure maintenance, well simulation, and well spacing to improve recovery from this reservoir.

  2. A Semi-Analytical Method for Rapid Estimation of Near-Well Saturation, Temperature, Pressure and Stress in Non-Isothermal CO2 Injection

    Science.gov (United States)

    LaForce, T.; Ennis-King, J.; Paterson, L.

    2015-12-01

    Reservoir cooling near the wellbore is expected when fluids are injected into a reservoir or aquifer in CO2 storage, enhanced oil or gas recovery, enhanced geothermal systems, and water injection for disposal. Ignoring thermal effects near the well can lead to under-prediction of changes in reservoir pressure and stress due to competition between increased pressure and contraction of the rock in the cooled near-well region. In this work a previously developed semi-analytical model for immiscible, nonisothermal fluid injection is generalised to include partitioning of components between two phases. Advection-dominated radial flow is assumed so that the coupled two-phase flow and thermal conservation laws can be solved analytically. The temperature and saturation profiles are used to find the increase in reservoir pressure, tangential, and radial stress near the wellbore in a semi-analytical, forward-coupled model. Saturation, temperature, pressure, and stress profiles are found for parameters representative of several CO2 storage demonstration projects around the world. General results on maximum injection rates vs depth for common reservoir parameters are also presented. Prior to drilling an injection well there is often little information about the properties that will determine the injection rate that can be achieved without exceeding fracture pressure, yet injection rate and pressure are key parameters in well design and placement decisions. Analytical solutions to simplified models such as these can quickly provide order of magnitude estimates for flow and stress near the well based on a range of likely parameters.

  3. Gluon saturation beyond (naive) leading logs

    Energy Technology Data Exchange (ETDEWEB)

    Beuf, Guillaume

    2014-12-15

    An improved version of the Balitsky–Kovchegov equation is presented, with a consistent treatment of kinematics. That improvement allows to resum the most severe of the large higher order corrections which plague the conventional versions of high-energy evolution equations, with approximate kinematics. This result represents a further step towards having high-energy QCD scattering processes under control beyond strict Leading Logarithmic accuracy and with gluon saturation effects.

  4. Estimation of Bank Erosion Due To Reservoir Operation in Cascade (Case Study: Citarum Cascade Reservoir

    Directory of Open Access Journals (Sweden)

    Sri Legowo

    2009-11-01

    Full Text Available Sedimentation is such a crucial issue to be noted once the accumulated sediment begins to fill the reservoir dead storage, this will then influence the long-term reservoir operation. The sediment accumulated requires a serious attention for it may influence the storage capacity and other reservoir management of activities. The continuous inflow of sediment to the reservoir will decrease the capacity of reservoir storage, the reservoir value in use, and the useful age of reservoir. Because of that, the rate of the sediment needs to be delayed as possible. In this research, the delay of the sediment rate is considered based on the rate of flow of landslide of the reservoir slope. The rate of flow of the sliding slope can be minimized by way of each reservoir autonomous efforts. This effort can be performed through; the regulation of fluctuating rate of reservoir surface current that does not cause suddenly drawdown and upraising as well. The research model is compiled using the searching technique of Non Linear Programming (NLP.The rate of bank erosion for the reservoir variates from 0.0009 to 0.0048 MCM/year, which is no sigrificant value to threaten the life time of reservoir.Mean while the rate of watershed sediment has a significant value, i.e: 3,02 MCM/year for Saguling that causes to fullfill the storage capacity in 40 next years (from years 2008.

  5. Ligand screening by saturation-transfer difference (STD) NMR spectroscopy.

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, V V

    2005-04-26

    NMR based methods to screen for high-affinity ligands have become an indispensable tool for designing rationalized drugs, as these offer a combination of good experimental design of the screening process and data interpretation methods, which together provide unprecedented information on the complex nature of protein-ligand interactions. These methods rely on measuring direct changes in the spectral parameters, that are often simpler than the complex experimental procedures used to study structure and dynamics of proteins. The goal of this review article is to provide the basic details of NMR based ligand-screening methods, with particular focus on the saturation transfer difference (STD) experiment. In addition, we provide an overview of other NMR experimental methods and a practical guide on how to go about designing and implementing them.

  6. THE SATURATION OF SASI BY PARASITIC INSTABILITIES

    International Nuclear Information System (INIS)

    Guilet, Jerome; Sato, Jun'ichi; Foglizzo, Thierry

    2010-01-01

    The standing accretion shock instability (SASI) is commonly believed to be responsible for large amplitude dipolar oscillations of the stalled shock during core collapse, potentially leading to an asymmetric supernovae explosion. The degree of asymmetry depends on the amplitude of SASI, but the nonlinear saturation mechanism has never been elucidated. We investigate the role of parasitic instabilities as a possible cause of nonlinear SASI saturation. As the shock oscillations create both vorticity and entropy gradients, we show that both Kelvin-Helmholtz and Rayleigh-Taylor types of instabilities are able to grow on a SASI mode if its amplitude is large enough. We obtain simple estimates of their growth rates, taking into account the effects of advection and entropy stratification. In the context of the advective-acoustic cycle, we use numerical simulations to demonstrate how the acoustic feedback can be decreased if a parasitic instability distorts the advected structure. The amplitude of the shock deformation is estimated analytically in this scenario. When applied to the set up of Fernandez and Thompson, this saturation mechanism is able to explain the dramatic decrease of the SASI power when both the nuclear dissociation energy and the cooling rate are varied. Our results open new perspectives for anticipating the effect, on the SASI amplitude, of the physical ingredients involved in the modeling of the collapsing star.

  7. Optimal oxygen saturation in premature infants

    Directory of Open Access Journals (Sweden)

    Meayoung Chang

    2011-09-01

    Full Text Available There is a delicate balance between too little and too much supplemental oxygen exposure in premature infants. Since underuse and overuse of supplemental oxygen can harm premature infants, oxygen saturation levels must be monitored and kept at less than 95% to prevent reactive oxygen species-related diseases, such as retinopathy of prematurity and bronchopulmonary dysplasia. At the same time, desaturation below 80 to 85% must be avoided to prevent adverse consequences, such as cerebral palsy. It is still unclear what range of oxygen saturation is appropriate for premature infants; however, until the results of further studies are available, a reasonable target for pulse oxygen saturation (SpO2 is 90 to 93% with an intermittent review of the correlation between SpO2 and the partial pressure of arterial oxygen tension (PaO2. Because optimal oxygenation depends on individuals at the bedside making ongoing adjustments, each unit must define an optimal target range and set alarm limits according to their own equipment or conditions. All staff must be aware of these values and adjust the concentration of supplemental oxygen frequently.

  8. Saturation and nucleation in hot nuclear systems

    International Nuclear Information System (INIS)

    Deangelis, A.R.

    1990-07-01

    We investigate nuclear fragmentation in a supersaturated system using classical nucleation theory. This allows us to go outside the normally applied constraint of chemical equilibrium. The system is governed by a virial equation of state, which we use to find an expression for the density as a function of pressure and temperature. The evolution of the system is discussed in terms of the phase diagram. Corrections are included to account for the droplet surface and all charges contained in the system. Using this model we investigate and discuss the effects of temperature and saturation, and compare the results to those of other models of fragmentation. We also discuss the limiting temperatures of the system for the cases with and without chemical equilibrium. We find that large nuclei will be formed in saturated systems, even above the limiting temperature as previously defined. We also find that saturation and temperature dominate surface and Coulomb effects. The effects are quite large, thus even a qualitative inspection of the yields may give an indication of the conditions during fragmentation

  9. Multipactor saturation in parallel-plate waveguides

    International Nuclear Information System (INIS)

    Sorolla, E.; Mattes, M.

    2012-01-01

    The saturation stage of a multipactor discharge is considered of interest, since it can guide towards a criterion to assess the multipactor onset. The electron cloud under multipactor regime within a parallel-plate waveguide is modeled by a thin continuous distribution of charge and the equations of motion are calculated taking into account the space charge effects. The saturation is identified by the interaction of the electron cloud with its image charge. The stability of the electron population growth is analyzed and two mechanisms of saturation to explain the steady-state multipactor for voltages near above the threshold onset are identified. The impact energy in the collision against the metal plates decreases during the electron population growth due to the attraction of the electron sheet on the image through the initial plate. When this growth remains stable till the impact energy reaches the first cross-over point, the electron surface density tends to a constant value. When the stability is broken before reaching the first cross-over point the surface charge density oscillates chaotically bounded within a certain range. In this case, an expression to calculate the maximum electron surface charge density is found whose predictions agree with the simulations when the voltage is not too high.

  10. Mass transfer in water-saturated concretes

    International Nuclear Information System (INIS)

    Atkinson, A.; Claisse, P.A.; Harris, A.W.; Nickerson, A.K.

    1990-01-01

    Cements and concretes are often considered as components of barriers for the containment of radioactive waste. The performance of such materials as mainly physical barriers to the transport of dissolved radionuclides depends on the mass transfer characteristics of the material. In particular the diffusion and sorption behavior of the radionuclides and the water permeability are important. These parameters also influence how the chemistry of the concrete is imposed on the repository. In addition, the transport of gas through concrete controls the way in which gases escape from the repository. Diffusion and gas transport have been measured in a variety of cementitious materials, covering both structural concretes and cementitious backfills; all possible repository construction materials. Measurements have been made using aqueous iodide, strontium and caesium ions and tritiated water as diffusants. The results show that the diffusion of tritiated water is more rapid than that of other species, whilst the transport of strontium and caesium is hindered by sorption; particularly in materials containing blast furnace slag. The transport of gas in these materials has been found to be very sensitive to the degree of water saturation and is extremely low in fully saturated structural concretes. Cementitious backfills have, nevertheless, been identified that have appreciable gas transport even when almost water saturated. The consequences of the results for the performance of cementitious barriers are discussed

  11. 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

  12. Reactivity of dolomite in water-saturated supercritical carbon dioxide: Significance for carbon capture and storage and for enhanced oil and gas recovery

    International Nuclear Information System (INIS)

    Wang Xiuyu; Alvarado, Vladimir; Swoboda-Colberg, Norbert; Kaszuba, John P.

    2013-01-01

    Highlights: ► Dolomite reactivity with wet and dry supercritical CO 2 were evaluated. ► Dolomite does not react with dry CO 2 . ► H 2 O-saturated supercritical CO 2 dissolves dolomite and precipitates carbonate mineral. ► Temperature/reaction time control morphology and extent of carbonate mineralization. ► Reaction with wet CO 2 may impact trapping, caprock integrity, and CCS/EOR injectivity. - Abstract: Carbon dioxide injection in porous reservoirs is the basis for carbon capture and storage, enhanced oil and gas recovery. Injected carbon dioxide is stored at multiple scales in porous media, from the pore-level as a residual phase to large scales as macroscopic accumulations by the injection site, under the caprock and at reservoir internal capillary pressure barriers. These carbon dioxide saturation zones create regions across which the full spectrum of mutual CO 2 –H 2 O solubility may occur. Most studies assume that geochemical reaction is restricted to rocks and carbon dioxide-saturated formation waters, but this paradigm ignores injection of anhydrous carbon dioxide against brine and water-alternating-gas flooding for enhanced oil recovery. A series of laboratory experiments was performed to evaluate the reactivity of the common reservoir mineral dolomite with water-saturated supercritical carbon dioxide. Experiments were conducted at reservoir conditions (55 and 110 °C, 25 MPa) and elevated temperature (220 °C, 25 MPa) for approximately 96 and 164 h (4 and 7 days). Dolomite dissolves and new carbonate mineral precipitates by reaction with water-saturated supercritical carbon dioxide. Dolomite does not react with anhydrous supercritical carbon dioxide. Temperature and reaction time control the composition, morphology, and extent of formation of new carbonate minerals. Mineral dissolution and re-precipitation due to reaction with water-saturated carbon dioxide may affect the contact line between phases, the carbon dioxide contact angle, and the

  13. Multigrid Methods for Fully Implicit Oil Reservoir Simulation

    Science.gov (United States)

    Molenaar, J.

    1996-01-01

    In this paper we consider the simultaneous flow of oil and water in reservoir rock. This displacement process is modeled by two basic equations: the material balance or continuity equations and the equation of motion (Darcy's law). For the numerical solution of this system of nonlinear partial differential equations there are two approaches: the fully implicit or simultaneous solution method and the sequential solution method. In the sequential solution method the system of partial differential equations is manipulated to give an elliptic pressure equation and a hyperbolic (or parabolic) saturation equation. In the IMPES approach the pressure equation is first solved, using values for the saturation from the previous time level. Next the saturations are updated by some explicit time stepping method; this implies that the method is only conditionally stable. For the numerical solution of the linear, elliptic pressure equation multigrid methods have become an accepted technique. On the other hand, the fully implicit method is unconditionally stable, but it has the disadvantage that in every time step a large system of nonlinear algebraic equations has to be solved. The most time-consuming part of any fully implicit reservoir simulator is the solution of this large system of equations. Usually this is done by Newton's method. The resulting systems of linear equations are then either solved by a direct method or by some conjugate gradient type method. In this paper we consider the possibility of applying multigrid methods for the iterative solution of the systems of nonlinear equations. There are two ways of using multigrid for this job: either we use a nonlinear multigrid method or we use a linear multigrid method to deal with the linear systems that arise in Newton's method. So far only a few authors have reported on the use of multigrid methods for fully implicit simulations. Two-level FAS algorithm is presented for the black-oil equations, and linear multigrid for

  14. Hydrogeologic controls on saturation profiles in heat-pipe-like hydrothermal systems: numerical study

    Science.gov (United States)

    Pervin, Mollika; Ghergut, Iulia; Graf, Thomas; Peche, Aaron

    2016-04-01

    work, we explore some mechanisms and geologic controls that can lead to the formation of extensive vapor-dominated zones within a two-phase system. In particular, we investigate the effect of vertical heterogeneity of permeability (stratified reservoir, containing a permeability barrier) on the liquid water saturation profile within a modified HP model. Though in field observations liquid water has been directly encountered only within the condensation zone at reservoir top, it was speculated that large amounts of liquid water might also exist below the condensation zone. This is of great practical significance to the exploitation of vapor-dominated reservoirs, as their longevity depends on the fluid reserves in place. Within this work, we demonstrate by numerical simulations of a modified HP model that high values of liquid water saturation (>0.8) can prevail even far below the condensation zone. Such findings are useful as a baseline for future calculations regarding the economic exploitation of vapor-dominated systems, where premature productivity drop (or dry-out) is the main issue of concern. References: Eastman, G. Y:, 1968: The heat pipe. Scientific American, 218(5):38-46. Preuss, K. A., 1985: A quantitative model of vapor-dominated geothermal reservoirs as heat pipes in fractured porous rock, Transactions, Geothermal Resources. Council, 9(2), 353-361. Truesdell, A. H., and White, D.E. 1973: Production of superheated Steam from Vapor- dominated geothermal reservoirs. Geothermics, 2(3-4), 154-173

  15. Detailed evaluation of gas hydrate reservoir properties using JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well downhole well-log displays

    Science.gov (United States)

    Collett, T.S.

    1999-01-01

    The JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well project was designed to investigate the occurrence of in situ natural gas hydrate in the Mallik area of the Mackenzie Delta of Canada. Because gas hydrate is unstable at surface pressure and temperature conditions, a major emphasis was placed on the downhole logging program to determine the in situ physical properties of the gas-hydrate-bearing sediments. Downhole logging tool strings deployed in the Mallik 2L-38 well included the Schlumberger Platform Express with a high resolution laterolog, Array Induction Imager Tool, Dipole Shear Sonic Imager, and a Fullbore Formation Microlmager. The downhole log data obtained from the log- and core-inferred gas-hydrate-bearing sedimentary interval (897.25-1109.5 m log depth) in the Mallik 2L-38 well is depicted in a series of well displays. Also shown are numerous reservoir parameters, including gas hydrate saturation and sediment porosity log traces, calculated from available downhole well-log and core data. The gas hydrate accumulation delineated by the Mallik 2L-38 well has been determined to contain as much as 4.15109 m3 of gas in the 1 km2 area surrounding the drill site.

  16. Transient response of a cylindrical cavity in viscoelastic saturated porous medium

    Directory of Open Access Journals (Sweden)

    LIU Tao

    2016-10-01

    Full Text Available The study on dynamic characteristics for fluid-solid coupling system in saturated porous medium is of significant academic value and potential application foreground.In this paper,the transient response of a cylindrical cavity in infinite viscoelastic saturated porous medium with the circular lining is studied,and the corresponding results can be used in the design of foundation engineering,such as the tunnel analyses in saturated soil,the nuclear waste disposal engineering,and the exploitation and utilization of geothermal reservoirs and so on.Firstly,based on the porous media theory,the governing equations of coupled system are presented,and the corresponding boundary conditions,initial conditions as well as the joint conditions are derived.Then,the differential quadrature element method and the second-order backward difference scheme are applied to discretize the governing differential equations of the coupled system on the spatial and temporal domains,respectively.Finally,the Newton-Raphson method is adopted to solve the discretization equations with the initial conditions,the transient responses of the coupled system are analyzed,the effects of the parameters are considered,and the validity of the numerical method is verified.

  17. Long-wave equivalent viscoelastic solids for porous rocks saturated by two-phase fluids

    Science.gov (United States)

    Santos, J. E.; Savioli, G. B.

    2018-04-01

    Seismic waves traveling across fluid-saturated poroelastic materials with mesoscopic-scale heterogeneities induce fluid flow and Biot's slow waves generating energy loss and velocity dispersion. Using Biot's equations of motion to model these type of heterogeneities would require extremely fine meshes. We propose a numerical upscaling procedure to determine the complex and frequency dependent P-wave and shear moduli of an effective viscoelastic medium long-wave equivalent to a poroelastic solid saturated by a two-phase fluid. The two-phase fluid is defined in terms of capillary pressure and relative permeability flow functions. The P-wave and shear effective moduli are determined using harmonic compressibility and shear experiments applied on representative samples of the bulk material. Each experiment is associated with a boundary value problem that is solved using the finite element method. Since a poroelastic solid saturated by a two-phase fluid supports the existence of two slow waves, this upscaling procedure allows to analyze their effect on the mesoscopic-loss mechanism in hydrocarbon reservoir formations. Numerical results show that a two-phase Biot medium model predicts higher attenuation than classic Biot models.

  18. Transport of water and ions in partially water-saturated porous media. Part 2. Filtration effects

    Science.gov (United States)

    Revil, A.

    2017-05-01

    A new set of constitutive equations describing the transport of the ions and water through charged porous media and considering the effect of ion filtration is applied to the problem of reverse osmosis and diffusion of a salt. Starting with the constitutive equations derived in Paper 1, I first determine specific formula for the osmotic coefficient and effective diffusion coefficient of a binary symmetric 1:1 salt (such as KCl or NaCl) as a function of a dimensionless number Θ corresponding to the ratio between the cation exchange capacity (CEC) and the salinity. The modeling is first carried with the Donnan model used to describe the concentrations of the charge carriers in the pore water phase. Then a new model is developed in the thin double layer approximation to determine these concentrations. These models provide explicit relationships between the concentration of the ionic species in the pore space and those in a neutral reservoir in local equilibrium with the pore space and the CEC. The case of reverse osmosis and diffusion coefficient are analyzed in details for the case of saturated and partially saturated porous materials. Comparisons are done with experimental data from the literature obtained on bentonite. The model predicts correctly the influence of salinity (including membrane behavior at high salinities), porosity, cation type (K+ versus Na+), and water saturation on the osmotic coefficient. It also correctly predicts the dependence of the diffusion coefficient of the salt with the salinity.

  19. Smart Waterflooding in Carbonate Reservoirs

    DEFF Research Database (Denmark)

    Zahid, Adeel

    brine solutions regarding phase behavior and viscosity measurements. This difference is attributed to the difference in composition of the different crude oils. More experiments are carried out in order to understand mechanisms of the crude oil viscosity reduction and emulsion formation. We observed...... with and without aging. The total oil recovery, recovery rate and interaction mechanisms of ions with rock were studied for different injected fluids under different temperatures and wettability conditions. Experimental results demonstrate that the oil recovery mechanism under high salinity seawater flooding...... phase could be the possible reasons for the observed increase in oil recovery with sulfate ions at high temperature in chalk reservoirs, besides the mechanism of the rock wettability alteration. * Crude oil/brine interaction study suggests that viscosity reduction for crude oil in contact with brine...

  20. Production Optimization of Oil Reservoirs

    DEFF Research Database (Denmark)

    Völcker, Carsten

    with emphasis on optimal control of water ooding with the use of smartwell technology. We have implemented immiscible ow of water and oil in isothermal reservoirs with isotropic heterogenous permeability elds. We use the method of lines for solution of the partial differential equation (PDE) system that governs...... the uid ow. We discretize the the two-phase ow model spatially using the nite volume method (FVM), and we use the two point ux approximation (TPFA) and the single-point upstream (SPU) scheme for computing the uxes. We propose a new formulation of the differential equation system that arise...... as a consequence of the spatial discretization of the two-phase ow model. Upon discretization in time, the proposed equation system ensures the mass conserving property of the two-phase ow model. For the solution of the spatially discretized two-phase ow model, we develop mass conserving explicit singly diagonally...

  1. Economics of Developing Hot Stratigraphic Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Greg Mines; Hillary Hanson; Rick Allis; Joseph Moore

    2014-09-01

    Stratigraphic geothermal reservoirs at 3 – 4 km depth in high heat-flow basins are capable of sustaining 100 MW-scale power plants at about 10 c/kWh. This paper examines the impacts on the levelized cost of electricity (LCOE) of reservoir depth and temperature, reservoir productivity, and drillhole/casing options. For a reservoir at 3 km depth with a moderate productivity index by hydrothermal reservoir standards (about 50 L/s/MPa, 5.6 gpm/psi), an LCOE of 10c/kWh requires the reservoir to be at about 200°C. This is the upper temperature limit for pumps. The calculations assume standard hydrothermal drilling costs, with the production interval completed with a 7 inch liner in an 8.5 inch hole. If a reservoir at 4 km depth has excellent permeability characteristics with a productivity index of 100 L/s/MPa (11.3 gpm/psi), then the LCOE is about 11 c/kWh assuming the temperature decline rate with development is not excessive (< 1%/y, with first thermal breakthrough delayed by about 10 years). Completing wells with modest horizontal legs (e.g. several hundred meters) may be important for improving well productivity because of the naturally high, sub-horizontal permeability in this type of reservoir. Reducing the injector/producer well ratio may also be cost-effective if the injectors are drilled as larger holes.

  2. Carbon emission from global hydroelectric reservoirs revisited.

    Science.gov (United States)

    Li, Siyue; Zhang, Quanfa

    2014-12-01

    Substantial greenhouse gas (GHG) emissions from hydropower reservoirs have been of great concerns recently, yet the significant carbon emitters of drawdown area and reservoir downstream (including spillways and turbines as well as river reaches below dams) have not been included in global carbon budget. Here, we revisit GHG emission from hydropower reservoirs by considering reservoir surface area, drawdown zone and reservoir downstream. Our estimates demonstrate around 301.3 Tg carbon dioxide (CO2)/year and 18.7 Tg methane (CH4)/year from global hydroelectric reservoirs, which are much higher than recent observations. The sum of drawdown and downstream emission, which is generally overlooked, represents 42 % CO2 and 67 % CH4 of the total emissions from hydropower reservoirs. Accordingly, the global average emissions from hydropower are estimated to be 92 g CO2/kWh and 5.7 g CH4/kWh. Nonetheless, global hydroelectricity could currently reduce approximate 2,351 Tg CO2eq/year with respect to fuel fossil plant alternative. The new findings show a substantial revision of carbon emission from the global hydropower reservoirs.

  3. Zooplankton of the Zaporiz’ke Reservoir

    Directory of Open Access Journals (Sweden)

    T. V. Mykolaichuk

    2006-01-01

    Full Text Available The paper is devoted to zooplankton species composition in the Zaporiz’ke Reservoir. The greatest species diversity was found in the macrophyte communities of the upper reservoir’s littoral, but the least zooplankton diversity – in the pelagic zone of the lower reservoir.

  4. Estimating Western U.S. Reservoir Sedimentation

    Science.gov (United States)

    Bensching, L.; Livneh, B.; Greimann, B. P.

    2017-12-01

    Reservoir sedimentation is a long-term problem for water management across the Western U.S. Observations of sedimentation are limited to reservoir surveys that are costly and infrequent, with many reservoirs having only two or fewer surveys. This work aims to apply a recently developed ensemble of sediment algorithms to estimate reservoir sedimentation over several western U.S. reservoirs. The sediment algorithms include empirical, conceptual, stochastic, and processes based approaches and are coupled with a hydrologic modeling framework. Preliminary results showed that the more complex and processed based algorithms performed better in predicting high sediment flux values and in a basin transferability experiment. However, more testing and validation is required to confirm sediment model skill. This work is carried out in partnership with the Bureau of Reclamation with the goal of evaluating the viability of reservoir sediment yield prediction across the western U.S. using a multi-algorithm approach. Simulations of streamflow and sediment fluxes are validated against observed discharges, as well as a Reservoir Sedimentation Information database that is being developed by the US Army Corps of Engineers. Specific goals of this research include (i) quantifying whether inter-algorithm differences consistently capture observational variability; (ii) identifying whether certain categories of models consistently produce the best results, (iii) assessing the expected sedimentation life-span of several western U.S. reservoirs through long-term simulations.

  5. Ichthyofauna of the reservoirs of Central Vietnam

    Directory of Open Access Journals (Sweden)

    I. A. Stolbunov

    2012-01-01

    Full Text Available Species composition, distribution and abundance of fish in the pelagic and littoral zone of four reservoirs of Central Vietnam (Suoi Chau, Kam Lam, Da Ban and Suoi Dau were studied first. According to the research data the fish community of the reservoirs is represented by 43 species of 19 fish families.

  6. 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.

  7. 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)

  8. Geothermal reservoir insurance study. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1981-10-09

    The principal goal of this study was to provide analysis of and recommendations on the need for and feasibility of a geothermal reservoir insurance program. Five major tasks are reported: perception of risk by major market sectors, status of private sector insurance programs, analysis of reservoir risks, alternative government roles, and recommendations.

  9. 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 .

  10. 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.

  11. INTELLIGENT COMPUTING SYSTEM FOR RESERVOIR ANALYSIS AND RISK ASSESSMENT OF THE RED RIVER FORMATION

    Energy Technology Data Exchange (ETDEWEB)

    Mark A. Sippel; William C. Carrigan; Kenneth D. Luff; Lyn Canter

    2003-11-12

    Integrated software has been written that comprises the tool kit for the Intelligent Computing System (ICS). The software tools in ICS have been developed for characterization of reservoir properties and evaluation of hydrocarbon potential using a combination of inter-disciplinary data sources such as geophysical, geologic and engineering variables. The ICS tools provide a means for logical and consistent reservoir characterization and oil reserve estimates. The tools can be broadly characterized as (1) clustering tools, (2) neural solvers, (3) multiple-linear regression, (4) entrapment-potential calculator and (5) file utility tools. ICS tools are extremely flexible in their approach and use, and applicable to most geologic settings. The tools are primarily designed to correlate relationships between seismic information and engineering and geologic data obtained from wells, and to convert or translate seismic information into engineering and geologic terms or units. It is also possible to apply ICS in a simple framework that may include reservoir characterization using only engineering, seismic, or geologic data in the analysis. ICS tools were developed and tested using geophysical, geologic and engineering data obtained from an exploitation and development project involving the Red River Formation in Bowman County, North Dakota and Harding County, South Dakota. Data obtained from 3D seismic surveys, and 2D seismic lines encompassing nine prospective field areas were used in the analysis. The geologic setting of the Red River Formation in Bowman and Harding counties is that of a shallow-shelf, carbonate system. Present-day depth of the Red River formation is approximately 8000 to 10,000 ft below ground surface. This report summarizes production results from well demonstration activity, results of reservoir characterization of the Red River Formation at demonstration sites, descriptions of ICS tools and strategies for their application.

  12. The freshwater reservoir effect in radiocarbon dating

    DEFF Research Database (Denmark)

    Philippsen, Bente

    2013-01-01

    of magnitude and degree of variability of the freshwater reservoir effect over short and long timescales. Radiocarbon dating of recent water samples, aquatic plants, and animals, shows that age differences of up to 2000 14C years can occur within one river. The freshwater reservoir effect has also implications......The freshwater reservoir effect can result in anomalously old radiocarbon ages of samples from lakes and rivers. This includes the bones of people whose subsistence was based on freshwater fish, and pottery in which fish was cooked. Water rich in dissolved ancient calcium carbonates, commonly known...... as hard water, is the most common reason for the freshwater reservoir effect. It is therefore also called hardwater effect. Although it has been known for more than 60 years, it is still less well-recognized by archaeologists than the marine reservoir effect. The aim of this study is to examine the order...

  13. Reservoir model for the Alameda Central waterflood

    Energy Technology Data Exchange (ETDEWEB)

    Randall, T E

    1968-01-01

    The basic approach used in developing the model to characterize the Alameda Central Unit Waterflood assumes continuity of the reservoir mechanics with time. The past performance was analyzed to describe the reservoir and future performance was assumed to follow the established patterns. To develop a mathematical picture of the Alameda Central Unit reservoir, a two-dimensional single-phase steady-state model was used in conjunction with material balance calculations, real-time conversion methods and oil-water interface advance calculations. The model was developed to optimize water injection allocation, determine the configuration of the frontal advance and evaluate the success of the waterflood. The model also provides a basis for continuing review and revision of the basic concepts of reservoir operation. The results of the reservoir study have confirmed the apparent lack of permeability orientation in the pool and indicate that the waterflood is progressing better than originally anticipated.

  14. The Alphabet Soup of HIV Reservoir Markers.

    Science.gov (United States)

    Sharaf, Radwa R; Li, Jonathan Z

    2017-04-01

    Despite the success of antiretroviral therapy in suppressing HIV, life-long therapy is required to avoid HIV reactivation from long-lived viral reservoirs. Currently, there is intense interest in searching for therapeutic interventions that can purge the viral reservoir to achieve complete remission in HIV patients off antiretroviral therapy. The evaluation of such interventions relies on our ability to accurately and precisely measure the true size of the viral reservoir. In this review, we assess the most commonly used HIV reservoir assays, as a clear understanding of the strengths and weaknesses of each is vital for the accurate interpretation of results and for the development of improved assays. The quantification of intracellular or plasma HIV RNA or DNA levels remains the most commonly used tests for the characterization of the viral reservoir. While cost-effective and high-throughput, these assays are not able to differentiate between replication-competent or defective fractions or quantify the number of infected cells. Viral outgrowth assays provide a lower bound for the fraction of cells that can produce infectious virus, but these assays are laborious, expensive and substantially underestimate the potential reservoir of replication-competent provirus. Newer assays are now available that seek to overcome some of these problems, including full-length proviral sequencing, inducible HIV RNA assays, ultrasensitive p24 assays and murine adoptive transfer techniques. The development and evaluation of strategies for HIV remission rely upon our ability to accurately and precisely quantify the size of the remaining viral reservoir. At this time, all current HIV reservoir assays have drawbacks such that combinations of assays are generally needed to gain a more comprehensive view of the viral reservoir. The development of novel, rapid, high-throughput assays that can sensitively quantify the levels of the replication-competent HIV reservoir is still needed.

  15. 2D X-ray scanner and its uses in laboratory reservoir characterization measurements

    Energy Technology Data Exchange (ETDEWEB)

    Maloney, D.; Doggett, K.

    1997-08-01

    X-ray techniques are used in petroleum laboratories for a variety of reservoir characterization measurements. This paper describes the configuration of a 2D X-ray scanner and many of the ways in which it simplifies and improves accuracy`s of laboratory measurements. Linear X-ray scanners are most often used to provide descriptions of fluid saturations within core plugs during flow tests. We configured our linear scanner for both horizontal and vertical movement. Samples can be scanned horizontally, vertically, or according to horizontal and vertical grids. X-ray measurements are fast, allowing measurements of two- and three-phase fluid saturations during both steady- and unsteady-state flow processes. Rock samples can be scanned while they are subjected to stress, pore pressure, and temperature conditions simulating those of a petroleum reservoir. Many types of measurements are possible by selecting appropriate X-ray power settings, dopes, filters, and collimator configurations. The scanner has been used for a variety of applications besides fluid saturation measurements. It is useful for measuring porosity distributions in rocks, concentrations of X-ray dopes within flow streams during tracer tests, gap widths in fracture flow cells, fluid interface levels in PVT cells and fluid separators, and other features and phenomena.

  16. Sedimentological Characterization of a Deepwater Methane Hydrate Reservoir in Green Canyon 955, Northern Gulf of Mexico

    Science.gov (United States)

    Meazell, K.; Flemings, P. B.

    2017-12-01

    Grain size is a controlling factor of hydrate saturation within a Pleistocene channel-levee system investigated by the UT-GOM2-1 expedition within the deepwater northern Gulf of Mexico. Laser diffraction and settling experiments conducted on sediments from 413-440 meters below the seafloor reveal the presence of two interbedded lithologic units, identified as a silty sand and a clayey silt, according Shepard's classification system. The sand-rich lithofacies has low density and high p-wave velocity, suggesting a high degree of hydrate saturation. Conversely, the clay and silt dominated lithofacies is characterized by a higher density and low p-wave velocity, suggesting low hydrate saturation. The sand-rich lithofacies is well-sorted and displays abundant ripple lamination, indicative of deposition within a high-energy environment. The clayey-silt is poorly-sorted and lacks sedimentary structures. The two lithofacies are interbedded throughout the reservoir unit; however, the relative abundance of the sand-rich lithofacies increases with depth, suggesting a potential decrease in flow energy or sediment flux over time, resulting in the most favorable reservoir properties near the base of the unit.

  17. Reservoir management under geological uncertainty using fast model update

    NARCIS (Netherlands)

    Hanea, R.; Evensen, G.; Hustoft, L.; Ek, T.; Chitu, A.; Wilschut, F.

    2015-01-01

    Statoil is implementing "Fast Model Update (FMU)," an integrated and automated workflow for reservoir modeling and characterization. FMU connects all steps and disciplines from seismic depth conversion to prediction and reservoir management taking into account relevant reservoir uncertainty. FMU

  18. Reservoir characterization using production data and time-lapse seismic data

    Energy Technology Data Exchange (ETDEWEB)

    Dadashpour, Mohsen

    2009-12-15

    The most commonly encountered, and probably the most challenging task in reservoir engineering, is to describe the reservoir accurately and efficiently. An accurate description of a reservoir is crucial to the management of production and efficiency of oil recovery. Reservoir modeling is an important step in a reservoir's future performance, which is in direct proportion to reservoir management, risk analysis and making key economic decisions. The purpose of reservoir modeling is to not only build a model that is consistent with currently available data, but to build one that gives a good prediction of its future behavior. Updating a reservoir model to behave as closely as possible to the real reservoir is called history matching, and the estimation of reservoir properties using this method is known as parameter estimation problem, which is an inversion process. Parameter estimation is a time consuming and non-unique problem with a large solution space. Saturation and pressure changes, and porosity and permeability distributions are the most common parameters to estimate in the oil industry. These parameters must be specified in every node within a petroleum reservoir simulator. These parameters will be adjusted until the model prediction data match the observation data to a sufficient degree. The solution space reduction in this project is done by adding time-lapse seismic data as a new set of dynamic data to the traditional production histories. Time-lapse (or 4D) seismic consists of two or more 3D seismic surveys shot at different calendar times. Time-lapse seismic surveys produce images at different times in a reservoir's history. The seismic response of a reservoir may change due to changes in pressure, fluid saturation and temperature. These changes in seismic images due to a variation in saturation and pressure can be used as additional observation data. Time-lapse seismic data are dynamical measurements which have a high resolution in the

  19. Effects of the Danish saturated fat tax on the demand for meat and dairy products

    DEFF Research Database (Denmark)

    Jensen, Jørgen Dejgård; Smed, Sinne; Aarup, Lars

    2016-01-01

    of saturated fat within three different types of food product group: minced beef, regular cream and sour cream. Design: We use an augmented version of the Linearized Almost Ideal Demand System (LAIDS) functional form for econometric analysis, allowing for tax-induced structural breaks. Setting: Data originate......Objective:  Taxation of unhealthy food is considered a regulation tool to improve diets. In 2011 Denmark introduced a tax on saturated fat in food products, the first country in the world to do so. The objective of the present paper is to investigate the effects of the tax on consumers’ intake...... for low- and medium-fat varieties, and led to a 13–16 % price increase for high-fat varieties of minced beef and cream products. The tax induced substitution effects, budget effects and preference change effects on consumption, yielding a total decrease of 4–6 % in the intake of saturated fat from minced...

  20. Efficient Reservoir Simulation with Cubic Plus Association and Cross-Association Equation of State for Multicomponent Three-Phase Compressible Flow with Applications in CO2 Storage and Methane Leakage

    Science.gov (United States)

    Moortgat, J.

    2017-12-01

    We present novel simulation tools to model multiphase multicomponent flow and transport in porous media for mixtures that contain non-polar hydrocarbons, self-associating polar water, and cross-associating molecules like methane, ethane, unsaturated hydrocarbons, CO2 and H2S. Such mixtures often occur when CO2 is injected and stored in saline aquifers, or when methane is leaking into groundwater. To accurately predict the species transfer between aqueous, gaseous and oleic phases, and the subsequent change in phase properties, the self- and cross-associating behavior of molecules needs to be taken into account, particularly at the typical temperatures and pressures in deep formations. The Cubic-Plus-Association equation-of-state (EOS) has been demonstrated to be highly accurate for such problems but its excessive computational cost has prevented widespread use in reservoir simulators. We discuss the thermodynamical framework and develop sophisticated numerical algorithms that allow reservoir simulations with efficiencies comparable to a simple cubic EOS. This approach improves our predictive powers for highly nonlinear fluid behavior related to geological carbon sequestration, such as density driven flow and natural convection (solubility trapping), evaporation of water into the CO2-rich gas phase, and competitive dissolution-evaporation when CO2 is injected in, e.g., methane saturated aquifers. Several examples demonstrate the accuracy and robustness of this EOS framework for complex applications.

  1. Soil aquifer treatment of artificial wastewater under saturated conditions

    KAUST Repository

    Essandoh, H. M K; Tizaoui, Chedly; Mohamed, Mostafa H A; Amy, Gary L.; Brdjanovic, Damir

    2011-01-01

    A 2000 mm long saturated laboratory soil column was used to simulate soil aquifer treatment under saturated conditions to assess the removal of chemical and biochemical oxygen demand (COD and BOD), dissolved organic carbon (DOC), nitrogen

  2. Calcium phosphate saturation in the western Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Naik, S.; Reddy, C.V.G.

    Temperature, inorganic phosphate concentration and pH seem to be the major factors influencing the degree of saturation of calcium phosphate in sea water. Two water regions can be demarcated in the study area based on the saturation patterns...

  3. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Joel Walls; M.T. Taner; Gary Mavko; Jack Dvorkin

    2002-01-01

    In Section 1 of this first report we will describe the work we are doing to collect and analyze rock physics data for the purpose of modeling seismic attenuation from other measurable quantities such as porosity, water saturation, clay content and net stress. This work and other empirical methods to be presented later, will form the basis for ''Q pseudo-well modeling'' that is a key part of this project. In Section 2 of this report, we will show the fundamentals of a new method to extract Q, dispersion, and attenuation from field seismic data. The method is called Gabor-Morlet time-frequency decomposition. This technique has a number of advantages including greater stability and better time resolution than spectral ratio methods.

  4. Automated agitation management accounting for saturation dynamics.

    Science.gov (United States)

    Rudge, A D; Chase, J G; Shaw, G M; Lee, D

    2004-01-01

    Agitation-sedation cycling in critically ill is damaging to patient health and increases length of and cost. A physiologically representative model of the agitation-sedation system is used as a platform to evaluate feedback controllers offering improved agitation management. A heavy-derivative controller with upper and infusion rate bounds maintains minimum plasma concentrations through a low constant infusion, and minimizes outbursts of agitation through strong, timely boluses. controller provides improved agitation management using from 37 critically ill patients, given the saturation of effect at high concentration. Approval was obtained the Canterbury Ethics Board for this research.

  5. Modelling contaminant transport in saturated aquifers

    International Nuclear Information System (INIS)

    Lakshminarayana, V.; Nayak, T.R.

    1990-01-01

    With the increase in population and industrialization the problem of pollution of groundwater has become critical. The present study deals with modelling of pollutant transport through saturated aquifers. Using this model it is possible to predict the concentration distribution, spatial as well as temporal, in the aquifer. The paper also deals with one of the methods of controlling the pollutant movement, namely by pumping wells. A simulation model is developed to determine the number, location and rate of pumping of a number of wells near the source of pollution so that the concentration is within acceptable limits at the point of interest. (Author) (18 refs., 14 figs., tab.)

  6. Elevated transferrin saturation and risk of diabetes

    DEFF Research Database (Denmark)

    Ellervik, Christina; Mandrup-Poulsen, Thomas; Andersen, Henrik Ullits

    2011-01-01

    OBJECTIVE We tested the hypothesis that elevated transferrin saturation is associated with an increased risk of any form of diabetes, as well as type 1 or type 2 diabetes separately. RESEARCH DESIGN AND METHODS We used two general population studies, The Copenhagen City Heart Study (CCHS, N = 9......,121) and The Copenhagen General Population Study (CGPS, N = 24,195), as well as a 1:1 age- and sex-matched population-based case-control study with 6,129 patients with diabetes from the Steno Diabetes Centre and 6,129 control subjects, totaling 8,535 patients with diabetes and 37,039 control subjects. RESULTS...

  7. Rectifier transformer saturation on commutation failure

    International Nuclear Information System (INIS)

    Lu, E.; Bronner, G.

    1989-01-01

    The rectifier transformer's service differs from the power transformer's service because of the rectifier load. Under certain fault conditions, such as a commutation failure, d.c. magnetization may be introduced into the rectifier transformer cores, resulting in possible saturation of the magnetic circuit, thus in degradation of the performance of the transformer. It is the purpose of this paper to present an approach for evaluating the electromagnetic transient process under such a fault condition. The studies were made on the operating 1000MVA converter system at the Princeton Plasma Physics Laboratory

  8. Chemical Tool Peer Review Summary.

    Energy Technology Data Exchange (ETDEWEB)

    Cashion, Avery Ted [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Cieslewski, Grzegorz [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-10-01

    Chemical tracers are commonly used to characterize fracture networks and to determine the connectivity between the injection and production wells. Currently, most tracer experiments involve injecting the tracer at the injection well, manually collecting liquid samples at the wellhead of the production well, and sending the samples off for laboratory analysis. While this method provides accurate tracer concentration data, it does not provide information regarding the location of the fractures conducting the tracer between wellbores. The goal of this project is to develop chemical sensors and design a prototype tool to help understand the fracture properties of a geothermal reservoir by monitoring tracer concentrations along the depth of the well. The sensors will be able to detect certain species of the ionic tracers (mainly iodide) and pH in-situ during the tracer experiment. The proposed high-temperature (HT) tool will house the chemical sensors as well as a standard logging sensor package of pressure, temperature, and flow sensors in order to provide additional information on the state of the geothermal reservoir. The sensors and the tool will be able to survive extended deployments at temperatures up to 225 °C and high pressures to provide real-time temporal and spatial feedback of tracer concentration. Data collected from this tool will allow for the real-time identification of the fractures conducting chemical tracers between wellbores along with the pH of the reservoir fluid at various depths.

  9. 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

  10. The Controls of Pore-Throat Structure on Fluid Performance in Tight Clastic Rock Reservoir: A Case from the Upper Triassic of Chang 7 Member, Ordos Basin, China

    Directory of Open Access Journals (Sweden)

    Yunlong Zhang

    2018-01-01

    Full Text Available The characteristics of porosity and permeability in tight clastic rock reservoir have significant difference from those in conventional reservoir. The increased exploitation of tight gas and oil requests further understanding of fluid performance in the nanoscale pore-throat network of the tight reservoir. Typical tight sandstone and siltstone samples from Ordos Basin were investigated, and rate-controlled mercury injection capillary pressure (RMICP and nuclear magnetic resonance (NMR were employed in this paper, combined with helium porosity and air permeability data, to analyze the impact of pore-throat structure on the storage and seepage capacity of these tight oil reservoirs, revealing the control factors of economic petroleum production. The researches indicate that, in the tight clastic rock reservoir, largest throat is the key control on the permeability and potentially dominates the movable water saturation in the reservoir. The storage capacity of the reservoir consists of effective throat and pore space. Although it has a relatively steady and significant proportion that resulted from the throats, its variation is still dominated by the effective pores. A combination parameter (ε that was established to be as an integrated characteristic of pore-throat structure shows effectively prediction of physical capability for hydrocarbon resource of the tight clastic rock reservoir.

  11. Geochemical and geological control on filling history of Eocene reservoirs, Maracaibo Basin, Venezuela

    Energy Technology Data Exchange (ETDEWEB)

    Alberdi, M.; Maguregui, J.; Toro, C.; Marquina, M. [Intevep S.A., Caracas (Venezuela)

    1996-08-01

    Crude oils of Eocene fluvio-deltaic reservoirs in {open_quotes}Bloque V{close_quotes} and {open_quotes}Centro Lago{close_quotes} fields in the center of the Maracaibo Lake show many differences in composition, which are due to stratigraphically and structurally controlled reservoir geometry and a low rate of in-reservoir mixing of at least two successive petroleum charges. Oils produced from the top of structural highs contain 18(H) oleanane, higher Pr/Ph and C{sub 23-3}/C{sub 24-4} ratios, a lower proportion of DBT/P compounds, and clearly different fingerprint patterns in the C{sub 6}-C{sub 15} range, than those observed in oils produced from the lower parts of the structures. These compositional differences suggest that two source rocks, or two distinctive organic facies within the same Cretaceous La Luna Formation, generated and filled vertically poorly connected Eocene reservoirs. On the other hand, saturate-biomarkers ratios, triaromatics (C{sub 21}/C{sub 21}+C{sub 28}), n-paraffins (n-C{sub 20}/n-C{sub 29}) and n-heptane index suggest that oils in upper reservoirs are slightly less mature than oils in lower reservoirs and, consequently filled the structure first. Additional evidence from formation water analysis and tectonic basin evolution allow us to interpret at least two petroleum pulses from Cretaceous source rocks during Upper Miocene to present day kitchens located in the Andes foredeep at the southeast of the study area.

  12. Bulk and Surface Aqueous Speciation of Calcite: Implications for Low-Salinity Waterflooding of Carbonate Reservoirs

    KAUST Repository

    Yutkin, Maxim P.

    2017-08-25

    Low-salinity waterflooding (LSW) is ineffective when reservoir rock is strongly water-wet or when crude oil is not asphaltenic. Success of LSW relies heavily on the ability of injected brine to alter surface chemistry of reservoir crude-oil brine/rock (COBR) interfaces. Implementation of LSW in carbonate reservoirs is especially challenging because of high reservoir-brine salinity and, more importantly, because of high reactivity of the rock minerals. Both features complicate understanding of the COBR surface chemistries pertinent to successful LSW. Here, we tackle the complex physicochemical processes in chemically active carbonates flooded with diluted brine that is saturated with atmospheric carbon dioxide (CO2) and possibly supplemented with additional ionic species, such as sulfates or phosphates. When waterflooding carbonate reservoirs, rock equilibrates with the injected brine over short distances. Injected-brine ion speciation is shifted substantially in the presence of reactive carbonate rock. Our new calculations demonstrate that rock-equilibrated aqueous pH is slightly alkaline quite independent of injected-brine pH. We establish, for the first time, that CO2 content of a carbonate reservoir, originating from CO2-rich crude oil and gas, plays a dominant role in setting aqueous pH and rock-surface speciation. A simple ion-complexing model predicts the calcite-surface charge as a function of composition of reservoir brine. The surface charge of calcite may be positive or negative, depending on speciation of reservoir brine in contact with the calcite. There is no single point of zero charge; all dissolved aqueous species are charge determining. Rock-equilibrated aqueous composition controls the calcite-surface ion-exchange behavior, not the injected-brine composition. At high ionic strength, the electrical double layer collapses and is no longer diffuse. All surface charges are located directly in the inner and outer Helmholtz planes. Our evaluation of

  13. Integrating gravimetric and interferometric synthetic aperture radar data for enhancing reservoir history matching of carbonate gas and volatile oil reservoirs

    KAUST Repository

    Katterbauer, Klemens; Arango, Santiago; Sun, Shuyu; Hoteit, Ibrahim

    2016-01-01

    Reservoir history matching is assuming a critical role in understanding reservoir characteristics, tracking water fronts, and forecasting production. While production data have been incorporated for matching reservoir production levels

  14. A demonstration experiment for studying the properties of saturated vapor

    Science.gov (United States)

    Grebenev, Igor V.; Lebedeva, Olga V.; Polushkina, Svetlana V.

    2017-11-01

    The paper proposes an important demonstration experiment that can be used at secondary schools in physics. The described experiment helps students learn the main concepts of the topic ‘saturated vapor’, namely, evaporation, condensation, dynamic equilibrium, saturation vapor, partial pressure, and the dependence of saturated vapor pressure on temperature.

  15. 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

    then compared to theoretical Umiat composition derived using the Pedersen method with original Umiat fluid properties published in the original reports. This comparison allowed estimation of the ‘lost’ light hydrocarbon fractions. An Umiat 'dead' oil sample then could be physically created by adding the lost light ends to the weatherized Umiat dead oil sample. This recreated sample was recombined with solution gas to create a 'pseudo-live' Umiat oil sample which was then used for experimental PVT and phase behavior studies to determine fluid properties over the range of reservoir pressures and temperatures. The phase behavior of the ‘pseudo-live’ oil was also simulated using the Peng- Robinson equations of state (EOS). The EOS model was tuned with measured experimental data to accurately simulate the differential liberation tests in order to obtain the necessary data for reservoir simulation studies, including bubble point pressure and oil viscosity. The bubble point pressure of the reconstructed Umiat oil is 345 psi, suggesting that maintenance of reservoir pressures above that pressure will be important for the any proposed production technique. A major part of predicting how the Umiat reservoir will perform is determining the relative permeability of oil in the presence of ice. Early in the project, UAF work on samples of the Umiat reservoir indicated that there is a significant reduction in the relatively permeability of oil in the presence of ice. However, it was not clear as to why this reduction occurred or where the ice resided. To explore this further, additional experimental and theoretical work was conducted. Core flood experiments were performed on two clean Berea sandstone cores under permafrost conditions to determine the relative permeability to oil (kro) over a temperature range of 23ºC to - 10ºC and for a range of connate water salinities. Both cores showed maximum reduction in relative permeability to oil when saturated

  16. In vivo detection of hemoglobin oxygen saturation and carboxyhemoglobin saturation with multiwavelength photoacoustic microscopy.

    Science.gov (United States)

    Chen, Zhongjiang; Yang, Sihua; Xing, Da

    2012-08-15

    A method for noninvasively detecting hemoglobin oxygen saturation (SO2) and carboxyhemoglobin saturation (SCO) in subcutaneous microvasculature with multiwavelength photoacoustic microscopy is presented. Blood samples mixed with different concentrations of carboxyhemoglobin were used to test the feasibility and accuracy of photoacoustic microscopy compared with the blood-gas analyzer. Moreover, fixed-point detection of SO2 and SCO in mouse ear was obtained, and the changes from normoxia to carbon monoxide hypoxia were dynamically monitored in vivo. Experimental results demonstrate that multiwavelength photoacoustic microscopy can detect SO2 and SCO, which has future potential clinical applications.

  17. The modified SWAT model for predicting fecal coliform in the Wachusett Reservoir Watershed, USA

    Science.gov (United States)

    Fecal contamination has been an issue for water quality because fecal coliform bacteria are used as an indicator organism to detect pathogens in water. In order to assess fecal contamination in the Wachusett Reservoir Watershed in Massachusetts, USA, the Soil and Water Assessment Tool (SWAT), a comm...

  18. Reservoir Management using seasonal forecasts in Lake Kariba and Lake Kahora Bassa: Initial results and plans

    CSIR Research Space (South Africa)

    Muchuru, S

    2012-06-01

    Full Text Available Seasonal forecasting as a tool to improve on reservoir management in Zimbabwe is presented. The focus of the talk is on predicting rainfall extremes over the Lake Kariba catchments. The forecast systems to do the predictions and the levels of skill...

  19. Hydrology and Mosquito Population Dynamics around a Hydropower Reservoir in Africa

    Science.gov (United States)

    Endo, N.; Eltahir, E. A.

    2013-12-01

    Malaria is associated with dams because their reservoirs provide mosquitoes, the vector of malaria, with permanent breeding sites. The risk of contracting malaria is likely to be enhanced following the increasing trend of hydropower dam construction to satisfy the expanding energy needs in developing countries. A close examination of its adverse health impacts is critical in the design, construction, and operation phases. We will present results of extensive field studies in 2012 and 2013 around the Koka Reservoir, Ethiopia. The results uncover the importance of reservoir management especially after the rainy seasons. Furthermore, we show the capability of a newly modified hydrology, entomology and malaria transmission simulator, HYDREMATS (Bomblies et al, 2008), and its potential as a tool for evaluating environmental management strategies to control malaria. HYDREMATS was developed to represent how the hydrology in nearby villages is impacted by the reservoir system, and the role of different types of vector ecologies associated with different Anopheles mosquito species. The hydrology component of HYDREMATS simulates three different mosquito breeding habitats: rain-fed pools, groundwater pools, and shoreline water. The entomology component simulates the life cycles of An. funestus and An. arabiensis, the two main vectors around the reservoir. The model was calibrated over the 2012-2013 period. The impact of reservoir water level management on the mosquito population is explored based on numerical model simulations and field experiments.

  20. Extracting maximum petrophysical and geological information from a limited reservoir database

    Energy Technology Data Exchange (ETDEWEB)

    Ali, M.; Chawathe, A.; Ouenes, A. [New Mexico Institute of Mining and Technology, Socorro, NM (United States)] [and others

    1997-08-01

    The characterization of old fields lacking sufficient core and log data is a challenging task. This paper describes a methodology that uses new and conventional tools to build a reliable reservoir model for the Sulimar Queen field. At the fine scale, permeability measured on a fine grid with a minipermeameter was used in conjunction with the petrographic data collected on multiple thin sections. The use of regression analysis and a newly developed fuzzy logic algorithm led to the identification of key petrographic elements which control permeability. At the log scale, old gamma ray logs were first rescaled/calibrated throughout the entire field for consistency and reliability using only four modem logs. Using data from one cored well and the rescaled gamma ray logs, correlations between core porosity, permeability, total water content and gamma ray were developed to complete the small scale characterization. At the reservoir scale, outcrop data and the rescaled gamma logs were used to define the reservoir structure over an area of ten square miles where only 36 wells were available. Given the structure, the rescaled gamma ray logs were used to build the reservoir volume by identifying the flow units and their continuity. Finally, history-matching results constrained to the primary production were used to estimate the dynamic reservoir properties such as relative permeabilities to complete the characterization. The obtained reservoir model was tested by forecasting the waterflood performance and which was in good agreement with the actual performance.

  1. Erosion index formulation with respect to reservoir life in the upper Citarum watershed

    Directory of Open Access Journals (Sweden)

    Bakhtiar

    2018-01-01

    Full Text Available This study aimed to formulate erosion index in the upper Citarum watershed with respect to the Saguling reservoir life. Soil and Water Assessment Tool model was incorporated to simulate hydrological processes in the catchment. From the calibration and validation results, the model is considerably of good performance. The simulated sediment inflow at Nanjung outlet was then extrapolated to determine the sediment inflow into the reservoir. The study revealed that the average value of sediment inflow into the reservoir is 29.24 tonnes/ha/year just below the tolerable erosion limit of 30 tonnes/ha/year assumed by Hammer (1981. It was also found that the relationship between sediment yield and sediment inflow is non linear. Erosion index is formulated as the ratio between the mean annual sediment yield generated in the watershed and the mean annual sediment yield that leads dead storage to be full in the designated life of the reservoir. Erosion index equals to 1.0 indicates that the dead storage will be full in the designated life of the reservoir. A classification of erosion index can be subsequently be made based on erosion index and reservoir life relationship.

  2. Improving Geologic and Engineering Models of Midcontinent Fracture and Karst-Modified Reservoirs Using New 3-D Seismic Attributes

    Energy Technology Data Exchange (ETDEWEB)

    Susan Nissen; Saibal Bhattacharya; W. Lynn Watney; John Doveton

    2009-03-31

    Our project goal was to develop innovative seismic-based workflows for the incremental recovery of oil from karst-modified reservoirs within the onshore continental United States. Specific project objectives were: (1) to calibrate new multi-trace seismic attributes (volumetric curvature, in particular) for improved imaging of karst-modified reservoirs, (2) to develop attribute-based, cost-effective workflows to better characterize karst-modified carbonate reservoirs and fracture systems, and (3) to improve accuracy and predictiveness of resulting geomodels and reservoir simulations. In order to develop our workflows and validate our techniques, we conducted integrated studies of five karst-modified reservoirs in west Texas, Colorado, and Kansas. Our studies show that 3-D seismic volumetric curvature attributes have the ability to re-veal previously unknown features or provide enhanced visibility of karst and fracture features compared with other seismic analysis methods. Using these attributes, we recognize collapse features, solution-enlarged fractures, and geomorphologies that appear to be related to mature, cockpit landscapes. In four of our reservoir studies, volumetric curvature attributes appear to delineate reservoir compartment boundaries that impact production. The presence of these compartment boundaries was corroborated by reservoir simulations in two of the study areas. Based on our study results, we conclude that volumetric curvature attributes are valuable tools for mapping compartment boundaries in fracture- and karst-modified reservoirs, and we propose a best practices workflow for incorporating these attributes into reservoir characterization. When properly calibrated with geological and production data, these attributes can be used to predict the locations and sizes of undrained reservoir compartments. Technology transfer of our project work has been accomplished through presentations at professional society meetings, peer-reviewed publications

  3. Particle Correlations in Saturated QCD Matter

    CERN Document Server

    Baier, R; Nardi, M; Wiedemann, Urs Achim; Baier, Rudolf; Kovner, Alex; Nardi, Marzia; Wiedemann, Urs Achim

    2005-01-01

    We study quantitatively angular correlations in the two-particle spectrum produced by an energetic probe scattering off a dense hadronic target with sizeable saturation momentum. To this end, two parton inclusive cross sections for arbitrary projectiles with small color charge density are derived in the eikonal formalism. Our results are the following: For large momenta of the observed particles, the perturbative limit with characteristic back-to-back correlation is recovered. As the trigger momenta get closer to the saturation scale Q_s, the angular distribution broadens. When the momenta are significantly smaller than Q_s, the azimuthal distribution is broad but still peaked back-to-back. However, in a narrow momentum range (0.5 - 1.5) Q_s, we observe that the azimuthal correlation splits into a double peak with maxima displaced away from 180 degree. We argue that it is the soft multiple scattering physics that is responsible for the appearance of this shift in the angle of maximal correlation. We also poin...

  4. Simulation of saturated tearing modes in tokamaks

    International Nuclear Information System (INIS)

    Nguyen, Canh N.; Bateman, Glenn; Kritz, Arnold H.

    2004-01-01

    A quasi-linear model, which includes the effect of the neoclassical bootstrap current, is developed for saturated tearing modes in order to compute magnetic island widths in axisymmetric toroidal plasmas with arbitrary aspect ratio and cross-sectional shape. The model is tested in a simple stand-alone code and is implemented in the BALDUR [C. E. Singer et al., Comput. Phys. Commun. 49, 275 (1982)] predictive modeling code. It is found that the widths of tearing mode islands increase with decreasing aspect ratio and with increasing elongation. Also, the island widths increase when the gradient of the current density increases at the edge of the islands and when the current density inside the islands is suppressed, such as the suppression caused by the near absence of the bootstrap current within the islands. In simulations of tokamak discharges, it is found that tearing mode island widths oscillate in time in response to periodic sawtooth crashes. The local enhancements in the transport produced by magnetic islands have a noticeable effect on global plasma confinement in simulations of low aspect ratio, high beta tokamaks, where saturated tearing mode islands can occur with widths that are greater than 15% of the plasma minor radius

  5. Thermal effects on tearing mode saturation

    International Nuclear Information System (INIS)

    Kim, J.S.; Chu, M.S.; Greene, J.M.

    1988-01-01

    The effect of geometry on tearing modes, saturated states of tearing modes, and the thermal effect on tearing modes are presented. The configuration of current and magnetic fields are quite different in slabs and in Tokamaks. However, for any magnetic island regardless of geometry and heating conditions, at island saturation the product of resistivity and current is the same at magnetic O and X lines. The temperature perturbation effect on the nonlinear development of tearing modes is investigated. Thermal conduction along the field lines is much faster than that in the perpendicular direction, and thus the temperature profile follows the island structure. Utilizing Spitzer's conductivity relation, the temperature perturbation is modelled as helical components of resistivity. For a usual tearing mode unstable Tokamak, where shear is positive, the islands continue to grow to a larger size when the islands are cooled. When they are heated, the island sizes are reduced. The temperature perturbation can induce islands even for equilibria stable with respect to tearing modes. Again, the islands appear when cooling takes place. The equilibria with the cooled islands show enhanced field line stochasticity, thus enhanced heat transport. Therefore, thermal instability can be directly related to pressure disruptions. (author)

  6. Facilitated transport near the carrier saturation limit

    Directory of Open Access Journals (Sweden)

    Anawat Sungpet

    2002-11-01

    Full Text Available Permeation of ethylbenzene, styrene and 1-hexene through perfluorosulfonate ionomer membranes was carried out with the feed concentrations ranging from 1 M to pure. On comparison, fluxes of ethylbenzene through the Ag+-form membrane were the lowest. Only a small increase in ethylbenzene flux was observed after the feed concentration exceeded 3 M, indicating the existence of carrier saturation. The increase in styrene flux was suppressed to some degree at high concentration driving forces. In contrast, 1-hexene flux was the highest and continued to increase even at very high feed concentrations. After the experiments with pure feeds, extraction of the solutes from the membranes revealed that 62.5% of Ag+ ions reacted with 1-hexene as against 40.6% for styrene and 28.9% for ethylbenzene. Equilibrium constants, determined by distribution method, of 1-hexene, styrene and ethylbenzene were 129, 2.2 and 0.7 M-1 respectively, which suggested that stability of the complex was a key factor in the carrier saturation phenomenon.

  7. Salt-saturated concrete strength and permeability

    International Nuclear Information System (INIS)

    Pfeifle, T.W.; Hansen, F.D.; Knowles, M.K.

    1996-01-01

    Laboratory-scale experiments applicable to the use of salt-saturated concrete as a seal material for a transuranic waste repository have been completed. Nitrogen gas permeability measurements were made using a flexible-wall permeameter, a confining pressure of 1 MPa, and gas pressure gradients ranging from 0.3 MPa to 0.75 MPa. Results show that salt-saturated concrete has very low intrinsic permeability with values ranging from 9.4 x 10 -22 m 2 to 9.7 x 10 -17 m 2 . Strength and deformation characteristics were investigated under conditions of triaxial compression with confining pressures ranging from 0 to 15 MPa using either axial strain-rate or axial stress-rate control and show that the failure strength of concrete increases with confining pressure which can be adequately described through pressure-sensitive failure criteria. Axial, radial, and volumetric strains were also measured during each test and these data were used to determine elastic properties. Experimental results are applicable in the design and analysis of scale-related functions and apply to other concrete structures subjected to compressive loadings such as dams and prestressed structural members

  8. Reflection Phenomena in Underground Pumped Storage Reservoirs

    Directory of Open Access Journals (Sweden)

    Elena Pummer

    2018-04-01

    Full Text Available Energy storage through hydropower leads to free surface water waves in the connected reservoirs. The reason for this is the movement of water between reservoirs at different elevations, which is necessary for electrical energy storage. Currently, the expansion of renewable energies requires the development of fast and flexible energy storage systems, of which classical pumped storage plants are the only technically proven and cost-effective technology and are the most used. Instead of classical pumped storage plants, where reservoirs are located on the surface, underground pumped storage plants with subsurface reservoirs could be an alternative. They are independent of topography and have a low surface area requirement. This can be a great advantage for energy storage expansion in case of environmental issues, residents’ concerns and an unusable terrain surface. However, the reservoirs of underground pumped storage plants differ in design from classical ones for stability and space reasons. The hydraulic design is essential to ensure their satisfactory hydraulic performance. The paper presents a hybrid model study, which is defined here as a combination of physical and numerical modelling to use the advantages and to compensate for the disadvantages of the respective methods. It shows the analysis of waves in ventilated underground reservoir systems with a great length to height ratio, considering new operational aspects from energy supply systems with a great percentage of renewable energies. The multifaceted and narrow design of the reservoirs leads to complex free surface flows; for example, undular and breaking bores arise. The results show excessive wave heights through wave reflections, caused by the impermeable reservoir boundaries. Hence, their knowledge is essential for a successful operational and constructive design of the reservoirs.

  9. Lithological control on gas hydrate saturation as revealed by signal classification of NMR logging data

    Science.gov (United States)

    Bauer, Klaus; Kulenkampff, Johannes; Henninges, Jan; Spangenberg, Erik

    2015-09-01

    In this paper, nuclear magnetic resonance (NMR) downhole logging data are analyzed with a new strategy to study gas hydrate-bearing sediments in the Mackenzie Delta (NW Canada). In NMR logging, transverse relaxation time (T2) distribution curves are usually used to determine single-valued parameters such as apparent total porosity or hydrocarbon saturation. Our approach analyzes the entire T2 distribution curves as quasi-continuous signals to characterize the rock formation. We apply self-organizing maps, a neural network clustering technique, to subdivide the data set of NMR curves into classes with a similar and distinctive signal shape. The method includes (1) preparation of data vectors, (2) unsupervised learning, (3) cluster definition, and (4) classification and depth mapping of all NMR signals. Each signal class thus represents a specific pore size distribution which can be interpreted in terms of distinct lithologies and reservoir types. A key step in the interpretation strategy is to reconcile the NMR classes with other log data not considered in the clustering analysis, such as gamma ray, hydrate saturation, and other logs. Our results defined six main lithologies within the target zone. Gas hydrate layers were recognized by their low signal amplitudes for all relaxation times. Most importantly, two subtypes of hydrate-bearing shaly sands were identified. They show distinct NMR signals and differ in hydrate saturation and gamma ray values. An inverse linear relationship between hydrate saturation and clay content was concluded. Finally, we infer that the gas hydrate is not grain coating, but rather, pore filling with matrix support is the preferred growth habit model for the studied formation.

  10. Computer Modeling of the Displacement Behavior of Carbon Dioxide in Undersaturated Oil Reservoirs

    Directory of Open Access Journals (Sweden)

    Ju Binshan

    2015-11-01

    Full Text Available The injection of CO2 into oil reservoirs is performed not only to improve oil recovery but also to store CO2 captured from fuel combustion. The objective of this work is to develop a numerical simulator to predict quantitatively supercritical CO2 flooding behaviors for Enhanced Oil Recovery (EOR. A non-isothermal compositional flow mathematical model is developed. The phase transition diagram is designed according to the Minimum Miscibility Pressure (MMP and CO2 maximum solubility in oil phase. The convection and diffusion of CO2 mixtures in multiphase fluids in reservoirs, mass transfer between CO2 and crude and phase partitioning are considered. The governing equations are discretized by applying a fully implicit finite difference technique. Newton-Raphson iterative technique was used to solve the nonlinear equation systems and a simulator was developed. The performances of CO2 immiscible and miscible flooding in oil reservoirs are predicted by the new simulator. The distribution of pressure and temperature, phase saturations, mole fraction of each component in each phase, formation damage caused by asphaltene precipitation and the improved oil recovery are predicted by the simulator. Experimental data validate the developed simulator by comparison with simulation results. The applications of the simulator in prediction of CO2 flooding in oil reservoirs indicate that the simulator is robust for predicting CO2 flooding performance.

  11. The influence of lumping on the behavior of reservoir with light oil and CO2

    Energy Technology Data Exchange (ETDEWEB)

    Scanavini, Helena Finardi Alvares [Universidade Estadual de Campinas (UNISIM/UNICAMP), SP (Brazil). Dept. de Engenharia de Petroleo. Pesquisa em Simulacao e Gerenciamento de Reservatorios; Schiozer, Denis Jose [Universidade Estadual de Campinas (DEP/FEM/UNICAMP), SP (Brazil). Fac. de Engenharia Mecanica. Dept. de Engenharia de Petroleo

    2012-07-01

    Compositional simulation demands a large number of equations and functions to be solved, once fluid properties depend on reservoir pressure and temperature and also on fluid composition. As a consequence, the number of components used influences considerably in the simulation run time and accuracy: more components yield more equations to be solved with expected higher run time. Giant petroleum fields discovered recently in Brazil (pre-salt reservoirs) demand compositional simulation due to the fluid characteristics (light oil with the presence of CO2). However, the computational time can be a limitation because of the number of grid blocks that are necessary to represent the reservoir. So, reducing the number of components is an important step for the simulation models. Under this context, this paper presents a study on the influence of different lumping clusters, used to reduce the number of components in a volatile oil, on reservoir simulation. Phase diagram, saturation pressure and simulation results were used for comparison purposes. The best results were obtained for the cases with 14, 9 and 7 pseudo components, which represented correctly the original fluid, reducing till three times the simulation run time, for the same production volumes of oil and gas. (author)

  12. SITE-SCALE SATURATED ZONE TRANSPORT

    International Nuclear Information System (INIS)

    S. KELLER

    2004-01-01

    This work provides a site-scale transport model for calculating radionuclide transport in the saturated zone (SZ) at Yucca Mountain, for use in the abstractions model in support of ''Total System Performance Assessment for License Application'' (TSPA-LA). The purpose of this model report is to provide documentation for the components of the site-scale SZ transport model in accordance with administrative procedure AP-SIII.10Q, Models. The initial documentation of this model report was conducted under the ''Technical Work Plan For: Saturated Zone Flow and Transport Modeling and Testing'' (BSC 2003 [DIRS 163965]). The model report has been revised in accordance with the ''Technical Work Plan For: Natural System--Saturated Zone Analysis and Model Report Integration'', Section 2.1.1.4 (BSC 2004 [DIRS 171421]) to incorporate Regulatory Integration Team comments. All activities listed in the technical work plan that are appropriate to the transport model are documented in this report and are described in Section 2.1.1.4 (BSC 2004 [DIRS 171421]). This report documents: (1) the advection-dispersion transport model including matrix diffusion (Sections 6.3 and 6.4); (2) a description and validation of the transport model (Sections 6.3 and 7); (3) the numerical methods for simulating radionuclide transport (Section 6.4); (4) the parameters (sorption coefficient, Kd ) and their uncertainty distributions used for modeling radionuclide sorption (Appendices A and C); (5) the parameters used for modeling colloid-facilitated radionuclide transport (Table 4-1, Section 6.4.2.6, and Appendix B); and (6) alternative conceptual models and their dispositions (Section 6.6). The intended use of this model is to simulate transport in saturated fractured porous rock (double porosity) and alluvium. The particle-tracking method of simulating radionuclide transport is incorporated in the finite-volume heat and mass transfer numerical analysis (FEHM) computer code, (FEHM V2.20, STN: 10086

  13. TRANSFER RESERVOIR AS A RAINWATER DRAINAGE SYSTEM

    Directory of Open Access Journals (Sweden)

    Robert Malmur

    2016-06-01

    Full Text Available Intensive rainfalls and snow melting often cause floods in protected areas and overflow the existing sewage systems. Such cases are particularly burdensome for the inhabitants and cause considerable physical losses. One of the possible constructional solutions to ensure the effective outflow of stormwater are transfer reservoirs located between the draining system and a receiver set discussed in this paper. If gravity outflow of sewage is impossible, the initial part of sewage volume is accumulated in the transfer reservoir and then it is transferred into the water receiver set. However, gravity discharge of sewage to the water receiver set occurs through transfer chambers in the transfer reservoir.

  14. Non-Markovian reservoir-dependent squeezing

    International Nuclear Information System (INIS)

    Paavola, J

    2010-01-01

    The squeezing dynamics of a damped harmonic oscillator are studied for different types of environment without making the Markovian approximation. The squeezing dynamics of a coherent state depend on the reservoir spectrum in a unique way that can, in the weak coupling approximation, be analysed analytically. Comparison of squeezing dynamics for ohmic, sub-ohmic and super-ohmic environments is done, showing a clear connection between the squeezing-non-squeezing oscillations and reservoir structure. Understanding the effects occurring due to structured reservoirs is important both from a purely theoretical point of view and in connection with evolving experimental techniques and future quantum computing applications.

  15. Gasbuggy reservoir evaluation - 1969 report

    International Nuclear Information System (INIS)

    Atkinson, C.H.; Ward, Don C.; Lemon, R.F.

    1970-01-01

    The December 10, 1967, Project Gasbuggy nuclear detonation followed the drilling and testing of two exploratory wells which confirmed reservoir characteristics and suitability of the site. Reentry and gas production testing of the explosive emplacement hole indicated a collapse chimney about 150 feet in diameter extending from the 4,240-foot detonation depth to about 3,900 feet, the top of the 300-foot-thick Pictured Cliffs gas sand. Production tests of the chimney well in the summer of 1968 and during the last 12 months have resulted in a cumulative production of 213 million cubic feet of hydrocarbons, and gas recovery in 20 years is estimated to be 900 million cubic feet, which would be an increase by a factor of at least 5 over estimated recovery from conventional field wells in this low permeability area. At the end of production tests the flow rate was 160,000 cubic feet per day, which is 6 to 7 times that of an average field well in the area. Data from reentry of a pre-shot test well and a new postshot well at distances from the detonation of 300 and 250 feet, respectively, indicate low productivity and consequently low permeability in any fractures at these locations. (author)

  16. Gasbuggy reservoir evaluation - 1969 report

    Energy Technology Data Exchange (ETDEWEB)

    Atkinson, C H; Ward, Don C [Bureau of Mines, U.S. Department of the Interior (United States); Lemon, R F [El Paso Natural Gas Company (United States)

    1970-05-01

    The December 10, 1967, Project Gasbuggy nuclear detonation followed the drilling and testing of two exploratory wells which confirmed reservoir characteristics and suitability of the site. Reentry and gas production testing of the explosive emplacement hole indicated a collapse chimney about 150 feet in diameter extending from the 4,240-foot detonation depth to about 3,900 feet, the top of the 300-foot-thick Pictured Cliffs gas sand. Production tests of the chimney well in the summer of 1968 and during the last 12 months have resulted in a cumulative production of 213 million cubic feet of hydrocarbons, and gas recovery in 20 years is estimated to be 900 million cubic feet, which would be an increase by a factor of at least 5 over estimated recovery from conventional field wells in this low permeability area. At the end of production tests the flow rate was 160,000 cubic feet per day, which is 6 to 7 times that of an average field well in the area. Data from reentry of a pre-shot test well and a new postshot well at distances from the detonation of 300 and 250 feet, respectively, indicate low productivity and consequently low permeability in any fractures at these locations. (author)

  17. Modelling the impacts of climate change on hydrology and water quality in a mediterranean limno-reservoir

    DEFF Research Database (Denmark)

    Molina-Navarro, Euginio; Trolle, Dennis; Martinez-Pérez, Silvia

    Assessment Tool (SWAT) model developed for a small Mediterranean catchment to quantify the potential effects of various climate change scenarios on catchment hydrology as well as the trophic state of a new kind of waterbody, a limno-reservoir (Pareja Limno-reservoir), created for environmental...... and recreational purposes. Simulations showed a noticeable impact of climate change in the river flow regime and consequently the water level of the limno-reservoir, especially during summer, complicating the fulfillment of its purposes. All the scenarios predicted a deterioration of trophic conditions...

  18. 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.

  19. 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

  20. Depositional sequence analysis and sedimentologic modeling for improved prediction of Pennsylvanian reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Watney, W.L.

    1994-12-01

    Reservoirs in the Lansing-Kansas City limestone result from complex interactions among paleotopography (deposition, concurrent structural deformation), sea level, and diagenesis. Analysis of reservoirs and surface and near-surface analogs has led to developing a {open_quotes}strandline grainstone model{close_quotes} in which relative sea-level stabilized during regressions, resulting in accumulation of multiple grainstone buildups along depositional strike. Resulting stratigraphy in these carbonate units are generally predictable correlating to inferred topographic elevation along the shelf. This model is a valuable predictive tool for (1) locating favorable reservoirs for exploration, and (2) anticipating internal properties of the reservoir for field development. Reservoirs in the Lansing-Kansas City limestones are developed in both oolitic and bioclastic grainstones, however, re-analysis of oomoldic reservoirs provides the greatest opportunity for developing bypassed oil. A new technique, the {open_quotes}Super{close_quotes} Pickett crossplot (formation resistivity vs. porosity) and its use in an integrated petrophysical characterization, has been developed to evaluate extractable oil remaining in these reservoirs. The manual method in combination with 3-D visualization and modeling can help to target production limiting heterogeneities in these complex reservoirs and moreover compute critical parameters for the field such as bulk volume water. Application of this technique indicates that from 6-9 million barrels of Lansing-Kansas City oil remain behind pipe in the Victory-Northeast Lemon Fields. Petroleum geologists are challenged to quantify inferred processes to aid in developing rationale geologically consistent models of sedimentation so that acceptable levels of prediction can be obtained.

  1. A fast complex domain-matching pursuit algorithm and its application to deep-water gas reservoir detection

    Science.gov (United States)

    Zeng, Jing; Huang, Handong; Li, Huijie; Miao, Yuxin; Wen, Junxiang; Zhou, Fei

    2017-12-01

    The main emphasis of exploration and development is shifting from simple structural reservoirs to complex reservoirs, which all have the characteristics of complex structure, thin reservoir thickness and large buried depth. Faced with these complex geological features, hydrocarbon detection technology is a direct indication of changes in hydrocarbon reservoirs and a good approach for delimiting the distribution of underground reservoirs. It is common to utilize the time-frequency (TF) features of seismic data in detecting hydrocarbon reservoirs. Therefore, we research the complex domain-matching pursuit (CDMP) method and propose some improvements. First is the introduction of a scale parameter, which corrects the defect that atomic waveforms only change with the frequency parameter. Its introduction not only decomposes seismic signal with high accuracy and high efficiency but also reduces iterations. We also integrate jumping search with ergodic search to improve computational efficiency while maintaining the reasonable accuracy. Then we combine the improved CDMP with the Wigner-Ville distribution to obtain a high-resolution TF spectrum. A one-dimensional modeling experiment has proved the validity of our method. Basing on the low-frequency domain reflection coefficient in fluid-saturated porous media, we finally get an approximation formula for the mobility attributes of reservoir fluid. This approximation formula is used as a hydrocarbon identification factor to predict deep-water gas-bearing sand of the M oil field in the South China Sea. The results are consistent with the actual well test results and our method can help inform the future exploration of deep-water gas reservoirs.

  2. Monte Carlo Analysis of Reservoir Models Using Seismic Data and Geostatistical Models

    Science.gov (United States)

    Zunino, A.; Mosegaard, K.; Lange, K.; Melnikova, Y.; Hansen, T. M.

    2013-12-01

    We present a study on the analysis of petroleum reservoir models consistent with seismic data and geostatistical constraints performed on a synthetic reservoir model. Our aim is to invert directly for structure and rock bulk properties of the target reservoir zone. To infer the rock facies, porosity and oil saturation seismology alone is not sufficient but a rock physics model must be taken into account, which links the unknown properties to the elastic parameters. We then combine a rock physics model with a simple convolutional approach for seismic waves to invert the "measured" seismograms. To solve this inverse problem, we employ a Markov chain Monte Carlo (MCMC) method, because it offers the possibility to handle non-linearity, complex and multi-step forward models and provides realistic estimates of uncertainties. However, for large data sets the MCMC method may be impractical because of a very high computational demand. To face this challenge one strategy is to feed the algorithm with realistic models, hence relying on proper prior information. To address this problem, we utilize an algorithm drawn from geostatistics to generate geologically plausible models which represent samples of the prior distribution. The geostatistical algorithm learns the multiple-point statistics from prototype models (in the form of training images), then generates thousands of different models which are accepted or rejected by a Metropolis sampler. To further reduce the computation time we parallelize the software and run it on multi-core machines. The solution of the inverse problem is then represented by a collection of reservoir models in terms of facies, porosity and oil saturation, which constitute samples of the posterior distribution. We are finally able to produce probability maps of the properties we are interested in by performing statistical analysis on the collection of solutions.

  3. Use of ``rock-typing`` to characterize carbonate reservoir heterogeneity. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Ikwuakor, K.C.

    1994-03-01

    The objective of the project was to apply techniques of ``rock-typing`` and quantitative formation evaluation to borehole measurements in order to identify reservoir and non-reservoir rock-types and their properties within the ``C`` zone of the Ordovician Red River carbonates in the northeast Montana and northwest North Dakota areas of the Williston Basin. Rock-typing discriminates rock units according to their pore-size distribution. Formation evaluation estimates porosities and pore fluid saturation. Rock-types were discriminated using crossplots involving three rock-typing criteria: (1) linear relationship between bulk density and porosity, (2) linear relationship between acoustic interval transit-time and porosity, and (3) linear relationship between acoustic interval transit-time and bulk density. Each rock-type was quantitatively characterized by the slopes and intercepts established for different crossplots involving the above variables, as well as porosities and fluid saturations associated with the rock-types. All the existing production was confirmed through quantitative formation evaluation. Highly porous dolomites and anhydritic dolomites contribute most of the production, and constitute the best reservoir rock-types. The results of this study can be applied in field development and in-fill drilling. Potential targets would be areas of porosity pinchouts and those areas where highly porous zones are downdip from non-porous and tight dolomites. Such areas are abundant. In order to model reservoirs for enhanced oil recovery (EOR) operations, a more localized (e.g. field scale) study, expanded to involve other rock-typing criteria, is necessary.

  4. Constructive Activation of Reservoir-Resident Microbes for Enhanced Oil Recovery

    Science.gov (United States)

    DeBruyn, R. P.

    2017-12-01

    Microbial communities living in subsurface oil reservoirs biodegrade oil, producing methane. If this process could create methane within the waterflooded pore spaces of an oilfield, the methane would be expected to remain and occupy pore space, decreasing water relative permeability, diverting water flow, and increasing oil recovery by expanding the swept zone of the waterflood. This approach was tested in an oilfield in northern Montana. Preliminary assessments were made of geochemical conditions and microbiological habitations. Then, a formulation of microbial activators, with composition tailored for the reservoir's conditions, was metered at low rates into the existing injection water system for one year. In the field, the responses observed included improved oil production performance; a slight increase in injection pressure; and increased time needed for tracers to move between injection and producing wells. We interpret these results to confirm that successful stimulation of the microbial community caused more methane to be created within the swept zone of the waterflooded reservoir. When the methane exsolved as water flowed between high-pressure injection and low-pressure production wells, the bubbles occupied pore space, reducing water saturation and relative permeability, and re-directing some water flow to "slower" unswept rock with lower permeability and higher oil saturation. In total, the waterflood's swept zone had been expanded to include previously-unflooded rock. This technology was applied in this field after screening based on careful anaerobic sampling, advanced microbiological analysis, and the ongoing success of its waterflood. No reservoir or geological or geophysical simulation models were employed, and physical modifications to field facilities were minor. This technology of utilizing existing microbial populations for enhanced oil recovery can therefore be considered for deployment into waterfloods where small scale, advanced maturity, or

  5. Sensitivity analysis and economic optimization studies of inverted five-spot gas cycling in gas condensate reservoir

    Science.gov (United States)

    Shams, Bilal; Yao, Jun; Zhang, Kai; Zhang, Lei

    2017-08-01

    Gas condensate reservoirs usually exhibit complex flow behaviors because of propagation response of pressure drop from the wellbore into the reservoir. When reservoir pressure drops below the dew point in two phase flow of gas and condensate, the accumulation of large condensate amount occurs in the gas condensate reservoirs. Usually, the saturation of condensate accumulation in volumetric gas condensate reservoirs is lower than the critical condensate saturation that causes trapping of large amount of condensate in reservoir pores. Trapped condensate often is lost due to condensate accumulation-condensate blockage courtesy of high molecular weight, heavy condensate residue. Recovering lost condensate most economically and optimally has always been a challenging goal. Thus, gas cycling is applied to alleviate such a drastic loss in resources. In gas injection, the flooding pattern, injection timing and injection duration are key parameters to study an efficient EOR scenario in order to recover lost condensate. This work contains sensitivity analysis on different parameters to generate an accurate investigation about the effects on performance of different injection scenarios in homogeneous gas condensate system. In this paper, starting time of gas cycling and injection period are the parameters used to influence condensate recovery of a five-spot well pattern which has an injection pressure constraint of 3000 psi and production wells are constraint at 500 psi min. BHP. Starting injection times of 1 month, 4 months and 9 months after natural depletion areapplied in the first study. The second study is conducted by varying injection duration. Three durations are selected: 100 days, 400 days and 900 days. In miscible gas injection, miscibility and vaporization of condensate by injected gas is more efficient mechanism for condensate recovery. From this study, it is proven that the application of gas cycling on five-spot well pattern greatly enhances condensate recovery

  6. Reduced-Order Model for Leakage Through an Open Wellbore from the Reservoir due to Carbon Dioxide Injection

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Lehua [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Oldenburg, Curtis M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-07-26

    Potential CO2 leakage through existing open wellbores is one of the most significant hazards that need to be addressed in geologic carbon sequestration (GCS) projects. In the framework of the National Risk Assessment Partnership (NRAP) which requires fast computations for uncertainty analysis, rigorous simulation of the coupled wellbore-reservoir system is not practical. We have developed a 7,200-point look-up table reduced-order model (ROM) for estimating the potential leakage rate up open wellbores in response to CO2 injection nearby. The ROM is based on coupled simulations using T2Well/ECO2H which was run repeatedly for representative conditions relevant to NRAP to create a look-up table response-surface ROM. The ROM applies to a wellbore that fully penetrates a 20-m thick reservoir that is used for CO2 storage. The radially symmetric reservoir is assumed to have initially uniform pressure, temperature, gas saturation, and brine salinity, and it is assumed these conditions are held constant at the far-field boundary (100 m away from the wellbore). In such a system, the leakage can quickly reach quasi-steady state. The ROM table can be used to estimate both the free-phase CO2 and brine leakage rates through an open well as a function of wellbore and reservoir conditions. Results show that injection-induced pressure and reservoir gas saturation play important roles in controlling leakage. Caution must be used in the application of this ROM because well leakage is formally transient and the ROM lookup table was populated using quasi-steady simulation output after 1000 time steps which may correspond to different physical times for the various parameter combinations of the coupled wellbore-reservoir system.

  7. Methods to evaluate some reservoir characterization by means of the geophysical data in the strata of limestone and marl

    Directory of Open Access Journals (Sweden)

    V. M. Seidov

    2017-12-01

    Full Text Available As we know, the main goal of interpreting the materials of well logging, including the allocation of collectors and assessment of their saturation, are successfully achieved when the process of interpretation has a strong methodological support. This means, that it is justified by the necessary interpretational models and effective instructional techniques are used. They are based on structural and petrophysical models of reservoirs of the section investigated. The problem of studying the marl rocks with the help of the geophysical methods is not worked out properly. Many years of experience of studying limestone and marl rocks has made it possible to justify the optimal method of data interpretation of geophysical research wells in carbonate sections, which was represented by limestone and marl formations. A new method was developed to study marl rocks. It includes the following main studies: detection of reservoirs in the carbonate section according to the materials of geophysical studies of wells; determination of the geophysical parameters of each reservoir; assessment of the quality of well logging curves; introduction of amendments; selection of reference layers; the calculation of the relative double differencing parameters; the involvement of core data; identifying the lithological rock composition; the rationale for structural models of reservoirs; the definition of the block and of the total porosity; determination of argillaceous carbonate rocks; determination of the coefficient of water saturation of formations based on the type of the collector; setting a critical value for effective porosity, etc. This method was applied in the Eocene deposits of the Interfluve of the Kura and Iori, which is a promising object of hydrocarbons in Azerbaijan. The following conclusions have been made: this methodology successfully solves the problem of petrophysical characteristics of marl rocks; bad connection is observed between some of the

  8. Energy dependent saturable and reverse saturable absorption in cube-like polyaniline/polymethyl methacrylate film

    Energy Technology Data Exchange (ETDEWEB)

    Thekkayil, Remyamol [Department of Chemistry, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram 695 547 (India); Philip, Reji [Light and Matter Physics Group, Raman Research Institute, C.V. Raman Avenue, Bangalore 560 080 (India); Gopinath, Pramod [Department of Physics, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram 695 547 (India); John, Honey, E-mail: honey@iist.ac.in [Department of Chemistry, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram 695 547 (India)

    2014-08-01

    Solid films of cube-like polyaniline synthesized by inverse microemulsion polymerization method have been fabricated in a transparent PMMA host by an in situ free radical polymerization technique, and are characterized by spectroscopic and microscopic techniques. The nonlinear optical properties are studied by open aperture Z-scan technique employing 5 ns (532 nm) and 100 fs (800 nm) laser pulses. At the relatively lower laser pulse energy of 5 μJ, the film shows saturable absorption both in the nanosecond and femtosecond excitation domains. An interesting switchover from saturable absorption to reverse saturable absorption is observed at 532 nm when the energy of the nanosecond laser pulses is increased. The nonlinear absorption coefficient increases with increase in polyaniline concentration, with low optical limiting threshold, as required for a good optical limiter. - Highlights: • Synthesized cube-like polyaniline nanostructures. • Fabricated polyaniline/PMMA nanocomposite films. • At 5 μJ energy, saturable absorption is observed both at ns and fs regime. • Switchover from SA to RSA is observed as energy of laser beam increases. • Film (0.1 wt % polyaniline) shows high β{sub eff} (230 cm GW{sup −1}) and low limiting threshold at 150 μJ.

  9. Simulation of the saturation process of a radwaste storage cell

    International Nuclear Information System (INIS)

    Robbe, M.F.; Clouard, A.

    2001-01-01

    This paper presents a simulation of the saturation of the barrier and the plug of a storage cell by the surrounding host rock. Generally speaking, the unsaturated barrier and plug start saturating immediately in the vicinity of the quasi-saturated host rock. Then the saturation front propagates towards the canisters and the symmetry axis. Apart from the part in contact with the plug, the barrier is saturated at about 30 years. The part of the barrier near the plug is saturated around 80 years. If the top of the plug is saturated very soon, the part in the corner near the gallery and the symmetry axis is not completely saturated after 100 years. In the site, we observe a small desaturation during the first month, at the limit with the plug and the barrier, and especially in the corner limited by both FoCa clay pieces. This transient phenomenon may be assigned to the time difference between the immediate suction of water by the unsaturated materials and the delayed water flows coming from the saturated host rock to compensate the water suction. The purpose of this computation was at once to estimate the time necessary for the saturation of the clay layers surrounding the radwaste canisters and to evaluate the hydro-mechanical behaviour of the storage cell during the saturation process. Therefore a mechanical simulation was performed using the present hydraulic results to initiate the mechanical computation. (authors)

  10. Phase Envelope Calculations for Reservoir Fluids in the Presence of Capillary Pressure

    DEFF Research Database (Denmark)

    Lemus, Diego; Yan, Wei; Michelsen, Michael L.

    2015-01-01

    the bubble and dew point curves but also other quality lines with vapor fractions between 0 and 1. The algorithm has been used to calculate the phase envelopes of binary, multicomponent and reservoir fluid systems for pore radius from 10 to 50 nm. The presence of capillary pressure changes the saturation...... pressures in the whole phase envelope except at the critical point. The bubble point curve shows a negative change while the dew point curve shows positive and negative changes in the upper dew point branch and the lower dew point branch, respectively. In particular, the cricondentherm is also shifted...

  11. Assembling evidence for identifying reservoirs of infection.

    Science.gov (United States)

    Viana, Mafalda; Mancy, Rebecca; Biek, Roman; Cleaveland, Sarah; Cross, Paul C; Lloyd-Smith, James O; Haydon, Daniel T

    2014-05-01

    Many pathogens persist in multihost systems, making the identification of infection reservoirs crucial for devising effective interventions. Here, we present a conceptual framework for classifying patterns of incidence and prevalence, and review recent scientific advances that allow us to study and manage reservoirs simultaneously. We argue that interventions can have a crucial role in enriching our mechanistic understanding of how reservoirs function and should be embedded as quasi-experimental studies in adaptive management frameworks. Single approaches to the study of reservoirs are unlikely to generate conclusive insights whereas the formal integration of data and methodologies, involving interventions, pathogen genetics, and contemporary surveillance techniques, promises to open up new opportunities to advance understanding of complex multihost systems. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  12. NYC Reservoirs Watershed Areas (HUC 12)

    Data.gov (United States)

    U.S. Environmental Protection Agency — This NYC Reservoirs Watershed Areas (HUC 12) GIS layer was derived from the 12-Digit National Watershed Boundary Database (WBD) at 1:24,000 for EPA Region 2 and...

  13. determination of verticality of reservoir engineering structure

    African Journals Online (AJOL)

    user

    applications is 3D survey and management of oil and gas facilities and other engineering structures. This recent .... also affect ground water contamination. 2. VERTICALITY ...... The soil, water and concrete in a Reservoir at the foundation bed ...

  14. Reservoir Greenhouse Gas Emissions at Russian HPP

    Energy Technology Data Exchange (ETDEWEB)

    Fedorov, M. P.; Elistratov, V. V.; Maslikov, V. I.; Sidorenko, G. I.; Chusov, A. N.; Atrashenok, V. P.; Molodtsov, D. V. [St. Petersburg State Polytechnic University (Russian Federation); Savvichev, A. S. [Russian Academy of Sciences, S. N. Vinogradskii Institute of Microbiology (Russian Federation); Zinchenko, A. V. [A. I. Voeikov Main Geophysical Observatory (Russian Federation)

    2015-05-15

    Studies of greenhouse-gas emissions from the surfaces of the world’s reservoirs, which has demonstrated ambiguity of assessments of the effect of reservoirs on greenhouse-gas emissions to the atmosphere, is analyzed. It is recommended that greenhouse- gas emissions from various reservoirs be assessed by the procedure “GHG Measurement Guidelines for Fresh Water Reservoirs” (2010) for the purpose of creating a data base with results of standardized measurements. Aprogram for research into greenhouse-gas emissions is being developed at the St. Petersburg Polytechnic University in conformity with the IHA procedure at the reservoirs impounded by the Sayano-Shushenskaya and Mainskaya HPP operated by the RusHydro Co.

  15. Zooplankton assemblage of Oyun Reservoir, Offa, Nigeria.

    Science.gov (United States)

    Mustapha, Moshood K

    2009-12-01

    The influence of physico-chemical properties of Oyun Reservoir, Offa, Nigeria (a shallow tropical African reservoir) on its zooplankton composition and abundance were investigated at three stations for two years between January 2002 and December 2003. Diversity is not high: only three groups of zooplankton were found: Rotifera with eight genera; and Cladocera and Copepoda with three genera each. Rotifera dominated numerically (71.02%), followed by Cladocera (16.45%) and Copepoda (12.53%). The zooplankton was more prevalent during the rainy season, and there were variations in the composition and abundance along the reservoir continuum. Factors such as temperature, nutrients, food availability, shape and hydrodynamics of the reservoir, as well as reproductive strategies of the organisms, strongly influence the generic composition and population density of zooplankton. Prevention of ecological deterioration of the water body would greatly should result in a more productive water body, rich in zooplankton and with better fisheries.

  16. Data Compression of Hydrocarbon Reservoir Simulation Grids

    KAUST Repository

    Chavez, Gustavo Ivan; Harbi, Badr M.

    2015-01-01

    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

  17. The freshwater reservoir effect in radiocarbon dating

    DEFF Research Database (Denmark)

    Philippsen, Bente

    case studies will show the degree of variability of the freshwater reservoir effect over short and long timescales. Radiocarbon dating of recent water samples, aquatic plants and animals, shows that age differences of up to 2000 years can occur within one river. In the Limfjord, freshwater influence......The freshwater reservoir effect can result in too high radiocarbon ages of samples from lakes and rivers, including the bones of people whose subsistence was based on freshwater fish, and pottery in which fish was cooked. In my talk, I will explain the causes and consequences of this effect. Two...... caused reservoir ages to vary between 250 and 700 years during the period 5400 BC - AD 700. Finally, I will discuss the implications of the freshwater reservoir effect for radiocarbon dating of Mesolithic pottery from inland sites of the Ertebølle culture in Northern Germany....

  18. Assembling evidence for identifying reservoirs of infection

    Science.gov (United States)

    Mafalda, Viana; Rebecca, Mancy; Roman, Biek; Sarah, Cleaveland; Cross, Paul C.; James O, Lloyd-Smith; Daniel T, Haydon

    2014-01-01

    Many pathogens persist in multihost systems, making the identification of infection reservoirs crucial for devising effective interventions. Here, we present a conceptual framework for classifying patterns of incidence and prevalence, and review recent scientific advances that allow us to study and manage reservoirs simultaneously. We argue that interventions can have a crucial role in enriching our mechanistic understanding of how reservoirs function and should be embedded as quasi-experimental studies in adaptive management frameworks. Single approaches to the study of reservoirs are unlikely to generate conclusive insights whereas the formal integration of data and methodologies, involving interventions, pathogen genetics, and contemporary surveillance techniques, promises to open up new opportunities to advance understanding of complex multihost systems.

  19. Lower Palaeozoic reservoirs of North Africa

    Energy Technology Data Exchange (ETDEWEB)

    Crossley, R.; McDougall, N. [Robertson Research International Ltd., Llandudno, Conwy (United Kingdom)

    1998-12-31

    This paper provides an overview of features considered significant in the exploration and development of Lower Palaeozoic reservoirs of North Africa. Information is derived from a review of literature on the Lower Palaeozoic successions of North Africa, combined with outcrop observations from the Anti Atlas mountains of Morocco. The focus of the exploration-oriented part of the review is on identification of potential traps other than two-way structural dip closure. Stratigraphic elements described include depositional models of reservoir facies, tectonic unconformities and possible eustatic unconformities. Cases of established or potential trapping by post-depositional faulting by diagenesis and by hydrodynamic flow are examined. Development-related topics highlighted include the impact on reservoir matrix quality of burial diagenesis and of palaeo-weathering at the Hercynian unconformity. Other issues discussed which additionally affect producibility from the reservoir matrix include tectonic fracturing, palaeotopography and unloading fracturing at the Hercynian unconformity, and induced fracturing within the present stress regimes. (author)

  20. 49 CFR 393.50 - Reservoirs required.

    Science.gov (United States)

    2010-10-01

    ... using air or vacuum braking must have either reserve capacity, or a reservoir, that would enable the... have a condensate drain valve that can be manually operated. Automatic condensate drain valves may be...

  1. Prediction of abrupt reservoir compaction and surface subsidence due to pore collapse in carbonates

    Energy Technology Data Exchange (ETDEWEB)

    Smits, R.M.M.; de Waal, A.; van Kooten, J.F.C.

    1986-01-01

    A new procedure has been developed to predict the abrupt in-situ compaction and the associated surface subsidence above high-porosity carbonate fields showing pore collapse. The approach is based on an extensive laboratory compaction study in which the effects of carbonate type, porosity, core preparation, pore saturant, horizontal to vertical stress ratio and loading rate on the pore collapse behaviour were investigated. For each carbonate type a trendline was established describing the relationship between the porosity after collapse and the vertical effective stress. This trendline concept, in combination with existing subsidence models, enables reservoir compaction and surface subsidence to be predicted on the basis of wireline porosity logs. Static and dynamic elastic constants were found to be uncorrelated during pore collapse. The position of the trendline depends strongly on carbonate type, pore saturant, loading rate and stress ratio. Therefore procedures are given to derive the correct in-situ trendline from laboratory compaction experiments.

  2. Prediction of abrupt reservoir compaction and surface subsidence caused by pore collapse in carbonates

    Energy Technology Data Exchange (ETDEWEB)

    Smits, R.M.M.; De Waal, J.A.; Van Kootan, J.F.C.

    1988-06-01

    A new procedure has been developed to predict the abrupt in-situ compaction and the associated surface subsidence above high-porosity carbonate fields that show pore collapse. The approach is based on an extensive laboratory compaction study in which the effects of carbonate type, porosity, core preparation, pore saturant, horizontal/vertical stress ratio, and loading rate on pore-collapse behavior were investigated. For a number of carbonate types, a trendline was established that describes the relationship between the porosity after collapse and the vertical effective stress. This trendline concept, in combination with existing subsidence models, enables reservoir compaction and surface subsidence to be predicted on the basis of wireline porosity logs. Static and dynamic elastic constants were found to be uncorrelated during pore collapse. The position of the trendline depends strongly on carbonate type, pore saturant, loading rate, and stress ratio. Therefore, procedures are given to derive the correct in-situ trendline from laboratory compaction experiments.

  3. Flow of a stream through a reservoir

    International Nuclear Information System (INIS)

    Sauerwein, K.

    1967-01-01

    If a reservoir is fed from a single source, which may not always be pure, the extent to which the inflowing stream mixes with the water in the reservoir is important for the quality of the water supplied by the reservoir. This question was investigated at the Lingese Reservoir, containing between one and two million cubic metres of water, in the Bergisches Land (North Rhine-Westphalia). The investigation was carried out at four different seasons so that the varying effects of the stream-water temperatures could be studied in relation to the temperature of the reservoir water. The stream was radioactively labelled at the point of inflow into the reservoir, and its flow through the reservoir was measured in length and depth from boats, by means of 1-m-long Geiger counters. In two cases the radioactivity of the outflowing water was also measured at fixed points. A considerable variety of intermixing phenomena were observed; these were mainly of limnological interest. The results of four experiments corresponding to the four different seasons are described in detail. They were as follows: (1) The mid-October experiment where the stream, with a temperature of 8.0 deg. C, was a good 5 deg. C colder than the water of the reservoir, whose temperature was almost uniform, ranging from 13.2 deg. C at the bed to 13.6 deg. C at the surface. (2) The spring experiment (second half of March), when the stream temperature was only 0.3 deg. C below that of the reservoir surface (7.8 deg. C), while the temperature of the bed was 5.8 deg. C. (3) The winter experiment (early December) where at first the temperature of the stream was approximately the same as that of the surface so that, once again, the stream at first flowed 1/2 - 1 m below the surface. During the almost wind-free night a sudden fall in temperature occurred, and the air temperature dropped from 0 deg. C to -12 deg. C. (4) The summer experiment (end of July to mid-August) when the stream was nearly 1 deg. C colder than

  4. Saturation of DNA repair in mammalian cells

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, F E; Setlow, R B

    1979-01-01

    Excision repair seems to reach a plateau in normal human cells at a 254 nm dose near 20 J/m/sup 2/. We measured excision repair in normal human fibroblasts up to 80 J/m/sup 2/. The four techniques used (unscheduled DNA synthesis, photolysis of BrdUrd incorporated during repair, loss of sites sensitive to a UV endonuclease from Micrococcus luteus, and loss of pyrimidine dimers from DNA) showed little difference between the two doses. Moreover, the loss of endonuclease sites in 24h following two 20 J/m/sup 2/ doses separated by 24h was similar to the loss observed following one dose. Hence, we concluded that the observed plateau in excision repair is real and does not represent some inhibitory process at high doses but a true saturation of one of the rate limiting steps in repair.

  5. The Danish tax on saturated fat

    DEFF Research Database (Denmark)

    Jensen, Jørgen Dejgård; Smed, Sinne

    2013-01-01

    and oils. This assessment is done by conducting an econometric analysis on weekly food purchase data from a large household panel dataset (GfK Consumer Tracking Scandinavia), spanning the period from January 2008 until July 2012.The econometric analysis suggest that the introduction of the tax on saturated...... and fats, a shift that seems to have been utilized by discount chains to raise the prices of butter and margarine by more than the pure tax increase. Due to the relatively short data period with the tax being active, interpretation of these findings from a long-run perspective should be done...... with considerable care. It is thus recommended to repeat – and broaden – the analysis at a later stage, when data are available for a longer period after the introduction of the fat tax....

  6. Pollination Reservoirs in Lowbush Blueberry (Ericales: Ericaceae)

    OpenAIRE

    Venturini, E. M.; Drummond, F. A.; Hoshide, A. K.; Dibble, A. C.; Stack, L. B.

    2017-01-01

    Abstract Pollinator-dependent agriculture heavily relies upon a single pollinator?the honey bee. To diversify pollination strategies, growers are turning to alternatives. Densely planted reservoirs of pollen- and nectar-rich flowers (pollination reservoirs, hereafter ?PRs?) may improve pollination services provided by wild bees. Our focal agroecosystem, lowbush blueberry (Vaccinium angustifolium Aiton), exists in a simple landscape uniquely positioned to benefit from PRs. First, we contrast b...

  7. Ecological operation for Three Gorges Reservoir

    Directory of Open Access Journals (Sweden)

    Wen-xian Guo

    2011-06-01

    Full Text Available The traditional operation of the Three Gorges Reservoir has mainly focused on water for flood control, power generation, navigation, water supply, and recreation, and given less attention to the negative impacts of reservoir operation on the river ecosystem. In order to reduce the negative influence of reservoir operation, ecological operation of the reservoir should be studied with a focus on maintaining a healthy river ecosystem. This study considered ecological operation targets, including maintaining the river environmental flow and protecting the spawning and reproduction of the Chinese sturgeon and four major Chinese carps. Using flow data from 1900 to 2006 at the Yichang gauging station as the control station data for the Yangtze River, the minimal and optimal river environmental flows were analyzed, and eco-hydrological targets for the Chinese sturgeon and four major Chinese carps in the Yangtze River were calculated. This paper proposes a reservoir ecological operation model, which comprehensively considers flood control, power generation, navigation, and the ecological environment. Three typical periods, wet, normal, and dry years, were selected, and the particle swarm optimization algorithm was used to analyze the model. The results show that ecological operation modes have different effects on the economic benefit of the hydropower station, and the reservoir ecological operation model can simulate the flood pulse for the requirements of spawning of the Chinese sturgeon and four major Chinese carps. According to the results, by adopting a suitable re-operation scheme, the hydropower benefit of the reservoir will not decrease dramatically while the ecological demand is met. The results provide a reference for designing reasonable operation schemes for the Three Gorges Reservoir.

  8. Analog readout for optical reservoir computers

    OpenAIRE

    Smerieri, Anteo; Duport, François; Paquot, Yvan; Schrauwen, Benjamin; Haelterman, Marc; Massar, Serge

    2012-01-01

    Reservoir computing is a new, powerful and flexible machine learning technique that is easily implemented in hardware. Recently, by using a time-multiplexed architecture, hardware reservoir computers have reached performance comparable to digital implementations. Operating speeds allowing for real time information operation have been reached using optoelectronic systems. At present the main performance bottleneck is the readout layer which uses slow, digital postprocessing. We have designed a...

  9. Geophysical monitoring in a hydrocarbon reservoir

    Science.gov (United States)

    Caffagni, Enrico; Bokelmann, Goetz

    2016-04-01

    Extraction of hydrocarbons from reservoirs demands ever-increasing technological effort, and there is need for geophysical monitoring to better understand phenomena occurring within the reservoir. Significant deformation processes happen when man-made stimulation is performed, in combination with effects deriving from the existing natural conditions such as stress regime in situ or pre-existing fracturing. Keeping track of such changes in the reservoir is important, on one hand for improving recovery of hydrocarbons, and on the other hand to assure a safe and proper mode of operation. Monitoring becomes particularly important when hydraulic-fracturing (HF) is used, especially in the form of the much-discussed "fracking". HF is a sophisticated technique that is widely applied in low-porosity geological formations to enhance the production of natural hydrocarbons. In principle, similar HF techniques have been applied in Europe for a long time in conventional reservoirs, and they will probably be intensified in the near future; this suggests an increasing demand in technological development, also for updating and adapting the existing monitoring techniques in applied geophysics. We review currently available geophysical techniques for reservoir monitoring, which appear in the different fields of analysis in reservoirs. First, the properties of the hydrocarbon reservoir are identified; here we consider geophysical monitoring exclusively. The second step is to define the quantities that can be monitored, associated to the properties. We then describe the geophysical monitoring techniques including the oldest ones, namely those in practical usage from 40-50 years ago, and the most recent developments in technology, within distinct groups, according to the application field of analysis in reservoir. This work is performed as part of the FracRisk consortium (www.fracrisk.eu); this project, funded by the Horizon2020 research programme, aims at helping minimize the

  10. Analytical estimation of effective charges at saturation in Poisson-Boltzmann cell models

    International Nuclear Information System (INIS)

    Trizac, Emmanuel; Aubouy, Miguel; Bocquet, Lyderic

    2003-01-01

    We propose a simple approximation scheme for computing the effective charges of highly charged colloids (spherical or cylindrical with infinite length). Within non-linear Poisson-Boltzmann theory, we start from an expression for the effective charge in the infinite-dilution limit which is asymptotically valid for large salt concentrations; this result is then extended to finite colloidal concentration, approximating the salt partitioning effect which relates the salt content in the suspension to that of a dialysing reservoir. This leads to an analytical expression for the effective charge as a function of colloid volume fraction and salt concentration. These results compare favourably with the effective charges at saturation (i.e. in the limit of large bare charge) computed numerically following the standard prescription proposed by Alexander et al within the cell model

  11. Low-frequency asymptotic analysis of seismic reflection from afluid-saturated medium

    Energy Technology Data Exchange (ETDEWEB)

    Silin, D.B.; Korneev, V.A.; Goloshubin, G.M.; Patzek, T.W.

    2004-04-14

    Reflection of a seismic wave from a plane interface betweentwo elastic media does not depend on the frequency. If one of the mediais poroelastic and fluid-saturated, then the reflection becomesfrequency-dependent. This paper presents a low-frequency asymptoticformula for the reflection of seismic plane p-wave from a fluid-saturatedporous medium. The obtained asymptotic scaling of the frequency-dependentcomponent of the reflection coefficient shows that it is asymptoticallyproportional to the square root of the product of the reservoir fluidmobility and the frequency of the signal. The dependence of this scalingon the dynamic Darcy's law relaxation time is investigated as well.Derivation of the main equations of the theory of poroelasticity from thedynamic filtration theory reveals that this relaxation time isproportional to Biot's tortuosity parameter.

  12. Relative Humidity in the Tropopause Saturation Layer

    Science.gov (United States)

    Selkirk, H. B.; Schoeberl, M. R.; Pfister, L.; Thornberry, T. D.; Bui, T. V.

    2017-12-01

    The tropical tropopause separates two very different atmospheric regimes: the stable lower stratosphere where the air is both extremely dry and nearly always so, and a transition layer in the uppermost tropical troposphere, where humidity on average increases rapidly downward but can undergo substantial temporal fluctuations. The processes that control the humidity in this layer below the tropopause include convective detrainment (which can result in either a net hydration or dehydration), slow ascent, wave motions and advection. Together these determine the humidity of the air that eventually passes through the tropopause and into the stratosphere, and we refer to this layer as the tropopause saturation layer or TSL. We know from in situ water vapor observations such as Ticosonde's 12-year balloonsonde record at Costa Rica that layers of supersaturation are frequently observed in the TSL. While their frequency is greatest during the local rainy season from June through October, supersaturation is also observed in the boreal winter dry season when deep convection is well south of Costa Rica. In other words, local convection is not a necessary condition for the presence of supersaturation. Furthermore, there are indications from airborne measurements during the recent POSIDON campaign at Guam that if anything deep convection tends to `reset' the TSL locally to a state of just-saturation. Conversely, it may be that layers of supersaturation are the result of slow ascent. To explore these ideas we take Ticosonde water vapor observations from the TSL, stratify them on the basis of relative humidity and report on the differences in the the history of upstream convective influence between supersaturated parcels and those that are not.

  13. On-line Optimization-Based Simulators for Fractured and Non-fractured Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Milind D. Deo

    2005-08-31

    Oil field development is a multi-million dollar business. Reservoir simulation is often used to guide the field management and development process. Reservoir characterization and geologic modeling tools have become increasingly sophisticated. As a result the geologic models produced are complex. Most reservoirs are fractured to a certain extent. The new geologic characterization methods are making it possible to map features such as faults and fractures, field-wide. Significant progress has been made in being able to predict properties of the faults and of the fractured zones. Traditionally, finite difference methods have been employed in discretizing the domains created by geologic means. For complex geometries, finite-element methods of discretization may be more suitable. Since reservoir simulation is a mature science, some of the advances in numerical methods (linear, nonlinear solvers and parallel computing) have not been fully realized in the implementation of most of the simulators. The purpose of this project was to address some of these issues. {sm_bullet} One of the goals of this project was to develop a series of finite-element simulators to handle problems of complex geometry, including systems containing faults and fractures. {sm_bullet} The idea was to incorporate the most modern computing tools; use of modular object-oriented computer languages, the most sophisticated linear and nonlinear solvers, parallel computing methods and good visualization tools. {sm_bullet} One of the tasks of the project was also to demonstrate the construction of fractures and faults in a reservoir using the available data and to assign properties to these features. {sm_bullet} Once the reservoir model is in place, it is desirable to find the operating conditions, which would provide the best reservoir performance. This can be accomplished by utilization optimization tools and coupling them with reservoir simulation. Optimization-based reservoir simulation was one of the

  14. Evaluation of an Empirical Reservoir Shape Function to Define Sediment Distributions in Small Reservoirs

    Directory of Open Access Journals (Sweden)

    Bogusław Michalec

    2015-08-01

    Full Text Available Understanding and defining the spatial distribution of sediment deposited in reservoirs is essential not only at the design stage but also during the operation. The majority of research concerns the distribution of sediment deposition in medium and large water reservoirs. Most empirical methods do not provide satisfactory results when applied to the determination of sediment deposition in small reservoirs. Small reservoir’s volumes do not exceed 5 × 106 m3 and their capacity-inflow ratio is less than 10%. Long-term silting measurements of three small reservoirs were used to evaluate the method described by Rahmanian and Banihashemi for predicting sediment distributions in small reservoirs. Rahmanian and Banihashemi stated that their model of distribution of sediment deposition in water reservoir works well for a long duration operation. In the presented study, the silting rate was used in order to determine the long duration operation. Silting rate is a quotient of volume of the sediment deposited in the reservoir and its original volume. It was stated that when the silting rate had reached 50%, the sediment deposition in the reservoir may be described by an empirical reservoir depth shape function (RDSF.

  15. The pollution of the 'iron gate' reservoir

    International Nuclear Information System (INIS)

    Babic-Mladenovic, M.; Varga, S; Popovic, L.; Damjanovic, M.

    2002-01-01

    The paper presents the characteristics of the Iron Gate I (the Djerdap) Water Power and Navigational System, one of the largest in Europe (completed in 1972 by joint efforts of Yugoslavia and Romania). In this paper the attention is devoted to review of the sediment monitoring program and impacts of reservoir sedimentation, as well as to the investigations of water and sediment quality. Special consideration is paid to the issue of sediment pollution research needs. Namely, the hot spot of the 'Iron Gate' sedimentation represents a scarcely known pollution of sediment deposits. The present pollution probably is considerable, since the 'Iron Gate' reservoir drains about 577000 km 2 , with over 80 million inhabitants, and developed municipal and industrial infrastructure. Therefore, in the thirty-year reservoir life various types of sediment-bound pollutants entered and deposited within it. Especially severe incidents happened during 1999 (as a result of NATO bombing campaign) and 2000 (two accidental pollutions in the Tisza river catchment). The study of the 'Iron Gate' reservoir pollution should be prepared in order to enlighten the present state of reservoir sedimentation and pollution. The main objectives of the study are to enhance the government and public awareness of the present environmental state of the 'Iron Gate' reservoir and to serve as a baseline for all future actions. (author)

  16. Inelastic neutron scattering reactions in fluid saturated rock as exploited in oil well logging

    International Nuclear Information System (INIS)

    Underwood, M.C.; Dyos, C.J.

    1986-01-01

    Oil saturated sandstone and limestone targets have been irradiated with 14 MeV neutrons. Gamma-ray spectra were accumulated and the γ-ray intensities arising from inelastic neutron scattering reactions upon carbon and oxygen measured. The results are compared with the predictions of a simple model. They enable some features of the response of (n,γ) tools used in oil well logging to be established and current uncertainties in understanding to be highlighted. (author)

  17. Using Neutron Radiography to Quantify Water Transport and the Degree of Saturation in Entrained Air Cement Based Mortar

    Science.gov (United States)

    Lucero, Catherine L.; Bentz, Dale P.; Hussey, Daniel S.; Jacobson, David L.; Weiss, W. Jason

    Air entrainment is commonly added to concrete to help in reducing the potential for freeze thaw damage. It is hypothesized that the entrained air voids remain unsaturated or partially saturated long after the smaller pores fill with water. Small gel and capillary pores in the cement matrix fill quickly on exposure to water, but larger pores (entrapped and entrained air voids) require longer times or other methods to achieve saturation. As such, it is important to quantitatively determine the water content and degree of saturation in air entrained cementitious materials. In order to further investigate properties of cement-based mortar, a model based on Beer's Law has been developed to interpret neutron radiographs. This model is a powerful tool for analyzing images acquired from neutron radiography. A mortar with a known volume of aggregate, water to cement ratio and degree of hydration can be imaged and the degree of saturation can be estimated.

  18. Interdisciplinary study of reservoir compartments and heterogeneity. Quarterly technical progress report, July 1995--September 1995

    Energy Technology Data Exchange (ETDEWEB)

    Kirk, C.W. Van; Thompson, R.S.

    1995-10-27

    This United States Department of Energy (DOE) research project was established to document the integrated team approach for solving reservoir engineering problems. A field study integrating the disciplines of geology, geophysics, and petroleum engineering will be the mechanism for documenting the integrated approach. This is an area of keen interest to the oil and gas industry. The goal will be to provide tools and approaches that can be used to detect reservoir compartments, reach a better reserve estimate, and improve profits early in the life of a field.

  19. Cross-flow analysis of injection wells in a multilayered reservoir

    Directory of Open Access Journals (Sweden)

    Mohammadreza Jalali

    2016-09-01

    Natural and forced cross-flow is modeled for some injection wells in an oil reservoir located at North Sea. The solution uses a transient implicit finite difference approach for multiple sand layers with different permeabilities separated by impermeable shale layers. Natural and forced cross-flow rates for each reservoir layer during shut-in are calculated and compared with different production logging tool (PLT measurements. It appears that forced cross-flow is usually more prolonged and subject to a higher flow rate when compared with natural cross-flow, and is thus worthy of more detailed analysis.

  20. 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.

  1. Estimation of Oil Production Rates in Reservoirs Exposed to Focused Vibrational Energy

    KAUST Repository

    Jeong, Chanseok

    2014-01-01

    Elastic wave-based enhanced oil recovery (EOR) is being investigated as a possible EOR method, since strong wave motions within an oil reservoir - induced by earthquakes or artificially generated vibrations - have been reported to improve the production rate of remaining oil from existing oil fields. To date, there are few theoretical studies on estimating how much bypassed oil within an oil reservoir could be mobilized by such vibrational stimulation. To fill this gap, this paper presents a numerical method to estimate the extent to which the bypassed oil is mobilized from low to high permeability reservoir areas, within a heterogeneous reservoir, via wave-induced cross-flow oscillation at the interface between the two reservoir permeability areas. This work uses the finite element method to numerically obtain the pore fluid wave motion within a one-dimensional fluid-saturated porous permeable elastic solid medium embedded in a non-permeable elastic semi-infinite solid. To estimate the net volume of mobilized oil from the low to the high permeability area, a fluid flow hysteresis hypothesis is adopted to describe the behavior at the interface between the two areas. Accordingly, the fluid that is moving from the low to the high permeability areas is assumed to transport a larger volume of oil than the fluid moving in the opposite direction. The numerical experiments were conducted by using a prototype heterogeneous oil reservoir model, subjected to ground surface dynamic loading operating at low frequencies (1 to 50 Hz). The numerical results show that a sizeable amount of oil could be mobilized via the elastic wave stimulation. It is observed that certain wave frequencies are more effective than others in mobilizing the remaining oil. We remark that these amplification frequencies depend on the formation’s elastic properties. This numerical work shows that the wave-based mobilization of the bypassed oil in a heterogeneous oil reservoir is feasible, especially

  2. Kinetics of carbonate mineral dissolution in CO2-acidified brines at storage reservoir conditions.

    Science.gov (United States)

    Peng, Cheng; Anabaraonye, Benaiah U; Crawshaw, John P; Maitland, Geoffrey C; Trusler, J P Martin

    2016-10-20

    We report experimental measurements of the dissolution rate of several carbonate minerals in CO 2 -saturated water or brine at temperatures between 323 K and 373 K and at pressures up to 15 MPa. The dissolution kinetics of pure calcite were studied in CO 2 -saturated NaCl brines with molalities of up to 5 mol kg -1 . The results of these experiments were found to depend only weakly on the brine molality and to conform reasonably well with a kinetic model involving two parallel first-order reactions: one involving reactions with protons and the other involving reaction with carbonic acid. The dissolution rates of dolomite and magnesite were studied in both aqueous HCl solution and in CO 2 -saturated water. For these minerals, the dissolution rates could be explained by a simpler kinetic model involving only direct reaction between protons and the mineral surface. Finally, the rates of dissolution of two carbonate-reservoir analogue minerals (Ketton limestone and North-Sea chalk) in CO 2 -saturated water were found to follow the same kinetics as found for pure calcite. Vertical scanning interferometry was used to study the surface morphology of unreacted and reacted samples. The results of the present study may find application in reactive-flow simulations of CO 2 -injection into carbonate-mineral saline aquifers.

  3. Advanced Gas Hydrate Reservoir Modeling Using Rock Physics

    Energy Technology Data Exchange (ETDEWEB)

    McConnell, Daniel

    2017-12-30

    Prospecting for high saturation gas hydrate deposits can be greatly aided with improved approaches to seismic interpretation and especially if sets of seismic attributes can be shown as diagnostic or direct hydrocarbon indicators for high saturation gas hydrates in sands that would be of most interest for gas hydrate production.

    A large 3D seismic data set in the deep water Eastern Gulf of Mexico was screened for gas hydrates using a set of techniques and seismic signatures that were developed and proven in the Central deepwater Gulf of Mexico in the DOE Gulf of Mexico Joint Industry Project JIP Leg II in 2009 and recently confirmed with coring in 2017.

    A large gas hydrate deposit is interpreted in the data where gas has migrated from one of the few deep seated faults plumbing the Jurassic hydrocarbon source into the gas hydrate stability zone. The gas hydrate deposit lies within a flat-lying within Pliocene Mississippi Fan channel that was deposited outboard in a deep abyssal environment. The uniform architecture of the channel aided the evaluation of a set of seismic attributes that relate to attenuation and thin-bed energy that could be diagnostic of gas hydrates. Frequency attributes derived from spectral decomposition also proved to be direct hydrocarbon indicators by pseudo-thickness that could be only be reconciled by substituting gas hydrate in the pore space. The study emphasizes that gas hydrate exploration and reservoir characterization benefits from a seismic thin bed approach.

  4. Electrical conductivity modeling in fractal non-saturated porous media

    Science.gov (United States)

    Wei, W.; Cai, J.; Hu, X.; Han, Q.

    2016-12-01

    The variety of electrical conductivity in non-saturated conditions is important to study electric conduction in natural sedimentary rocks. The electrical conductivity in completely saturated porous media is a porosity-function representing the complex connected behavior of single conducting phases (pore fluid). For partially saturated conditions, the electrical conductivity becomes even more complicated since the connectedness of pore. Archie's second law is an empirical electrical conductivity-porosity and -saturation model that has been used to predict the formation factor of non-saturated porous rock. However, the physical interpretation of its parameters, e.g., the cementation exponent m and the saturation exponent n, remains questionable. On basis of our previous work, we combine the pore-solid fractal (PSF) model to build an electrical conductivity model in non-saturated porous media. Our theoretical porosity- and saturation-dependent models contain endmember properties, such as fluid electrical conductivities, pore fractal dimension and tortuosity fractal dimension (representing the complex degree of electrical flowing path). We find the presented model with non-saturation-dependent electrical conductivity datasets indicate excellent match between theory and experiments. This means the value of pore fractal dimension and tortuosity fractal dimension change from medium to medium and depends not only on geometrical properties of pore structure but also characteristics of electrical current flowing in the non-saturated porous media.

  5. Correcting saturation of detectors for particle/droplet imaging methods

    International Nuclear Information System (INIS)

    Kalt, Peter A M

    2010-01-01

    Laser-based diagnostic methods are being applied to more and more flows of theoretical and practical interest and are revealing interesting new flow features. Imaging particles or droplets in nephelometry and laser sheet dropsizing methods requires a trade-off of maximized signal-to-noise ratio without over-saturating the detector. Droplet and particle imaging results in lognormal distribution of pixel intensities. It is possible to fit a derived lognormal distribution to the histogram of measured pixel intensities. If pixel intensities are clipped at a saturated value, it is possible to estimate a presumed probability density function (pdf) shape without the effects of saturation from the lognormal fit to the unsaturated histogram. Information about presumed shapes of the pixel intensity pdf is used to generate corrections that can be applied to data to account for saturation. The effects of even slight saturation are shown to be a significant source of error on the derived average. The influence of saturation on the derived root mean square (rms) is even more pronounced. It is found that errors on the determined average exceed 5% when the number of saturated samples exceeds 3% of the total. Errors on the rms are 20% for a similar saturation level. This study also attempts to delineate limits, within which the detector saturation can be accurately corrected. It is demonstrated that a simple method for reshaping the clipped part of the pixel intensity histogram makes accurate corrections to account for saturated pixels. These outcomes can be used to correct a saturated signal, quantify the effect of saturation on a derived average and offer a method to correct the derived average in the case of slight to moderate saturation of pixels

  6. Determination of diagnostic standards on saturated soil extracts for cut roses grown in greenhouses.

    Science.gov (United States)

    Franco-Hermida, John Jairo; Quintero, María Fernanda; Cabrera, Raúl Iskander; Guzman, José Miguel

    2017-01-01

    This work comprises the theoretical determination and validation of diagnostic standards for the analysis of saturated soil extracts for cut rose flower crops (Rosa spp.) growing in the Bogota Plateau, Colombia. The data included 684 plant tissue analyses and 684 corresponding analyses of saturated soil extracts, all collected between January 2009 and June 2013. The tissue and soil samples were selected from 13 rose farms, and from cultivars grafted on the 'Natal Briar' rootstock. These concurrent samples of soil and plant tissues represented 251 production units (locations) of approximately 10,000 m2 distributed across the study area. The standards were conceived as a tool to improve the nutritional balance in the leaf tissue of rose plants and thereby define the norms for expressing optimum productive potential relative to nutritional conditions in the soil. To this end, previously determined diagnostic standard for rose leaf tissues were employed to obtain rates of foliar nutritional balance at each analyzed location and as criteria for determining the diagnostic norms for saturated soil extracts. Implementing this methodology to foliar analysis, showed a higher significant correlation for diagnostic indices. A similar behavior was observed in saturated soil extracts analysis, becoming a powerful tool for integrated nutritional diagnosis. Leaf analyses determine the most limiting nutrients for high yield and analyses of saturated soil extracts facilitate the possibility of correcting the fertigation formulations applied to soils or substrates. Recommendations are proposed to improve the balance in soil-plant system with which the possibility of yield increase becomes more probable. The main recommendations to increase and improve rose crop flower yields would be: continuously check pH values of SSE, reduce the amounts of P, Fe, Zn and Cu in fertigation solutions and carefully analyze the situation of Mn in the soil-plant system.

  7. Nuclear Well Log Properties of Natural Gas Hydrate Reservoirs

    Science.gov (United States)

    Burchwell, A.; Cook, A.

    2015-12-01

    Characterizing gas hydrate in a reservoir typically involves a full suite of geophysical well logs. The most common method involves using resistivity measurements to quantify the decrease in electrically conductive water when replaced with gas hydrate. Compressional velocity measurements are also used because the gas hydrate significantly strengthens the moduli of the sediment. At many gas hydrate sites, nuclear well logs, which include the photoelectric effect, formation sigma, carbon/oxygen ratio and neutron porosity, are also collected but often not used. In fact, the nuclear response of a gas hydrate reservoir is not known. In this research we will focus on the nuclear log response in gas hydrate reservoirs at the Mallik Field at the Mackenzie Delta, Northwest Territories, Canada, and the Gas Hydrate Joint Industry Project Leg 2 sites in the northern Gulf of Mexico. Nuclear logs may add increased robustness to the investigation into the properties of gas hydrates and some types of logs may offer an opportunity to distinguish between gas hydrate and permafrost. For example, a true formation sigma log measures the thermal neutron capture cross section of a formation and pore constituents; it is especially sensitive to hydrogen and chlorine in the pore space. Chlorine has a high absorption potential, and is used to determine the amount of saline water within pore spaces. Gas hydrate offers a difference in elemental composition compared to water-saturated intervals. Thus, in permafrost areas, the carbon/oxygen ratio may vary between gas hydrate and permafrost, due to the increase of carbon in gas hydrate accumulations. At the Mallik site, we observe a hydrate-bearing sand (1085-1107 m) above a water-bearing sand (1107-1140 m), which was confirmed through core samples and mud gas analysis. We observe a decrease in the photoelectric absorption of ~0.5 barnes/e-, as well as an increase in the formation sigma readings of ~5 capture units in the water-bearing sand as

  8. Fractal analysis of fracture increasing spontaneous imbibition in porous media with gas-saturated

    KAUST Repository

    Cai, Jianchao; Sun, Shuyu

    2013-01-01

    Spontaneous imbibition (SI) of wetting liquid into matrix blocks due to capillary pressure is regarded as an important recovery mechanism in low permeability fractured reservoir. In this paper, an analytical model is proposed for characterizing SI horizontally from a single plane fracture into gas-saturated matrix blocks. The presented model is based on the fractal character of pores in porous matrix, with gravity force included in the entire imbibition process. The accumulated mass of wetting liquid imbibed into matrix blocks is related to a number of factors such as contact area, pore fractal dimension, tortuosity, maximum pore size, porosity, liquid density and viscosity, surface tension, contact angle, as well as height and tilt angle of the fracture. The mechanism of fracture-enhanced SI is analyzed accordingly. Because of the effect of fracture, the gravity force is positive to imbibition process. Additionally, the farther away from the fracture top of the pore, the more influential the hydrostatic pressure is upon the imbibition action. The presented fractal analysis of horizontal spontaneous imbibition from a single fracture could also shed light on the scaling study of the mass transfer function between matrix and fracture system of fractured reservoirs. © 2013 World Scientific Publishing Company.

  9. Fractal analysis of fracture increasing spontaneous imbibition in porous media with gas-saturated

    KAUST Repository

    Cai, Jianchao

    2013-08-01

    Spontaneous imbibition (SI) of wetting liquid into matrix blocks due to capillary pressure is regarded as an important recovery mechanism in low permeability fractured reservoir. In this paper, an analytical model is proposed for characterizing SI horizontally from a single plane fracture into gas-saturated matrix blocks. The presented model is based on the fractal character of pores in porous matrix, with gravity force included in the entire imbibition process. The accumulated mass of wetting liquid imbibed into matrix blocks is related to a number of factors such as contact area, pore fractal dimension, tortuosity, maximum pore size, porosity, liquid density and viscosity, surface tension, contact angle, as well as height and tilt angle of the fracture. The mechanism of fracture-enhanced SI is analyzed accordingly. Because of the effect of fracture, the gravity force is positive to imbibition process. Additionally, the farther away from the fracture top of the pore, the more influential the hydrostatic pressure is upon the imbibition action. The presented fractal analysis of horizontal spontaneous imbibition from a single fracture could also shed light on the scaling study of the mass transfer function between matrix and fracture system of fractured reservoirs. © 2013 World Scientific Publishing Company.

  10. Bayesian inversion of seismic and electromagnetic data for marine gas reservoir characterization using multi-chain Markov chain Monte Carlo sampling

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Huiying; Ray, Jaideep; Hou, Zhangshuan; Huang, Maoyi; Bao, Jie; Swiler, Laura

    2017-12-01

    In this study we developed an efficient Bayesian inversion framework for interpreting marine seismic amplitude versus angle (AVA) and controlled source electromagnetic (CSEM) data for marine reservoir characterization. The framework uses a multi-chain Markov-chain Monte Carlo (MCMC) sampler, which is a hybrid of DiffeRential Evolution Adaptive Metropolis (DREAM) and Adaptive Metropolis (AM) samplers. The inversion framework is tested by estimating reservoir-fluid saturations and porosity based on marine seismic and CSEM data. The multi-chain MCMC is scalable in terms of the number of chains, and is useful for computationally demanding Bayesian model calibration in scientific and engineering problems. As a demonstration, the approach is used to efficiently and accurately estimate the porosity and saturations in a representative layered synthetic reservoir. The results indicate that the seismic AVA and CSEM joint inversion provides better estimation of reservoir saturations than the seismic AVA-only inversion, especially for the parameters in deep layers. The performance of the inversion approach for various levels of noise in observational data was evaluated – reasonable estimates can be obtained with noise levels up to 25%. Sampling efficiency due to the use of multiple chains was also checked and was found to have almost linear scalability.

  11. Bayesian inversion of seismic and electromagnetic data for marine gas reservoir characterization using multi-chain Markov chain Monte Carlo sampling

    International Nuclear Information System (INIS)

    Ren, Huiying; Ray, Jaideep; Hou, Zhangshuan; Huang, Maoyi; Bao, Jie; Swiler, Laura

    2017-01-01

    In this paper we developed an efficient Bayesian inversion framework for interpreting marine seismic Amplitude Versus Angle and Controlled-Source Electromagnetic data for marine reservoir characterization. The framework uses a multi-chain Markov-chain Monte Carlo sampler, which is a hybrid of DiffeRential Evolution Adaptive Metropolis and Adaptive Metropolis samplers. The inversion framework is tested by estimating reservoir-fluid saturations and porosity based on marine seismic and Controlled-Source Electromagnetic data. The multi-chain Markov-chain Monte Carlo is scalable in terms of the number of chains, and is useful for computationally demanding Bayesian model calibration in scientific and engineering problems. As a demonstration, the approach is used to efficiently and accurately estimate the porosity and saturations in a representative layered synthetic reservoir. The results indicate that the seismic Amplitude Versus Angle and Controlled-Source Electromagnetic joint inversion provides better estimation of reservoir saturations than the seismic Amplitude Versus Angle only inversion, especially for the parameters in deep layers. The performance of the inversion approach for various levels of noise in observational data was evaluated — reasonable estimates can be obtained with noise levels up to 25%. Sampling efficiency due to the use of multiple chains was also checked and was found to have almost linear scalability.