WorldWideScience

Sample records for underlying rock formations

  1. A 3-D wellbore simulator (WELLTHER-SIM) to determine the thermal diffusivity of rock-formations

    Science.gov (United States)

    Wong-Loya, J. A.; Santoyo, E.; Andaverde, J.

    2017-06-01

    Acquiring thermophysical properties of rock-formations in geothermal systems is an essential task required for the well drilling and completion. Wellbore thermal simulators require such properties for predicting the thermal behavior of a wellbore and the formation under drilling and shut-in conditions. The estimation of static formation temperatures also needs the use of these properties for the wellbore and formation materials (drilling fluids and pipes, cements, casings, and rocks). A numerical simulator (WELLTHER-SIM) has been developed for modeling the drilling fluid circulation and shut-in processes of geothermal wellbores, and for the in-situ determination of thermal diffusivities of rocks. Bottomhole temperatures logged under shut-in conditions (BHTm), and thermophysical and transport properties of drilling fluids were used as main input data. To model the thermal disturbance and recovery processes in the wellbore and rock-formation, initial drilling fluid and static formation temperatures were used as initial and boundary conditions. WELLTHER-SIM uses these temperatures together with an initial thermal diffusivity for the rock-formation to solve the governing equations of the heat transfer model. WELLTHER-SIM was programmed using the finite volume technique to solve the heat conduction equations under 3-D and transient conditions. Thermal diffusivities of rock-formations were inversely computed by using an iterative and efficient numerical simulation, where simulated thermal recovery data sets (BHTs) were statistically compared with those temperature measurements (BHTm) logged in some geothermal wellbores. The simulator was validated using a well-documented case reported in the literature, where the thermophysical properties of the rock-formation are known with accuracy. The new numerical simulator has been successfully applied to two wellbores drilled in geothermal fields of Japan and Mexico. Details of the physical conceptual model, the numerical

  2. Rock pushing and sampling under rocks on Mars

    Science.gov (United States)

    Moore, H.J.; Liebes, S.; Crouch, D.S.; Clark, L.V.

    1978-01-01

    Viking Lander 2 acquired samples on Mars from beneath two rocks, where living organisms and organic molecules would be protected from ultraviolet radiation. Selection of rocks to be moved was based on scientific and engineering considerations, including rock size, rock shape, burial depth, and location in a sample field. Rock locations and topography were established using the computerized interactive video-stereophotogrammetric system and plotted on vertical profiles and in plan view. Sampler commands were developed and tested on Earth using a full-size lander and surface mock-up. The use of power by the sampler motor correlates with rock movements, which were by plowing, skidding, and rolling. Provenance of the samples was determined by measurements and interpretation of pictures and positions of the sampler arm. Analytical results demonstrate that the samples were, in fact, from beneath the rocks. Results from the Gas Chromatograph-Mass Spectrometer of the Molecular Analysis experiment and the Gas Exchange instrument of the Biology experiment indicate that more adsorbed(?) water occurs in samples under rocks than in samples exposed to the sun. This is consistent with terrestrial arid environments, where more moisture occurs in near-surface soil un- der rocks than in surrounding soil because the net heat flow is toward the soil beneath the rock and the rock cap inhibits evaporation. Inorganic analyses show that samples of soil from under the rocks have significantly less iron than soil exposed to the sun. The scientific significance of analyses of samples under the rocks is only partly evaluated, but some facts are clear. Detectable quantities of martian organic molecules were not found in the sample from under a rock by the Molecular Analysis experiment. The Biology experiments did not find definitive evidence for Earth-like living organisms in their sample. Significant amounts of adsorbed water may be present in the martian regolith. The response of the soil

  3. Representation and judgement of possible host rock formations and areas under consideration of geology and safety

    International Nuclear Information System (INIS)

    2005-08-01

    This comprehensive report issued by the Swiss National Cooperative for the Disposal of Radioactive Waste NAGRA takes a look at the representation and judgement of possible host rock formations and areas as far as safety and geological aspects are concerned. Nagra has to demonstrate the basic feasibility of the safe disposal of spent fuel (SF), vitrified high-level waste (HLW) and long-lived intermediate-level waste (ILW) in a deep geological repository, The report shows which possibilities for the disposal of SF, HLW and ILW exist in Switzerland and summarises the current state of general academic and applied geo-scientific research as well as the project-specific knowledge base that has been developed by Nagra over the past 30 years. The descriptions and assessments of the potential host rocks and areas are based on attributes that take into account experience gained both in Switzerland and abroad and are in agreement with international practice. An assessment of potential siting areas is looked at, in view of the preparation of a General Licence application, Nagra will also have to consider land-use planning and socio-economic aspects. This will be carried out in the next step according to the Sectoral Plan for Geological Disposal under the guidance of the relevant Swiss authorities

  4. Dust input in the formation of rock varnish from the Dry Valleys (Antarctica)

    Science.gov (United States)

    Zerboni, A.; Guglielmin, M.

    2017-12-01

    Rock varnish is a glossy, yellowish to dark brown coating that covers geomorphically stable, aerially exposed rock surfaces and landforms in warm and cold arid lands. In warm deserts, rock varnish consists of clay minerals, Mn-Fe oxides/hydroxides, and Si+alkalis dust; it occasionally containis sulphates, phosphates, and organic remains. In Antarctica, rock varnish developed on a variety of bedrocks and has been described being mostly formed of Si, Al, Fe, and sulphates, suggesting a double process in its formation, including biomineralization alternated to dust accretion. We investigated rock coatings developed on sandstones outcropping in the Dry Valleys of Antarctica and most of the samples highlithed an extremely complex varnish structure, alternating tihn layer of different chemical compostion. Optical microscope evidenced the occurrence of highly birefringent minerals, occasionally thinly laminated and consisitng of Si and Al-rich minerals (clays). These are interlayered by few micron-thick dark lenses and continous layers. The latter are well evident under the scanning electron microscope and chemical analysis confirmed that they consist of different kinds of sulphates; jarosite is the most represented species, but gypsum crystals were also found. Fe-rich hypocoatings and intergranula crusts were also detected, sometimes preserving the shape of the hyphae they have replaced. Moreover, small weathering pits on sandstone surface display the occurrence of an amorphous, dark Mn/Fe-rich rock varnish. The formation of rock varnish in the Dry Valleys is a complex process, which required the accretion of airborne dust of variable composition and subsequent recrystallization of some constituent, possibly promoted by microorganisms. In particualr, the formation of sulphates seems to preserve the memory of S-rich dust produced by volcanic eruptions. On the contrary, the formation of Mn-rich varnish should be in relation with the occurrence of higher environmental

  5. Rock burst governance of working face under igneous rock

    Science.gov (United States)

    Chang, Zhenxing; Yu, Yue

    2017-01-01

    As a typical failure phenomenon, rock burst occurs in many mines. It can not only cause the working face to cease production, but also cause serious damage to production equipment, and even result in casualties. To explore how to govern rock burst of working face under igneous rock, the 10416 working face in some mine is taken as engineering background. The supports damaged extensively and rock burst took place when the working face advanced. This paper establishes the mechanical model and conducts theoretical analysis and calculation to predict the fracture and migration mechanism and energy release of the thick hard igneous rock above the working face, and to obtain the advancing distance of the working face when the igneous rock fractures and critical value of the energy when rock burst occurs. Based on the specific conditions of the mine, this paper put forward three kinds of governance measures, which are borehole pressure relief, coal seam water injection and blasting pressure relief.

  6. The formation of technic soil in a revegetated uranium ore waste rock pile (Limousin, France)

    Science.gov (United States)

    Boekhout, Flora; Gérard, Martine; Kanzari, Aisha; Calas, Georges; Descostes, Michael

    2014-05-01

    Mining took place in France between 1945 and 2001 during which time ~210 different sites were exploited and/or explored. A total of 76 Kt of uranium was produced, 52 Mt of ore was extracted, but also 200 Mt of waste rocks was produced, the majority of which, with uranium levels corresponding to the natural environment. So far, the processes of arenisation and technic soil formation in waste rock piles are not well understood but have important implications for understanding the environmental impact and long-term speciation of uranium. Understanding weathering processes in waste rock piles is essential to determine their environmental impact. The main objectives of this work are to assess 1) the micromorphological features and neo-formed U-bearing phases related to weathering and 2) the processes behind arenisation of the rock pile. The site that was chosen is the Vieilles Sagnes waste rock pile in Fanay (Massif Central France) that represents more or less hydrothermally altered granitic rocks that have been exposed to weathering since the construction of the waste rock pile approximately 50 years ago. Two trenches were excavated to investigate the vertical differentiation of the rock pile. This site serves as a key location for studying weathering processes of waste rock piles, as it has not been reworked after initial construction and has therefore preserved information on the original mineralogy of the waste rock pile enabling us to access post emplacement weathering processes. The site is currently overgrown by moss, meter high ferns and small trees. At present day the rock pile material can be described as hydrothermally altered rocks and rock fragments within a fine-grained silty clay matrix exposed to surface conditions and weathering. A sandy "paleo" technic soil underlies the waste rock pile and functions as a natural liner by adsorption of uranium on clay minerals. Post-mining weathering of rock-pile material is superimposed on pre-mining hydrothermal and

  7. The Rapid Formation of Localized Compaction Bands Under Hydrostatic Load Leading to Pore-pressure Transients in Compacting Rocks

    Science.gov (United States)

    Faulkner, D.; Leclere, H.; Bedford, J. D.; Behnsen, J.; Wheeler, J.

    2017-12-01

    Compaction of porous rocks can occur uniformly or within localized deformation bands. The formation of compaction bands and their effects on deformation behaviour are poorly understood. Porosity may be primary and compaction can occur with burial, or it can be produced by metamorphic reactions with a solid volume reduction, that can then undergo collapse. We report results from hydrostatic compaction experiments on porous bassanite (CaSO4.0.5H2O) aggregates. Gypsum (CaSO4.2H2O) is first dehydrated under low effective pressure, 4 MPa, to produce a bassanite aggregate with a porosity of 27%. Compaction is induced by increasing confining pressure at rates from 0.001 MPa/s to 0.02 MPa/s while the sample is maintained at a temperature of 115°C. At slow compaction rates, porosity collapse proceeds smoothly. At higher compaction rates, sudden increases in the pore-fluid pressure occur with a magnitude of 5 MPa. Microstructural investigations using X-ray microtomography and SEM observations show that randomly oriented localized compaction features occur in all samples, where the bulk porosity of 18% outside the band is reduced to 5% inside the band. Previous work on deformation bands has suggested that localized compactive features only form under an elevated differential stress and not under a hydrostatic stress state. The magnitude of the pore-pressure pulses can be explained by the formation of compaction bands. The results indicate that the compaction bands can form by rapid (unstable) propagation across the sample above a critical strain rate, or quasi-statically at low compaction rates without pore-fluid pressure bursts. The absence of pore-fluid pressure bursts at slow compaction rates can be explained by viscous deformation of the bassanite aggregate around the tip of a propagating compaction band, relaxing stress, and promoting stable propagation. Conversely, at higher compaction rates, viscous deformation cannot relax the stress sufficiently and unstable

  8. Rock strength under explosive loading

    International Nuclear Information System (INIS)

    Rimer, N.; Proffer, W.

    1993-01-01

    This presentation emphasizes the importance of a detailed description of the nonlinear deviatoric (strength) response of the surrounding rock in the numerical simulation of underground nuclear explosion phenomenology to the late times needed for test ban monitoring applications. We will show how numerical simulations which match ground motion measurements in volcanic tuffs and in granite use the strength values obtained from laboratory measurements on small core samples of these rocks but also require much lower strength values after the ground motion has interacted with the rock. The underlying physical mechanisms for the implied strength reduction are not yet well understood, and in fact may depend on the particular rock type. However, constitutive models for shock damage and/or effective stress have been used successfully at S-Cubed in both the Geophysics Program (primarily for DARPA) and the Containment Support Program (for DNA) to simulate late time ground motions measured at NTS in many different rock types

  9. ADDIGAS. Advective and diffusive gas transport in rock salt formations. Final report

    International Nuclear Information System (INIS)

    Jockwer, Norbert; Wieczorek, Klaus

    2008-04-01

    Beside granite and clay formations also rock salt is investigated as potential host rock for the disposal or radioactive waste. As a result of the mining activities the stress and strain state is changed which leads to dilatancy (i.e., volume increase, manly caused by microfracturing) in the vicinity of the excavations. The affected area is termed as Excavation Disturbed Zone (EDZ) and is characterized by an increased porosity and permeability with micro- and potential macrofractures. For the radioactive waste disposal in a geologic formation the properties of the EDZ with its permeability, extent, and evolution with time is of importance especially for the construction and building of geotechnical barriers. In the recent years the EDZ in rock salt formations was investigated at GRS in the frame of various projects. Main subjects of these projects were the characterisation of the EDZ with regard to its extent, hydraulic behaviour and possible healing at the in-situ stress conditions. The main emphasis of the ADDIGAS project reported here was the evolution of the EDZ after cutting off the drift contour, the anisotropy of permeability, and the diffusive gas transport which had not been investigated in earlier projects. Moreover, an constitutive model for calculating EDZ behaviour which had been developed in the frame of the BAMBUS II project was tested. The experimental work was performed on the 800-m level of the ASSe salt mine. The project ran from 2004 to 2007 and was funded by German Ministry of Economics and Labour (BMWA) under the contract No. 02 E 9924. The modelling work was co-funded by the CEC in the frame of the Integrated Project NF-PRO under contract no. F16W-CT-2003-002389. (orig.)

  10. Petrological-geochemical characteristics of coarse-grained clastic sedimentary rocks of Quantou Formation, Cretaceous in Songliao basin and their geological significance

    International Nuclear Information System (INIS)

    Wang Gan; Zhang Bangtong

    2005-01-01

    Clastic sedimentary rocks of Quantou Formation, Cretaceous in Qing-an area, Songliao basin are mainly composed of sandstone, mudstone and siltstone. The petrological-chemical analysis of clastic sedimentary rocks from Quantou Formation, Cretaceous indicates that their lithology mainly consists of arkose, shale and minor rock debris sandstone and greywacke by chemical classification of bulk elements. REE distribution pattern displays the apparent enrichment of LREE and negative anomaly of Eu and is similar to that of NASC and PAAS. The ratio of trace-element in sedimentary rocks to that of upper crust shows gentle character. All the above features indicate that these sedimentary rocks were slowly deposited under weakly active tectonic setting. They are sediments typical for passive continental margin and active continental margin. It is suggested that material source of clastic sediments of Quantou Formation, Cretaceous in Qing-an area, Songliao basin was originated from Hercynian granite of Zhangguangchai Mountain, and the granite was originated from upper crust. (authors)

  11. Hydrocarbon Source Rock Potential of the Sinamar Formation, Muara Bungo, Jambi

    Directory of Open Access Journals (Sweden)

    Moh. Heri Hermiyanto Zajuli

    2014-07-01

    Full Text Available DOI: 10.17014/ijog.v1i1.175The Oligocene Sinamar Formation consists of shale, claystone, mudstone, sandstone, conglomeratic sandstone, and intercalation of coal seams. The objective of study was to identify the hydrocarbon source rock potential of the Sinamar Formation based on geochemichal characteristics. The analyses were focused on fine sediments of the Sinamar Formation comprising shale, claystone, and mudstone. Primary data collected from the Sinamar Formation well and outcrops were analyzed according to TOC, pyrolisis analysis, and gas chromatography - mass spectometry of normal alkanes that include isoprenoids and sterane. The TOC value indicates a very well category. Based on TOC versus Pyrolysis Yields (PY diagram, the shales of Sinamar Formation are included into oil prone source rock potential with good to excellent categories. Fine sediments of the Sinamar Formation tend to produce oil and gas originated from kerogen types I and III. The shales tend to generate oil than claystone and mudstone and therefore they are included into a potential source rock

  12. Research into basic rocks types

    International Nuclear Information System (INIS)

    1993-06-01

    Teollisuuden Voima Oy (TVO) has carried out research into basic rock types in Finland. The research programme has been implemented in parallel with the preliminary site investigations for radioactive waste disposal in 1991-1993. The program contained two main objectives: firstly, to study the properties of the basic rock types and compare those with the other rock types under the investigation; secondly, to carry out an inventory of rock formations consisting of basic rock types and suitable in question for final disposal. A study of environmental factors important to know regarding the final disposal was made of formations identified. In total 159 formations exceeding the size of 4 km 2 were identified in the inventory. Of these formations 97 were intrusive igneous rock types and 62 originally extrusive volcanic rock types. Deposits consisting of ore minerals, industrial minerals or building stones related to these formations were studied. Environmental factors like natural resources, protected areas or potential for restrictions in land use were also studied

  13. Whole-rock U-Pb dating of the Shuijingtuo formation sedimentary rocks in the Yangtze Gorge

    International Nuclear Information System (INIS)

    Zheng, Y.F.; Huang, B.

    1990-01-01

    Black shale and enclosed limestone lenticule from Lower Cambrian Shuijingtuo Formation in the Yangtze Gorge is successfully dated by whole-rock U-Pb method. The results yield a concordant age of about 573±14 Ma, in excellent agreement with both stratigraphic and palaeontologic evidence. The whole-rock U-Pb method can provide a reliable approach for age determination of sedimentary stratum. (orig.) [de

  14. Integrated system for investigating sub-surface features of a rock formation

    Science.gov (United States)

    Vu, Cung Khac; Skelt, Christopher; Nihei, Kurt; Johnson, Paul A.; Guyer, Robert; Ten Cate, James A.; Le Bas, Pierre -Yves; Larmat, Carene S.

    2015-08-18

    A system for investigating non-linear properties of a rock formation around a borehole is provided. The system includes a first sub-system configured to perform data acquisition, control and recording of data; a second subsystem in communication with the first sub-system and configured to perform non-linearity and velocity preliminary imaging; a third subsystem in communication with the first subsystem and configured to emit controlled acoustic broadcasts and receive acoustic energy; a fourth subsystem in communication with the first subsystem and the third subsystem and configured to generate a source signal directed towards the rock formation; and a fifth subsystem in communication with the third subsystem and the fourth subsystem and configured to perform detection of signals representative of the non-linear properties of the rock formation.

  15. Uranium mineralization in tertiary volcanic rocks of the Los Frailes formation (Bolivia)

    International Nuclear Information System (INIS)

    Aparicio, A.

    1981-01-01

    The Los Frailes Formation, a 9000 km 2 area of Miocene-Pliocene age, contains uranium mineralization in acid tuffs, ignimbrites and lavas. Uranium also occurs in sedimentary rocks of various types and ages which outcrop in adjacent areas. So far the most extensive mineralization seems to be confined in volcanic pyroclastic rocks. Although the surface mineralization varies in grade from 0.01% to more than 2.5%, the average grade in the only deposit being mined (Cotaje) is 0.05% of U 3 O 8 . On the basis of the available data it is believed that certain leaching processes, during the last erosion cycle (Pliocene-Pleistocene) and under very humid conditions, brought about the mobilization of the uranium from the volcanic rocks in aqueous alkaline and calco-alkaline solutions circulating on the surface and underground. Uranium minerals were deposited, generally by chemical reduction, in tectonic zones and/or zones of high porosity. The common metallogenetic model in the western area, defined as the 'Sevaruyo uraniferous district', is exogenic and is characterized by epigenetic uranium occurrences and deposits formed by supergene enrichment. On the basis of their mechanism of formation, control of mineralization and mineral associations, these deposits are classified according to: those with strictly tectonic control, those with sedimentary control and those of mixed genetics. Recent discoveries in the eastern area of the volcanic complex give evidence of epigenetic mineralization, apparently linked with hypogene hydrothermal processes, in addition to exogenic mineralizations contained in rocks stratigraphically subjacent to the Los Frailes Formation. There is no intention of making an evaluation of the recently discovered resources since the studies and exploration are still at too early a stage to warrant prediction of their real potential. (author)

  16. Growing Pebbles and Conceptual Prisms - Understanding the Source of Student Misconceptions about Rock Formation.

    Science.gov (United States)

    Kusnick, Judi

    2002-01-01

    Analyzes narrative essays--stories of rock formation--written by pre-service elementary school teachers. Reports startling misconceptions among preservice teachers on pebbles that grow, human involvement in rock formation, and sedimentary rocks forming as puddles as dry up, even though these students had completed a college level course on Earth…

  17. Survey on the characteristics of rock under low and high temperature

    International Nuclear Information System (INIS)

    Shin, Koich; Kitano, Koichi

    1987-01-01

    Rock caverns for Superconducting Magnetic Energy Storage (SMES), Radioactive Waste Disposal, or Liquified Natural Gas Storage will suffer extraordinary temperature. Therefore, authors have researched the rock characteristics under the low temperature conditions and the rock mass behavior when it is heated, by papers so far reported. As a result, rock characteristics such as strength, linear expansion coefficient, thermal conductivity etc. are found to be ready to change with temperature condition and the kind of rocks. Even an anisotropy of some kind appears under some conditions. So, when sitting those facilities before mentioned, rock characteristics under each temperature condition must be enough clarified for the purpose of the evaluation of rock cavern stability and especially, rock behavior when it is loaded dynamically under low temperature must be cleared from now on, for such studies have been few. (author)

  18. Simulation of CO2–water–rock interactions on geologic CO2 sequestration under geological conditions of China

    International Nuclear Information System (INIS)

    Wang, Tianye; Wang, Huaiyuan; Zhang, Fengjun; Xu, Tianfu

    2013-01-01

    Highlights: • We determined the feasibilities of geologic CO 2 sequestration in China. • We determined the formation of gibbsite suggested CO 2 can be captured by rocks. • We suggested the mechanisms of CO 2 –water–rock interactions. • We found the corrosion and dissolution of the rock increased as temperature rose. -- Abstract: The main purpose of this study focused on the feasibility of geologic CO 2 sequestration within the actual geological conditions of the first Carbon Capture and Storage (CCS) project in China. This study investigated CO 2 –water–rock interactions under simulated hydrothermal conditions via physicochemical analyses and scanning electron microscopy (SEM). Mass loss measurement and SEM showed that corrosion of feldspars, silica, and clay minerals increased with increasing temperature. Corrosion of sandstone samples in the CO 2 -containing fluid showed a positive correlation with temperature. During reaction at 70 °C, 85 °C, and 100 °C, gibbsite (an intermediate mineral product) formed on the sample surface. This demonstrated mineral capture of CO 2 and supported the feasibility of geologic CO 2 sequestration. Chemical analyses suggested a dissolution–reprecipitation mechanism underlying the CO 2 –water–rock interactions. The results of this study suggested that mineral dissolution, new mineral precipitation, and carbonic acid formation-dissociation are closely interrelated in CO 2 –water–rock interactions

  19. Transport of suspended matter through rock formations

    International Nuclear Information System (INIS)

    Wahlig, B.G.

    1980-01-01

    It may be hypothesized that significant quantities of some waste nuclides could be adsorbed on the surfaces of particles suspended in the flowing groundwater and thereby migrate farther or faster than they would in dissolved form. This thesis deals with one aspect of this proposed migration mechanism, the transport of suspended matter through rock formations. A theoretical examination of the forces effecting suspended particles in flowing groundwater indicates that only two interaction energies are likely to be significant compared to the particles' thermal energies. The responsible interactions are van der Waals attraction between the particles and the rock, and electrolytic double-layer repulsion between the atmospheres of ions near the surfaces of the particles and the rock. This theoretical understanding was tested in column flow adsorption experiments using fine kaolin particles as the suspended matter and crushed basalt as the rock medium. The effects of several parameters on kaolin mobility were explored, including the influences of the following: solution ion concentration, solution cation valence, degree of solution oxygen saturation, solution flow velocity, and degree of rock surface ageing. The experimental results indicate that the migration of suspended matter over kilometer distances in the lithosphere is very unlikely unless the average pore size of the conducting mediumis fairly large (> 1mm), or the flow occurs in large fractures

  20. Radioactivity of rocks from the geological formations belonging to the Tibagi River hydrographic basin

    International Nuclear Information System (INIS)

    Bastos, Rodrigo Oliveira

    2008-01-01

    This work is a study of the 40 K and the 238 U and 232 Th series radioactivity in rocks measured with high resolution gamma ray spectrometry. The rocks were taken from the geologic formations in the region of the Tibagi river hydrographic basin. The course of this river cuts through the Paleozoic and Mesozoic stratigraphic sequences of the Parana sedimentary basin. In order to take into account the background radiation attenuation by the samples, a technique was developed that eliminated the need to measure a blank sample. The effects of the radiation's self-attenuation in the sample matrix were taken into account by using a gamma ray direct transmission method. The results for 87 rock samples, taken from 14 distinct formations, and their corresponding radioactivity variations are presented and discussed according to the possible geological processes from which they originated. Among the most discussed results are: an outcrop that profiles shale, limestone and rhythmite in the Irati Formation; a sandstone and siltstone sequence from the Rio do Rasto Formation; and a profile sampled in a coal mine located in the Rio Bonito Formation. The calculations of the rocks' contributions to the outdoor gamma radiation dose rate agree with the values presented by other authors for similar rocks. The highest dose values were obtained from felsic rocks (rhyolite of the Castro group, 129.8 ± 3.7 nGy.h -1 , and Cunhaporanga granite, 167 ± 37 nGy.h -1 ). The other highest values correspond to the shale rocks from the Irati Formation (109 ± 16 nGy.h -1 ) and the siltic shale rocks from the Ponta Grossa Formation (107.9 ± 0.7 nGy.h -1 ). The most recent geological formations presented the lowest dose values (e.g. the Botucatu sandstone, 3.3 ± 0.6 nGy.h -1 ). The average value for sedimentary rocks from seven other formations is equal to 59 ± 26 nGy.h -1 . The Rio Bonito Formation presented the highest dose value (334 ± 193 nGy.h -1 ) mainly due to the anomalous 226 Ra

  1. THM-coupled modeling of selected processes in argillaceous rock relevant to rock mechanics

    International Nuclear Information System (INIS)

    Czaikowski, Oliver

    2012-01-01

    Scientific investigations in European countries other than Germany concentrate not only on granite formations (Switzerland, Sweden) but also on argillaceous rock formations (France, Switzerland, Belgium) to assess their suitability as host and barrier rock for the final storage of radioactive waste. In Germany, rock salt has been under thorough study as a host rock over the past few decades. According to a study by the German Federal Institute for Geosciences and Natural Resources, however, not only salt deposits but also argillaceous rock deposits are available at relevant depths and of extensions in space which make final storage of high-level radioactive waste basically possible in Germany. Equally qualified findings about the suitability/unsuitability of non-saline rock formations require fundamental studies to be conducted nationally because of the comparatively low level of knowledge. The article presents basic analyses of coupled mechanical and hydraulic properties of argillaceous rock formations as host rock for a repository. The interaction of various processes is explained on the basis of knowledge derived from laboratory studies, and open problems are deduced. For modeling coupled processes, a simplified analytical computation method is proposed and compared with the results of numerical simulations, and the limits to its application are outlined. (orig.)

  2. Evolution Procedure of Multiple Rock Cracks under Seepage Pressure

    Directory of Open Access Journals (Sweden)

    Taoying Liu

    2013-01-01

    Full Text Available In practical geotechnical engineering, most of rock masses with multiple cracks exist in water environment. Under such circumstance, these adjacent cracks could interact with each other. Moreover, the seepage pressure, produced by the high water pressure, can change cracks’ status and have an impact on the stress state of fragile rocks. According to the theory of fracture mechanics, this paper discusses the law of crack initiation and the evolution law of stress intensity factor at the tip of a wing crack caused by compression-shear stress and seepage pressure. Subsequently, considering the interaction of the wing cracks and the additional stress caused by rock bridge damage, this paper proposes the intensity factor evolution equation under the combined action of compression-shear stress and seepage pressure. In addition, this paper analyzes the propagation of cracks under different seepage pressure which reveals that the existence of seepage pressure facilitates the wing crack’s growth. The result indicates that the high seepage pressure converts wing crack growth from stable form to unstable form. Meanwhile, based on the criterion and mechanism for crack initiation and propagation, this paper puts forward the mechanical model for different fracture transfixion failure modes of the crag bridge under the combined action of seepage pressure and compression-shear stress. At the last part, this paper, through investigating the flexibility tensor of the rock mass’s initial damage and its damage evolution in terms of jointed rock mass's damage mechanics, deduces the damage evolution equation for the rock mass with multiple cracks under the combined action of compression-shear stress and seepage pressure. The achievement of this investigation provides a reliable theoretical principle for quantitative research of the fractured rock mass failure under seepage pressure.

  3. Basic feature of host rock and its relation to the formation of leachable sandstone type uranium deposit in Shihongtan

    International Nuclear Information System (INIS)

    Quan Zhigao; Zhang Jiamin; Ji Haijun; Sun Yanhuan; Zhang Fa

    2012-01-01

    Basic feature of sedimentology and petrology and lithogeochemistry of middle Jurassic Xishanyao formation were discussed for Shihongtan uranium deposit in the paper. The relation between host rock and ore formation was analysed. It is indicated that the formation of Shihongtan uranium deposit de-ponds on the following host features in sedimentology, petrology, lithogeochemistry and the intense oxidized epigenetic alteration under hot dry climate condition during the formation of peneplain caused by the slow tilting uplift. (authors)

  4. The Eocene Rusayl Formation, Oman, carbonaceous rocks in calcareous shelf sediments: Environment of deposition, alteration and hydrocarbon potential

    Energy Technology Data Exchange (ETDEWEB)

    Dill, H.G.; Wehner, H.; Kus, J. [Federal Institute for Geosciences and Natural Resources, P.O. Box 510163, D-30631 Hannover (Germany); Botz, R. [University Kiel, Geological-Paleontological Department, Olshausenstrasse 40-60, D-24118 Kiel (Germany); Berner, Z.; Stueben, D. [Technical University Karlsruhe, Institute for Mineralogy and Geochemistry, Fritz-Haber-Weg 2, D-76131 Karlsruhe (Germany); Al-Sayigh, A. [Sultan Qaboos University, Geological Dept. PO Box 36, Al-Khod (Oman)

    2007-10-01

    Paralic carbonaceous series intercalated among calcareous shelf sediments have seldom been investigated. During the early Eocene, calcareous and siliciclastic sediments were deposited on a wide shelf in front of low-reliefed hinterland in the Al Khawd region in NE Oman. The siliciclastic-calcareous sediments originated from strongly reworked debris of the Arabic Shield. The underlying Semail Ophiolite did not act as a direct source of debris but provided some heat to increase the maturity of carbonaceous rocks and modify the isotope signal of the calcareous minerals in the Rusayl Formation. A multidisciplinary approach involving sedimentology, mineralogy, chemistry, coal petrography and paleontology resulted in the establishment of nine stratigraphic lithofacies units and provides the reader with a full picture from deposition of the mixed carbonaceous-calcareous-siliciclastic rocks to the most recent stages of post-depositional alteration of the Paleogene formations. The calcareous Jafnayn Formation (lithofacies unit I) developed in a subtidal to intertidal regime, influenced episodically by storms. Deepening of the calcareous shelf towards younger series was ground to a halt by paleosols developing on a disconformity (lithofacies unit II) and heralding the onset of the Rusayl Formation. The stratigraphic lithofacies units III and IV reflect mangrove swamps which from time to time were flooded through washover fans from the open sea. The presence of Spinozonocolpites and the taxon Avicennia, which today belong to a coastal marsh vegetational community, furnish palynological evidence to the idea of extensive mangrove swamps in the Rusayl Formation [El Beialy, S.Y., 1998. Stratigraphic and palaeonenvironmental significance of Eocene palynomorphs from the Rusayl Shale Formation, Al Khawd, northern Oman. Review of Palaeobotany and Palynology 102, 249-258]. During the upper Rusayl Formation (lithofacies units V through VII) algal mats episodically flooded by marine

  5. Geochemistry of the Oruatemanu Formation, Arrow Rocks, Northland, New Zealand

    International Nuclear Information System (INIS)

    Hori, R.S.; Higuchi, Y.; Fujiki, T.; Maeda, T.; Ikehara, M.

    2007-01-01

    We investigated the geochemical characteristics of sedimentary rocks from the Upper Permian - Middle Triassic Oruatemanu Formation on Arrow Rocks, Waipapa Terrane, New Zealand. The sedimentary rocks consist of limestone, tuffaceous shale, vari-coloured bedded chert, hemipelagic shale and green siliceous mudstone (= green argillite), in ascending order, a typical oceanic plate sequence. Shale and green argillite have higher Zr/Nb ratios than do chert and tuffaceous shales, and show similar REE patterns to PAAS (Post-Archean average Australian shale). In contrast, chert sequences from the basal part and intercalated tuff layers have high TiO 2 contents and Zr/Nb ratios similar to those of basaltic rocks from Arrow Rocks. These geochemical characteristics suggest that the sedimentary environment of the Oruatemanu Formation changed upward, from an open sea setting to the continental margin of Gondwanaland. Chemical compositions of bedded cherts from Arrow Rocks indicate a mixing of biogenic silica, detritus from continents and basaltic materials. In the interval from Upper Permian to Lower Middle Triassic this mixing shows remarkable secular variations. We detected geochemical signals of two Oceanic Anoxic Events (OAEs), one at the Permian/Triassic (P/T) boundary, and the other at the middle Upper Induan level. We name them the OAEα (P/T OAE) and OAEβ (Upper Induan OAE). These OAE horizons are enriched in S, U and other heavy metals (e.g. Mo and Cr), and also have high V/(V+Ni) ratios. Based on a comparison between enrichment factors of Cr and other redox-sensitive trace elements (e.g. Zn, Pb, Co, Cu), the Upper Induan OAEβ is considered to be more intense than the P/T boundary OAEα. This result is not in agreement with the superanoxia model previously proposed. In addition, OAEβ corresponds well with the radiolarian faunal turnover from Permian to Triassic forms documented from the Oruatemanu Formation in this volume. These results may suggest that peak time and

  6. X-ray color maps of the zoned garnets from Silgará Formation metamorphic rocks,SantanderMassif, Eastern Cordillera (Colombia

    Directory of Open Access Journals (Sweden)

    Takasu Akira

    2010-12-01

    Full Text Available

    The metamorphic rocks of the Lower Paleozoic Silgará Formation of the Santander Massif, Eastern Cordillera (Colombia, were affected by a Barrovian-type metamorphism under low to high temperature and medium pressure conditions. These rocks contain garnet porphyroblasts, which show several kinds of chemical zoning patterns. The garnet grains behave as closed systems with respect to the rock matrix. Most of the observed zoning patterns are due to gradual changes in physicochemical conditions during growth. However, some garnet grains show complex zoning patterns during multiple deformation and metamorphic events.

  7. Development of a method for the comparison of final repository sites in different host rock formations; Weiterentwicklung einer Methode zum Vergleich von Endlagerstandorten in unterschiedlichen Wirtsgesteinsformationen

    Energy Technology Data Exchange (ETDEWEB)

    Fischer-Appelt, Klaus; Frieling, Gerd; Kock, Ingo; and others

    2017-10-15

    The report on the development of a method for the comparison of final repository sites in different host rock formations covers the following issues: influence of the requirement of retrievability on the methodology, study on the possible extension of the methodology for repository sites with crystalline host rocks: boundary conditions in Germany, final disposal concept for crystalline host rocks, generic extension of the VerSi method, identification, classification and relevance weighting of safety functions, relevance of the safety functions for the crystalline host rock formation, review of the methodological need for changes for crystalline rock sites under low-permeability covering; study on the applicability of the methodology for the determination of site regions for surface exploitation (phase 1).

  8. Smectite Formation from Basaltic Glass Under Acidic Conditions on Mars

    Science.gov (United States)

    Peretyazhko, T. S.; Sutter, B.; Morris, R. V.; Agresti, D. G.; Le, L.; Ming, D. W.

    2015-01-01

    Massive deposits of phyllosilicates of the smectite group, including Mg/Fe-smectite, have been identified in Mars's ancient Noachian terrain. The observed smectite is hypothesized to form through aqueous alteration of basaltic crust under neutral to alkaline pH conditions. These pH conditions and the presence of a CO2-rich atmosphere suggested for ancient Mars were favorable for the formation of large carbonate deposits. However, the detection of large-scale carbonate deposits is limited on Mars. We hypothesized that smectite deposits may have formed under acidic conditions that prevented carbonate precipitation. In this work we investigated formation of saponite at a pH of approximately 4 from Mars-analogue synthetic Adirondack basaltic glass of composition similar to Adirondack class rocks located at Gusev crater. Hydrothermal (200º Centigrade) 14 day experiments were performed with and without 10 millimoles Fe(II) or Mg under anoxic condition [hereafter denoted as anoxic_Fe, anoxic_Mg and anoxic (no addition of Fe(II) or Mg)] and under oxic condition [hereafter denoted as oxic (no addition of Fe(II) or Mg)]. Characterization and formation conditions of the synthesized saponite provided insight into the possible geochemical conditions required for saponite formation on Mars.

  9. Crack propagation of brittle rock under high geostress

    Science.gov (United States)

    Liu, Ning; Chu, Weijiang; Chen, Pingzhi

    2018-03-01

    Based on fracture mechanics and numerical methods, the characteristics and failure criterions of wall rock cracks including initiation, propagation, and coalescence are analyzed systematically under different conditions. In order to consider the interaction among cracks, adopt the sliding model of multi-cracks to simulate the splitting failure of rock in axial compress. The reinforcement of bolts and shotcrete supporting to rock mass can control the cracks propagation well. Adopt both theory analysis and simulation method to study the mechanism of controlling the propagation. The best fixed angle of bolts is calculated. Then use ansys to simulate the crack arrest function of bolt to crack. Analyze the influence of different factors on stress intensity factor. The method offer more scientific and rational criterion to evaluate the splitting failure of underground engineering under high geostress.

  10. Behavior of uranium under conditions of interaction of rocks and ores with subsurface water

    Science.gov (United States)

    Omel'Yanenko, B. I.; Petrov, V. A.; Poluektov, V. V.

    2007-10-01

    The behavior of uranium during interaction of subsurface water with crystalline rocks and uranium ores is considered in connection with the problem of safe underground insulation of spent nuclear fuel (SNF). Since subsurface water interacts with crystalline rocks formed at a high temperature, the mineral composition of these rocks and uranium species therein are thermodynamically unstable. Therefore, reactions directed toward the establishment of equilibrium proceed in the water-rock system. At great depths that are characterized by hindered water exchange, where subsurface water acquires near-neutral and reducing properties, the interaction is extremely sluggish and is expressed in the formation of micro- and nanoparticles of secondary minerals. Under such conditions, the slow diffusion redistribution of uranium with enrichment in absorbed forms relative to all other uranium species is realized as well. The products of secondary alteration of Fe- and Ti-bearing minerals serve as the main sorbents of uranium. The rate of alteration of minerals and conversion of uranium species into absorbed forms is slow, and the results of these processes are insignificant, so that the rocks and uranium species therein may be regarded as unaltered. Under reducing conditions, subsurface water is always saturated with uranium. Whether water interacts with rock or uranium ore, the equilibrium uranium concentration in water is only ≤10-8 mol/l. Uraninite ore under such conditions always remains stable irrespective of its age. The stability conditions of uranium ore are quite suitable for safe insulation of SNF, which consists of 95% uraninite (UO2) and is a confinement matrix for all other radionuclides. The disposal of SNF in massifs of crystalline rocks at depths below 500 m, where reducing conditions are predominant, is a reliable guarantee of high SNF stability. Under oxidizing conditions of the upper hydrodynamic zone, the rate of interaction of rocks with subsurface water

  11. Failure Mechanisms of Brittle Rocks under Uniaxial Compression

    Science.gov (United States)

    Liu, Taoying; Cao, Ping

    2017-09-01

    The behaviour of a rock mass is determined not only by the properties of the rock matrix, but mostly by the presence and properties of discontinuities or fractures within the mass. The compression test on rock-like specimens with two prefabricated transfixion fissures, made by pulling out the embedded metal inserts in the pre-cured period was carried out on the servo control uniaxial loading tester. The influence of the geometry of pre-existing cracks on the cracking processes was analysed with reference to the experimental observation of crack initiation and propagation from pre-existing flaws. Based on the rock fracture mechanics and the stress-strain curves, the evolution failure mechanism of the fissure body was also analyzed on the basis of exploring the law of the compression-shear crack initiation, wing crack growth and rock bridge connection. Meanwhile, damage fracture mechanical models of a compression-shear rock mass are established when the rock bridge axial transfixion failure, tension-shear combined failure, or wing crack shear connection failure occurs on the specimen under axial compression. This research was of significance in studying the failure mechanism of fractured rock mass.

  12. Rock Abrasion and Ventifact Formation on Mars from Field Analog, Theoretical, and Experimental Studies

    Science.gov (United States)

    Bridges, N. T.; Laity, J. E.

    2001-01-01

    rocks on Mars should erode at a rate of 7.7 to 210 micrometers/yr. These rates cannot have operated over the entire history of the Pathfinder site or elsewhere on Mars, because craters, knobs, and other obstacles would be quickly worn away. More likely, rock abrasion occurs over short time periods when sand supplies are sufficient and saltation friction speeds are frequently reached. Depletion or exhaustion of sand and a decline in wind fluxes at speeds greater than that of saltation friction will then act to reduce the rate of further abrasion. We are currently engaged in a new set of wind tunnel experiments coupled with theoretical models and field studies that address rock abrasion and ventifact formation on Mars and Earth. These studies have implications for the Noachian, when sand supplies were probably more plentiful and the threshold friction speed was possibly lower because of a more dense atmosphere. Under these conditions, erosion rates from the wind could have been much greater than to day, contributing, along with probable fluvial erosion, to the Noachian landscape that is in limited preservation today.

  13. Hydrothermal Alteration Products as Key to Formation of Duricrust and Rock Coatings on Mars

    Science.gov (United States)

    Bishop, J. L.

    1999-03-01

    A model is presented for the formation of duricrust and rock coatings on Mars. Hydrothermal alteration of volcanic tephra may produce a corrosive agent that attacks rock surfaces and binds dust particles to form duricrust.

  14. Normal dynamic deformation characteristics of non-consecutive jointed rock masses under impact loads

    Science.gov (United States)

    Zeng, Sheng; Jiang, Bowei; Sun, Bing

    2017-08-01

    In order to study deformation characteristics of non-consecutive single jointed rock masses under impact loads, we used the cement mortar materials to make simulative jointed rock mass samples, and tested the samples under impact loads by the drop hammer. Through analyzing the time-history signal of the force and the displacement, first we find that the dynamic compression displacement of the jointed rock mass is significantly larger than that of the intact jointless rock mass, the compression displacement is positively correlated with the joint length and the impact height. Secondly, the vertical compressive displacement of the jointed rock mass is mainly due to the closure of opening joints under small impact loads. Finally, the peak intensity of the intact rock mass is larger than that of the non-consecutive jointed rock mass and negatively correlated with the joint length under the same impact energy.

  15. The geology and mechanics of formation of the Fort Rock Dome, Yavapai County, Arizona

    Science.gov (United States)

    Fuis, Gary S.

    1996-01-01

    The Fort Rock Dome, a craterlike structure in northern Arizona, is the erosional product of a circular domal uplift associated with a Precambrian shear zone exposed within the crater and with Tertiary volcanism. A section of Precambrian to Quaternary rocks is described, and two Tertiary units, the Crater Pasture Formation and the Fort Rock Creek Rhyodacite, are named. A mathematical model of the doming process is developed that is consistent with the history of the Fort Rock Dome.

  16. Rock Fracture Toughness Study Under Mixed Mode I/III Loading

    Science.gov (United States)

    Aliha, M. R. M.; Bahmani, A.

    2017-07-01

    Fracture growth in underground rock structures occurs under complex stress states, which typically include the in- and out-of-plane sliding deformation of jointed rock masses before catastrophic failure. However, the lack of a comprehensive theoretical and experimental fracture toughness study for rocks under contributions of out-of plane deformations (i.e. mode III) is one of the shortcomings of this field. Therefore, in this research the mixed mode I/III fracture toughness of a typical rock material is investigated experimentally by means of a novel cracked disc specimen subjected to bend loading. It was shown that the specimen can provide full combinations of modes I and III and consequently a complete set of mixed mode I/III fracture toughness data were determined for the tested marble rock. By moving from pure mode I towards pure mode III, fracture load was increased; however, the corresponding fracture toughness value became smaller. The obtained experimental fracture toughness results were finally predicted using theoretical and empirical fracture models.

  17. Carbonate rock depositional models: A microfacies approach

    Energy Technology Data Exchange (ETDEWEB)

    Carozzi, A.V.

    1988-01-01

    Carbonate rocks contain more than 50% by weight carbonate minerals such as calcite, dolomite, and siderite. Understanding how these rocks form can lead to more efficient methods of petroleum exploration. Micofacies analysis techniques can be used as a method of predicting models of sedimentation for carbonate rocks. Micofacies in carbonate rocks can be seen clearly only in thin sections under a microscope. This section analysis of carbonate rocks is a tool that can be used to understand depositional environments, diagenetic evolution of carbonate rocks, and the formation of porosity and permeability in carbonate rocks. The use of micofacies analysis techniques is applied to understanding the origin and formation of carbonate ramps, carbonate platforms, and carbonate slopes and basins. This book will be of interest to students and professionals concerned with the disciplines of sedimentary petrology, sedimentology, petroleum geology, and palentology.

  18. The paleomagnetic field and possible mechanisms for the formation of reversed rock magnetization

    International Nuclear Information System (INIS)

    Trukhin, Vladimir I.; Bezaeva, Natalia; Kurochkina, Evgeniya

    2006-01-01

    Investigations of ancient magnetized rocks show that their natural remanent magnetization (NRM) can be oriented in the direction of modern geomagnetic field (GMF) as well as in the opposite direction. It is supposed that reversed NRM is related to reversals of the GMF in the past geological periods. During reversals, the strength of the GMF is near zero and can cause the destruction of living organisms as a result of powerful space and solar radiation, which, in the absence of the GMF, can reach the Earth's surface. That is why the question of reality of the GMF reversals is of global ecological importance. There is also another natural mechanism for the formation of reversed NRM-the self-reversal of magnetization as a result of thermomagnetization of rocks. In the paper, both natural processes for the formation of reversed NRM in rocks are discussed, and the results of experimental research on the physical mechanism of self-reversal of magnetization in continental and oceanic rocks are presented. The results of computer modeling of the self-reversal phenomenon are also presented

  19. The paleomagnetic field and possible mechanisms for the formation of reversed rock magnetization

    Energy Technology Data Exchange (ETDEWEB)

    Trukhin, Vladimir I. [Faculty of Physics, Moscow State University, 119992 Moscow (Russian Federation)]. E-mail: trukhin@phys.msu.ru; Bezaeva, Natalia [Faculty of Physics, Moscow State University, 119992 Moscow (Russian Federation); Kurochkina, Evgeniya [Faculty of Physics, Moscow State University, 119992 Moscow (Russian Federation)

    2006-05-15

    Investigations of ancient magnetized rocks show that their natural remanent magnetization (NRM) can be oriented in the direction of modern geomagnetic field (GMF) as well as in the opposite direction. It is supposed that reversed NRM is related to reversals of the GMF in the past geological periods. During reversals, the strength of the GMF is near zero and can cause the destruction of living organisms as a result of powerful space and solar radiation, which, in the absence of the GMF, can reach the Earth's surface. That is why the question of reality of the GMF reversals is of global ecological importance. There is also another natural mechanism for the formation of reversed NRM-the self-reversal of magnetization as a result of thermomagnetization of rocks. In the paper, both natural processes for the formation of reversed NRM in rocks are discussed, and the results of experimental research on the physical mechanism of self-reversal of magnetization in continental and oceanic rocks are presented. The results of computer modeling of the self-reversal phenomenon are also presented.

  20. Recent studies on radiation damage formation in synthetic NaCl and natural rock salt for radioactive waste disposal applications

    International Nuclear Information System (INIS)

    Swyler, K.J.; Klaffky, R.W.; Levy, P.W.

    1980-01-01

    Radiation damage formation in natural rock salt is described as a function of irradiation temperature and plastic deformation. F-center formation decreases with increasing temperature while significant colloidal sodium formation occurs over a restricted temperature range around 150 0 C. Plastic deformation increases colloid formation; it is estimated that colloid concentrations may be increased by a factor of 3 if the rock salt near radioactive waste disposal canisters is heavily deformed. Optical bandshape analysis indicates systematic differences between the colloids formed in synthetic and natural rock salts

  1. Evaluation of Uranium depositional system in sedimentary rocks of Sibolga formation, Tapanuli Tengah

    International Nuclear Information System (INIS)

    I Gde Sukadana; Heri Syaeful

    2016-01-01

    Uranium in nature formed in various deposit type, depends on its sources, process, and depositional environments. Uranium occurrence in Sibolga, hosted in sedimentary rocks of Sibolga Formation, is properly potential to develop; nevertheless, the depositional pattern and uranium mineralization process so far had not been recognized. The research aim is to determine the rock distribution patterns and the existence of uranium grade anomalies based on surface geology and borehole log data. Mineralization occurrences from borehole log data distributed from basalt conglomerate unit (Kgl 1), sandstone 1 unit (Bp 1), conglomerate 2 unit (Kgl 2), and sandstone 2 unit (Bp 2) with their distribution and thickness are thinning to the top. Mineralization distribution in the eastern area, mainly on Kgl 1 unit, dominated by detritus materials from epi-genetic depositional in the form of monazite which is formed along with the formation of granite as its source rock. Meanwhile, mineralization on the upper rocks units formed a channel pattern trending northeast-southwest, which formed in syn-genetic process consist of uraninite, carnotite, and coffinite. Sibolga Formation deposition originated from east to west and uranium deposit formed because of the differences of depositional environment from oxidation in the east to the more reductive in the southwest. The increasing of organic materials in southwest basin caused the reduction condition of depositional environment. (author)

  2. Source rock

    Directory of Open Access Journals (Sweden)

    Abubakr F. Makky

    2014-03-01

    Full Text Available West Beni Suef Concession is located at the western part of Beni Suef Basin which is a relatively under-explored basin and lies about 150 km south of Cairo. The major goal of this study is to evaluate the source rock by using different techniques as Rock-Eval pyrolysis, Vitrinite reflectance (%Ro, and well log data of some Cretaceous sequences including Abu Roash (E, F and G members, Kharita and Betty formations. The BasinMod 1D program is used in this study to construct the burial history and calculate the levels of thermal maturity of the Fayoum-1X well based on calibration of measured %Ro and Tmax against calculated %Ro model. The calculated Total Organic Carbon (TOC content from well log data compared with the measured TOC from the Rock-Eval pyrolysis in Fayoum-1X well is shown to match against the shale source rock but gives high values against the limestone source rock. For that, a new model is derived from well log data to calculate accurately the TOC content against the limestone source rock in the study area. The organic matter existing in Abu Roash (F member is fair to excellent and capable of generating a significant amount of hydrocarbons (oil prone produced from (mixed type I/II kerogen. The generation potential of kerogen in Abu Roash (E and G members and Betty formations is ranging from poor to fair, and generating hydrocarbons of oil and gas prone (mixed type II/III kerogen. Eventually, kerogen (type III of Kharita Formation has poor to very good generation potential and mainly produces gas. Thermal maturation of the measured %Ro, calculated %Ro model, Tmax and Production index (PI indicates that Abu Roash (F member exciting in the onset of oil generation, whereas Abu Roash (E and G members, Kharita and Betty formations entered the peak of oil generation.

  3. Elastic Rock Heterogeneity Controls Brittle Rock Failure during Hydraulic Fracturing

    Science.gov (United States)

    Langenbruch, C.; Shapiro, S. A.

    2014-12-01

    For interpretation and inversion of microseismic data it is important to understand, which properties of the reservoir rock control the occurrence probability of brittle rock failure and associated seismicity during hydraulic stimulation. This is especially important, when inverting for key properties like permeability and fracture conductivity. Although it became accepted that seismic events are triggered by fluid flow and the resulting perturbation of the stress field in the reservoir rock, the magnitude of stress perturbations, capable of triggering failure in rocks, can be highly variable. The controlling physical mechanism of this variability is still under discussion. We compare the occurrence of microseismic events at the Cotton Valley gas field to elastic rock heterogeneity, obtained from measurements along the treatment wells. The heterogeneity is characterized by scale invariant fluctuations of elastic properties. We observe that the elastic heterogeneity of the rock formation controls the occurrence of brittle failure. In particular, we find that the density of events is increasing with the Brittleness Index (BI) of the rock, which is defined as a combination of Young's modulus and Poisson's ratio. We evaluate the physical meaning of the BI. By applying geomechanical investigations we characterize the influence of fluctuating elastic properties in rocks on the probability of brittle rock failure. Our analysis is based on the computation of stress fluctuations caused by elastic heterogeneity of rocks. We find that elastic rock heterogeneity causes stress fluctuations of significant magnitude. Moreover, the stress changes necessary to open and reactivate fractures in rocks are strongly related to fluctuations of elastic moduli. Our analysis gives a physical explanation to the observed relation between elastic heterogeneity of the rock formation and the occurrence of brittle failure during hydraulic reservoir stimulations. A crucial factor for understanding

  4. Preliminary investigation on the sedimentary facies of the middle silurian uraniferous rock formations in western Qinling Region

    International Nuclear Information System (INIS)

    Mao Yunian; Min Yongming.

    1987-01-01

    The Middle Silurian stratabound uranium deposits in Western Qinling were formed due to hydrothermal modification of ground water and reconcentration of uranium from the sedimentary source rocks. The Silurian system consists of the sediments deposited in the marginal sea of the passive continent, to the south of which is the Ruoergai palaeocontinent. The Middle Silurian is divided into three formations. The lower members of each formation are composed of fine-grained clastic rocks with bay-lagoon facies, while the upper members of each formation are uraniferous rock formations consisted of carbonaceous-siliceous-limestone-argillaceous rocks. During the Middle Silurian period there occurred an island chain barrier which is roughly parallel to the palaeocoast and was formed by undersea uplifts. The uraniferous rock formations belong to the assemblage of lagoon-reef-back tidal flat-reef beach facies. Nearshore shallow water environment, abundant terrestrial fine detritus, local reduction facies and zones are three cardinal conditions for the formation of uranium-rich sediments. Uranium deposition mainly took place in the environments of the inner part of reef beach and reef-back tidal flat, which are characterized by having medium to slightly lower energy, the terrestrial fine detritus involved, and local reduction field resulting from the decomposition of organism after their massive death. Furing the process of relative slow deposition, UO 2 2+ in the sea water was formed by means of infiltration, diffusion and alternative absorption of water at the bottom into organic matter and clay

  5. Technical support for GEIS: radioactive waste isolation in geologic formations. Volume 7. Baseline rock properties-basalt

    International Nuclear Information System (INIS)

    1978-04-01

    This volume, Y/OWI/TM-36/7 Baseline Rock Properties--Basalt, is one of a 23-volume series, ''Technical Support for GEIS: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-36'' which supplements a ''Contribution to Draft Generic Environmental Impact Statement on Commercial Waste Management: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-44.'' The series provides a more complete technical basis for the preconceptual designs, resource requirements, and environmental source terms associated with isolating commercial LWR wastes in underground repositories in salt, granite, shale and basalt. Wastes are considered from three fuel cycles: uranium and plutonium recycling, no recycling of spent fuel and uranium-only recycling. This report contains an evaluation of the results of a literature survey to define the rock mass properties of a generic basalt, which could be considered as a geological medium for storing radioactive waste. The general formation and structure of basaltic rocks is described. This is followed by specific descriptions and rock property data for the Dresser Basalt, the Amchitka Island Basalt, the Nevada Test Site Basalt and the Columbia River Group Basalt. Engineering judgment has been used to derive the rock mass properties of a typical basalt from the relevant intact rock property data and the geological information pertaining to structural defects, such as joints and faults

  6. Rock Directed Breaking Under the Impulse Load

    Science.gov (United States)

    Khomeriki, Sergo; Mataradze, Edgar; Chikhradze, Nikoloz; Losaberidze, Marine; Khomeriki, Davit; Shatberashvili, Grigol

    2016-10-01

    In the work the problem of directed chipping of facing stone material by means of managing of explosion process is considered. The technology of the mining of decorative stone by the use of explosion energy means the very rapid transfer of potential energy of elastic deformations to kinetic energy. As a result, the explosion impulse, in the expanse of the inertia of rock massive, does not cause the increase of existing cracks. In the course of explosion, the shock wave is propagated by ultrasonic velocity and in this case the medium parameters (pressure, density, temperature, velocity) increase in spurts. In spite of this fact the all three conservation laws of mechanics remain valid on basis of three laws the equations are derived by which the parameters of shock wave may be defined by means of the rock physical-mechanical properties. The load on the body volume at breaking under explosion acts over very small period of the time. Therefore, stressed-deformed state of the rock was studied when the impulse load acts on the boundary. It was considered that the mining of the blocks of facing stone is performed from the hard rocks. This means that the breaking proceeds in the zone of elastic deformation. In the conditions of mentioned assumptions, the expression of the stress tensor and displacement of vector components initiated by stressed-deformed state in the rock are written.

  7. Effect of Micro-Structure on Fatigue Behavior of Intact Rocks under Completely Reversed Loading

    Directory of Open Access Journals (Sweden)

    Saeed Jamali Zavareh

    2017-01-01

    Full Text Available Rock formations and structures can be subjected to both static and dynamic loadings. Static loadings resulting from different sources such as gravity and tectonic forces and dynamic forces are intermittently transmitted via vibrations of the earth’s crust, through major earthquakes, rock bursts, rock blasting and drilling and also, traffic. Reaction of rocks to cyclic and repetitive stresses resulting from dynamic loads has been generally neglected with the exception of a few rather limited studies. In this study, , two crystalline quarry stones in Iran; (Natanz gabbro and Green onyx and one non-crystalline rock (Asmari limestone are used to evaluate the effect of micro-structure of intact rock on fatigue behavior. These rocks have different mineral compositions and formation conditions. A new apparatus based on rotating beam fatigue testing machine (R.R.Moore, which is commonly used for laboratory fatigue test in metals, is developed and fatigue behavior and existence of the endurance limit were evaluated for the mentioned rocks based on stress-life method. The obtained results in the variation of applied amplitude stress versus loading cycle number (S-N diagram followed common relationship in other materials. In addition, the endurance limit is perceived for all tested rocks. The results also illustrated that the endurance limits for all types of tested rocks in this study are ranged between 0.4 and 0.6 of their tensile strengths. The endurance limit to tensile strength fraction of green onyx and Natanz gabbro were approximated in a higher value compared to the Asmari limestone with non-crystalline micro-structure.

  8. Final Report: Geothermal dual acoustic tool for measurement of rock stress

    Energy Technology Data Exchange (ETDEWEB)

    Normann, Randy A. [Perma Works LLC, Pattonville, TX (United States)

    2014-12-01

    This paper outlines the technology need for a rock formation stress measurement in future EGS wells. This paper reports on the results of work undertaken under a Phase I, DOE/SBIR on the feasibility to build an acoustic well logging tool for measuring rock formation stress.

  9. Final Report. Geothermal Dual Acoustic Tool for Measurement of Rock Stress

    Energy Technology Data Exchange (ETDEWEB)

    Normann, Randy A [Perma Works LLC, Pattonville, TX (United States)

    2014-12-01

    This paper outlines the technology need for a rock formation stress measurement in future EGS wells. This paper reports on the results of work undertaken under a Phase I, DOE/SBIR on the feasibility to build an acoustic well logging tool for measuring rock formation stress.

  10. THM-coupled modeling of selected processes in argillaceous rock relevant to rock mechanics; THM-Gekoppelte Modellierung ausgewaehlter gesteinsmechanisch relevanter Prozesse im Tongestein

    Energy Technology Data Exchange (ETDEWEB)

    Czaikowski, Oliver [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, Braunschweig (Germany). Repository Safety Research Div.

    2012-08-15

    Scientific investigations in European countries other than Germany concentrate not only on granite formations (Switzerland, Sweden) but also on argillaceous rock formations (France, Switzerland, Belgium) to assess their suitability as host and barrier rock for the final storage of radioactive waste. In Germany, rock salt has been under thorough study as a host rock over the past few decades. According to a study by the German Federal Institute for Geosciences and Natural Resources, however, not only salt deposits but also argillaceous rock deposits are available at relevant depths and of extensions in space which make final storage of high-level radioactive waste basically possible in Germany. Equally qualified findings about the suitability/unsuitability of non-saline rock formations require fundamental studies to be conducted nationally because of the comparatively low level of knowledge. The article presents basic analyses of coupled mechanical and hydraulic properties of argillaceous rock formations as host rock for a repository. The interaction of various processes is explained on the basis of knowledge derived from laboratory studies, and open problems are deduced. For modeling coupled processes, a simplified analytical computation method is proposed and compared with the results of numerical simulations, and the limits to its application are outlined. (orig.)

  11. Experimental Rock-on-Rock Abrasive Wear Under Aqueous Conditions: its Role in Subglacial Abrasion

    Science.gov (United States)

    Rutter, E. H.; Lee, A. G.

    2003-12-01

    We have determined experimentally the rate of abrasive wear of rock on rock for a range of rock types as a function of normal stress and shear displacement. Unlike abrasive wear in fault zones, where wear products accumulate as a thickening gouge zone, in our experiments wear particles were removed by flowing water. The experiments are thus directly pertinent to one of the most important processes in subglacial erosion, and to some extent in river incision. Wear was produced between rotating discs machined from rock samples and measured from the progressive approach of the disc axes towards each other under various levels of normal load. Shear displacements of several km were produced. Optical and scanning electron microscopy were used to study the worn rock surfaces, and particle size distributions in wear products were characterized using a laser particle size analyzer. Rock types studied were sandstones of various porosities and cement characteristics, schists and a granite. In all cases abrasion rate decreased logarithmically with displacement by up to 2 orders of magnitude until a steady state was approached, but only after at least 1 km displacement. The more porous, less-well cemented rocks wore fastest. Amount of abrasion could be characterized quantitatively using an exponentially decaying plus a steady-state term. Wear rate increased non-linearly with normal contact stress, apparently to an asymptote defined by the unconfined compressive strength. Microstructural study showed that the well-cemented and/or lowest porosity rocks wore by progressive abrasion of grains without plucking, whereas whole grains were plucked out of weakly-cemented and/or more porous rocks. This difference in behavior was reflected in wear-product particle size distributions. Where whole-grain plucking was possible, wear products were dominated by particles of the original grain size rather than finer rock flour. Comparison of our results to glacier basal abrasive wear estimated

  12. A study on spalling in soft rock under low confining stress

    International Nuclear Information System (INIS)

    Tomita, Atsunori; Ebina, Takahito; Toida, Masaru; Shirasagi, Suguru; Kishida, Kiyoshi; Adachi, Toshihisa

    2007-01-01

    The aim of this paper is to study spalling in soft rock excavation. During the test cavern excavation of the radioactive waste disposal project, spalling occurred. Therefore, it has been estimated performing the stress path simulation test and measuring the induced stress. In the stress path simulation test, the splitting failure has been confirmed under low confining stress. In the induced stress measurements, the rock mass around the cavern has shifted to the low radial confinement. Hence, spalling in soft rock was interpreted by the splitting failure caused by the induced stress under low confinement. Furthermore, the failure zone was proved by the numerical analysis applying the criterion based on the results of the above triaxial test. (author)

  13. Barringerite Fe2P from Pyrometamorphic Rocks of the Hatrurim Formation, Israel

    Science.gov (United States)

    Britvin, S. N.; Murashko, M. N.; Vapnik, E.; Polekhovsky, Yu. S.; Krivovichev, S. V.

    2017-12-01

    The article provides a detailed mineralogical and crystallochemical description (including refinement of the crystal structure) of the first finding of the phosphide class mineral barringerite, Fe2P, from terrestrial pyrometamorphic rocks of the Hatrurim Formation in Israel. The mineral occurs in the association of the so-called paralavas—initially silicate—carbonate sedimentary rocks that remelted during pyrometamorphic processes at a temperature above 1000°C and at a low pressure. Questions on the genesis and crystal chemistry of barringerite are discussed in connection with another polymorphic iron phosphide, allabogdanite (Fe,Ni)2P.

  14. Organic petrology and Rock-Eval characteristics in selected surficial samples of the Tertiary Formation, South Sumatra Basin

    Directory of Open Access Journals (Sweden)

    M. H. Hermiyanto

    2014-06-01

    Full Text Available http://dx.doi.org/10.17014/ijog.vol4no3.20096Organic petrologic data of the DOM of Talangakar and Muaraenim Formations show that the organic matter consisting mainly of vitrinite group is essentially composed of telocollinite (1.0 – 70.8 % and desmocollinite (0.8 – 66.6 % with minor telinite (0.6 – 9.4 %, detrovitrinite (0.6 – 6.0 %, and cor- pocollinite (0.6 – 2.0 %. Minor exinite (0.4 – 7.8 % and inertinite (0.4 – 8.0 % are also determined. However, mineral matter varies from 0.6 – 99.44 %. Downwards, the increase in vitrinite reflectance (0.33 – 0.48 % is concomitant with the depth of each formation. Furthermore, based on Rock-eval pyrolysis, TOC value of the Talangakar Formation ranges from 0.09 – 15.38 %, Gumai 0.34 – 0.39 %, Airbenakat 0.32 – 4.82 %, and Muaraenim between 0.08 – 15.22 %. Moreover the PY (Potential Yield value variation of the Talangakar, Gumai, Airbenakat, and Muaraenim Formations are between 0.04 – 36.61 mg HC/g rock, 0.53 – 0.81 mg HC/g rock, 0.1 – 4.37 mg HC/g rock, and 0.07 – 129.8 mg HC/g rock respectively. Therefore, on the basis of those two parameters, the four formations are included into a gas - oil prone source rock potential. However, the Talangakar and Muaraenim Formations are poor to excellent category, whereas the Air Benakat tends to indicate a poor – fair category and Gumai Formation are only within a poor category. Tmax value of the Talangakar ranges from 237 – 4380 C, Gumai 316 – 3590 C, Airbenakat 398 – 4340 C with exceptions of 4970 C and 5180 C, and Muaraenim Forma- tions 264 – 4250 C. The Talangakar Formation contains kerogen Type II dan III, with the HI (Hydrogen Index value varies from 45.16 – 365.43. However two samples show value of 0. The organic content of the Gumai and Air Benakat Formations are included into kerogen type III, with HI value ranges from11.87 – 40.82, and 19 – 114 respectively. Moreover the Muaraenim Formation has two category of

  15. Mapping the productive sands of Lower Goru Formation by using seismic stratigraphy and rock physical studies in Sawan area, southern Pakistan: A case study

    KAUST Repository

    Munir, K.

    2011-02-24

    This study has been conducted in the Sawan gas field located in southern Pakistan. The aim of the study is to map the productive sands of the Lower Goru Formation of the study area. Rock physics parameters (bulk modulus, Poisson\\'s ratio) are analysed after a detailed sequence stratigraphic study. Sequence stratigraphy helps to comprehend the depositional model of sand and shale. Conformity has been established between seismic stratigraphy and the pattern achieved from rock physics investigations, which further helped in the identification of gas saturation zones for the reservoir. Rheological studies have been done to map the shear strain occurring in the area. This involves the contouring of shear strain values throughout the area under consideration. Contour maps give a picture of shear strain over the Lower Goru Formation. The identified and the productive zones are described by sands, high reflection strengths, rock physical anomalous areas and low shear strain.

  16. Phosphate rock formation and marine phosphorus geochemistry: the deep time perspective.

    Science.gov (United States)

    Filippelli, Gabriel M

    2011-08-01

    The role that phosphorite formation, the ultimate source rock for fertilizer phosphate reserves, plays in the marine phosphorus (P) cycle has long been debated. A shift has occurred from early models that evoked strikingly different oceanic P cycling during times of widespread phosphorite deposition to current thinking that phosphorite deposits may be lucky survivors of a series of inter-related tectonic, geochemical, sedimentological, and oceanic conditions. This paradigm shift has been facilitated by an awareness of the widespread nature of phosphogenesis-the formation of authigenic P-bearing minerals in marine sediments that contributes to phosphorite formation. This process occurs not just in continental margin sediments, but in deep sea oozes as well, and helps to clarify the driving forces behind phosphorite formation and links to marine P geochemistry. Two processes come into play to make phosphorite deposits: chemical dynamism and physical dynamism. Chemical dynamism involves the diagenetic release and subsequent concentration of P-bearing minerals particularly in horizons, controlled by a number of sedimentological and biogeochemical factors. Physical dynamism involves the reworking and sedimentary capping of P-rich sediments, which can either concentrate the relatively heavy and insoluble disseminated P-bearing minerals or provide an episodic change in sedimentology to concentrate chemically mobilized P. Both processes can result from along-margin current dynamics and/or sea level variations. Interestingly, net P accumulation rates are highest (i.e., the P removal pump is most efficient) when phosphorites are not forming. Both physical and chemical pathways involve processes not dominant in deep sea environments and in fact not often coincide in space and time even on continental margins, contributing to the rarity of high-quality phosphorite deposits and the limitation of phosphate rock reserves. This limitation is becoming critical, as the human demand

  17. Self-Healing Characteristics of Damaged Rock Salt under Different Healing Conditions

    Directory of Open Access Journals (Sweden)

    Lin Li

    2013-08-01

    Full Text Available Salt deposits are commonly regarded as ideal hosts for geologic energy reservoirs. Underground cavern construction-induced damage in salt is reduced by self-healing. Thus, studying the influencing factors on such healing processes is important. This research uses ultrasonic technology to monitor the longitudinal wave velocity variations of stress-damaged rock salts during self-recovery experiments under different recovery conditions. The influences of stress-induced initial damage, temperature, humidity, and oil on the self-recovery of damaged rock salts are analyzed. The wave velocity values of the damaged rock salts increase rapidly during the first 200 h of recovery, and the values gradually increase toward stabilization after 600 h. The recovery of damaged rock salts is subjected to higher initial damage stress. Water is important in damage recovery. The increase in temperature improves damage recovery when water is abundant, but hinders recovery when water evaporates. The presence of residual hydraulic oil blocks the inter-granular role of water and restrains the recovery under triaxial compression. The results indicate that rock salt damage recovery is related to the damage degree, pore pressure, temperature, humidity, and presence of oil due to the sealing integrity of the jacket material.

  18. Organic geochemical characterization of terrestrial source rocks of the Triassic Madygen formation (Southern Tien Shan, Kyrgyzstan)

    Energy Technology Data Exchange (ETDEWEB)

    Berner, U.; Scheeder, G.; Kus, J. [Section Geochemistry of Petroleum and Coal, BGR, Hannover (Germany); Voigt, S.; Schneider, J.W. [Geological Inst., TU Bergakademic Freiberg (Germany)

    2009-09-15

    Along the northern foothills of the Turkestan-Alai Range (SW Kyrgyzstan), a 1000 to 1500m thick succession of Mesozoic deposits is exposed recording regional changes of the paleo-landscape during Triassic to Cretaceous times. Detailed litho- and biofacies analyses, conducted by the TU Bergakademie Freiberg since 2006, provided for the first time a nearly complete columnar section of the continental Triassic Madygen Formation of Kyrgyzstan. Organic petrographical and organic geochemical methods (including RockEval pyrolyses, and biomarker analyses) have been applied to a suite of terrestrial sedimentary rocks of Triassic age with the intention to identify the depositional environment. Our investigations suggest that the potential source rocks of the terrestrial pluvial Madygen Formation might generate predominantly gaseous hydrocarbons at higher maturities. (orig.)

  19. Rocking motion of structures under earthquakes. Overturning of 2-DOF system

    International Nuclear Information System (INIS)

    Kobayashi, Koichi; Watanabe, Tetsuya; Tanaka, Kihachiro; Tomoda, Akinori

    2011-01-01

    In recent years, huge earthquakes happen, for example, The South Hyogo prefecture Earthquake in 1995, The Mid Niigata Prefecture Earthquake in 2004, The Iwate-Miyagi Nairiku Earthquake in 2008. In The Niigataken Chuetsu-oki Earthquake in 2007, hundreds of drums fell down and water spilled out. A lot of studies about rocking behavior of rigid body had been performed from 1960's. However, these studies were only for a specific condition of the structure size or input vibration characteristics. Therefore, generalizes fall condition for earthquake is required. This paper deals with the analytical and the experimental study of the rocking vibration of 1-DOF rocking system, 2-DOF vibration-rocking system and 2-DOF rocking system under earthquakes. In this study, the equation of motion for each rocking systems are developed. The numerical model of 2-DOF rocking system is evaluated by free rocking experiment. In this paper, 'Overturning Map' which can distinguish whether structures falls or not is proposed. The overturning map of each rocking systems excited by the artificial earthquake wave calculated from the design spectrum is shown. As the result, overturning condition of structures is clarified. (author)

  20. Triaxial slide-hold-slide shear experiment of sedimentary rock under drain condition

    International Nuclear Information System (INIS)

    Kishida, Kiyoshi; Yano, Takao; Elsworth, Derek; Yasuhara, Hideaki; Nakashima, Shinichiro

    2011-01-01

    When discussing the mechanical and hydro-mechanical properties of rock masses under the long-term holding, the variation of rock structure and the change of shear band condition should be discussed in considering the effect of thermal and chemical influences. In this research, the triaxial shear experiment under drain condition was conducted through sedimentary rock, and in the residual stress state, the slide-hold-slide processes were applied to these triaxial experiments. The experiments were carried out in 3 kinds of confining conditions and 2 kinds of thermal conditions. Consequently, the healing phenomena can be observed and the shear strength recovery is also confirmed in process of the holding time. (author)

  1. Distribution of uranium in the carbonate rock of Um Bogma formation, Southwest, Sinai, Egypt

    International Nuclear Information System (INIS)

    El-AAssy, I.E.; Ahmed, F.Y.; Morsy, A.M.; El-Fawal, F.M.; Mansour, M.Gh.

    1998-01-01

    The lower carboniferous Um bogma Formation is a potential source for Mn, Cu and U. it is mainly composed of dolostone and limestone with few clastic different interbeds of clay stone, siltstone and sandstone. The different diagenetic processes which affected this formation are mainly, compaction, cementation, neomorphism, dissolution, dolomitization, silicification and filling the veins and pores. The distribution of uranium and thorium within the three members and their correlation with the iron oxides and organic matter, were studied. The channel porosity and intercrystalline spaces which resulted from dolomitization acted as pathways for uraniferous solutions in the carbonate rocks. On the other hand, the shales and clay stones underneath the carbonates of Um bogma formation acted as barriers and good depositional environment for the accumulation of uranium on the surfaces of joints and fractures.The accumulated uranium minerals in the carbonate rocks are most likely of the efflorescent deposits

  2. Drying-induced deformation of Horonobe sedimentary rock in the Koetoi and Wakkanai formations

    International Nuclear Information System (INIS)

    Illankoon, Thilini Nuwanradha; Yee, Suu Mon; Osada, Masahiko; Maekawa, Keisuke; Tada, Hiroyuki; Kumasaka, Hiroo

    2013-01-01

    In order to increase the long-term safety of geological disposal sites, knowledge of the drying-induced deformation characteristics of the rock mass in underground ventilated galleries is necessary to understand its cracking susceptibility and the chance of further propagation of the excavation damaged zone. Hence, strain was measured in ten cylindrical mudstone specimens (4 from Koetoi formation and 6 from Wakkanai formation respectively) cored at Horonobe Underground Research Laboratory (URL), an off-site (generic) URL, to examine deformation behavior during desiccation. The specimens were prepared in one-dimensional drying conditions in a 25degC or 40degC climatic chamber with 50% relative humidity. Mercury intrusion porosimetry (MIP) was also conducted to measure the pore size distributions of each formation. The recorded data showed that the Koetoi formation specimens generated smaller maximum shrinkage values (10,000 μ) compared to those from the Wakkanai formation (13,000 μ and 24,000 μ for Wakkanai groups I and II respectively). Wakkanai formation specimens were divided into two groups (Wakkanai groups I and II) according to their strain behavior. The porosity of the Koetoi formation was 54% whereas that of the Wakkanai formation was 27 - 38%. MIP results clearly indicate that the Wakkanai formation has a greater mesopore volume (63% and 73% of porosity for Wakkanai groups I and II respectively) than the Koetoi formation (8% of porosity) which contributes to its greater shrinkage. In addition, Wakkanai groups I and II have different pore size distribution patterns. Therefore, Wakkanai groups I and II exhibit distinct strain behaviors during drying. Similarities in grain density, a decrease in porosity and a gradual increase in mesopore volume with depth confirm the progressive hardening of Horonobe sedimentary rock. The pore volume in the 0.013 - 0.025 μm pore radius range exerts a strong influence on shrinkage generation in the Wakkanai formation

  3. Investigation of block foundations resting on soil–rock and rock–rock media under coupled vibrations

    Directory of Open Access Journals (Sweden)

    Renuka Darshyamkar

    2017-04-01

    Full Text Available In the present study, the dynamic response of block foundations of different equivalent radius to mass (Ro/m ratios under coupled vibrations is investigated for various homogeneous and layered systems. The frequency-dependent stiffness and damping of foundation resting on homogeneous soils and rocks are determined using the half-space theory. The dynamic response characteristics of foundation resting on the layered system considering rock–rock combination are evaluated using finite element program with transmitting boundaries. Frequencies versus amplitude responses of block foundation are obtained for both translational and rotational motion. A new methodology is proposed for determination of dynamic response of block foundations resting on soil–rock and weathered rock–rock system in the form of equations and graphs. The variations of dimensionless natural frequency and dimensionless resonant amplitude with shear wave velocity ratio are investigated for different thicknesses of top soil/weathered rock layer. The dynamic behaviors of block foundations are also analyzed for different rock–rock systems by considering sandstone, shale and limestone underlain by basalt. The variations of stiffness, damping and amplitudes of block foundations with frequency are shown in this study for various rock–rock combinations. In the analysis, two resonant peaks are observed at two different frequencies for both translational and rotational motion. It is observed that the dimensionless resonant amplitudes decrease and natural frequencies increase with increase in shear wave velocity ratio. Finally, the parametric study is performed for block foundations with dimensions of 4 m × 3 m × 2 m and 8 m × 5 m × 2 m by using generalized graphs. The variations of natural frequency and peak displacement amplitude are also studied for different top layer thicknesses and eccentric moments.

  4. Recreating Rocks

    DEFF Research Database (Denmark)

    Posth, Nicole R

    2008-01-01

    Nicole Posth and colleagues spent a month touring South African rock formations in their quest to understand the origin of ancient iron and silicate layers.......Nicole Posth and colleagues spent a month touring South African rock formations in their quest to understand the origin of ancient iron and silicate layers....

  5. Geochemical evaluation of Pabdeh Formation in Nosrat field, southeast Persian Gulf using Rock- Eval VI pyrolysis

    Directory of Open Access Journals (Sweden)

    mohammad sadeghi

    2015-02-01

    Full Text Available The present study was performed on 59 drillhole cuttings from Pabdeh Formation in Nosrat oil field using Rock- Eval VI pryrolysis. Geochemical analysis indicated that Pabdeh Formation possesses poor to good hydrocarbon potential. Plotting S1 against TOC suggests that samples were not affected by polluting substances such as crude oil and lubricants while drilling operation. Jones organic fancies diagram shows B-BC area indicating that Pabdeh Formation was deposited in marine anoxic to oxic environments. HI vesus Tmax shows that most samples initially have had type II kerogen and now reflecting a mixture of type II to III kerogen (capable of generating oil that have already entered oil generation window. In addition, S1+S2 versus TOC plot also suggests that Pabdeh Formation can be considered as a capable hydrocarbon generating source rock in the study area.

  6. Rapid formation of rock armour for soil - rock fragment mixture during simulated rainfall

    Science.gov (United States)

    Poultney, E.; McGrath, G. S.; Hinz, C.

    2009-04-01

    Preventing erosion is an important issue in disturbed semi-arid and arid landscapes. This is in particular of highest importance for mining companies while undertaking land rehabilitation. An onsite investigation of the impact of surface rock fragments on erosion was conducted at Telfer goldmine in the Great Sandy Desert, Western Australia. The study site is a waste rock dump designed to mimic the concave slope of a natural mesa to both discourage erosion and blend in with its natural surroundings. Four treatments were used to construct the slope: two are topsoil mixed with rock fragments, and two are unmixed topsoil. A field study investigating erosion rills, particle size distribution, rock fragment coverage surface roughness and vegetation was carried out to determine changes down and across slope. The treatments constructed by mixing topsoil and rock fragments are more stable and show rock fragment distributions that more closely resemble patterns found on natural mesas surrounding Telfer. A controlled study using trays of topsoil mixed with rock fragment volumes of 50%, 60%, 70% and 80% were used to investigate how varying mixtures of rock fragments and topsoil erode using rainfall intensities between 20 and 100 mm h-1. Two runs of 25 minutes each were used to assess the temporal evolution of rock armouring. Surface coverage results converged for the 50%, 60% and 70% mixtures after the first run to coverage of about 90%, suggesting that fine sediment proportion does not affect rate and degree of rock armouring.

  7. Rock.XML - Towards a library of rock physics models

    Science.gov (United States)

    Jensen, Erling Hugo; Hauge, Ragnar; Ulvmoen, Marit; Johansen, Tor Arne; Drottning, Åsmund

    2016-08-01

    Rock physics modelling provides tools for correlating physical properties of rocks and their constituents to the geophysical observations we measure on a larger scale. Many different theoretical and empirical models exist, to cover the range of different types of rocks. However, upon reviewing these, we see that they are all built around a few main concepts. Based on this observation, we propose a format for digitally storing the specifications for rock physics models which we have named Rock.XML. It does not only contain data about the various constituents, but also the theories and how they are used to combine these building blocks to make a representative model for a particular rock. The format is based on the Extensible Markup Language XML, making it flexible enough to handle complex models as well as scalable towards extending it with new theories and models. This technology has great advantages as far as documenting and exchanging models in an unambiguous way between people and between software. Rock.XML can become a platform for creating a library of rock physics models; making them more accessible to everyone.

  8. Experimental research on rock fracture failure characteristics under liquid nitrogen cooling conditions

    Science.gov (United States)

    Gao, Feng; Cai, Chengzheng; Yang, Yugui

    2018-06-01

    As liquid nitrogen is injected into a wellbore as fracturing fluid, it can rapidly absorb heat from warmer rock and generate cryogenic condition in downhole region. This will alter the physical conditions of reservoir rocks and further affect rock failure characteristics. To investigate rock fracture failure characteristics under liquid nitrogen cooling conditions, the fracture features of four types of sandstones and one type of marble were tested on original samples (the sample without any treatment) and cryogenic samples (the samples just taken out from the liquid nitrogen), respectively. The differences between original samples and cryogenic samples in load-displacement curves, fracture toughness, energy evolution and the crack density of ruptured samples were compared and analyzed. The results showed that at elastic deformation stage, cryogenic samples presented less plastic deformation and more obvious brittle failure characteristics than original ones. The average fracture toughness of cryogenic samples was 10.47%-158.33% greater than that of original ones, indicating that the mechanical strength of rocks used were enhanced under cooling conditions. When the samples ruptured, the cryogenic ones were required to absorb more energy and reserve more elastic energy. In general, the fracture degree of cryogenic samples was higher than that of original ones. As the samples were entirely fractured, the crack density of cryogenic samples was about 536.67% at most larger than that of original ones. This indicated that under liquid nitrogen cooling conditions, the stimulation reservoir volume is expected to be improved during fracturing. This work could provide a reference to the research on the mechanical properties and fracture failure of rock during liquid nitrogen fracturing.

  9. Research on Dynamic Dissolving Model and Experiment for Rock Salt under Different Flow Conditions

    Directory of Open Access Journals (Sweden)

    Xinrong Liu

    2015-01-01

    Full Text Available Utilizing deep rock salt cavern is not only a widely recognized energy reserve method but also a key development direction for implementing the energy strategic reserve plan. And rock salt cavern adopts solution mining techniques to realize building cavity. In view of this, the paper, based on the dissolving properties of rock salt, being simplified and hypothesized the dynamic dissolving process of rock salt, combined conditions between dissolution effect and seepage effect in establishing dynamic dissolving models of rock salt under different flow quantities. Devices were also designed to test the dynamic dissolving process for rock salt samples under different flow quantities and then utilized the finite-difference method to find the numerical solution of the dynamic dissolving model. The artificial intelligence algorithm, Particle Swarm Optimization algorithm (PSO, was finally introduced to conduct inverse analysis of parameters on the established model, whose calculation results coincide with the experimental data.

  10. Influence of deformation on the fluid transport properties of salt rocks

    NARCIS (Netherlands)

    Peach, C.J.

    1991-01-01

    While the fluid transport properties of rocks are well understood under hydrostatic conditions, little is known regarding these properties in rocks undergoing crystal plastic deformation. However, such data are needed as input in the field of radioactive waste disposal in salt formations. They

  11. Thermo-mechanical Properties of Upper Jurassic (Malm) Carbonate Rock Under Drained Conditions

    Science.gov (United States)

    Pei, Liang; Blöcher, Guido; Milsch, Harald; Zimmermann, Günter; Sass, Ingo; Huenges, Ernst

    2018-01-01

    The present study aims to quantify the thermo-mechanical properties of Neuburger Bankkalk limestone, an outcrop analog of the Upper Jurassic carbonate formation (Germany), and to provide a reference for reservoir rock deformation within future enhanced geothermal systems located in the Southern German Molasse Basin. Experiments deriving the drained bulk compressibility C were performed by cycling confining pressure p c between 2 and 50 MPa at a constant pore pressure p p of 0.5 MPa after heating the samples to defined temperatures between 30 and 90 °C. Creep strain was then measured after each loading and unloading stage, and permeability k was obtained after each creep strain measurement. The drained bulk compressibility increased with increasing temperature and decreased with increasing differential pressure p d = p c - p p showing hysteresis between the loading and unloading stages above 30 °C. The apparent values of the indirectly calculated Biot coefficient α ind containing contributions from inelastic deformation displayed the same temperature and pressure dependencies. The permeability k increased immediately after heating and the creep rates were also temperature dependent. It is inferred that the alteration of the void space caused by temperature changes leads to the variation of rock properties measured under isothermal conditions while the load cycles applied under isothermal conditions yield additional changes in pore space microstructure. The experimental results were applied to a geothermal fluid production scenario to constrain drawdown and time-dependent effects on the reservoir, overall, to provide a reference for the hydromechanical behavior of geothermal systems in carbonate, and more specifically, in Upper Jurassic lithologies.

  12. Effect of Hydrothermal Alteration on Rock Properties in Active Geothermal Setting

    Science.gov (United States)

    Mikisek, P.; Bignall, G.; Sepulveda, F.; Sass, I.

    2012-04-01

    Hydrothermal alteration records the physical-chemical changes of rock and mineral phases caused by the interaction of hot fluids and wall rock, which can impact effective permeability, porosity, thermal parameters, rock strength and other rock properties. In this project, an experimental approach has been used to investigate the effects of hydrothermal alteration on rock properties. A rock property database of contrastingly altered rock types and intensities has been established. The database details horizontal and vertical permeability, porosity, density, thermal conductivity and thermal heat capacity for ~300 drill core samples from wells THM12, THM13, THM14, THM17, THM18, THM22 and TH18 in the Wairakei-Tauhara geothermal system (New Zealand), which has been compared with observed hydrothermal alteration type, rank and intensity obtained from XRD analysis and optical microscopy. Samples were selected from clay-altered tuff and intercalated siltstones of the Huka Falls Formation, which acts as a cap rock at Wairakei-Tauhara, and tuffaceous sandstones of the Waiora Formation, which is a primary reservoir-hosting unit for lateral and vertical fluid flows in the geothermal system. The Huka Falls Formation exhibits argillic-type alteration of varying intensity, while underlying Waiora Formations exhibits argillic- and propylithic-type alteration. We plan to use a tempered triaxial test cell at hydrothermal temperatures (up to 200°C) and pressures typical of geothermal conditions, to simulate hot (thermal) fluid percolation through the rock matrix of an inferred "reservoir". Compressibility data will be obtained under a range of operating (simulation reservoir) conditions, in a series of multiple week to month-long experiments that will monitor change in permeability and rock strength accompanying advancing hydrothermal alteration intensity caused by the hot brine interacting with the rock matrix. We suggest, our work will provide new baseline information concerning

  13. Experimental Studies on Permeability of Intact and Singly Jointed Meta-Sedimentary Rocks Under Confining Pressure

    Science.gov (United States)

    Wong, Louis Ngai Yuen; Li, Diyuan; Liu, Gang

    2013-01-01

    Three different types of permeability tests were conducted on 23 intact and singly jointed rock specimens, which were cored from rock blocks collected from a rock cavern under construction in Singapore. The studied rock types belong to inter-bedded meta-sandstone and meta-siltstone with very low porosity and high uniaxial compressive strength. The transient pulse water flow method was employed to measure the permeability of intact meta-sandstone under a confining pressure up to 30 MPa. It showed that the magnitude order of meta-sandstone's intrinsic permeability is about 10-18 m2. The steady-state gas flow method was used to measure the permeability of both intact meta-siltstone and meta-sandstone in a triaxial cell under different confining pressures spanning from 2.5 to 10 MPa. The measured permeability of both rock types ranged from 10-21 to 10-20 m2. The influence of a single natural joint on the permeability of both rock types was studied by using the steady-state water flow method under different confining pressures spanning from 1.25 to 5.0 MPa, including loading and unloading phases. The measured permeability of both jointed rocks ranged from 10-13 to 10-11 m2, where the permeability of jointed meta-siltstone was usually slightly lower than that of jointed meta-sandstone. The permeability of jointed rocks decreases with increasing confining pressure, which can be well fitted by an empirical power law relationship between the permeability and confining pressure or effective pressure. The permeability of partly open cracked specimens is lower than that of open cracked specimens, but it is higher than that of the specimen with a dominant vein for the meta-sandstone under the same confining pressure. The permeability of open cracked rock specimens will partially recover during the unloading confining pressure process. The equivalent crack (joint) aperture is as narrow as a magnitude order of 10-6 m (1 μm) in the rock specimens under confining pressures

  14. Influence of deformation on the fluid transport properties of salt rocks

    NARCIS (Netherlands)

    Peach, C.J.

    1991-01-01

    While the fluid transport properties of rocks are well understood under hydrostatic conditions, little is known regarding these properties in rocks undergoing crystal plastic deformation. However, such data are needed as input in the field of radioactive waste disposal in salt formations. They are

  15. Correlation of the Canol Formation source rock with oil from Norman Wells

    Energy Technology Data Exchange (ETDEWEB)

    Snowdon, L.R.; Brooks, P.W.; Williams, G.K.; Goodarzi, F.

    1987-01-01

    The source of the oil at Norman Wells has long been assumed to have been the Canol Formation and/or the Bluefish Member of the Hare Indian Formation. These two units are stratigraphically above and below the Kee Scarp Formation reservoir unit respectively, and are both bituminous shales. A wide range of analytical techniques including Rock-Eval pyrolysis, solvent extraction and fractionation, capillary gas chromatography, gas chromatography-mass spectrometry, and white light and fluorescence microscopy has been used to characterize core samples of these two units and two samples of crude oil from the Norman Wells field. Most of the analytical techniques were insufficiently refined to either differentiate the extracts from each other or to make a definitive oil/source rock correlation. Collision activated decomposition coupled with multiple ion detection mass spectrometry (GC-MS-MS) did provide sufficient chemical compositional detail of the oils and the two potential sources to demonstrate that the Canol Formation has been the effective source of the Normal Wells oil whereas the Bluefish Member has not. The level of thermal maturity of the core samples ranges from immature to moderately mature in the vicinity of the Norman Wells field to overmature for the samples obtained to the west and north of the field. The level of thermal maturity of the oil was observed to be somewhat higher than that of the samples of the source formation directly above the field. It was thus inferred that some lateral migration from more mature areas has occurred but the extent of this migration was not necessarily more than a few to tens of kilometers.

  16. Peroxy defects in Rocks and H2O2 formation on the early Earth

    Science.gov (United States)

    Gray, A.; Balk, M.; Mason, P.; Freund, F.; Rothschild, L.

    2013-12-01

    An oxygen-rich atmosphere appears to have been a prerequisite for complex life to evolve on Earth and possibly elsewhere in the Universe. The question is still shrouded in uncertainty how free oxygen became available on the early Earth. Here we study processes of peroxy defects in silicate minerals which, upon weathering, generate mobilized electronic charge carriers resulting in oxygen formation in an initially anoxic subsurface environment. Reactive Oxygen Species (ROS) are precursors to molecular oxygen during this process. Due to their toxicity they may have strongly influenced the evolution of life. ROS are generated during hydrolysis of peroxy defects, which consist of pairs of oxygen anions. A second pathway for formation occurs during (bio) transformations of iron sulphide minerals. ROS are produced and consumed by intracellular and extracellular reactions of Fe, Mn, C, N, and S species. We propose that despite an overall reducing or neutral oxidation state of the macroenvironment and the absence of free O2 in the atmosphere, microorganisms on the early Earth had to cope with ROS in their microenvironments. They were thus under evolutionary pressure to develop enzymatic and other defenses against the potentially dangerous, even lethal effects of ROS and oxygen. We have investigated how oxygen might be released through weathering and test microorganisms in contact with rock surfaces. Our results show how early Life might have adapted to oxygen. Early microorganisms must have "trained" to detoxify ROS prior to the evolution of aerobic metabolism and oxygenic photosynthesis. A possible way out of this dilemma comes from a study of igneous and high-grade metamorphic rocks, whose minerals contain a small but significant fraction of oxygen anions in the valence state 1- , forming peroxy links of the type O3Si-OO-SiO3 [1, 2]. As water hydrolyzes the peroxy links hydrogen peroxide, H2O2, forms. Continued experimental discovery of H2O2 formation at rock

  17. Measurement of diffusive properties of intact rock

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, K B

    1996-12-01

    In the Postclosure Assessment of a Reference System for the Disposal of Canada`s Nuclear Fuel Waste (Goodwin et al. 1994) the disposal vault is assumed to be surrounded by a zone of intact rock, referred to as the `exclusion zone.` A sensitivity analysis of the relative effectiveness of the several engineered and natural barriers that contribute to the safety of the reference disposal system has shown that this zone of intact rock is the most effective of these barriers to the movement of radionuclides through the reference system. Peer review of the geosphere model used in the case study for the EIS (Environmental Impact Statement) of the Canadian Nuclear Fuel Waste Management Program has identified the need to quantify the properties of the intact rock surrounding the disposal vault that would control the transport of radionuclides by diffusion. The Postclosure Assessment also identified the need for appropriate values of the free water diffusion coefficient (D{sub o}) for {sup 129}1 and {sup 14}C. The measurement of rock resistivity allows the calculation of the Formation Factor for a rock This review describes the Formation Factor, diffusivity, permeability, and porosity, and how these properties might be measured or inferred for insitu rock under the conditions that apply to the intact rock surrounding a potential disposal vault. The importance of measuring the intrinsic diffusion coefficient (D{sup i}) of diffusing species under solution salinities simulating those of groundwaters is emphasised, and a method of measurement is described that is independent of the diffusing medium, and which would be appropriate for measurements made in chemically complex media such as groundwaters. (author). 95 refs., 4 tabs., 39 figs.

  18. Measurement of diffusive properties of intact rock

    International Nuclear Information System (INIS)

    Harvey, K.B.

    1996-12-01

    In the Postclosure Assessment of a Reference System for the Disposal of Canada's Nuclear Fuel Waste (Goodwin et al. 1994) the disposal vault is assumed to be surrounded by a zone of intact rock, referred to as the 'exclusion zone.' A sensitivity analysis of the relative effectiveness of the several engineered and natural barriers that contribute to the safety of the reference disposal system has shown that this zone of intact rock is the most effective of these barriers to the movement of radionuclides through the reference system. Peer review of the geosphere model used in the case study for the EIS (Environmental Impact Statement) of the Canadian Nuclear Fuel Waste Management Program has identified the need to quantify the properties of the intact rock surrounding the disposal vault that would control the transport of radionuclides by diffusion. The Postclosure Assessment also identified the need for appropriate values of the free water diffusion coefficient (D o ) for 129 1 and 14 C. The measurement of rock resistivity allows the calculation of the Formation Factor for a rock This review describes the Formation Factor, diffusivity, permeability, and porosity, and how these properties might be measured or inferred for insitu rock under the conditions that apply to the intact rock surrounding a potential disposal vault. The importance of measuring the intrinsic diffusion coefficient (D i ) of diffusing species under solution salinities simulating those of groundwaters is emphasised, and a method of measurement is described that is independent of the diffusing medium, and which would be appropriate for measurements made in chemically complex media such as groundwaters. (author). 95 refs., 4 tabs., 39 figs

  19. The potentiality of hydrocarbon generation of the Jurassic source rocks in Salam-3x well,

    Directory of Open Access Journals (Sweden)

    Mohamed M. El Nady

    2016-03-01

    Full Text Available The present work deals with the identification of the potential and generating capability of oil generation in the Jurassic source rocks in the Salam-3x well. This depending on the organo-geochemical analyses of cutting samples representative of Masajid, Khatatba and Ras Qattara formations, as well as, representative extract samples of the Khatatba and Ras Qattara formations. The geochemical analysis suggested the potential source intervals within the encountered rock units as follows: Masajid Formation bears mature source rocks and have poor to fair generating capability for generating gas (type III kerogen. Khatatba Formation bears mature source rock, and has poor to good generating capability for both oil and gas. Ras Qattara Formation constituting mature source rock has good to very good generating capability for both oil and gas. The burial history modeling shows that the Masajid Formation lies within oil and gas windows; Khatatba and Ras Qattara formations lie within the gas window. From the biomarker characteristics of source rocks it appears that the extract is genetically related as the majority of them were derived from marine organic matters sources (mainly algae deposited under reducing environment and take the direction of increasing maturity and far away from the direction of biodegradation. Therefore, Masajid Formation is considered as effective source rocks for generating hydrocarbons, while Khatatba and Ras Qattara formations are the main source rocks for hydrocarbon accumulations in the Salam-3x well.

  20. Dynamic Brazilian Test of Rock Under Intermediate Strain Rate: Pendulum Hammer-Driven SHPB Test and Numerical Simulation

    Science.gov (United States)

    Zhu, W. C.; Niu, L. L.; Li, S. H.; Xu, Z. H.

    2015-09-01

    The tensile strength of rock subjected to dynamic loading constitutes many engineering applications such as rock drilling and blasting. The dynamic Brazilian test of rock specimens was conducted with the split Hopkinson pressure bar (SHPB) driven by pendulum hammer, in order to determine the indirect tensile strength of rock under an intermediate strain rate ranging from 5.2 to 12.9 s-1, which is achieved when the incident bar is impacted by pendulum hammer with different velocities. The incident wave excited by pendulum hammer is triangular in shape, featuring a long rising time, and it is considered to be helpful for achieving a constant strain rate in the rock specimen. The dynamic indirect tensile strength of rock increases with strain rate. Then, the numerical simulator RFPA-Dynamics, a well-recognized software for simulating the rock failure under dynamic loading, is validated by reproducing the Brazilian test of rock when the incident stress wave retrieved at the incident bar is input as the boundary condition, and then it is employed to study the Brazilian test of rock under the higher strain rate. Based on the numerical simulation, the strain-rate dependency of tensile strength and failure pattern of the Brazilian disc specimen under the intermediate strain rate are numerically simulated, and the associated failure mechanism is clarified. It is deemed that the material heterogeneity should be a reason for the strain-rate dependency of rock.

  1. Structural and kinematic analysis from Montevideo Formation rocks

    International Nuclear Information System (INIS)

    Masquelin, E.; Gutierrez, L.; Sienra, M.

    2004-01-01

    The main purpose of this work is to bring new advances about structural and kinematic analysis from Montevideo Formation rocks. This information was collected by means of the classic methodology used for metamorphic terrains: (i) to recognize the nature of the protoliths, (ii) to discriminate the diversity of intrusive rocks and their relative age, (iii) to evaluate the intensity of strain, and (iv) to find the relationship between this strain and related displacements, in accordance to the unified theory for ductile shear zones. The exposed results show that there are not enough evidences to prove that the layering found in para-amphibolites and para-gneisses is the bedding surface. Although various lava primary structures were presented, these structures do not bring the bedding plane directly, and sedimentary structures are suspicious. In the other hand, the strain has proved to be very intense, by the development of isoclinal folds (may be intrafolial), highly strained veins of plagioclase-bearing gneiss and the boudinage of the duplicated sequence parallel to the axes of D2 later folds. The D2 fold axes parallel direction could be acted as the transport direction of a major strike-slip shear zone, striking N70 0 E. The fact is that various ductile flow vorticity indicators were found in para-amphibolites showing a dextral shear sense [es

  2. Investigating Microbial Biofilm Formations on Crustal Rock Substrates

    Science.gov (United States)

    Weiser, M.; D'Angelo, T.; Carr, S. A.; Orcutt, B.

    2017-12-01

    Ocean crust hosts microbial life that, in some cases, alter the component rocks as a means of obtaining energy. Variations in crust lithology, included trace metal and mineral content, as well as the chemistry of the fluids circulating through them, provide substrates for some microbes to metabolize, leading to formation of biofilm community structures. Microbes have different parameters for the situations in which they will form biofilms, but they must have some source of energy in excess at the site of biofilm formation for them to become stationary and form the carbohydrate-rich structures connecting the cells to one another and the substrate. Generally, the requirements for microbes to form biofilms on crustal minerals are unclear. We designed two experiments to test (1) mineral preference and biofilm formation rates by natural seawater microbial communities, and (2) biofilm development as a function of phosphate availability for an organism isolated from subseafloor ocean crust. In Experiment 1, we observed that phyric basalt groundmass is preferentially colonized over aphyric basalt or metal sulfides in a shallow water and oxic seawater environment. In experiment 2, tests of the anaerobic heterotroph Thalassospira bacteria isolated from oceanic crustal fluids showed that they preferentially form biofilms, lose motility, and increase exponentially in number over time in higher-PO4 treatments (50 micromolar), including with phosphate-doped basalts, than in treatments with low phosphate concentrations (0.5 micromolar) often found in crustal fluids. These observations suggest phosphate as a main driver of biofilm formation in subsurface crust. Overall, these data suggest that the drivers of microbial biofilm formation on crustal substrates are selective to the substrate conditions, which has important implications for estimating the global biomass of life harbored in oceanic crust.

  3. Technical support for GEIS: radioactive waste isolation in geologic formations. Volume 5. Baseline rock properties-granite

    International Nuclear Information System (INIS)

    1978-04-01

    This volume, Y/OWI/TM-36/5, Baseline Rock Properties--Granite, is one of a 23-volume series, ''Technical Support for GEIS: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-36'' which supplements a ''Contribution to Draft Generic Environmental Impact Statement on Commercial Waste Management: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-44.'' The series provides a more complete technical basis for the preconceptual designs, resource requirements, and environmental source terms associated with isolating commercial LWR wastes in underground repositories in salt, granite, shale and basalt. Wastes are considered from three fuel cycles: uranium and plutonium recycling, no recycling of spent fuel and uranium-only recycling. This report, on the rock properties of typical granites, includes an evaluation of the various test results reported in the literature. Firstly, a literature survey was made in order to obtain a feel for the range of rock properties encountered. Then, granites representative of different geologic ages and from different parts of the United States were selected and studied in further detail. Some of the special characteristics of granite, such as anisotropy, creep and weathering were also investigated. Lastly, intact properties for a typical granite were selected and rock mass properties were derived using appropriate correction factors

  4. Mechanics of graben formation in crustal rocks - A finite element analysis

    Science.gov (United States)

    Melosh, H. J.; Williams, C. A., Jr.

    1989-01-01

    The mechanics of the initial stages of graben formation are examined, showing that the configuration of a graben (a pair of antithetically dipping normal faults) is the most energetically favorable fault configuration in elastic-brittle rocks subjected to pure extension. The stress field in the vicinity of a single initial normal fault is computed with a two-dimensional FEM. It is concluded that the major factor controlling graben width is the depth of the initial fault.

  5. Mechanical Behavior of Shale Rock under Uniaxial Cyclic Loading and Unloading Condition

    Directory of Open Access Journals (Sweden)

    Baoyun Zhao

    2018-01-01

    Full Text Available In order to investigate the mechanical behavior of shale rock under cyclic loading and unloading condition, two kinds of incremental cyclic loading tests were conducted. Based on the result of the short-term uniaxial incremental cyclic loading test, the permanent residual strain, modulus, and damage evolution were analyzed firstly. Results showed that the relationship between the residual strains and the cycle number can be expressed by an exponential function. The deformation modulus E50 and elastic modulus ES first increased and then decreased with the peak stress under the loading condition, and both of them increased approximately linearly with the peak stress under the unloading condition. On the basis of the energy dissipation, the damage variables showed an exponential increasing with the strain at peak stress. The creep behavior of the shale rock was also analyzed. Results showed that there are obvious instantaneous strain, decay creep, and steady creep under each stress level and the specimen appears the accelerated creep stage under the 4th stress of 51.16 MPa. Based on the characteristics of the Burgers creep model, a viscoelastic-plastic creep model was proposed through viscoplastic mechanics, which agrees very well with the experimental results and can better describe the creep behavior of shale rock better than the Burgers creep model. Results can provide some mechanics reference evidence for shale gas development.

  6. Source rock formation evaluation using TOC & Ro log model based on well-log data procesing: study case of Ngimbang formation, North East Java basin

    Directory of Open Access Journals (Sweden)

    Fatahillah Yosar

    2017-01-01

    Full Text Available Ngimbang Formation is known as one major source of hydrocarbon supply in the North Eastern Java Basin. Aged Mid-Eocene, Ngimbang is dominated by sedimentary clastic rocks mostly shale, shaly sandstone, and thick layers of limestone (CD Limestone, with thin layers of coal. Although, laboratory analyses show the Ngimbang Formation to be a relatively rich source-rocks, such data are typically too limited to regionally quantify the distribution of organic matter. To adequately sample the formation both horizontally and vertically on a basin–wide scale, large number of costly and time consuming laboratory analyses would be required. Such analyses are prone to errors from a number of sources, and core data are frequently not available at key locations. In this paper, the authors established four TOC (Total Organic Carbon Content logging calculation models; Passey, Schmoker-Hester, Meyer-Nederloff, and Decker/Density Model by considering the geology of Ngimbang. Well data along with its available core data was used to determine the most suitable model to be applied in the well AFA-1, as well as to compare the accuracy of these TOC model values. The result shows good correlation using Decker (TOC Model and Mallick-Raju (Ro- Vitrinite Reflectance Model. Two source rocks potential zones were detected by these log models.

  7. Mechanical and Thermophysical Properties of Cubic Rock-Salt AlN Under High Pressure

    Science.gov (United States)

    Lebga, Noudjoud; Daoud, Salah; Sun, Xiao-Wei; Bioud, Nadhira; Latreche, Abdelhakim

    2018-03-01

    Density functional theory, density functional perturbation theory, and the Debye model have been used to investigate the structural, elastic, sound velocity, and thermodynamic properties of AlN with cubic rock-salt structure under high pressure, yielding the equilibrium structural parameters, equation of state, and elastic constants of this interesting material. The isotropic shear modulus, Pugh ratio, and Poisson's ratio were also investigated carefully. In addition, the longitudinal, transverse, and average elastic wave velocities, phonon contribution to the thermal conductivity, and interesting thermodynamic properties were predicted and analyzed in detail. The results demonstrate that the behavior of the elastic wave velocities under increasing hydrostatic pressure explains the hardening of the corresponding phonons. Based on the elastic stability criteria under pressure, it is found that AlN with cubic rock-salt structure is mechanically stable, even at pressures up to 100 GPa. Analysis of the Pugh ratio and Poisson's ratio revealed that AlN with cubic rock-salt structure behaves in brittle manner.

  8. SHRIMP zircon U-Pb age and its significances of volcanic rocks from banshi basin in south jiangxi province

    International Nuclear Information System (INIS)

    Wang Baofeng; Wu Jianhua

    2011-01-01

    SHRIMP zircon U-Pb dating is applied to geochronological study for tuff of original Jilongzhang formation and rhyolite of original Banshi formation in Banshi basin, located in the Sannan (Longnan, Dingnan, Quannan) -Xunwu volcanic rocks belts in the south of Jiangxi. The result shows that zircon SHRIMP U-Pb age of the tuff is (142.5 ± 1.3) Ma and the age of the rhyolite is (131.4 ± 1.3) Ma. According to the latest international stratigraphic chart, the boundary between Jurassic and Cretaceous is (145.4 ± 4.0) Ma. So original Jilongzhang Formation and original Banshi Formation in Banshi basin were formed during early Early Cretaceous. The volcanic series in Banshi basin belongs to only one volcanic cycle. The features of the rock associations consistent with Wuyi group on the Xiajiang-Guangfeng volcanic rocks belts in the north of Jiangxi, so original Jilongzhang formation falls under E'huling formation and original Banshi formation falls under Shixi formation. (authors)

  9. Model test study on propagation law of plane stress wave in jointed rock mass under different in-situ stresses

    Science.gov (United States)

    Dong, Qian

    2017-12-01

    The study of propagation law of plane stress wave in jointed rock mass under in-situ stress has important significance for safety excavation of underground rock mass engineering. A model test of the blasting stress waves propagating in the intact rock and jointed rock mass under different in-situ stresses was carried out, and the influencing factors on the propagation law, such as the scale of static loads and the number of joints were studied respectively. The results show that the transmission coefficient of intact rock is larger than that of jointed rock mass under the same loading condition. With the increase of confining pressure, the transmission coefficients of intact rock and jointed rock mass both show an trend of increasing first and then decreasing, and the variation of transmission coefficients in intact rock is smaller than that of jointed rock mass. Transmission coefficient of jointed rock mass decreases with the increase of the number of joints under the same loading condition, when the confining pressure is relatively small, the reduction of transmission coefficients decreases with the increasing of the number of joints, and the variation law of the reduction of transmission coefficients is contrary when the confining pressure is large.

  10. Experimental Research on Internal Behaviors of Caved Rocks under the Uniaxial Confined Compression

    Directory of Open Access Journals (Sweden)

    Yu-jiang Zhang

    2017-01-01

    Full Text Available As main composition of longwall gob, caved rocks’ behaviors and their impacts under compression crucially influence strata control, subsidence, associated resources extraction, and many other aspects. However, current researches are based on a whole sample, due to looseness of caved rocks and limitation of observation technology. In this paper, an experiment system was built to investigate internal behaviors of caved rocks’ sample, under the uniaxial confined compression, including movement and breakage behavior by the digital image processing technologies. The results show that the compression process of caved rocks could be divided into two stages by relative density. Boundary effect and changes of voids and contact pressure among caved rocks lead to different movement law in different position in sample’s interior. A stratification phenomenon of breakage was discovered, which presents breakage concentration in the middle of the sample. The nonlinear movement and shear dislocation induced by shifts among caved rocks are the reason of the breakage stratification phenomenon. This phenomenon would have an effect on the permeability and seepage research of similar medium.

  11. Stratigraphical sequence and geochronology of the volcanic rock series in caifang basin, south jiangxi

    International Nuclear Information System (INIS)

    Xu Xunsheng; Wu Jianhua

    2010-01-01

    The late Mesozoic volcanic rocks in Jiangxi constitute two volcanic belts: the northern is Xiajiang-Guangfeng volcanic belt, the volcanic rocks series belong to one volcano cycle and named Wuyi group which is subdivided into three formations (Shuangfengling formation, Ehuling formation and Shixi formation); the southern is Sannan-Xunwu volcanic belt, the volcanic rocks series in Caifang basin which locates on Sannan-Xunwu volcanic belt also belong to only one volcano cycle. It can be subdivided into two lithology and lithofacies units (upper and lower): the lower unit consists of sedimentary rocks and associated with a subordinate amount of volcanic rocks, it belongs to erupt-deposit facies which is the product of early volcanic stage; the upper unit is mostly composed of volcanic rocks, it belongs to erupt facies that is the volcanic eruption product. SHRIMP zircon U-Pb age of rhyolite? which locates at the top of the upper unit is 130.79 ± 0.73) Ma. According to the new International Stratigraphic Chart, the boundary of Jurassic and Cretaceous is (145.4 ± 4.0) Ma, so the age shows that the geologic period of Caifang volcanic rocks series is early Early Cretaceous epoch. On the basis of lithological correlation, lithofacies and stratigraphic horizon analysis, the volcanic rock series in Caifang basin fall under Wuyi group, and the lower unit could be incorporated into Shuangfengling formation, the upper unit could be incorporated into Ehuling formation. The subdivision of sequence and the determination of geochronology of the volcanic rock series in Caifang basin provide some references for the study of the late Mesozoic volcanic rocks series of the Sannan-Xunwu volcanic belt. (authors)

  12. 76 FR 771 - Reorganization/Expansion of Foreign-Trade Zone 14 Under Alternative Site Framework; Little Rock, AR

    Science.gov (United States)

    2011-01-06

    ... DEPARTMENT OF COMMERCE Foreign-Trade Zones Board [Order No. 1729] Reorganization/Expansion of Foreign-Trade Zone 14 Under Alternative Site Framework; Little Rock, AR Pursuant to its authority under... the Little Rock Customs and Border [[Page 772

  13. Nanggulan Formation and Its Problem As a Basement in Kulonprogo Basin, Yogyakarta

    Directory of Open Access Journals (Sweden)

    Hill Gendoet Hartono

    2017-03-01

    Full Text Available DOI: 10.17014/ijog.4.2.71-80Nanggulan Formation consists of the oldest clastic rock sequence exposed in Kulonprogo area, Yogyakarta. This paper discusses the position of Nanggulan Formation as a basement. The method used in this research is surface and subsurface investigations based on gravity surveys. The rock assemblage is exposed and distributed partly in the east flank of Kulonprogo Mountains with weak undulated morphology. The rock sequence is composed of sand to clay grain sizes such as sandstone, quartz sandstone, calcareous sandstone, claystone, fossiliferous claystone, calcareous claystone, siltstone, and coal seam intercalations. The total thickness of the sequence is less than 200 m. Based on the fossil and palynology investigations, previous investigators concluded the age of the rock was Eocene to Middle Miocene. The geological structures developed in the rocks are the lithological stratification, fractures, folding, and faulting. The subsurface interpretation based on gravity data revealed the rock was located under the andesite breccias with 2.44 g/cc density. The density of the rock sequence was 2.63 g/cc. The gravity interpretation shows a strong indication that Nanggulan Formation underlies the andesitic breccias presumably associated with Old Andesite Formation exposed in Kulonprogo Mountains. The limited distribution, the thickness, and the closed environmental deposition of Nanggulan Formation found in the present investigation raised problems on the position of the formation as the basement of Old Andesite Formation occurring in the Kulonprogo Mountain.

  14. Sampling and treatment of rock cores and groundwater under reducing environments of deep underground

    International Nuclear Information System (INIS)

    Ebashi, Katsuhiro; Yamaguchi, Tetsuji; Tanaka, Tadao

    2005-01-01

    A method of sampling and treatment of undisturbed rock cores and groundwater under maintained reducing environments of deep underground was developed and demonstrated in a Neogene's sandy mudstone layer at depth of GL-100 to -200 m. Undisturbed rock cores and groundwater were sampled and transferred into an Ar gas atmospheric glove box with minimized exposure to the atmosphere. The reducing conditions of the sampled groundwater and rock cores were examined in the Ar atmospheric glove box by measuring pH and Eh of the sampled groundwater and sampled groundwater contacting with disk type rock samples, respectively. (author)

  15. Radiation induced color center and colloid formation in synthetic NaCl and natural rock salt

    International Nuclear Information System (INIS)

    Levy, P.W.; Swyler, K.J.; Klaffky, R.W.

    1979-01-01

    F-center and colloid particle formation has been studied in synthetic NaCl and natural rock salt crystals with apparatus for making optical absorption measurements during irradiation. F-center and colloid formation are functions of temperature, dose, dose rate, strain applied prior to irradiation and numerous other factors. Many of the observed properties are in accord with the Jain-Lidiard theory for radiation induced F-center and colloid growth above room temperature

  16. NanoRocks: Design and performance of an experiment studying planet formation on the International Space Station

    Science.gov (United States)

    Brisset, Julie; Colwell, Joshua; Dove, Adrienne; Maukonen, Doug

    2017-07-01

    In an effort to better understand the early stages of planet formation, we have developed a 1.5U payload that flew on the International Space Station (ISS) in the NanoRacks NanoLab facility between September 2014 and March 2016. This payload, named NanoRocks, ran a particle collision experiment under long-term microgravity conditions. The objectives of the experiment were (a) to observe collisions between mm-sized particles at relative velocities of acrylic, glass, and copper beads and 0.75 mm-sized JSC-1 lunar regolith simulant grains. The particles were placed in sample cells carved out of an aluminum tray. This tray was attached to one side of the payload casing with three springs. Every 60 s, the tray was agitated, and the resulting collisions between the particles in the sample cells were recorded by the experiment camera. During the 18 months the payload stayed on ISS, we obtained 158 videos, thus recording a great number of collisions. The average particle velocities in the sample cells after each shaking event were around 1 cm/s. After shaking stopped, the inter-particle collisions damped the particle kinetic energy in less than 20 s, reducing the average particle velocity to below 1 mm/s, and eventually slowing them to below our detection threshold. As the particle velocity decreased, we observed the transition from bouncing to sticking collisions. We recorded the formation of particle clusters at the end of each experiment run. This paper describes the design and performance of the NanoRocks ISS payload.

  17. Temporal evolution of a granitic rock under thermal loads generated by fission products

    International Nuclear Information System (INIS)

    Ventura, M.A.; Ferreri, J.C.

    1985-01-01

    A parametric study of the thermal history of a granitic mass under thermal loads originating in terminal subproducts of the fuel cycle is performed. Variations of the conductivity and density of the rock and the unit cell dimensions are considered. In this way it was tried to delimit (for short time intervals of the order of 100 years) the influence of possible uncertainties in the rock's knowledge on the results of interest for the engineering design. In the reasonable situations considered, the maximum temperature in the rock did not rise over 80 deg C. (Author) [es

  18. Thermal characteristics of rocks for high-level waste repository

    International Nuclear Information System (INIS)

    Shimooka, Kenji; Ishizaki, Kanjiro; Okamoto, Masamichi; Kumata, Masahiro; Araki, Kunio; Amano, Hiroshi

    1980-12-01

    Heat released by the radioactive decay of high-level waste in an underground repository causes a long term thermal disturbance in the surrounding rock mass. Several rocks constituting geological formations in Japan were gathered and specific heat, thermal conductivity, thermal expansion coefficient and compressive strength were measured. Thermal analysis and chemical analysis were also carried out. It was found that volcanic rocks, i.e. Andesite and Basalt had the most favorable thermal characteristics up to around 1000 0 C and plutonic rock, i.e. Granite had also favorable characteristics under 573 0 C, transition temperature of quartz. Other igneous rocks, i.e. Rhyolite and Propylite had a problem of decomposition at around 500 0 C. Sedimentary rocks, i.e. Zeolite, Tuff, Sandstone and Diatomite were less favorable because of their decomposition, low thermal conductivity and large thermal expansion coefficient. (author)

  19. Estimating the Wet-Rock P-Wave Velocity from the Dry-Rock P-Wave Velocity for Pyroclastic Rocks

    Science.gov (United States)

    Kahraman, Sair; Fener, Mustafa; Kilic, Cumhur Ozcan

    2017-07-01

    Seismic methods are widely used for the geotechnical investigations in volcanic areas or for the determination of the engineering properties of pyroclastic rocks in laboratory. Therefore, developing a relation between the wet- and dry-rock P-wave velocities will be helpful for engineers when evaluating the formation characteristics of pyroclastic rocks. To investigate the predictability of the wet-rock P-wave velocity from the dry-rock P-wave velocity for pyroclastic rocks P-wave velocity measurements were conducted on 27 different pyroclastic rocks. In addition, dry-rock S-wave velocity measurements were conducted. The test results were modeled using Gassmann's and Wood's theories and it was seen that estimates for saturated P-wave velocity from the theories fit well measured data. For samples having values of less and greater than 20%, practical equations were derived for reliably estimating wet-rock P-wave velocity as function of dry-rock P-wave velocity.

  20. Geochemical investigation of petroleum source rocks by using Rock- Eval data in the Agha-Jari oilfield

    Directory of Open Access Journals (Sweden)

    Behzad khani

    2015-01-01

    Full Text Available In this study, 40 drilling cutting of the Pabdeh, Gurpi, kazhdumi and Gadvan Formations from the Agha-Jari Oilfield were analyzed by using Rock-Eval pyrolysis. In order to recognizing sedimentary environmental conditions of studied Formations, they are divided to 4 zones which A (Kazhdumi Formation#187 and C (Kazhdumi Formation#140 zones show reduction conditions by presence of sea organic materials and B (Gadvan Formation #140 and D(Gadvan Formation#187 zones show oxidation conditions by presence of continental organic materials to basin. Based on the Rock-Eval pyrolysis data, the Pabeh, Gurpi, Kazhdumi and Gadvan Formations have variable hydrocarbon generative potential. HI vs. OI plot revealed that the kerogen type in this Formations is a mixed of types II & III. The intensity of matrix effect in the Pabdeh, Gurpi, Kazhdumi and Gadvan Formations was compared by using S2 vs. TOC plot and calculating its regression equation. The results show that the significant amount of S2 adsorption by matrix was happened in the Pabdeh (4.98-6.96 mg HC/gr rock in wells 113 and 121 and Gurpi Formations ‌(4.33 mg HC/gr rock in well 113 which is due to their low thermal maturity‌(Tmax

  1. 东滩煤矿煤层底板岩层阻水能力试验研究%Experiment of reduction infiltration ability of rock formation under the coal seam floor at Dongtan Coal Mine

    Institute of Scientific and Technical Information of China (English)

    张维建; 张新武; 张冬

    2015-01-01

    底板岩层压水试验能够获得可靠的底板岩层阻水能力实测数据, 为深部煤层开采底板岩层阻水能力提供量化依据,对东滩煤矿深部煤层底板岩层进行压水测试,获得了大量的实测数据并依此计算出岩层的渗透系数. 试验结果表明测试底板岩层段在原始状态下的渗透性很低,阻水能力较强.研究结果可为矿区深部工作面的安全开采提供重要的参考依据.%The reliable reduction infiltration characteristics of rock mass could be obtained by the water injection experiment under the coal seem floor. The data of water injection experimnt were obtained and permeability coefficient of floor formation were deduced through water in-jection experiment at Dongtan Coal Mine. Result shows that the test rock formations are all low-permeability, which mean they have high re-duction infiltration ability. The results make a important reference for safety-mining of deep coal seam working face.

  2. Influence of infiltrated water on the change of formation water and oil permeability of crude oil bearing rocks

    Energy Technology Data Exchange (ETDEWEB)

    Cubric, S

    1970-09-01

    A brief desription is given of the causes of permeability reduction of oil-bearing rocks, due to well damage during the drilling and well completion or when working over wells. The physical properties of 2-phase flow (crude oil-water) and the possibility of increasing the existing permeability of the formation, because of the water infiltrated from the well into the crude oil layer, are described in detail. Field examples show that there are such cases, and that the artificially increased existing permeability of water-bearing rocks can be reduced and even brought to normal, if the adjacent formation zone layer is treated with surfactants (e.g., Hyflo dissolved in crude oil).

  3. Experimental studies of the deformation of carbonated rocks by dissolution crystallization under stress

    International Nuclear Information System (INIS)

    Zubtsov, Sergey

    2003-01-01

    The first part of this research thesis reports the experimental investigation and the modelling of the deformation of poly-mineral rocks under the influence of mechanism of dissolution-crystallization under stress. This mechanism has a significant role in the compaction of sedimentary rocks, in the folding process of the earth's crust. The author notably reports the results of the experimental deformation of calcite in presence of water (calcite is present in marls in which the deposit of nuclear wastes in planned in France). The second part deals with the fact that healing is possible between two grains of similar mineralogy, and slows down or even stops deformation

  4. Multiscale heterogeneity characterization of tidal channel, tidal delta and foreshore facies, Almond Formation outcrops, Rock Springs uplift, Wyoming

    Energy Technology Data Exchange (ETDEWEB)

    Schatzinger, R.A.; Tomutsa, L. [BDM Petroleum Technologies, Bartlesville, OK (United States)

    1997-08-01

    In order to accurately predict fluid flow within a reservoir, variability in the rock properties at all scales relevant to the specific depositional environment needs to be taken into account. The present work describes rock variability at scales from hundreds of meters (facies level) to millimeters (laminae) based on outcrop studies of the Almond Formation. Tidal channel, tidal delta and foreshore facies were sampled on the eastern flank of the Rock Springs uplift, southeast of Rock Springs, Wyoming. The Almond Fm. was deposited as part of a mesotidal Upper Cretaceous transgressive systems tract within the greater Green River Basin. Bedding style, lithology, lateral extent of beds of bedsets, bed thickness, amount and distribution of depositional clay matrix, bioturbation and grain sorting provide controls on sandstone properties that may vary more than an order of magnitude within and between depositional facies in outcrops of the Almond Formation. These features can be mapped on the scale of an outcrop. The products of diagenesis such as the relative timing of carbonate cement, scale of cemented zones, continuity of cemented zones, selectively leached framework grains, lateral variability of compaction of sedimentary rock fragments, and the resultant pore structure play an equally important, although less predictable role in determining rock property heterogeneity. A knowledge of the spatial distribution of the products of diagenesis such as calcite cement or compaction is critical to modeling variation even within a single facies in the Almond Fin. because diagenesis can enhance or reduce primary (depositional) rock property heterogeneity. Application of outcrop heterogeneity models to the subsurface is greatly hindered by differences in diagenesis between the two settings. The measurements upon which this study is based were performed both on drilled outcrop plugs and on blocks.

  5. Clay mineral formation under oxidized conditions and implications for paleoenvironments and organic preservation on Mars.

    Science.gov (United States)

    Gainey, Seth R; Hausrath, Elisabeth M; Adcock, Christopher T; Tschauner, Oliver; Hurowitz, Joel A; Ehlmann, Bethany L; Xiao, Yuming; Bartlett, Courtney L

    2017-11-01

    Clay mineral-bearing locations have been targeted for martian exploration as potentially habitable environments and as possible repositories for the preservation of organic matter. Although organic matter has been detected at Gale Crater, Mars, its concentrations are lower than expected from meteoritic and indigenous igneous and hydrothermal reduced carbon. We conducted synthesis experiments motivated by the hypothesis that some clay mineral formation may have occurred under oxidized conditions conducive to the destruction of organics. Previous work has suggested that anoxic and/or reducing conditions are needed to synthesize the Fe-rich clay mineral nontronite at low temperatures. In contrast, our experiments demonstrated the rapid formation of Fe-rich clay minerals of variable crystallinity from aqueous Fe 3+ with small amounts of aqueous Mg 2+ . Our results suggest that Fe-rich clay minerals such as nontronite can form rapidly under oxidized conditions, which could help explain low concentrations of organics within some smectite-containing rocks or sediments on Mars.

  6. Clay mineral formation under oxidized conditions and implications for paleoenvironments and organic preservation on Mars

    Energy Technology Data Exchange (ETDEWEB)

    Gainey, Seth R.; Hausrath, Elisabeth M.; Adcock, Christopher T.; Tschauner, Oliver; Hurowitz, Joel A.; Ehlmann, Bethany L.; Xiao, Yuming; Bartlett, Courtney L. (CIW); (UNLV); (CIT); (SBU)

    2017-11-01

    Clay mineral-bearing locations have been targeted for martian exploration as potentially habitable environments and as possible repositories for the preservation of organic matter. Although organic matter has been detected at Gale Crater, Mars, its concentrations are lower than expected from meteoritic and indigenous igneous and hydrothermal reduced carbon. We conducted synthesis experiments motivated by the hypothesis that some clay mineral formation may have occurred under oxidized conditions conducive to the destruction of organics. Previous work has suggested that anoxic and/or reducing conditions are needed to synthesize the Fe-rich clay mineral nontronite at low temperatures. In contrast, our experiments demonstrated the rapid formation of Fe-rich clay minerals of variable crystallinity from aqueous Fe3+ with small amounts of aqueous Mg2+. Our results suggest that Fe-rich clay minerals such as nontronite can form rapidly under oxidized conditions, which could help explain low concentrations of organics within some smectite-containing rocks or sediments on Mars.

  7. Numerical analysis on the crack propagation and failure characteristics of rocks with double fissures under the uniaxial compression

    Directory of Open Access Journals (Sweden)

    Leyong Chen

    2015-12-01

    Full Text Available The fissures and rock bridges with different dips had different contributions to crack's initiation, propagation, convergence and penetration. In this paper, based on the rock fracture theory, the crack's propagation and evolution process on rock specimen with double fissures under uniaxial compression was simulated. As a result, the crack propagation and evolution law of rocks with different fissure dips (α = 0°, 15°, 30°, 45°, 60°, 75°, 90°; β = 45° and different rock bridge dips (β = 0°, 30°, 45°, 60°, 90°; α = 45° was obtained by numerical tests. Meanwhile, the fissure and rock bridge dips influence on the macro mechanical properties of rock was analyzed. Besides, the paper investigated the influences of different fissure dips and different rock bridge dips on the bridge transfixion. The study is of great significance to reveal the impact of different dips on the mechanical mechanism of multiple-fissures rock under specific conditions, and it also has important theoretical significance for the research on multiple-fissure rock.

  8. A computer-assisted rock type data catalogue for gas formations; Ein rechnergestuetzter Gesteinsdatenkatalog fuer Gasformationen

    Energy Technology Data Exchange (ETDEWEB)

    Reitenbach, V.; Pusch, G.; Moeller, M.; Koll, S. [TU Clausthal (Germany). Inst. fuer Erdoel- und Erdgastechnik; Constantini, A.; Junker, A.; Anton, H. [RWE Dea AG, Hamburg (Germany)

    2007-09-13

    Modern reservoir management commonly requires versatile reservoir data which are neces-sary for integrated reservoir characterization, evaluation and development planning. The rock data necessary for numerical reservoir simulation studies often have to be collected from different sources, analysed and sorted with a considerable effort. In a framework of DGMK research program (DGMK project 593-9/4), the Institute of Petro-leum Engineering (Clausthal University of Technology) and RWE DEA AG have developed a new tool named Rock Data Catalogue, which is capable of managing large amounts of rock data more efficiently and deriving new specific correlations for European rock types. The use of Rock Data Catalogue can facilitate the essential input data generation and proc-essing procedure for reservoir simulation studies. The Rock Data Catalogue is comprised of a Data Base Module of digitalized reservoir rock data and an interactive Data Correlation Module. Both modules are built-up as an interface to common reservoir simulation software. The universal structure of the software also makes it possible to exchange the data with other rock data information systems. The Data Correlation Module implements a ''Decision-Structure'' module, which helps the reservoir engineer to select the rock data for analysis and correlation depending on its litho-facial type and permeability class. The Data Base Module enables a quick search of appro-priated data sets and their export into the correlation module. The open source data of the North German Rotliegend gas formations as well as the data of measurements on Rotliegend core samples performed at the ITE in course of the DGMK tight gas projects were implemented in the rock data base. Correlations of poro/perm data, two-phase flow and capillary pressure functions of the Rotliegend sandstones with the per-meability range between 20 and 0.01 mD are implemented in the rock data base and serve for quality checking of the

  9. Precambrian-Cambrian boundary in the Tal formation of Garhwal Lesser Himalaya : Rb-Sr age evidence from black shales underlying phosphorites

    International Nuclear Information System (INIS)

    Sharma, K.K.; Rameshwar Rao, D.; Azmi, R.J.; Gopalan, K.; Pantulu, G.V.C.

    1991-01-01

    The recently reported faunal evidence for placing the Precambrian-Cambrian boundary within the main phosphorite unit of the Chert-Phosphorite Member of the Tal Formation, Garhwal Lesser Himalaya, is supported by the present report of 626 ± 13 myr for the whole-rock Rb-Sr isochron age of the black shales directly underlying the phosphorite band. (author). 15 refs., 2 figs., 1 tab

  10. Dynamic elastic moduli of rocks under pressure

    Energy Technology Data Exchange (ETDEWEB)

    Schock, R N [Lawrence Radiation Laboratory, University of California, Livermore, CA (United States)

    1970-05-01

    Elastic moduli are determined as a function of confining pressure to 10 kb on rocks in which Plowshare shots are to be fired. Numerical simulation codes require accurate information on the mechanical response of the rock medium to various stress levels in order to predict cavity dimensions. The theoretical treatment of small strains in an elastic medium relates the propagation velocity of compressional and shear waves to the elastic moduli. Velocity measurements can provide, as unique code input data, the rigidity modulus, Poisson' ratio and the shear wave velocity, as well as providing checks on independent determinations of the other moduli. Velocities are determined using pulsed electro-mechanical transducers and measuring the time-of-flight in the rock specimen. A resonant frequency of 1 MHz is used to insure that the wavelength exceeds the average grain dimension and is subject to bulk rock properties. Data obtained on a variety of rock types are presented and analyzed. These data are discussed in terms of their relationship to moduli measured by static methods as well as the effect of anisotropy, porosity, and fractures. In general, fractured rocks with incipient cracks show large increases in velocity and moduli in the first 1 to 2 kb of compression as a result of the closing of these voids. After this, the velocities increase much more slowly. Dynamic moduli for these rocks are often 10% higher than corresponding static moduli at low pressure, but this difference decreases as the voids are closed until the moduli agree within experimental error. The discrepancy at low pressure is a result of the elastic energy in the wave pulse being propagated around cracks, with little effect on propagation velocity averaged over the entire specimen. (author)

  11. Dynamic elastic moduli of rocks under pressure

    International Nuclear Information System (INIS)

    Schock, R.N.

    1970-01-01

    Elastic moduli are determined as a function of confining pressure to 10 kb on rocks in which Plowshare shots are to be fired. Numerical simulation codes require accurate information on the mechanical response of the rock medium to various stress levels in order to predict cavity dimensions. The theoretical treatment of small strains in an elastic medium relates the propagation velocity of compressional and shear waves to the elastic moduli. Velocity measurements can provide, as unique code input data, the rigidity modulus, Poisson' ratio and the shear wave velocity, as well as providing checks on independent determinations of the other moduli. Velocities are determined using pulsed electro-mechanical transducers and measuring the time-of-flight in the rock specimen. A resonant frequency of 1 MHz is used to insure that the wavelength exceeds the average grain dimension and is subject to bulk rock properties. Data obtained on a variety of rock types are presented and analyzed. These data are discussed in terms of their relationship to moduli measured by static methods as well as the effect of anisotropy, porosity, and fractures. In general, fractured rocks with incipient cracks show large increases in velocity and moduli in the first 1 to 2 kb of compression as a result of the closing of these voids. After this, the velocities increase much more slowly. Dynamic moduli for these rocks are often 10% higher than corresponding static moduli at low pressure, but this difference decreases as the voids are closed until the moduli agree within experimental error. The discrepancy at low pressure is a result of the elastic energy in the wave pulse being propagated around cracks, with little effect on propagation velocity averaged over the entire specimen. (author)

  12. Technical support for GEIS: radioactive waste isolation in geologic formations. Volume 6. Baseline rock properties-shale

    International Nuclear Information System (INIS)

    1978-04-01

    This volume, Y/OWI/TM36/6 Baseline Rock Properties--Shale, is one of a 23-volume series, ''Technical Support for GEIS: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-36'' which supplements a ''Contribution to Draft Generic Environmental Impact Statement on Commercial Waste Management: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-44.'' The series provides a more complete technical basis for the preconceptual designs, resource requirements, and environmental source terms associated with isolating commercial LWR wastes in underground repositories in salt, granite, shale and basalt. Wastes are considered from three fuel cycles: uranium and plutonium recycling, no recycling of spent fuel and uranium-only recycling. The report is a result of a literature survey of the rock properties of shales occurring in the United States. Firstly, data were collected from a wide variety of sources in order to obtain a feel for the range of properties encountered. Secondly, some typical shales were selected for detailed review and these are written up as separate chapters in this report. Owing to the wide variability in lithology and properties of shales occurring in the United States, it became necessary to focus the study on consolidated illite shales. Using the specific information already generated, a consistent set of intact properties for a typical, consolidated illite shale was obtained. Correction factors, largely based on geological considerations, were then applied to the intact data in order to yield typical rock mass properties for this type of shale. Lastly, excavation problems in shale formations were reviewed and three tunnel jobs were written up as case histories

  13. Temporal evolution of a granitic rock under thermal loads generated by fission products

    International Nuclear Information System (INIS)

    Ventura, M.A.; Ferreri, J.C.

    1985-01-01

    The thermal time history of a granitic mass under thermal loads, generated by the terminal subproducts arising from the Argentine nuclear programme is analyzed. This rock will be the final repository of those subproducts. The analysis is based on the consideration of a representative unit cell of the rock's centre using the Heating 5 programme. A preliminary analysis is made in order to obtain criteria with respect to the accuracy of the problem. Temporal evolution curves of the temperature on zones of interest of the unit cell considered are shown. Under the thermal loads considered, 500W by container, a maximum temperature of 55 deg C at the wall of the orifice subproducts' deposit is obtained. (Author) [es

  14. Reproducing early Martian atmospheric carbon dioxide partial pressure by modeling the formation of Mg-Fe-Ca carbonate identified in the Comanche rock outcrops on Mars

    Science.gov (United States)

    Berk, Wolfgang; Fu, Yunjiao; Ilger, Jan-Michael

    2012-10-01

    The well defined composition of the Comanche rock's carbonate (Magnesite0.62Siderite0.25Calcite0.11Rhodochrosite0.02) and its host rock's composition, dominated by Mg-rich olivine, enable us to reproduce the atmospheric CO2partial pressure that may have triggered the formation of these carbonates. Hydrogeochemical one-dimensional transport modeling reveals that similar aqueous rock alteration conditions (including CO2partial pressure) may have led to the formation of Mg-Fe-Ca carbonate identified in the Comanche rock outcrops (Gusev Crater) and also in the ultramafic rocks exposed in the Nili Fossae region. Hydrogeochemical conditions enabling the formation of Mg-rich solid solution carbonate result from equilibrium species distributions involving (1) ultramafic rocks (ca. 32 wt% olivine; Fo0.72Fa0.28), (2) pure water, and (3) CO2partial pressures of ca. 0.5 to 2.0 bar at water-to-rock ratios of ca. 500 molH2O mol-1rock and ca. 5°C (278 K). Our modeled carbonate composition (Magnesite0.64Siderite0.28Calcite0.08) matches the measured composition of carbonates preserved in the Comanche rocks. Considerably different carbonate compositions are achieved at (1) higher temperature (85°C), (2) water-to-rock ratios considerably higher and lower than 500 mol mol-1 and (3) CO2partial pressures differing from 1.0 bar in the model set up. The Comanche rocks, hosting the carbonate, may have been subjected to long-lasting (>104 to 105 years) aqueous alteration processes triggered by atmospheric CO2partial pressures of ca. 1.0 bar at low temperature. Their outcrop may represent a fragment of the upper layers of an altered olivine-rich rock column, which is characterized by newly formed Mg-Fe-Ca solid solution carbonate, and phyllosilicate-rich alteration assemblages within deeper (unexposed) units.

  15. Characteristics of the Triassic Source Rocks of the Aitutu Formation in the (West Timor Basin

    Directory of Open Access Journals (Sweden)

    Asep Kurnia Permana

    2014-12-01

    Full Text Available DOI:10.17014/ijog.v1i3.192The Triassic rocks of the (West Timor Basin have been identified that was mainly deposited in the  marine environment. The fine grained clastics and carbonate  rocks of this Triassic marine  facies are considered to be the most promising source rocks potential in this basin. In this paper we present geochemical and petrographic data from outcrop samples of the Triassic carbonate Aitutu Formation, due to emphasized the organic maturation, kerogen type of the organic matter and the origin of the organic matter.  A representative of selected sample were subjected to the Rock-Eval Pyrolisis, vitrinite reflectance and thermal alteration index, bitumen extraction, were analyzed on the GC-MS. The samples were collected from marine deposit of the Triassic Sequence. The TOC values of the analyzed sample range between rich and rich organic richness (0.51% - 9.16%, wt.%, TOC, which consists mainly of type II and III kerogen and the organic matter consider to be predominantly oil/gas prone and gas prone potential. The thermal maturity assessed from Tmax, TAI, and vitrinite reflectance shows an immature to early peak mature stage of the organic matter. The GC-MS analyses of the biomarkers indicate mainly the organic matter derived from mixed source rocks facies containing alga debris and higher plant terrestrial origin.

  16. CO2 storage in deep aquifers. Study in real conditions of cap-rock confinement properties and of their alteration

    International Nuclear Information System (INIS)

    Bachaud, P.

    2010-01-01

    A promising solution to reduce anthropogenic emissions of greenhouse effect gases consists in the injection and long-term storage of a part of the industrial carbon dioxide discharges in underground formations. These formations must be composed of a reservoir surrounded by tight cap-rocks, which represent the first barrier preventing fluids migration. The characterization of their confining properties and of their evolution in presence of CO 2 is thus a key element regarding a storage site security. This work presents a methodology allowing the measurement of cap-rocks transport parameters and the consequences of an alteration under representative conditions of deep aquifers storage. This methodology was applied to carbonate rocks from the Paris basin. The breakthrough pressure, the diffusion coefficient of CO 2 dissolution products,and the permeability, controlling parameters of leakage mechanisms, were measured before and after alteration of the materials by reaction with a CO 2 -saturated brine under reservoir thermodynamic conditions (about 80 C and 100 bar). Results revealed a satisfactory global behaviour under these aggressive conditions, but also a strong diminution of the confinement potential in presence of initial structural faults (sealed fractures, large-diameter pores...) forming higher-permeability zones. A numeric simulation describing the evolution of a homogeneous rock formation during 1000 years was also realized based on parameters directly measured or obtained by modelling of the alteration experiments. It showed that the transformations brought by the CO 2 storage under a rock formation with no initial faults remain very localized spatially. (author)

  17. Apparatus for sealing access holes to cavities within the earth with rock glass

    International Nuclear Information System (INIS)

    Holman, R.R.

    1979-01-01

    Apparatus is disclosed for establishing a solid, very low permeable rock glass plug to seal access holes through rock to underground storage vaults. The apparatus is designed to supply a filler material having a constituency substantially matching that of the rock formation surrounding the access port to the vault, through a central feeder tube under pressure to the vault. Means are provided for heating the filler material and surrounding rock formation at the point where the filler material exits the feeder tube, to a temperature sufficient to melt both the rock formation and the filler material. The remaining portion of the feeder tube is cooled to preserve the surrounding rock formaion spaced from the feeder orifice. The melt at the extremity of the feeder tube is forced through the orifice to a region below the tool by the force of the pressure feed. As the melt is forced below the tool, the tool is retracted until the access hole is completely sealed. A second embodiment is provided to seal enlarged openings which further includes a cooled core follower that enables the deposit to be fused in layers closing in the circumference of the hole until a final pass fuses the central core

  18. From dust to varnish: Geochemical constraints on rock varnish formation in the Negev Desert, Israel

    Science.gov (United States)

    Goldsmith, Yonaton; Stein, Mordechai; Enzel, Yehouda

    2014-02-01

    Chemical compositions of rock varnish from the Negev Desert of Israel and local settled dust were used to constrain the mechanisms of varnish formation and patterns of Mn enrichment and accumulation in the varnish. Rock varnish was sampled from coeval, undisturbed prehistoric flint artifacts along a south-north climatic transect (˜30-120 mm/yr of rain). Our analyses indicate that Mn, Ba and Pb in the varnish are significantly enriched (˜100×) in respect to the local settling dust and that Mn content systematically fluctuates with depth in the varnish. The varnish and settled dust data combined with basic thermodynamic and kinetic reasoning are used to constrain the following geochemical model of rock varnish formation: dust accumulates in micro-basins on exposed rock surfaces, under pH ˜8 (common Negev value) and during wetting by dew and rain, Mn in the dust is mobilized and leached to a depth of ˜5 μm under the varnish surface where Hollandite Mn-oxides precipitate and are adsorbed onto and between the porous clay minerals that comprise most of the varnish. During its mobile phase Mn-oxide is negatively charged and adsorbs rare earth elements. Once the solution dries abrasion removes the upper, weakly cemented dust sediment, which contains mainly Si, Al and Fe (which are not mobile at pH ˜8). Ca is also removed in large quantities. Mn, Ba, Pb and the REE are deposited at a depth and thus, protected from erosion. Reoccurrences of these processes result in a noticeable accumulation of these elements, but not of Si, Al or Fe. The alternating Mn-rich and Mn-poor laminas form as a result of a competition between the leaching rate of Mn and the adhesion rate of the clay minerals. When moisture is high (low), lamina with high (low) Mn/clay mineral ratio forms. The oxidation states involved in the varnish formation are unknown, therefore, to use Morgan's calculations we must assume, in agreement with the thermodynamic considerations (presented above), that during

  19. Rock Fragmentation Characteristics by TBM Cutting and Efficiency under Bi-Lateral Confinement

    Directory of Open Access Journals (Sweden)

    Yulong Chen

    2018-03-01

    Full Text Available In this study, the mechanisms of rock breakage are assessed using tunnel boring machine (TBM disc cutters under bi-axial pressure. Sequential indentation tests were conducted on granite specimens using a tri-axial testing platform. The morphology and volume of the fractured surface were measured and analyzed using a three-dimensional surface profilometer. An analysis of rock breaking growth and efficiency was performed as well. When the minor confining pressure (σ1 is constant, the results show that a larger difference in confining pressure leads to a larger volume of fractured surface, thereafter improving the rock-breaking efficiency even though the penetration energy is enlarged. On the other hand, when the major confining pressure (σ2 is constant, the penetration energy increases proportionally with the σ1; however, the volume of fractured surface is decreased, and the breaking efficiency is attenuated as well.

  20. 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

  1. Water-rock interaction during diagenesis and thermal recovery, Cold Lake, Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Abercrombie, H.J.

    1988-12-01

    Fluid and rocks interact at high temperatures during diagenesis and steam assisted thermal recovery of bitumen from the Clearwater Formation at Cold Lake, Alberta. A study was carried out to assess the effects of natural diagenesis in rocks of the formation, and using these data, to relate the chemical and isotopic compositions of fluids produced during thermal recovery to water-rock interactions occurring in the reservoir. X-ray diffraction (XRD) studies on core from Leming and Marguerite Lake document a variety of diagenetic clays including mixed layer minerals smectite-illite and chlorite-smectite, chlorite, illite, berthierine and kaolinite. A method for internally generating factors to convert clay mineral XRD peak heights to relative weight percents was used. Semi-quantitative results show that smectite-illite is ubiquitous and the most abundant clay present. Details are provided of the diagenetic sequence illustrating water-rock interaction over a prolonged period. Three types of water were found to be produced from the wells: injected water, formation water associated with bitumen, and bottom water from the underlying McMurray Formation. Produced water compositions were used to estimate in-situ temperatures of fluids produced from reservoirs. It is concluded that equilibrium closed-system models can be applied to natural diagenesis and artificial diagenesis induced during thermal recovery. 132 refs., 52 figs., 5 tabs.

  2. Superhard nanophase cutter materials for rock drilling applications; FINAL

    International Nuclear Information System (INIS)

    Voronov, O.; Tompa, G.; Sadangi, R.; Kear, B.; Wilson, C.; Yan, P.

    2000-01-01

    The Low Pressure-High Temperature (LPHT) System has been developed for sintering of nanophase cutter and anvil materials. Microstructured and nanostructured cutters were sintered and studied for rock drilling applications. The WC/Co anvils were sintered and used for development of High Pressure-High Temperature (HPHT) Systems. Binderless diamond and superhard nanophase cutter materials were manufactured with help of HPHT Systems. The diamond materials were studied for rock machining and drilling applications. Binderless Polycrystalline Diamonds (BPCD) have high thermal stability and can be used in geothermal drilling of hard rock formations. Nanophase Polycrystalline Diamonds (NPCD) are under study in precision machining of optical lenses. Triphasic Diamond/Carbide/Metal Composites (TDCC) will be commercialized in drilling and machining applications

  3. Weathering profiles in granitoid rocks of the Sila Massif uplands, Calabria, southern Italy: New insights into their formation processes and rates

    Science.gov (United States)

    Scarciglia, Fabio; Critelli, Salvatore; Borrelli, Luigi; Coniglio, Sabrina; Muto, Francesco; Perri, Francesco

    2016-05-01

    In this paper we characterized several weathering profiles developed on granitoid rocks in the Sila Massif upland (Calabria, southern Italy), integrating detailed macro- and micromorphological observations with physico-mechanical field tests and petrographic, mineralogical and geochemical analyses. We focused our attention on the main weathering and pedogenetic processes, trying to understand apparent discrepancies between weathering grade classes based on field description and geomechanical properties, and two common weathering indices, such as the micropetrographic index (Ip) and the chemical index of alteration (CIA). Our results showed that sericite on plagioclase and biotite chloritization, that represent inherited features formed during late-stage hydrothermal alteration of granitoid rocks, may cause an overestimation of the real degree of weathering of primary mineral grains under meteoric conditions, especially in lower weathering grade classes. Moreover, the frequent identification of Fe-Mn oxides and clay coatings of illuvial origin (rather than or in addition to those formed in situ), both at the macro- and microscale, may also explain an overestimation of the weathering degree with respect to field-based classifications. Finally, some apparent inconsistencies between field geomechanical responses and chemical weathering were interpreted as related to physical weathering processes (cryoclastism and thermoclastism), that lead to rock breakdown even when chemical weathering is not well developed. Hence, our study showed that particular caution is needed for evaluating weathering grades, because traditional field and geochemical-petrographic tools may be biased by inherited hydrothermal alteration, physical weathering and illuvial processes. On the basis of chronological constraints to soil formation obtained from a 42 ka-old volcanic input (mixed to granite parent materials) detected in the soil cover of the Sila Massif upland, a first attempt to estimate

  4. Stress–strain state of adjacent rock mass under slice mining of steeply dipping ore bodies

    Science.gov (United States)

    Baryshnikov, VD; Gakhova, LN

    2018-03-01

    Under analysis is the stress state of rock mass surrounding stopes in the initial cutting layer displaced in plan relative to the above-lying extracted layer in the overcut rock mass. The authors determine the boundaries of the post-limiting deformation zones during stoping advance using the Mohr–Coulomb criterion. The sequence of stoping to ensure better support conditions is proposed.

  5. Radionuclide migration in non-saline rock formations - status and perspectives

    International Nuclear Information System (INIS)

    Kienzler, B.; Geckeis, H.; Fanghaenel, T.

    2002-01-01

    The article is a condensed version of a paper presented at a workshop on 'Final Storage in Non-saline Rock Formations - Previous and Future German R and D Activities' at the Karlsruhe Research Center on April 8-9, 2002. The objectives, methods, and results of the research work performed at the Institute for Nuclear Waste Management (INE) of the Karlsruhe Research Center on the migration of radionuclides, in particular of the actinides, and the perspectives derived from these activities are described. The R and D work presented comprises laboratory studies of granite and clay as well as in situ experiments at the underground laboratories of Aespoe, Sweden, and Grimsel, Switzerland. An exemplary overview is presented of the findings about actinide migration in fractures, colloid migration in the shear zone of a granite formation, and the sorption of actinides and lanthanides onto clay and various argillaceous materials. Fundamental studies by INE of the problems outlined here include the elucidation of the structures and binding patterns of species sorbed onto surfaces, the stability and characteristics of colloids, the relevant basic thermodynamic features, and methodological developments. (orig.) [de

  6. K-U-Th systematics of terrestrial igneous rocks for planetological comparisons: volcanic rocks of the Earth oceanic island arc and Venus surface material

    International Nuclear Information System (INIS)

    Nikolaeva, O.V.

    1997-01-01

    Principles of the formation o data base for 339 samples of oceanic island arc (OIA) igneous rocks of the Earth available in literature are described as well as of the formation of fresh rock sample, characteristics of this sample, and K-U-Th-systematics of the fresh igneous rocks of Earth OIA. Results of comparison of the Venus measured rocks and Earth OIA rocks by K, U, Th

  7. Discovery and basic characteristics of high-quality source rocks found in the Yuertusi Formation of the Cambrian in Tarim Basin, China

    Directory of Open Access Journals (Sweden)

    Guangyou Zhu

    2016-02-01

    Full Text Available The Upper Paleozoic strata of the Tarim Basin have abundant resources of marine oil and gas. In the Tahe area, Halahatang area, and Tazhong area of the basin, many large-scale oilfields have been found. These oilfields have a confirmed oil and gas reserves worth more than 2.5 billion tons and have completed the annual output of more than 14 million tons of marine oil and gas equivalent. The belief that the only main hydrocarbon source rocks are of the Cambrian or Ordovician is still controversial. Chemists have made significant progress and have effectively lead the oil and gas exploration in Tarim Basin. Due to the complexity of the basin and the limitation of samples, the research work, and fine contrast is restricted. In this article, we investigated the Cambrian strata outcrop of Tarim Basin in detail. By analyzing a lot of outcrops, high-quality hydrocarbon source rocks of Yuertusi Formation have been found in more than 10 outcrop points in Aksu region. The source rocks' lithology is black shale with total organic carbon (TOC content that ranges between 2% and 16%. Total organic carbon (TOC of the black shale layer could be as much as 4%–16%, especially in the outcrops of the Yutixi and Shiairike. This by far is the best marine hydrocarbon source rock that was found in China. The source rocks were distributed consistently in the Aksu region, the thickness of which is about 10–15 m. It was formed in a sedimentary environment of a middle gentle slope to a low gentle slope. Organic matter enrichment is controlled by the upwelling currents. The thick strata of dolostone that developed in the Xiaoerblak Formation are considered to be good reservoirs of the beach and microbial reef in the upper strata of Yuertusi Formation. No hydrocarbon source rocks have been found in the outcrop of Xiaoerblak Formation. The thick strata of gyprock and mudstone development are a set of satisfactory cap layer in the Lower Cambrian. This hydrocarbon

  8. Waste-rock interactions in the immediate repository

    International Nuclear Information System (INIS)

    McCarthy, G.J.

    1977-01-01

    The high level wastes (HLW's) to be placed underground in rock formations will contain significant amounts of radioactive decay heat for the first hundred-or-so years of isolation. Several physical-chemical changes analogous to natural geochemical processes can occur during this ''thermal period.'' The waste canister can act as a heat source and cause changes in the mineralogy and properties of the surrounding rocks. Geochemically, this is ''contact metamorphism.'' In the event that the canister is corroded and breached, chemical reactions can occur between the HLW, the surrounding rock and possibly the remains of the canister. In a dry repository which has not been backfilled (and thus pressurized) these interactions could be slow at best and with rates decreasing rapidly as the HLW cools. However, significant interactions can occur in years, months or even days under hydrothermal conditions. These conditions could be created by the combination of HLW heat, overburden pressure and water mobilized from the rocks or derived from groundwater intrusion. At the end of the thermal period these interaction products would constitute the actual HLW form (or ''source term'') subject to the low temperature leaching and migration processes under investigation in other laboratories. It is quite possible that these interaction product waste forms will have superior properties compared to the original HLW. Experimental programs initiated at Penn State during the last year aim at determining the nature of any chemical or mineralogical changes in, or interactions between, HLW solids and host rocks under various repository ambients. The accompanying figures describe the simulated HLW forms and the experimental approach and techniques. Studies with basalts as the repository rock are supported by Rockwell Hanford Operations and with shales by the Office of Waste Isolation

  9. Rho kinase inhibition drives megakaryocyte polyploidization and proplatelet formation through MYC and NFE2 downregulation.

    Science.gov (United States)

    Avanzi, Mauro P; Goldberg, Francine; Davila, Jennifer; Langhi, Dante; Chiattone, Carlos; Mitchell, William Beau

    2014-03-01

    The processes of megakaryocyte polyploidization and demarcation membrane system (DMS) formation are crucial for platelet production, but the mechanisms controlling these processes are not fully determined. Inhibition of Rho kinase (ROCK) signalling leads to increased polyploidization in umbilical cord blood-derived megakaryocytes. To extend these findings we determined the effect of ROCK inhibition on development of the DMS and on proplatelet formation. The underlying mechanisms were explored by analysing the effect of ROCK inhibition on the expression of MYC and NFE2, which encode two transcription factors critical for megakaryocyte development. ROCK inhibition promoted DMS formation, and increased proplatelet formation and platelet release. Rho kinase inhibition also downregulated MYC and NFE2 expression in mature megakaryocytes, and this down-regulation correlated with increased proplatelet formation. Our findings suggest a model whereby ROCK inhibition drives polyploidization, DMS growth and proplatelet formation late in megakaryocyte maturation through downregulation of MYC and NFE2 expression. © 2014 John Wiley & Sons Ltd.

  10. The source rock characters of U-rich granite

    Energy Technology Data Exchange (ETDEWEB)

    Mingyue, Feng; Debao, He [CNNC Key Laboratory of Uranium Resources Exploration and Evaluation Technology, Beijing Research Institute of Uranium Geology (China)

    2012-03-15

    This paper discusses the stratum composition, lithological association, uranium content of crust and the activation, migration, concentration of uranium at each tectonic cycle in South China. The authors point out that the source rock of U-rich granite is U-rich continental crust which is rich in Si, Al and K. The lithological association is mainly composed of terrestrial clastic rocks formation of mudstone and sandstone, mingled with intermediate-acidic, mafic pyroclastic rocks and carbonate rocks formation. During tectonic movements, the rocks had undergone regional metamorphism, migmatitization, granitization, and formed U-rich granites finally. (authors)

  11. The source rock characters of U-rich granite

    International Nuclear Information System (INIS)

    Feng Mingyue; He Debao

    2012-01-01

    This paper discusses the stratum composition, lithological association, uranium content of crust and the activation, migration, concentration of uranium at each tectonic cycle in South China. The authors point out that the source rock of U-rich granite is U-rich continental crust which is rich in Si, Al and K. The lithological association is mainly composed of terrestrial clastic rocks formation of mudstone and sandstone, mingled with intermediate-acidic, mafic pyroclastic rocks and carbonate rocks formation. During tectonic movements, the rocks had undergone regional metamorphism, migmatitization, granitization, and formed U-rich granites finally. (authors)

  12. Evaluation of strength and failure of brittle rock containing initial cracks under lithospheric conditions

    Science.gov (United States)

    Li, Xiaozhao; Qi, Chengzhi; Shao, Zhushan; Ma, Chao

    2018-02-01

    Natural brittle rock contains numerous randomly distributed microcracks. Crack initiation, growth, and coalescence play a predominant role in evaluation for the strength and failure of brittle rocks. A new analytical method is proposed to predict the strength and failure of brittle rocks containing initial microcracks. The formulation of this method is based on an improved wing crack model and a suggested micro-macro relation. In this improved wing crack model, the parameter of crack angle is especially introduced as a variable, and the analytical stress-crack relation considering crack angle effect is obtained. Coupling the proposed stress-crack relation and the suggested micro-macro relation describing the relation between crack growth and axial strain, the stress-strain constitutive relation is obtained to predict the rock strength and failure. Considering different initial microcrack sizes, friction coefficients and confining pressures, effects of crack angle on tensile wedge force acting on initial crack interface are studied, and effects of crack angle on stress-strain constitutive relation of rocks are also analyzed. The strength and crack initiation stress under different crack angles are discussed, and the value of most disadvantaged angle triggering crack initiation and rock failure is founded. The analytical results are similar to the published study results. Rationality of this proposed analytical method is verified.

  13. Radioactivity of rocks from the geological formations belonging to the Tibagi River hydrographic basin; Radioatividade de rochas provenientes das formacoes geologicas pertencentes a bacia hidrografica do Rio Tibagi

    Energy Technology Data Exchange (ETDEWEB)

    Bastos, Rodrigo Oliveira

    2008-07-01

    This work is a study of the {sup 40}K and the {sup 238}U and {sup 232}Th series radioactivity in rocks measured with high resolution gamma ray spectrometry. The rocks were taken from the geologic formations in the region of the Tibagi river hydrographic basin. The course of this river cuts through the Paleozoic and Mesozoic stratigraphic sequences of the Parana sedimentary basin. In order to take into account the background radiation attenuation by the samples, a technique was developed that eliminated the need to measure a blank sample. The effects of the radiation's self-attenuation in the sample matrix were taken into account by using a gamma ray direct transmission method. The results for 87 rock samples, taken from 14 distinct formations, and their corresponding radioactivity variations are presented and discussed according to the possible geological processes from which they originated. Among the most discussed results are: an outcrop that profiles shale, limestone and rhythmite in the Irati Formation; a sandstone and siltstone sequence from the Rio do Rasto Formation; and a profile sampled in a coal mine located in the Rio Bonito Formation. The calculations of the rocks' contributions to the outdoor gamma radiation dose rate agree with the values presented by other authors for similar rocks. The highest dose values were obtained from felsic rocks (rhyolite of the Castro group, 129.8 {+-} 3.7 nGy.h{sup -1}, and Cunhaporanga granite, 167 {+-} 37 nGy.h{sup -1}). The other highest values correspond to the shale rocks from the Irati Formation (109 {+-} 16 nGy.h{sup -1}) and the siltic shale rocks from the Ponta Grossa Formation (107.9 {+-} 0.7 nGy.h{sup -1}). The most recent geological formations presented the lowest dose values (e.g. the Botucatu sandstone, 3.3 {+-} 0.6 nGy.h{sup -1}). The average value for sedimentary rocks from seven other formations is equal to 59 {+-} 26 nGy.h{sup -1}. The Rio Bonito Formation presented the highest dose value (334

  14. Grains of Nonferrous and Noble Metals in Iron-Manganese Formations and Igneous Rocks of Submarine Elevations of the Sea of Japan

    Science.gov (United States)

    Kolesnik, O. N.; Astakhova, N. V.

    2018-01-01

    Iron-manganese formations and igneous rocks of submarine elevations in the Sea of Japan contain overlapping mineral phases (grains) with quite identical morphology, localization, and chemical composition. Most of the grains conform to oxides, intermetallic compounds, native elements, sulfides, and sulfates in terms of the set of nonferrous, noble, and certain other metals (Cu, Zn, Sn, Pb, Ni, Mo, Ag, Pd, and Pt). The main conclusion that postvolcanic hydrothermal fluids are the key sources of metals is based upon a comparison of the data of electron microprobe analysis of iron-manganese formations and igneous rocks dredged at the same submarine elevations in the Sea of Japan.

  15. Fracture Initiation of an Inhomogeneous Shale Rock under a Pressurized Supercritical CO2 Jet

    Directory of Open Access Journals (Sweden)

    Yi Hu

    2017-10-01

    Full Text Available Due to the advantages of good fracture performance and the application of carbon capture and storage (CCS, supercritical carbon dioxide (SC-CO2 is considered a promising alternative for hydraulic fracturing. However, the fracture initiation mechanism and its propagation under pressurized SC-CO2 jet are still unknown. To address these problems, a fluid–structure interaction (FSI-based numerical simulation model along with a user-defined code was used to investigate the fracture initiation in an inhomogeneous shale rock. The mechanism of fracturing under the effect of SC-CO2 jet was explored, and the effects of various influencing factors were analyzed and discussed. The results indicated that higher velocity jets of SC-CO2 not only caused hydraulic-fracturing ring, but also resulted in the increase of stress in the shale rock. It was found that, with the increase of perforation pressure, more cracks initiated at the tip. In contrast, the length of cracks at the root decreased. The length-to-diameter ratio and the aperture ratio distinctly affected the pressurization of SC-CO2 jet, and contributed to the non-linear distribution and various maximum values of the stress in shale rock. The results proved that Weibull probability distribution was appropriate for analysis of the fracture initiation. The studied parameters explain the distribution of weak elements, and they affect the stress field in shale rock.

  16. Multi-scale investigation into the mechanisms of fault mirror formation in seismically active carbonate rocks

    Science.gov (United States)

    Ohl, Markus; Chatzaras, Vasileios; Niemeijer, Andre; King, Helen; Drury, Martyn; Plümper, Oliver

    2017-04-01

    Mirror surfaces along principal slip zones in carbonate rocks have recently received considerable attention as they are thought to form during fault slip at seismic velocities and thus may be a marker for paleo-seismicity (Siman-Tov et al., 2013). Therefore, these structures represent an opportunity to improve our understanding of earthquake mechanics in carbonate faults. Recent investigations reported the formation of fault mirrors in natural rocks as well as in laboratory experiments and connected their occurrence to the development of nano-sized granular material (Spagnuolo et al., 2015). However, the underlying formation and deformation mechanisms of these fault mirrors are still poorly constrained and warrant further research. In order to understand the influence and significance of these fault products on the overall fault behavior, we analysed the micro-, and nanostructural inventory of natural fault samples containing mirror slip surfaces. Here we present first results on the possible formation mechanisms of fault mirrors and associated deformation mechanisms operating in the carbonate fault gouge from two seismically active fault zones in central Greece. Our study specifically focuses on mirror slip surfaces obtained from the Arkitsa fault in the Gulf of Evia and the Schinos fault in the Gulf of Corinth. The Schinos fault was reactivated by a magnitude 6.7 earthquake in 1981 while the Arkitsa fault is thought to have been reactivated by a magnitude 6.9 earthquake in 1894. Our investigations encompass a combination of state-of-the-art analytical techniques including X-ray computed tomography, focused ion beam scanning electron microscopy (FIB-SEM), transmission electron microscopy (TEM) and Raman spectroscopy. Using this multiscale analytical approach, we report decarbonation-reaction structures, considerable calcite twinning and grain welding immediately below the mirror slip surface. Grains or areas indicating decarbonation reactions show a foam

  17. Characterisation of gas transport properties of the Opalinus clay, a potential host rock formation for radioactive waste disposal

    International Nuclear Information System (INIS)

    Marschall, P.; Horseman, S.; Gimmi, T.

    2005-01-01

    The Opalinus Clay in Northern Switzerland has been identified as a potential host rock formation for the disposal of radioactive waste. Comprehensive understanding of gas transport processes through this low-permeability formation forms a key issue in the assessment of repository performance. Field investigations and laboratory experiments suggest an intrinsic permeability of the Opalinus Clay in the order of 10 -20 to 10 -21 m 2 and a moderate anisotropy ratio ≤ 10. Porosity depends on clay content and burial depth; values of ∼ 0.12 are reported for the region of interest. Porosimetry indicates that about 10-30% of voids can be classed as macro-pores, corresponding to an equivalent pore radius > 25 nm. The determined entry pressures are in the range of 0.4-10 MPa and exhibit a marked dependence on intrinsic permeability. Both in situ gas tests and gas permeameter tests on drill-cores demonstrate that gas transport through the rock is accompanied by pore water displacement, suggesting that classical flow concepts of immiscible displacement in porous media can be applied when the gas entry pressure (i.e. capillary threshold pressure) is less than the minimum principal stress acting within the rock. Essentially, the pore space accessible to gas flow is restricted to the network of connected macro-pores, which implies a very low degree of desaturation of the rock during the gas imbibition process. At elevated gas pressures (i.e. when gas pressure approaches the level of total stress that acts on the rock body), evidence was seen for dilatancy controlled gas transport mechanisms. Further field experiments were aimed at creating extended tensile fractures with high fracture transmissivity (hydro- or gas-fractures). The test results lead to the conclusion that gas fracturing can be largely ruled out as a risk for post-closure repository performance. (authors)

  18. Rock glaciers in the Suntar‑Khayata Range

    Directory of Open Access Journals (Sweden)

    V. M. Lytkin

    2016-01-01

    Full Text Available The remote map‑making technique and results of field investigations made possible for the first time to reveal a great number of rock glaciers within the area of the Suntar‑Khayata Range (North‑East Asia. A total of 540 formations were identified. Among them, 47 rock glaciers were classified as corrie (cirque tongue‑shaped formations and 493 ones – as niche lobe‑shaped (single‑ and multi‑lobe rock glaciers. Occurrence of such formations is 8.4/100 km2, that is the largest in the North‑East Asia. The rock glaciers in this region are found within a range of true altitudes from 1297 up to 2402 m asl. The majority of active features, however, are confined to the interval between 1500 and 1900 m asl. Rock glaciers occur in the altitudinal range of 1297 to 2402 m asl. The majority of active features, however, are confined to the interval between 1500 and 1900 m asl, and the main part of active formations is located within the range of 1500‑2500 m. The frequency analysis of true altitudes of the rock‑glacier occurrence indicates that their formation can be caused by the hypsometry of the region relation to morphoclimatic zonality.

  19. Rb-Sr measurements on metamorphic rocks from the Barro Alto Complex, Goias, Brazil

    International Nuclear Information System (INIS)

    Fuck, R.A.; Neves, B.B.B.; Cordani, U.G.; Kawashita, K.

    1988-01-01

    The Barro Alto Complex comprises a highly deformed and metamorphosed association of plutonic, volcanic, and sedimentary rocks exposed in a 150 x 25 Km boomerang-like strip in Central Goias, Brazil. It is the southernmost tip of an extensive yet discontinuous belt of granulite and amphibolite facies metamorphic rocks which include the Niquelandia and Cana Brava complexes to the north. Two rock associations are distinguished within the granulite belt. The first one comprises a sequence of fine-grained mafic granulite, hypersthene-quartz-feldspar granulite, garnet quartzite, sillimanite-garnet-cordierite gneiss, calc-silicate rock, and magnetite-rich iron formation. The second association comprises medium-to coarse-grained mafic rocks. The medium-grade rocks of the western/northern portion (Barro Alto Complex) comprise both layered mafic rocks and a volcanic-sedimentary sequence, deformed and metamorphosed under amphibolite facies conditions. The fine-grained amphibolite form the basal part of the Juscelandia meta volcanic-sedimentary sequence. A geochronologic investigation by the Rb-Sr method has been carried out mainly on felsic rocks from the granulite belt and gneisses of the Juscelandia sequence. The analytical results for the Juscelandia sequence are presented. Isotope results for rocks from different outcrops along the gneiss layer near Juscelandia are also presented. In conclusion, Rb-Sr isotope measurements suggest that the Barro Alto rocks have undergone at least one important metamorphic event during Middle Proterozoic times, around 1300 Ma ago. During that event volcanic and sedimentary rocks of the Juscelandia sequence, as well as the underlying gabbro-anorthosite layered complex, underwent deformation and recrystallization under amphibolite facies conditions. (author)

  20. Chaotic characteristic of electromagnetic radiation time series of coal or rock under different scales

    Energy Technology Data Exchange (ETDEWEB)

    Zhen-Tang Liu; En-Lai Zhao; En-Yuan Wang; Jing Wang [China University of Mining and Technology, Xuzhou (China). School of Safety Engineering

    2009-02-15

    Based on chaos theory, the chaotic characteristics of electromagnetic radiation time series of coal or rock under different loads was studied. The results show that the correlation of electromagnetic radiation time series of small-scale coal or rock and coal mine converges to a stable saturation value, which shows that these electromagnetic radiation time series have chaos characteristics. When there is danger of coal seam burst, the value of the saturation correlation dimension D{sub 2} of the electromagnetic radiation time series is bigger and it changes greatly; when there is no danger, its value is smaller and changes smoothly. The change of saturation correlation of electromagnetic radiation time series can be used to forecast coal or rock dynamic disasters. 11 refs., 4 figs.

  1. Analysis of gas migration patterns in fractured coal rocks under actual mining conditions

    Directory of Open Access Journals (Sweden)

    Gao Mingzhong

    2017-01-01

    Full Text Available Fracture fields in coal rocks are the main channels for gas seepage, migration, and extraction. The development, evolution, and spatial distribution of fractures in coal rocks directly affect the permeability of the coal rock as well as gas migration and flow. In this work, the Ji-15-14120 mining face at the No. 8 Coal Mine of Pingdingshan Tian’an Coal Mining Co. Ltd., Pingdingshan, China, was selected as the test site to develop a full-parameter fracture observation instrument and a dynamic fracture observation technique. The acquired video information of fractures in the walls of the boreholes was vectorized and converted to planarly expanded images on a computer-aided design platform. Based on the relative spatial distances between the openings of the boreholes, simultaneous planar images of isolated fractures in the walls of the boreholes along the mining direction were obtained from the boreholes located at various distances from the mining face. Using this information, a 3-D fracture network under mining conditions was established. The gas migration pattern was calculated using a COMSOL computation platform. The results showed that between 10 hours and 1 day the fracture network controlled the gas-flow, rather than the coal seam itself. After one day, the migration of gas was completely controlled by the fractures. The presence of fractures in the overlying rock enables the gas in coal seam to migrate more easily to the surrounding rocks or extraction tunnels situated relatively far away from the coal rock. These conclusions provide an important theoretical basis for gas extraction.

  2. Hydrogeloogic characterization of fractured rock formations: A guide for groundwater remediators

    International Nuclear Information System (INIS)

    Cohen, A.J.B.

    1995-10-01

    A field site was developed in the foothills of the Sierra Nevada, California to develop and test a multi-disciplinary approach to the characterization of ground water flow and transport in fractured rocks. Nine boreholes were drilled into the granitic bedrock, and a wide variety of new and traditional subsurface characterization tools were implemented. The hydrogeologic structure and properties of the field site were deduced by integrating results from the various geologic, geophysical, hydrologic, and other investigative methods. The findings of this work are synthesized into this report, which is structured in a guidebook format. The applications of the new and traditional technologies, suggestions on how best to use, integrate, and analyze field data, and comparisons of the shortcoming and benefits of the different methods are presented

  3. Hydrogeloogic characterization of fractured rock formations: A guide for groundwater remediators

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, A.J.B.

    1995-10-01

    A field site was developed in the foothills of the Sierra Nevada, California to develop and test a multi-disciplinary approach to the characterization of ground water flow and transport in fractured rocks. Nine boreholes were drilled into the granitic bedrock, and a wide variety of new and traditional subsurface characterization tools were implemented. The hydrogeologic structure and properties of the field site were deduced by integrating results from the various geologic, geophysical, hydrologic, and other investigative methods. The findings of this work are synthesized into this report, which is structured in a guidebook format. The applications of the new and traditional technologies, suggestions on how best to use, integrate, and analyze field data, and comparisons of the shortcoming and benefits of the different methods are presented.

  4. Evaluation of hydraulic conductivities of bentonite and rock under hyper alkaline and nitrate conditions

    International Nuclear Information System (INIS)

    Iriya, K.; Fujii, K.; Kubo, H.

    2002-02-01

    The chemical conditions of TRU waste repository were estimated as alkaline conditions effected by cementitious materials. And, some TRU wastes include soluble nitrate salt, we have to consider the repository conditions might be high ionic strength condition leaching of nitrate salt. In this study, experimental studies were carried out to evaluate hydraulic conductivities of bentonite and rock under hyper alkaline and nitrate conditions. The followings results were obtained for bentonite. 1) In the immersion experiments of bentonite in hyper alkaline fluids with and without nitrate, the disappearance of montmorillonite of bentonite was observed and CSH formation was found after 30 days. In hyper alkaline fluid with nitrate, minerals at θ=37 nm by XRD was identified. 2) Significant effects of hyper alkaline on hydraulic conductivity of compacted bentonite were not observed. However, hydraulic conductivities of hyper alkaline fluid with nitrate and ion exchanged bentonite increased. In hyper alkaline with nitrate, more higher hydraulic conductivities of exchanged bentonite were measured. The followings results were obtained for rock. 1) In the immersion experiments of crushed tuff in hyper alkaline fluids with and without nitrate, CSH and CASH phases were observed. 2) The hydraulic conductivity of tuff in hyper alkaline fluids decreased gradually. Finally, hyper alkaline flow in tuff stopped after 2 months and hyper alkaline flow with nitrate stopped shorter than without nitrate. In the results of analysis of tuff after experiment, we could identified secondary minerals, but we couldn't find the clogging evidence of pores in tuff by secondary minerals. (author)

  5. PRINCIPLE ROCK TYPES FOR RADIOACTIVE WASTE REPOSITORIES

    Directory of Open Access Journals (Sweden)

    Sibila Borojević Šostarić

    2012-07-01

    Full Text Available Underground geological storage of high- and intermediate/low radioactive waste is aimed to represent a barrier between the surface environment and potentially hazardous radioactive elements. Permeability, behavior against external stresses, chemical reacatibility and absorption are the key geological parameters for the geological storage of radioactive waste. Three principal rock types were discussed and applied to the Dinarides: (1 evaporites in general, (2 shale, and (3 crystalline basement rocks. (1 Within the Dinarides, evaporite formations are located within the central part of a Carbonate platform and are inappropriate for storage. Offshore evaporites are located within diapiric structures of the central and southern part of the Adriatic Sea and are covered by thick Mesozoic to Cenozoic clastic sediment. Under very specific circumstances they can be considered as potential site locations for further investigation for the storage of low/intermediate level radioactive wast e. (2 Thick flysch type formation of shale to phyllite rocks are exposed at the basement units of the Petrova and Trgovska gora regions whereas (3 crystalline magmatic to metamorphic basement is exposed at the Moslavačka Gora and Slavonian Mts. regions. For high-level radioactive waste, basement phyllites and granites may represent the only realistic potential option in the NW Dinarides.

  6. CAPILLARY BARRIERS IN UNSATURATED FRACTURED ROCKS OF YUCCA MOUNTAIN, NEVADA

    International Nuclear Information System (INIS)

    Wu, Y.S.; Zhang, W.; Pan, L.; Hinds, J.; Bodvarsson, G.

    2000-01-01

    This work presents modeling studies investigating the effects of capillary barriers on fluid-flow and tracer-transport processes in the unsaturated zone of Yucca Mountain, Nevada, a potential site for storing high-level radioactive waste. These studies are designed to identify factors controlling the formation of capillary barriers and to estimate their effects on the extent of possible large-scale lateral flow in unsaturated fracture rocks. The modeling approach is based on a continuum formulation of coupled multiphase fluid and tracer transport through fractured porous rock. Flow processes in fractured porous rock are described using a dual-continuum concept. In addition, approximate analytical solutions are developed and used for assessing capillary-barrier effects in fractured rocks. This study indicates that under the current hydrogeologic conceptualization of Yucca Mountain, strong capillary-barrier effects exist for significantly diverting moisture flow

  7. Correlation between Bieniawski’s RMR index and Barton’s Q index in fine-grained sedimentary rock formations

    Directory of Open Access Journals (Sweden)

    J. D. Fernández-Gutiérrez

    2017-09-01

    Full Text Available From the XX century, various rock mass classification systems have been proposed. Among them, the Bieniawski’s RMR system and Barton’s Q system have emerged as the most used rock mass classification worldwide. Correlations between both indices have been proposed, usually with a wide scattering of the data used in deriving the equations. However, it has been observed that correlations established for a specific geological unit fit better. The aim of this paper is to propose a correlation between RMR and Q indices for fine-grained sedimentary rock formations, normally found in the area of Bilbao (Spain, by means of the collected data during the excavation of the tunnel Etxebarri-Casco Viejo of the line 3 of the Metropolitan Railway of Bilbao. Obtained equation shows a high correlation coefficient and a unique relationship between the two classification systems has been proposed, not depending on the choice of the independent variable.

  8. Mechanical behavior of host rock close to H.L.W. disposal cavities in a deep granitic formation

    International Nuclear Information System (INIS)

    Hoorelbeke, J.M.; Dourthe, M.

    1986-01-01

    The construction of a H.L.W. repository in a deep granitic formation creates mechanical disturbances in the rock on the scale of the massif and in the nearfield. Amongst all the disturbances noted in the nearfield, this study is concerned with examining the evolution of stresses linked with the excavation of the rock and the rise in temperature in the proximity of the waste packages. Several linear elasticity calculations were made using on the one hand finite element models and on the other simple analytical models. These calculations concern two different storage concepts - in room concept and in floor concept- whose differences in mechanical behavior are analyzed. A study of sensitivity with regard to the characteristics of the rock and to the initial geostatic stresses is presented. The comparison of the calculated stresses with three-dimensional failure criteria gives a clear indication of the satisfactory behavior of granite for final storage. However, the need for experimental study and complementary calculation must be emphasized

  9. Exploration of the Karvinskiy formation covering in Beskidakh

    Energy Technology Data Exchange (ETDEWEB)

    Strakoa, Z

    1980-01-01

    The Karvinskiy formation of coal-bearing carbon in the Upper Silesian basin was established by drilling wells in 1965 under the tectonic covers in Beskidakh. It forms a large eroded residual rock of 600 km/sup 2/ with industrial layers of rock coal. Work over the last few years has established the area over which the strata in the south are distributed, the position of the base, the new oil phenomena, the tectonic data of the southern region of the Upper Silesian basin. The rock coal fields were explored to define the borders of the mine fields of West Frenshtadt and East Frenshtadt. Eighteen coal layers were identified in the Karvinskiy formation. These belonged to 7 layer groups in the stratigraphy of the continental formations of Upper Silesian carbon, numbered 40 to 33. In the same mine fields, continental coal-bearing deposits of timber strata covering the Karvinskiy depression were discovered.

  10. Oil source rocks in the Adiyaman area, southeast Turkey

    Science.gov (United States)

    Soylu, Cengiz

    In the Adiyaman area, southeast Turkey, two carbonate source rock units, the Karababa-A Member and the Karabogaz Formation, are identified. The maturity levels of the source rock units increase towards the north and the west. Both the Karababa-A Member and the Karabogaz Formation are good to excellent oil-source rocks with widespread "kitchen areas".

  11. 'Escher' Rock

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] Chemical Changes in 'Endurance' Rocks [figure removed for brevity, see original site] Figure 1 This false-color image taken by NASA's Mars Exploration Rover Opportunity shows a rock dubbed 'Escher' on the southwestern slopes of 'Endurance Crater.' Scientists believe the rock's fractures, which divide the surface into polygons, may have been formed by one of several processes. They may have been caused by the impact that created Endurance Crater, or they might have arisen when water leftover from the rock's formation dried up. A third possibility is that much later, after the rock was formed, and after the crater was created, the rock became wet once again, then dried up and developed cracks. Opportunity has spent the last 14 sols investigating Escher, specifically the target dubbed 'Kirchner,' and other similar rocks with its scientific instruments. This image was taken on sol 208 (Aug. 24, 2004) by the rover's panoramic camera, using the 750-, 530- and 430-nanometer filters. The graph above shows that rocks located deeper into 'Endurance Crater' are chemically altered to a greater degree than rocks located higher up. This chemical alteration is believed to result from exposure to water. Specifically, the graph compares ratios of chemicals between the deep rock dubbed 'Escher,' and the more shallow rock called 'Virginia,' before (red and blue lines) and after (green line) the Mars Exploration Rover Opportunity drilled into the rocks. As the red and blue lines indicate, Escher's levels of chlorine relative to Virginia's went up, and sulfur down, before the rover dug a hole into the rocks. This implies that the surface of Escher has been chemically altered to a greater extent than the surface of Virginia. Scientists are still investigating the role water played in influencing this trend. These data were taken by the rover's alpha particle X-ray spectrometer.

  12. Mineral and rock chemistry of Mata da Corda Kamafugitic Rocks (Minas Gerais State, Brazil)

    International Nuclear Information System (INIS)

    Albuquerque Sgarbi, Patricia B. de; Valenca, Joel G.

    1995-01-01

    The volcanic rocks of the Mata da Corda Formation (Upper Cretaceous) in Minas Gerais, Brazil, are mafic potassic to ultra potassic rocks of kamafugitic affinity containing essentially clinopyroxenes, perovskite, magnetite and occasionally olivine, phlogopite, melilite pseudomorphs and apatite. The felsic phases are kalsilite and/or leucite pseudomorphs. The rocks are classified as mafitites, leucitites and kalsilitites. The analysis of the available data of the rocks studied, based on the relevant aspects of the main proposals for the classification of alkaline mafic to ultramafic potassic rocks leads to the conclusion that Sahama's (1974) proposal to divide potassium rich alkaline rocks in two large families is the one to which the Mata da Corda rocks adapt best. According to this and the data in the literature on the mineralogy and mineral and rock chemistries of the other similar occurrences, these rocks may be interpreted as alkaline potassic to ultra potassic rocks of hamafugitic affinity. 11 figs., 5 tabs

  13. Experimental Investigation on the Fatigue Mechanical Properties of Intermittently Jointed Rock Models Under Cyclic Uniaxial Compression with Different Loading Parameters

    Science.gov (United States)

    Liu, Yi; Dai, Feng; Dong, Lu; Xu, Nuwen; Feng, Peng

    2018-01-01

    Intermittently jointed rocks, widely existing in many mining and civil engineering structures, are quite susceptible to cyclic loading. Understanding the fatigue mechanism of jointed rocks is vital to the rational design and the long-term stability analysis of rock structures. In this study, the fatigue mechanical properties of synthetic jointed rock models under different cyclic conditions are systematically investigated in the laboratory, including four loading frequencies, four maximum stresses, and four amplitudes. Our experimental results reveal the influence of the three cyclic loading parameters on the mechanical properties of jointed rock models, regarding the fatigue deformation characteristics, the fatigue energy and damage evolution, and the fatigue failure and progressive failure behavior. Under lower loading frequency or higher maximum stress and amplitude, the jointed specimen is characterized by higher fatigue deformation moduli and higher dissipated hysteresis energy, resulting in higher cumulative damage and lower fatigue life. However, the fatigue failure modes of jointed specimens are independent of cyclic loading parameters; all tested jointed specimens exhibit a prominent tensile splitting failure mode. Three different crack coalescence patterns are classified between two adjacent joints. Furthermore, different from the progressive failure under static monotonic loading, the jointed rock specimens under cyclic compression fail more abruptly without evident preceding signs. The tensile cracks on the front surface of jointed specimens always initiate from the joint tips and then propagate at a certain angle with the joints toward the direction of maximum compression.

  14. Experimental Acid Weathering of Fe-Bearing Mars Analog Minerals and Rocks: Implications for Aqueous Origin of Hematite-Bearing Sediments in Meridiani Planum, Mars

    Science.gov (United States)

    Golden, D. C.; Koster, A. M.; Ming, D. W.; Morris, R. V.; Mertzman, S. A.

    2011-01-01

    A working hypothesis for Meridiani evaporite formation involves the evaporation of fluids derived from acid weathering of Martian basalts and subsequent diagenesis [1, 2]. However, there are no reported experimental studies for the formation of jarosite and gray hematite (spherules), which are characteristic of Meridiani rocks from Mars analog precursor minerals. A terrestrial analog for hematite spherule formation from basaltic rocks under acidic hydrothermal conditions has been reported [3], and we have previously shown that the hematite spherules and jarosite can be synthetically produced in the laboratory using Fe3+ -bearing sulfate brines under hydrothermal conditions [4]. Here we expand and extend these studies by reacting Mars analog minerals with sulfuric acid to form Meridiani-like rock-mineral compositions. The objective of this study is to provide environmental constraints on past aqueous weathering of basaltic materials on Mars.

  15. Preliminary view of geotechnical properties of soft rocks of Semanggol formation at Pokok Sena, Kedah

    Science.gov (United States)

    Ahmad, N. R.; Jamin, N. H.

    2018-04-01

    The research was inspired by series of geological studies on Semanggol formation found exposed at North Perak, South Kedah and North Kedah. The chert unit comprised interbedded chert-shale rocks are the main lithologies sampled in a small-scale outcrop of Pokok Sena area. Black shale materials were also observed associated with these sedimentary rocks. The well-known characteristics of shale that may swell when absorb water and leave shrinkage when dried make the formation weaker when load is applied on it. The presence of organic materials may worsen the condition apart from the other factors such as the history of geological processes and depositional environment. Thus, this research is important to find the preliminary relations of the geotechnical properties of soft rocks and the geological reasoning behind it. Series of basic soil tests and 1-D compression tests were carried out to obtain the soil parameters. The results obtained gave some preliminary insight to mechanical behaviour of these two samples. The black shale and weathered interbedded chert-shale were classified as sandy-clayey-SILT and clayey-silty-SAND respectively. The range of specific gravity of black shale and interbedded chert/shale 2.3 – 2.6 and fall in the common range of shale and chert specific gravity value. In terms of degree of plasticity, the interbedded chert/shale samples exhibit higher plastic degree compared to the black shale samples. Results from oedometer tests showed that black shale samples had higher overburden pressure (Pc) throughout its lifetime compare to weathered interbedded chert-shale, however the compression index (Cc) of black shale were 0.15 – 0.185 which was higher than that found in interbedded chert-shale. The geotechnical properties of these two samples were explained in correlation with their provenance and their history of geological processes involved which predominantly dictated the mechanical behaviour of these two samples.

  16. Formation of heterocyclic amines in Chinese marinated meat: effects of animal species and ingredients (rock candy, soy sauce and rice wine).

    Science.gov (United States)

    Wang, Pan; Hong, Yanting; Ke, Weixin; Hu, Xiaosong; Chen, Fang

    2017-09-01

    Heterocyclic aromatic amines (HAAs) are one type of neo-formed contaminants in protein-rich foods during heat processing. Recently, accumulative studies have focused on the formation of HAs in Western foods. However, there is little knowledge about the occurrence of HAAs in traditional Chinese foods. The objective of this study was to determinate the contents of main HAs in traditional marinated meat products by UPLC-MS/MS, and to investigate the effects of animal species and the ingredients (soy sauce, rock candy, and rice wine) on the formation of HAAs in marinated meats. Five HAs - 2-amino-3-methylimidazo[4,5-f]-quinolone (IQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4-dimethylimidazo[4,5-f]quinoxaline (MeIQ), 9H-pyrido[3,4-b]indole (Norharman) and l-methyl-9H-pyrido[3,4-b]indole (Harman) - were detected in 12 marinated meats, but 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) was only found in three chicken marinates. The animal species and ingredients (soy sauce, rock candy and rice wine) have significant influence on the formation of HAAs in meat marinates. Beef had the highest content of total HAAs compared with pork, mutton and chicken. Meanwhile, soy sauce contributed to the formation of HAAs more greatly than rock candy, soy sauce, and rice wine. Choice of raw materials and optimisation of ingredients recipe should be become a critical point to control the HAAs formation in marinated meats. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  17. Stress history influence on sedimentary rock porosity estimates: Implications for geological CO2 storage in Northern Taiwan

    Directory of Open Access Journals (Sweden)

    Wen-Jie Wu

    2017-01-01

    Full Text Available We established a stress-history-dependent porosity model of potential target rocks for CO2 geosequestration based on rock sample porosity measurements under various effective stresses (5 - 120 MPa. The measured samples were collected from shallow boreholes (< 300 m depth drilled at the frontal fold in northern Taiwan. The lithology, density, and the stress-history-dependent porosity derived from shallow boreholes enabled us to predict the porosity-depth relationship of given rock formations at (burial depths of approximately 3170 - 3470 m potential sites for CO2 geosequestration located near the Taoyuan Tableland coastline. Our results indicate that the porosity of samples derived from laboratory tests under atmospheric pressure is significantly greater than the porosity measured under stress caused by sediment burial. It is therefore strongly recommended that CO2 storage capacity assessment not be estimated from the porosity measured under atmospheric pressure. Neglecting the stress history effect on the porosity of compacted and uplifted rocks may induce a percentage error of 7.7% at a depth of approximately 1000 m, where the thickness of the eroded, formerly overlying formation is 2.5 km in a synthetic case. The CO2 injection pressure effect on the porosity was also evaluated using the stress-history-dependent porosity model. As expected, the pore pressure buildup during CO2 injection will induce an increase in the rock porosity. For example, a large injection pressure of 13 MPa at a depth of approximately 1000 m will increase the rock porosity by a percentage error of 6.7%. Our results have implications for CO2 storage capacity injection pressure estimates.

  18. An Alternative to Conventional Rock Fragmentation Methods Using SCDA: A Review

    Directory of Open Access Journals (Sweden)

    Radhika Vidanage De Silva

    2016-11-01

    Full Text Available Global energy and material consumption are expected to rise in exponential proportions during the next few decades, generating huge demands for deep earth energy (oil/gas recovery and mineral processing. Under such circumstances, the continuation of existing methods in rock fragmentation in such applications is questionable due to the proven adverse environmental impacts associated with them. In this regard; the possibility of using more environmentally friendly options as Soundless Chemical Demolition Agents (SCDAs play a vital role in replacing harmful conventional rock fragmentation techniques for gas; oil and mineral recovery. This study reviews up to date research on soundless cracking demolition agent (SCDA application on rock fracturing including its limitations and strengths, possible applications in the petroleum industry and the possibility of using existing rock fragmentation models for SCDA-based rock fragmentation; also known as fracking. Though the expansive properties of SCDAs are currently used in some demolition works, the poor usage guidelines available reflect the insufficient research carried out on its material’s behavior. SCDA is a cementitious powdery substance with quicklime (CaO as its primary ingredient that expands upon contact with water; which results in a huge expansive pressure if this CaO hydration reaction occurs in a confined condition. So, the mechanism can be used for rock fragmentation by injecting the SCDA into boreholes of a rock mass; where the resulting expansive pressure is sufficient to create an effective fracture network in the confined rock mass around the borehole. This expansive pressure development, however, dependent on many factors, where formation water content creates a negative influence on this due to required greater degree of hydration under greater water contents and temperature creates a positive influence by accelerating the reaction. Having a precise understanding of the fracture

  19. Origin and evolution of formation water at the Jujo-Tecominoacan oil reservoir, Gulf of Mexico. Part 1: Chemical evolution and water-rock interaction

    Energy Technology Data Exchange (ETDEWEB)

    Birkle, Peter, E-mail: birkle@iie.org.mx [Instituto de Investigaciones Electricas (IIE), Gerencia de Geotermia, Av. Reforma 113, Cuernavaca, Morelos 62490 (Mexico); Garcia, Bernardo Martinez; Milland Padron, Carlos M. [PEMEX Exploracion y Produccion, Region Sur, Activo Integral Bellota-Jujo, Diseno de Explotacion, Cardenas, Tabasco (Mexico)

    2009-04-15

    The origin and evolution of formation water from Upper Jurassic to Upper Cretaceous mudstone-packstone-dolomite host rocks at the Jujo-Tecominoacan oil reservoir, located onshore in SE-Mexico at a depth from 5200 to 6200 m.b.s.l., have been investigated, using detailed water geochemistry from 12 producer wells and six closed wells, and related host rock mineralogy. Saline waters of Cl-Na type with total dissolved solids from 10 to 23 g/L are chemically distinct from hypersaline Cl-Ca-Na and Cl-Na-Ca type waters with TDS between 181 and 385 g/L. Bromine/Cl and Br/Na ratios suggest the subaerial evaporation of seawater beyond halite precipitation to explain the extreme hypersaline components, while less saline samples were formed by mixing of high salinity end members with surface-derived, low salinity water components. The dissolution of evaporites from adjacent salt domes has little impact on present formation water composition. Geochemical simulations with Harvie-M{phi}ller-Weare and PHRQPITZ thermodynamic data sets suggest secondary fluid enrichment in Ca, HCO{sub 3} and Sr by water-rock interaction. The volumetric mass balance between Ca enrichment and Mg depletion confirms dolomitization as the major alteration process. Potassium/Cl ratios below evaporation trajectory are attributed to minor precipitation of K feldspar and illitization without evidence for albitization at the Jujo-Tecominoacan reservoir. The abundance of secondary dolomite, illite and pyrite in drilling cores from reservoir host rock reconfirms the observed water-rock exchange processes. Sulfate concentrations are controlled by anhydrite solubility as indicated by positive SI-values, although anhydrite deposition is limited throughout the lithological reservoir column. The chemical variety of produced water at the Jujo-Tecominoacan oil field is related to a sequence of primary and secondary processes, including infiltration of evaporated seawater and original meteoric fluids, the subsequent

  20. Origin and evolution of formation water at the Jujo-Tecominoacan oil reservoir, Gulf of Mexico. Part 1: Chemical evolution and water-rock interaction

    International Nuclear Information System (INIS)

    Birkle, Peter; Garcia, Bernardo Martinez; Milland Padron, Carlos M.

    2009-01-01

    The origin and evolution of formation water from Upper Jurassic to Upper Cretaceous mudstone-packstone-dolomite host rocks at the Jujo-Tecominoacan oil reservoir, located onshore in SE-Mexico at a depth from 5200 to 6200 m.b.s.l., have been investigated, using detailed water geochemistry from 12 producer wells and six closed wells, and related host rock mineralogy. Saline waters of Cl-Na type with total dissolved solids from 10 to 23 g/L are chemically distinct from hypersaline Cl-Ca-Na and Cl-Na-Ca type waters with TDS between 181 and 385 g/L. Bromine/Cl and Br/Na ratios suggest the subaerial evaporation of seawater beyond halite precipitation to explain the extreme hypersaline components, while less saline samples were formed by mixing of high salinity end members with surface-derived, low salinity water components. The dissolution of evaporites from adjacent salt domes has little impact on present formation water composition. Geochemical simulations with Harvie-Mφller-Weare and PHRQPITZ thermodynamic data sets suggest secondary fluid enrichment in Ca, HCO 3 and Sr by water-rock interaction. The volumetric mass balance between Ca enrichment and Mg depletion confirms dolomitization as the major alteration process. Potassium/Cl ratios below evaporation trajectory are attributed to minor precipitation of K feldspar and illitization without evidence for albitization at the Jujo-Tecominoacan reservoir. The abundance of secondary dolomite, illite and pyrite in drilling cores from reservoir host rock reconfirms the observed water-rock exchange processes. Sulfate concentrations are controlled by anhydrite solubility as indicated by positive SI-values, although anhydrite deposition is limited throughout the lithological reservoir column. The chemical variety of produced water at the Jujo-Tecominoacan oil field is related to a sequence of primary and secondary processes, including infiltration of evaporated seawater and original meteoric fluids, the subsequent mixing of

  1. Organic Geochemistry of the Cenomanian-Turonian Bahloul Formation Petroleum Source Rock, Central and Northern Tunisia

    OpenAIRE

    Affouri , Hassene; Montacer , Mabrouk; Disnar , Jean-Robert

    2013-01-01

    International audience; Total organic carbon (TOC) determination, Rock-Eval pyrolysis, extractable organic matter content (EOM) fractionation, gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analyses, were carried out on 79 samples from eleven outcrop cross sections of the Bahloul Formation in central and northern Tunisia. The TOC content varied between 0.23 to 35.6%, the highest average values (18.73%, 8.46% and 4.02%) being at the east of the study area (at Ain Zakk...

  2. Study of Different Argillaceous Formations Performed in the Context of the FUNMIG project

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, A. M.; Melon, A.; Sanchez, D. M.; Gaucher, E.; Tournassat, C.; Altmann, S.C.; Vinsot, A.; Maes, N.; Craen, M. de; Leupin, O.; Wersin, P.; Astudillo, J.

    2010-07-01

    Argillaceous Rock Formations of low permeability have been selected in several countries as potential geological host rock for the disposal of high level radioactive wastes (HLRW). The general barrier function of the host rock is to retard and attenuate the migration of radionuclides to the biosphere, and the properties of clay minerals sustain this barrier functions. Nowadays, a number of Underground Research Laboratories (URL) have been constructed for a more in depth investigation of the indurated as well as plastic clay rock formations indifferent countries. The HADES under ground research facility (URF) was constructed at Mol (Belgium), where the Boom Clay formation is being studied as a reference host rock formation. The Opalinus Clay formation has been studied in the Mont Terri Rock Laboratory (Switzerland). The Callovo- Oxfordian clayrock is being characterised in the Meuse/Haute-Marne Site at Bure (France). The Boda Claystone is being analysed at Mecsek in Hungary. The knowledge on biogeochemical processes which affect the transport of radionuclides through the geosphere is a key parameter for the safety case of a HLRW repository, which was the aim of the EC Project FUNMIG: Fundamental Processes of Radionuclide Migration. The main factors controlling the mobility of the radionuclides are the chemistry of the pore water, the chemical reactions involving the radionuclides and the sorption processes on clay minerals. There fore, the pore water chemistry plays an important role in determining radionuclide migration characteristics in clay-rock formations. (Author)

  3. Uranium migration and retention during weathering of a granitic waste rock pile

    International Nuclear Information System (INIS)

    Boekhout, F.; Gérard, M.; Kanzari, A.; Michel, A.; Déjeant, A.; Galoisy, L.; Calas, G.; Descostes, M.

    2015-01-01

    Highlights: • We investigate the environmental impact of the granitic waste rock piles. • The majority of the waste rocks in the pile is barren- or overburden rock. • The main neo-formed U-bearing phases are (Ca) and (Cu) uranyl phosphates. • Under circum-neutral pH conditions they do not pose an environment threat. - Abstract: This study investigates the post-mining evolution of S-type granitic waste rocks around a former uranium mine, Vieilles Sagnes (Haute Vienne, NW Massif Central, France). This mine was operated between 1957 and 1965 in the La Crouzille former world-class uranium mining district and is representative of intra-granitic vein-type deposits. 50 years after mine closure and the construction and subsequent re-vegetation of the granitic waste rock pile, we evaluate the environmental evolution of the rock pile, including rock alteration, neo-formation of U-bearing phases during weathering, and U migration. Vertical trenches have been excavated through the rock pile down to an underlying paleo-soil, allowing the investigation of the vertical differentiation of the rock pile and its influence on water pathways, weathering processes and U migration and retention. Arenization dominantly drives liberation of U, by dissolution of uraninite inclusions in the most alterable granitic minerals (i.e. K-feldspar and biotite). Retention of U in the matrix at the base of the waste rock pile, and in the underlying paleo-soil most likely occurs by precipitation of (nano-) uranyl phosphates or a combination of co-precipitation and adsorption reactions of U onto Fe (oxy)hydroxides and/or clay minerals. Even though U-migration was observed, U is retained in stable secondary mineral phases, provided the current conditions will not be modified

  4. Experimental Rock Deformation under micro-CT: ERDμ

    Science.gov (United States)

    Tisato, Nicola; Zhao, Qi; Biryukov, Anton; Grasselli, Giovanni

    2015-04-01

    Typically, the static elastic moduli of a rock differ from the corresponding dynamic rock-moduli. Such frequency-dependent characteristic, called modulus dispersion, implies also velocity dispersion (i.e. Vp- and Vs-dispersion). Velocity dispersion can be seen, in fact, as the result of a viscoelastic response of the geo-material to the externally imposed stress (e.g. seismic wave). Viscoelasticity can be conveniently expressed as attenuation (1/Q), which describes the loss of elastic energy for each stress cycle and comprises the measurement of the complex elastic modulus. As 1/Q at frequencies important seismic attribute as it can aid the subsurface imaging accuracy. For instance, the study of 1/Q is fundamental for the oil and gas industry as valuable natural resources, such as oil-sands or gas-shales, exhibit significant attenuation (e.g. 1/Q ~ 0.3 at 1 Hz), or for volcanic and earthquake related studies as fluids are often involved in those natural processes. In the last five years, employing the Broad Band Attenuation Vessel (BBAV), the attenuation of partially saturated rocks has been investigated along with the fluid pressure transient caused by a sudden increase of stress. In particular, those studies shed light on the relationships between 1/Q and i) saturation, ii) confining pressure, and iii) strain. The combination of laboratory and numerical results helped demonstrating that wave induced fluid flow (WIFF) on the mesoscopic scale is responsible for the large and frequency-dependent attenuation observed in the laboratory measurements of a partially saturated sandstone. However, these studies lay bare limitations: the behavior of attenuation as a function of i) the distribution of fluids in the pore space and ii) the role of dissolution-precipitation of new mineral phases are still unclear. For instance, when CO2 is injected in the Earth's crust to pursuit carbon sequestration it would be extremely useful understanding the impact of the gas-water-rock

  5. Derivation of muon range spectrum under rock from the recent primary spectrum

    International Nuclear Information System (INIS)

    Pal, P.; Bhattacharyya, D.P.

    1985-01-01

    The muon range spectra under Mont Blanc Tunnel and Kolar Gold Field rocks have been calculated from the recently measured primary cosmic ray spectrum. The scaling hypothesis of Feynman has been used for the calculation of pion and kaon spectra in the atmosphere. The meson atmospheric diffusion equation has been solved by following the method of Bugaev et al. The derived muon energy spectrum has been found to be in good agreement with the measured data of the Kiel, Durham, DEIS, and Moscow University groups. The calculated muon energy spectra at large polar angles have been compared with the different experimental results. The integral muon spectrum up to 20 TeV supports the MARS burst data favourably. Using the procedure of Kobayakawa, the muon energy loss in rock due to ionization, pair production, and bremsstrahlung and nuclear interactions from Bezrukov and Bugaev, we have constructed the range-energy relation in Mont Blanc and Kolar Gold Field rocks. The estimated range spectra have been corrected for range fluctuations and have been compared with the Mont Blanc Tunnel data of Castagnoli et al., Bergamasco et al., and Sheldon et al. and the Kolar Gold Field data compilation by Krishnaswamy et al

  6. Dynamic Response and Failure Mechanism of Brittle Rocks Under Combined Compression-Shear Loading Experiments

    Science.gov (United States)

    Xu, Yuan; Dai, Feng

    2018-03-01

    A novel method is developed for characterizing the mechanical response and failure mechanism of brittle rocks under dynamic compression-shear loading: an inclined cylinder specimen using a modified split Hopkinson pressure bar (SHPB) system. With the specimen axis inclining to the loading direction of SHPB, a shear component can be introduced into the specimen. Both static and dynamic experiments are conducted on sandstone specimens. Given carefully pulse shaping, the dynamic equilibrium of the inclined specimens can be satisfied, and thus the quasi-static data reduction is employed. The normal and shear stress-strain relationships of specimens are subsequently established. The progressive failure process of the specimen illustrated via high-speed photographs manifests a mixed failure mode accommodating both the shear-dominated failure and the localized tensile damage. The elastic and shear moduli exhibit certain loading-path dependence under quasi-static loading but loading-path insensitivity under high loading rates. Loading rate dependence is evidently demonstrated through the failure characteristics involving fragmentation, compression and shear strength and failure surfaces based on Drucker-Prager criterion. Our proposed method is convenient and reliable to study the dynamic response and failure mechanism of rocks under combined compression-shear loading.

  7. Rocks under pressure

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-05-01

    Physicists have used nuclear magnetic resonance to investigate the destructive effects of the crystallization of salt. Salt-weathering is one of the main causes of rock disintegration in nature, particularly in deserts, polar regions and along coastlines. However, it is also a very widespread cause of damage to man-made constructions. Bridges, for example, are attacked by de-icing salts, and cities such as Bahrain, Abu Dhabi and Adelaide are affected by rising damp from high ground-water levels. Indeed, many examples of cultural heritage, including the Islamic sites of Bokhara and Petra in Jordan and the Sphinx in Egypt, may ultimately be destroyed due to the effects of salt-weathering. Now Lourens Rijniers and colleagues at Eindhoven University in the Netherlands have developed a way to observe the solubility of various salts inside porous materials directly (Phys. Rev. Lett. 94 075503). (U.K.)

  8. Heat production / host rock compatibility; Waermeentwicklung / Gesteinsvertraeglichkeit

    Energy Technology Data Exchange (ETDEWEB)

    Meleshyn, A.; Weyand, T.; Bracke, G.; Kull, H.; Wieczorek, K.

    2016-05-15

    For the final high-level radioactive waste repository potential host rock formations are either rock salt or clays (Kristallin). Heat generating waste (decay heat of the radioactive materials) can be absorbed by the host rock. The effect of temperature increase on the thermal conductivity, the thermal expansion and the mechanical properties of salt, Kristallin, clays and argilliferous geotechnical barriers are described. Further issues of the report are the mineralogical behavior, phase transformations, hydrochemistry, microbial processes, gas formation, thermochemical processes and gas ingress. Recommendations for further research are summarized.

  9. Bioremediation in fractured rock: 2. Mobilization of chloroethene compounds from the rock matrix

    Science.gov (United States)

    Shapiro, Allen M.; Tiedeman, Claire; Imbrigiotta, Thomas; Goode, Daniel J.; Hsieh, Paul A.; Lacombe, Pierre; DeFlaun, Mary F.; Drew, Scott R.; Curtis, Gary P.

    2018-01-01

    A mass balance is formulated to evaluate the mobilization of chlorinated ethene compounds (CE) from the rock matrix of a fractured mudstone aquifer under pre- and postbioremediation conditions. The analysis relies on a sparse number of monitoring locations and is constrained by a detailed description of the groundwater flow regime. Groundwater flow modeling developed under the site characterization identified groundwater fluxes to formulate the CE mass balance in the rock volume exposed to the injected remediation amendments. Differences in the CE fluxes into and out of the rock volume identify the total CE mobilized from diffusion, desorption, and nonaqueous phase liquid dissolution under pre- and postinjection conditions. The initial CE mass in the rock matrix prior to remediation is estimated using analyses of CE in rock core. The CE mass mobilized per year under preinjection conditions is small relative to the total CE mass in the rock, indicating that current pump-and-treat and natural attenuation conditions are likely to require hundreds of years to achieve groundwater concentrations that meet regulatory guidelines. The postinjection CE mobilization rate increased by approximately an order of magnitude over the 5 years of monitoring after the amendment injection. This rate is likely to decrease and additional remediation applications over several decades would still be needed to reduce CE mass in the rock matrix to levels where groundwater concentrations in fractures achieve regulatory standards.

  10. Almahata Sitta MS-MU-011 and MS-MU-012: Formation Conditions of Two Unusual Rocks From the Ureilite Parent Body

    Science.gov (United States)

    Mikouchi, T.; Takenouchi, A.; Zolensky, M. E.; Hoffmann, V. H.

    2018-01-01

    Almahata Sitta meteorites are unique polymict breccia, comprising of many different meteorite groups as individual fragments dominated by ureilite lithologies and are considered to be recovered fragments of the asteroid 2008TC3. Recently, two unusual Almahata Sitta samples (MS-MU-011 and MS-MU-012) have been reported that show close petrogenetic relationships to ureilites. MS-MU-011 is a trachyandesite mainly composed of feldspar (plagioclase and anorthoclase) and pyroxene (pigeonite and augite) having ureilitic oxygen isotopic ratios. MS-MU-012 is the first ureilite example (unbrecciated) containing primary plagioclase crystals. The findings of these two rock types are important to better understand formation conditions of ureilites and the evolution of their parent body(s). In this abstract we discuss formation conditions of these ureilite-related rocks using redox state estimate by Fe valence states of plagioclase and olivine cooling rate calculations.

  11. Oxygen influx and geochemistry of percolate water from reactive mine waste rock underlying a sloping channelled soil cover

    Energy Technology Data Exchange (ETDEWEB)

    Song Qing, E-mail: qsong3@uwo.ca [Geotechnical Research Center, Department of Civil and Environmental Engineering, University of Western Ontario, 1151 Richmond Street, London, ON, N6A 5B9 (Canada); Yanful, Ernest K., E-mail: eyanful@eng.uwo.ca [Geotechnical Research Center, Department of Civil and Environmental Engineering, University of Western Ontario, 1151 Richmond Street, London, ON, N6A 5B9 (Canada)

    2011-05-15

    Research Highlights: > A channelled cover with preferential flow can still mitigate ARD to some extent. > Oxygen ingress was more sensitive to the location of the channel than to K{sub s}. > The channel in the barrier layer was a major passage for O{sub 2} ingress. > Actual flushing was an important factor when estimating O{sub 2} decay coefficient. - Abstract: An ideal engineered soil cover can mitigate acid rock drainage (ARD) by limiting water and gaseous O{sub 2} ingress into an underlying waste rock pile. However, the barrier layer in the soil cover almost invariably tends to develop cracks or fractures after placement. These cracks may change water flow and O{sub 2} transport in the soil cover and decrease performance in the long run. The present study employed a 10-cm-wide sand-filled channel installed in a soil barrier layer (silty clay) to model the aggregate of cracks or fractures that may be present in the cover. The soil cover had a slope of 20%. Oxygen transport through the soil cover and oxidation of the underlying waste rock were investigated and compared to a controlled column test with bare waste rock (without soil cover). Moreover, gaseous O{sub 2} transport in the soil cover with channel and its sensitivity to channel location as well as the influence of the saturated hydraulic conductivity of the channel material were modeled using the commercial software VADOSE/W. The results indicted that the waste rock underlying the soil cover with channel had a lower oxidation rate than the waste rock without cover because of reduced O{sub 2} ingress and water flushing in the soil cover with channel, which meant a partial soil cover might still be effective to some extent in reducing ARD generation. Gaseous O{sub 2} ingress into the covered waste rock was more sensitive to the channel location than to the saturated hydraulic conductivity of the material filling the channel. Aqueous equilibrium speciation modeling and scanning electron microscopy with energy

  12. A Rock Mechanics and Coupled Hydro mechanical Analysis of Geological Repository of High Level Nuclear Waste in Fractured Rocks

    International Nuclear Information System (INIS)

    Min, Kibok

    2011-01-01

    This paper introduces a few case studies on fractured hard rock based on geological data from Sweden, Korea is one of a few countries where crystalline rock is the most promising rock formation as a candidate site of geological repository of high level nuclear waste. Despite the progress made in the area of rock mechanics and coupled hydro mechanics, extensive site specific study on multiple candidate sites is essential in order to choose the optimal site. For many countries concerned about the safe isolation of nuclear wastes from the biosphere, disposal in a deep geological formation is considered an attractive option. In geological repository, thermal loading continuously disturbs the repository system in addition to disturbances a recent development in rock mechanics and coupled hydro mechanical study using DFN(Discrete Fracture Network) - DEM(Discrete Element Method) approach mainly applied in hard, crystalline rock containing numerous fracture which are main sources of deformation and groundwater flow

  13. New Data on the Composition of Cretaceous Volcanic Rocks of the Alazeya Plateau, Northeastern Yakutia

    Science.gov (United States)

    Tsukanov, N. V.; Skolotnev, S. G.

    2018-02-01

    This work presents new data on the composition of volcanics, developed within the Alazeya Plateau of the Kolyma-Indigirka fold area (Northeast Russia), which indicate essential differences in their composition and, accordingly, different geodynamic settings of the formation of rocks. The studied igneous rocks are subdivided into two groups. Volcanics of the first group of the Late Cretaceous age, which are represented by differentiated volcanic rock series (from andesitobasalts to dacites and rhyolites), were formed under island arc conditions in the continent-ocean transition zone. Volcanics of the second group are ascribed to the tholeiitic series and were formed under the other geodynamic setting, which is associated with the regime of extension and riftogenesis, manifested in the studied area probably at the later stage.

  14. U-Th-Pb zircon geochronology on igneous rocks in the Toija and Salittu Formations, Orijärvi area, southwestern Finland: constraints on the age of volcanism and metamorphism

    Directory of Open Access Journals (Sweden)

    Christopher L. Kirkland

    2008-01-01

    Full Text Available Zircons from a felsic volcanic rock in the Toija Formation and a synvolcanic gabbro intrusion in the Salittu Formation within the Orijärvi area were dated by U-Th-Pb SIMS in order to provide depositional constraints on these formations. Zircon crystals from the felsic rock preserve a two-stage crystallisation history with zoned core domains and homogeneous rim domains. Inner domains yield a 1878±4 Ma concordia age, interpreted to determine the crystallisation of this rock. Rims yield a 1815±3 Ma concordia age interpretedto determine the regional metamorphism. Small rounded zircon grains from the Salittu gabbro, located within the Jyly shear zone, yield a concordia age of 1792±5 Ma. We interpret the grain textures to suggest that they recrystallised from inherited zircon seeds during the heat and fluid flow into the shear zone. Although no direct ages for the Salittu Formation have been recovered, field relationships imply that it was deposited between 1878−1875 Ma.

  15. Biodiversity of shallow subtidal, under-rock invertebrates in Europe's first marine reserve: Effects of physical factors and scientific sampling

    Science.gov (United States)

    Trowbridge, Cynthia D.; Kachmarik, Katy; Plowman, Caitlin Q.; Little, Colin; Stirling, Penny; McAllen, Rob

    2017-03-01

    At Lough Hyne Marine Reserve in SW Ireland, shallow subtidal, under-rock biodiversity was investigated to assess (i) any deleterious effects of scientific sampling and (ii) quantitative baseline community patterns. Comparisons were made between 10 sites with annual rock-turning disturbance and 10 with multi-decadal (historical) disturbance. At each site, shallow subtidal rocks (N = 1289 total) were lifted, organisms recorded, and rocks replaced in their original position. Biodiversity indices were calculated to evaluate how diversity varied with location within the lough, frequency of sampling disturbance, degree of hypoxia/anoxia, dissolved oxygen (DO) concentration, and number of rocks turned. The richness of solitary invertebrates surveyed in situ averaged 21 taxa per site with significantly more in the South Basin (near the lough's connection to the ocean) than in the North Basin. The Shannon-Wiener Index did not differ significantly with variables investigated. However, evenness was higher at annually disturbed sites than at historical ones where anemones with algal symbionts often dominated. Several sites were hypoxic to anoxic under the shallow subtidal rocks. Cup corals were most abundant in the South Basin; DO was a crucial explanatory variable of these sensitive species. Solitary ascidians were most abundant at South-Basin annual sites with DO levels being a highly significant explanatory variable.

  16. Eclogite facies rocks

    National Research Council Canada - National Science Library

    Carswell, D. A

    1990-01-01

    .... This is the first volume to provide a coherent and comprehensive review of the conditions necessary for the formation of eclogites and eclogite facies rocks and assemblages, and a detailed account...

  17. Experimental and numerical study on frost heave of saturated rock under uniform freezing conditions

    Science.gov (United States)

    Lv, Zhitao; Xia, Caichu; Li, Qiang

    2018-04-01

    A series of freezing experiments are conducted on saturated sandstone and mortar specimens to investigate the frost heave of saturated rock under uniform freezing conditions. The experimental results show that the frost heave of saturated rock is isotropic under uniform freezing conditions. During the freezing process, three stages are observed in the curves of variation of total frost heaving strain versus time: the thermal contraction stage, the frost heaving stage and the steady stage. Moreover, the amount of final stable frost heave first increases and then decreases with decrease in freezing temperature, and the maximum final stable frost heave occurs at different freezing temperature in saturated sandstone and mortar. Furthermore, a coupled thermal-mechanical (TM) model of frost heave of saturated rock is proposed in which a constraint coefficient \\zeta is used to consider the susceptibility of the internal rock grain structure to the expansion of pore ice. Then, numerical simulations are implemented with COMSOL to solve the governing equations of the TM model. Comparisons of the numerical results with the experimental results are performed to demonstrate the reliability of the model. The influences of elastic modulus and porosity on frost heave are also investigated, and the results show that the total frost heaving strain decreases non-linearly with increasing elastic modulus, and the decrease is significant when the elastic modulus is less than 3000 MPa, or approximately five times the elastic modulus of ice. In addition, the total frost heaving strain increases linearly with increasing porosity. Finally, an empirical equation between total frost heaving strain and freezing temperature is proposed and the equation well describes the variation of total frost heaving strain with freezing temperature.

  18. Bioremediation in Fractured Rock: 2. Mobilization of Chloroethene Compounds from the Rock Matrix.

    Science.gov (United States)

    Shapiro, Allen M; Tiedeman, Claire R; Imbrigiotta, Thomas E; Goode, Daniel J; Hsieh, Paul A; Lacombe, Pierre J; DeFlaun, Mary F; Drew, Scott R; Curtis, Gary P

    2018-03-01

    A mass balance is formulated to evaluate the mobilization of chlorinated ethene compounds (CE) from the rock matrix of a fractured mudstone aquifer under pre- and postbioremediation conditions. The analysis relies on a sparse number of monitoring locations and is constrained by a detailed description of the groundwater flow regime. Groundwater flow modeling developed under the site characterization identified groundwater fluxes to formulate the CE mass balance in the rock volume exposed to the injected remediation amendments. Differences in the CE fluxes into and out of the rock volume identify the total CE mobilized from diffusion, desorption, and nonaqueous phase liquid dissolution under pre- and postinjection conditions. The initial CE mass in the rock matrix prior to remediation is estimated using analyses of CE in rock core. The CE mass mobilized per year under preinjection conditions is small relative to the total CE mass in the rock, indicating that current pump-and-treat and natural attenuation conditions are likely to require hundreds of years to achieve groundwater concentrations that meet regulatory guidelines. The postinjection CE mobilization rate increased by approximately an order of magnitude over the 5 years of monitoring after the amendment injection. This rate is likely to decrease and additional remediation applications over several decades would still be needed to reduce CE mass in the rock matrix to levels where groundwater concentrations in fractures achieve regulatory standards. © 2017, National Ground Water Association.

  19. Radwaste storage in crystalline rocks: a natural analog

    International Nuclear Information System (INIS)

    Brookins, D.G.; Abashian, M.S.; Cohen, L.H.; Wollenberg, H.A.

    1982-01-01

    The Eldora-Bryan Stock (Colorado) intruded the 1.4-1.6 billion year old metamorphic rocks of the Idaho Springs Formation 55 million years ago. The stock may be considered a giant analog of a radwaste form without canister or engineered backfill barriers. The authors' lanthanide studies show the following: (1) The intrusive rocks remained as a closed system. (2) Lanthanide/chondrite versus ionic radius plots show only local redistribution in the immediate contact zone, and that rocks in this zone have not gained lanthanides from the magma. (3) No whole rock perturbations for the lanthanides are noted at distances greater than 3 m from the contact. Stable oxygen isotopic variations show a narrow 9.0 +- 0.3 per mille range for the intrusive rocks and whole rock values from 7.6 to 10.0 per mille for the intruded rocks. The authors conclude: (1) The Idaho Springs Formation was not penetrated by hydrothermal fluids from the Eldora-Bryan magma except possibly on a local scale within 3 m of the contact. (2) The light lanthanides may be locally redistributed in the immediate contact zone, but without additions from the magma. (3) The oxygen isotopic data imply lack of hydrothermal fluids from the magma penetrating the intruded rocks, even in the highest temperature contact zones. Whole rock data imply closed system conditions for Rb, Sr, Th, U, Pb even where mineral ages have been lowered. Data for Co, Cr, Sc, Fe, Cs also indicate retention in whole rock systems and no exchange with the magma. The combined chemical, isotopic, petrographic and theoretical data and calculations indicate suitability of rocks of the Idaho Springs Formation, and thus of many types of crystalline rocks as well, for possible use for the storage of radioactive waste

  20. Thermal properties of rock salt and quartz monzonite to 5730K and 50-MPa confining pressure

    International Nuclear Information System (INIS)

    Durham, W.B.; Abey, A.E.

    1981-01-01

    Measurements of thermal conductivity, thermal diffusivity, and thermal linear expansion have been made on two rock types, a rock salt and a quartz monzonite, at temperatures from 300 to 573 0 K and confining pressures from 10 to 50 MPa. The samples were taken from deep rock formations under consideration as possible sites for a nuclear waste repository - the rock salt from a domal salt formation at Avery Island, Louisiana, and the quartz monzonite from the Climax Stock, Nevada Test Site, Nevada. The testing temperature and pressures are meant to bracket conditions expected in the repository. In both rock types, the thermal properties show a strong dependence upon temperature and a weak or non-dependence upon confining pressure. Thermal conductivity and diffusivity both decrease with increasing temperature in approximately linear fashion for samples which have not been previously heated. At 50 MPa in both rocks this decrease closely matches the measured or expected intrinsic (crack-free) behavior of the material. Preliminary indications from the quartz monzonite suggest that conductivity and diffusivity at low pressure and temperature may decrease as a result of heat treatment above 400 0 K

  1. Requirements for a long-term safety certification for chemotoxic substances stored in a final storage facility for high radioactive and heat-generating radioactive waste in rock salt formations

    International Nuclear Information System (INIS)

    Tholen, M.; Hippler, J.; Herzog, C.

    2007-01-01

    Within the scope of a project funded by the German Federal Ministry of Economics and Technology (Bundesministerium fuer Wirtschaft und Technologie, BMWi), a safety certification concept for a future permanent final storage for high radioactive and heat-generating radioactive waste (HAW disposal facility) in rock salt formations is being prepared. For a reference concept, compliance with safety requirements in regard to operational safety as well as radiological and non-radiological protection objectives related to long-term safety, including ground water protection, will be evaluated. This paper deals with the requirements for a long-term safety certification for the purpose of protecting ground water from chemotoxic substances. In particular, longterm safety certifications for the permanent disposal of radioactive waste in a HAW disposal facility in rock salt formations and for the dumping of hazardous waste in underground storage facilities in rock salt formations are first discussed, followed by an evaluation as to whether these methods can be applied to the long-term safety certification for chemotoxic substances. The authors find it advisable to apply the long-term safety certification for underground storage facilities to the long-term safety certification for chemotoxic substances stored in a HAW disposal facility in rock salt formations. In conclusion, a corresponding certification concept is introduced. (orig.)

  2. Geochemistry of the alkaline volcanicsubvolcanic rocks of the Fernando de Noronha Archipelago, southern Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    Rosana Peporine Lopes

    Full Text Available The Fernando de Noronha Archipelago presents, on its main island, a centrally-located stratigraphic unit, the Remédios Formation (age around 8 - 12 Ma constituted by basal pyroclastic rocks intruded by dikes, plugs and domes of varied igneous rocks, capped by flows and pyroclastics of mafic to ultramafic rocks of the Quixaba Formation (age around 1 - 3 Ma, which is limited from the underlying unit by an extensive irregular erosion surface. A predominant sodic Remédios series (basanites, tephrites, tephriphonolites, essexite, phonolites can be separated from a moderately potassic Remédios sequence (alkali basalts, trachyandesites, trachytes, both alkaline series showing mostly continuous geochemical trends in variation diagrams for major as well as trace elements, indicating evolution by crystal fractionation (mainly, separation of mafic minerals, including apatites and titanites. There are textural and mineralogical evidences pointing to hybrid origin of some intermediate rocks (e.g., resorbed pyroxene phenocrysts in basaltic trachyandesites, and in some lamprophyres. The primitive Quixaba rocks are mostly melanephelinites and basanites, primitive undersaturated sodic types. Geology (erosion surface, stratigraphy (two distinct units separated by a large time interval, petrography (varied Remédios Formation, more uniform Quixaba unit and geochemistry indicate that the islands represent the activity of a protracted volcanic episode, fueled by intermittent melting of an enriched mantle, not related to asthenospheric plume activity.

  3. Formation of neutrophil extracellular traps under low oxygen level

    Directory of Open Access Journals (Sweden)

    Katja Branitzki-Heinemann

    2016-11-01

    Full Text Available Since their discovery, neutrophil extracellular traps (NETs have been characterized as a fundamental host innate immune defense mechanism. Conversely, excessive NET release may have a variety of detrimental consequences for the host. A fine balance between NET formation and elimination is necessary to sustain a protective effect during an infectious challenge. Our own recently published data revealed that stabilization of hypoxia inducible factor 1α (HIF-1α by the iron chelating HIF-1α-agonist desferoxamine or AKB-4924 enhanced the release of phagocyte extracellular traps. Since HIF-1α is a global regulator of the cellular response to low oxygen, we hypothesized that NET formation may be similarly increased under low oxygen conditions. Hypoxia occurs in tissues during infection or inflammation, mostly due to overconsumption of oxygen by pathogens and recruited immune cells. Therefore, experiments were performed to characterize the formation of NETs under hypoxic oxygen conditions compared to normoxia. Human blood-derived neutrophils were isolated and incubated under normoxic (21% oxygen level and compared to hypoxic (1% conditions. Dissolved oxygen levels were monitored in the primary cell culture using a Fibox4-PSt3 measurement system. The formation of NETs was quantified by fluorescence microscopy in response to the known NET-inducer phorbol 12-myristate 13-acetate (PMA or S. aureus wildtype and a nuclease-deficient mutant. In contrast to our hypothesis, spontaneous NET formation of neutrophils incubated under hypoxia was distinctly reduced compared to control neutrophils incubated under normoxia. Furthermore, neutrophils incubated under hypoxia showed significantly reduced formation of NETs in response to PMA. Gene expression analysis revealed that mRNA level of hif-1α as well as hif-1α target genes was not altered. However, in good correlation to the decreased NET formation under hypoxia, the cholesterol content of the neutrophils was

  4. Location-independent study concerning the construction, operation and closure of possible facilities for the final storage of radioactive waste in rock-salt formations in the Netherlands

    International Nuclear Information System (INIS)

    1986-04-01

    Final storage of radioactive waste has been studied on the base of two main concepts: in deep boreholes and caverns from the mowing-field, and for a, for this purpose to be developed, underground ore. Storage supplies have been designed, including the closing constructions after finishing the storage activities, with a, much longer than usually, technical lifetime. Herein use has been made of in general known materials whose properties and behaviour were assumed to remain unaltered over long periods and also will not be influenced by the rock-salt environment. The possible storage concepts described are location independent and based upon the geological and geomechanical information which have been provided with the task and which are indicative for the rock-salt formations occurring in the Netherlands. In first instance the authors have started from the thermodynamical, chemical and fysical properties of the storage rock-formations as are mentioned in the apendices of the task. It particularly concerns properties of the storage rock-formations and the construction materials needed for a qualitatively good and reliable closing of the storage. The construction and operation of the in this report described storage concepts is based upon the storage scenario's as indicated in the task circumscriptions

  5. Geochemistry and origin of metamorphosed mafic rocks from the Lower Paleozoic Moretown and Cram Hill Formations of North-Central Vermont: Delamination magmatism in the western New England appalachians

    Science.gov (United States)

    Coish, Raymond; Kim, Jonathan; Twelker, Evan; Zolkos, Scott P.; Walsh, Gregory J.

    2015-01-01

    The Moretown Formation, exposed as a north-trending unit that extends from northern Vermont to Connecticut, is located along a critical Appalachian litho-tectonic zone between the paleomargin of Laurentia and accreted oceanic terranes. Remnants of magmatic activity, in part preserved as metamorphosed mafic rocks in the Moretown Formation and the overlying Cram Hill Formation, are a key to further understanding the tectonic history of the northern Appalachians. Field relationships suggest that the metamorphosed mafic rocks might have formed during and after Taconian deformation, which occurred at ca. 470 to 460 Ma. Geochemistry indicates that the sampled metamorphosed mafic rocks were mostly basalts or basaltic andesites. The rocks have moderate TiO2 contents (1–2.5 wt %), are slightly enriched in the light-rare earth elements relative to the heavy rare earths, and have negative Nb-Ta anomalies in MORB-normalized extended rare earth element diagrams. Their chemistry is similar to compositions of basalts from western Pacific extensional basins near volcanic arcs. The metamorphosed mafic rocks of this study are similar in chemistry to both the pre-Silurian Mount Norris Intrusive Suite of northern Vermont, and also to some of Late Silurian rocks within the Lake Memphremagog Intrusive Suite, particularly the Comerford Intrusive Complex of Vermont and New Hampshire. Both suites may be represented among the samples of this study. The geochemistry of all samples indicates that parental magmas were generated in supra-subduction extensional environments during lithospheric delamination.

  6. Investigations into the sorption of neptunium by loose rock from the cap rock of the Gorleben salt dome under aerobic and anaerobic conditions

    International Nuclear Information System (INIS)

    Muehlenweg, U.

    1988-01-01

    In the experiments with the natural loose rock the sorption behaviour of neptunium was essentially determined by the chemical form in which the neptunium occurred in the ground waters. Under aerobic conditions with Eh values of 300 mV, neptunium in its oxidation state +5 occurred. At a pH of 2 + , and at pH > 8 as carbonato complex. The found neptunium species were relatively mobile, with sorption values from 1 ml/g to 20 ml/g. The sorption of neptunium is comparable to that of alkali and alkaline earth ions, such as Cs + or Sr 2+ . Cations attached to the rock surface are exchanged for NpO 2 + . Sorption in this case is reversible. (orig.) [de

  7. Performance of the Opalinus Clay under thermal loading: experimental results from Mont Terri rock laboratory (Switzerland)

    Energy Technology Data Exchange (ETDEWEB)

    Gens, A. [Universitat Politència de Catalunya, Barcelona (Spain); Wieczorek, K. [Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) GmbH, Braunschweig (Germany); Gaus, I. [National Cooperative for the Disposal of Radioactive Waste (NAGRA), Wettingen (Switzerland); and others

    2017-04-15

    The paper presents an overview of the behaviour of Opalinus Clay under thermal loading as observed in three in situ heating tests performed in the Mont Terri rock laboratory: HE-B, HE-D and HE-E. The three tests are summarily described; they encompass a broad range of test layouts and experimental conditions. Afterwards, the following topics are examined: determination of thermal conductivity, thermally-induced pore pressure generation and thermally-induced mechanical effects. The mechanisms underlying pore pressure generation and dissipation are discussed in detail and the relationship between rock damage and thermal loading is examined using an additional in situ test: SE-H. The paper concludes with an evaluation of the various thermo-hydro-mechanical (THM) interactions identified in the heating tests. (authors)

  8. Dissecting the roles of ROCK isoforms in stress-induced cell detachment.

    Science.gov (United States)

    Shi, Jianjian; Surma, Michelle; Zhang, Lumin; Wei, Lei

    2013-05-15

    The homologous Rho kinases, ROCK1 and ROCK2, are involved in stress fiber assembly and cell adhesion and are assumed to be functionally redundant. Using mouse embryonic fibroblasts (MEFs) derived from ROCK1(-/-) and ROCK2(-/-) mice, we have recently reported that they play different roles in regulating doxorubicin-induced stress fiber disassembly and cell detachment: ROCK1 is involved in destabilizing the actin cytoskeleton and cell detachment, whereas ROCK2 is required for stabilizing the actin cytoskeleton and cell adhesion. Here, we present additional insights into the roles of ROCK1 and ROCK2 in regulating stress-induced impairment of cell-matrix and cell-cell adhesion. In response to doxorubicin, ROCK1(-/-) MEFs showed significant preservation of both focal adhesions and adherens junctions, while ROCK2(-/-) MEFs exhibited impaired focal adhesions but preserved adherens junctions compared with the wild-type MEFs. Additionally, inhibition of focal adhesion or adherens junction formations by chemical inhibitors abolished the anti-detachment effects of ROCK1 deletion. Finally, ROCK1(-/-) MEFs, but not ROCK2(-/-) MEFs, also exhibited preserved central stress fibers and reduced cell detachment in response to serum starvation. These results add new insights into a novel mechanism underlying the anti-detachment effects of ROCK1 deletion mediated by reduced peripheral actomyosin contraction and increased actin stabilization to promote cell-cell and cell-matrix adhesion. Our studies further support the differential roles of ROCK isoforms in regulating stress-induced loss of central stress fibers and focal adhesions as well as cell detachment.

  9. Numerical Simulation on Zonal Disintegration in Deep Surrounding Rock Mass

    Directory of Open Access Journals (Sweden)

    Xuguang Chen

    2014-01-01

    Full Text Available Zonal disintegration have been discovered in many underground tunnels with the increasing of embedded depth. The formation mechanism of such phenomenon is difficult to explain under the framework of traditional rock mechanics, and the fractured shape and forming conditions are unclear. The numerical simulation was carried out to research the generating condition and forming process of zonal disintegration. Via comparing the results with the geomechanical model test, the zonal disintegration phenomenon was confirmed and its mechanism is revealed. It is found to be the result of circular fracture which develops within surrounding rock mass under the high geostress. The fractured shape of zonal disintegration was determined, and the radii of the fractured zones were found to fulfill the relationship of geometric progression. The numerical results were in accordance with the model test findings. The mechanism of the zonal disintegration was revealed by theoretical analysis based on fracture mechanics. The fractured zones are reportedly circular and concentric to the cavern. Each fracture zone ruptured at the elastic-plastic boundary of the surrounding rocks and then coalesced into the circular form. The geometric progression ratio was found to be related to the mechanical parameters and the ground stress of the surrounding rocks.

  10. Numerical simulation on zonal disintegration in deep surrounding rock mass.

    Science.gov (United States)

    Chen, Xuguang; Wang, Yuan; Mei, Yu; Zhang, Xin

    2014-01-01

    Zonal disintegration have been discovered in many underground tunnels with the increasing of embedded depth. The formation mechanism of such phenomenon is difficult to explain under the framework of traditional rock mechanics, and the fractured shape and forming conditions are unclear. The numerical simulation was carried out to research the generating condition and forming process of zonal disintegration. Via comparing the results with the geomechanical model test, the zonal disintegration phenomenon was confirmed and its mechanism is revealed. It is found to be the result of circular fracture which develops within surrounding rock mass under the high geostress. The fractured shape of zonal disintegration was determined, and the radii of the fractured zones were found to fulfill the relationship of geometric progression. The numerical results were in accordance with the model test findings. The mechanism of the zonal disintegration was revealed by theoretical analysis based on fracture mechanics. The fractured zones are reportedly circular and concentric to the cavern. Each fracture zone ruptured at the elastic-plastic boundary of the surrounding rocks and then coalesced into the circular form. The geometric progression ratio was found to be related to the mechanical parameters and the ground stress of the surrounding rocks.

  11. Chemical variations in Yellowknife Bay formation sedimentary rocks analyzed by ChemCam on board the Curiosity rover on Mars

    Science.gov (United States)

    Mangold, Nicolas; Forni, Olivier; Dromart, G.; Stack, K.M.; Wiens, Roger C.; Gasnault, Olivier; Sumner, Dawn Y.; Nachon, Marion; Meslin, Pierre-Yves; Anderson, Ryan B.; Barraclough, Bruce; Bell, J.F.; Berger, G.; Blaney, D.L.; Bridges, J.C.; Calef, F.; Clark, Brian R.; Clegg, Samuel M.; Cousin, Agnes; Edgar, L.; Edgett, Kenneth S.; Ehlmann, B.L.; Fabre, Cecile; Fisk, M.; Grotzinger, John P.; Gupta, S.C.; Herkenhoff, Kenneth E.; Hurowitz, J.A.; Johnson, J. R.; Kah, Linda C.; Lanza, Nina L.; Lasue, Jeremie; Le Mouélic, S.; Lewin, Eric; Malin, Michael; McLennan, Scott M.; Maurice, S.; Melikechi, Noureddine; Mezzacappa, Alissa; Milliken, Ralph E.; Newsome, H.L.; Ollila, A.; Rowland, Scott K.; Sautter, Violaine; Schmidt, M.E.; Schroder, S.; D'Uston, C.; Vaniman, Dave; Williams, R.A.

    2015-01-01

    The Yellowknife Bay formation represents a ~5 m thick stratigraphic section of lithified fluvial and lacustrine sediments analyzed by the Curiosity rover in Gale crater, Mars. Previous works have mainly focused on the mudstones that were drilled by the rover at two locations. The present study focuses on the sedimentary rocks stratigraphically above the mudstones by studying their chemical variations in parallel with rock textures. Results show that differences in composition correlate with textures and both manifest subtle but significant variations through the stratigraphic column. Though the chemistry of the sediments does not vary much in the lower part of the stratigraphy, the variations in alkali elements indicate variations in the source material and/or physical sorting, as shown by the identification of alkali feldspars. The sandstones contain similar relative proportions of hydrogen to the mudstones below, suggesting the presence of hydrous minerals that may have contributed to their cementation. Slight variations in magnesium correlate with changes in textures suggesting that diagenesis through cementation and dissolution modified the initial rock composition and texture simultaneously. The upper part of the stratigraphy (~1 m thick) displays rocks with different compositions suggesting a strong change in the depositional system. The presence of float rocks with similar compositions found along the rover traverse suggests that some of these outcrops extend further away in the nearby hummocky plains.

  12. Uranium and thorium in rocks and minerals of Zaangarsk alkaline massif

    International Nuclear Information System (INIS)

    Zhmodin, S.M.; Gofman, A.M.; Ksenzova, V.I.; Malmova, Z.V.; Nemirovskaya, N.A.

    1981-01-01

    U and Th distribution in rocks of the massif of alkaline-granitoid formation is studied using the methods of γ-spectrometry and neutron- fragment radiography. Predominant accumulation of U and Th in final products of magmatic differentiation - foyaites - is established. U and Th concentrations increased sharply during postmagmatic stage of alkaline massif formation - in permatites and metasomatically alterated rocks (Th/U and U/K ratios can serve as criteria for identification of such formations). The increase of U part, connected with accessory minerals in pegmatites and metasomatically alterated rocks, is pointed out. For U in postmagmatically alterated rocks high concentrations due to microcracks are characteristic [ru

  13. Experimental and Numerical Studies on Development of Fracture Process Zone (FPZ) in Rocks under Cyclic and Static Loadings

    Science.gov (United States)

    Ghamgosar, M.; Erarslan, N.

    2016-03-01

    The development of fracture process zones (FPZ) in the Cracked Chevron Notched Brazilian Disc (CCNBD) monsonite and Brisbane tuff specimens was investigated to evaluate the mechanical behaviour of brittle rocks under static and various cyclic loadings. An FPZ is a region that involves different types of damage around the pre-existing and/or stress-induced crack tips in engineering materials. This highly damaged area includes micro- and meso-cracks, which emerge prior to the main fracture growth or extension and ultimately coalescence to macrofractures, leading to the failure. The experiments and numerical simulations were designed for this study to investigate the following features of FPZ in rocks: (1) ligament connections and (2) microcracking and its coalescence in FPZ. A Computed Tomography (CT) scan technique was also used to investigate the FPZ behaviour in selected rock specimens. The CT scan results showed that the fracturing velocity is entirely dependent on the appropriate amount of fracture energy absorbed in rock specimens due to the change of frequency and amplitudes of the dynamic loading. Extended Finite Element Method (XFEM) was used to compute the displacements, tensile stress distribution and plastic energy dissipation around the propagating crack tip in FPZ. One of the most important observations, the shape of FPZ and its extension around the crack tip, was made using numerical and experimental results, which supported the CT scan results. When the static rupture and the cyclic rupture were compared, the main differences are twofold: (1) the number of fragments produced is much greater under cyclic loading than under static loading, and (2) intergranular cracks are formed due to particle breakage under cyclic loading compared with smooth and bright cracks along cleavage planes under static loading.

  14. Analysis of the Variations in Rock Magnetic Properties of the Quaternary Blackwater Draw (Eolian) Formation, West Texas

    Science.gov (United States)

    Stine, J. M.; Ferguson, J. F.; Geissman, J. W.; Sweet, D. E.

    2017-12-01

    The Quaternary Blackwater Draw Formation consists of the surficial deposits ( 10 + m thick) that directly overlie the Neogene Ogallala Formation in the Southern High Plains (SHP). These Quaternary deposits display a rhythmic pattern where eolian derived sediments (loess) are in turn punctuated by several paleosol layers, implying that Quaternary glacial-interglacial climate cycles are recorded in the Blackwater Draw Formation. In order to investigate this hypothesis, several rock magnetic parameters obtained from the Blackwater Draw Formation were analyzed using exploratory data analysis (EDA) techniques. The Blackwater Draw Formation was sampled at high resolution (2.5-5 cm intervals in depth, which serves as a proxy for time). Rock magnetic parameters measured are bulk magnetic susceptibility (χ, median: 1.56 * 10-4 SI volume), anhysteretic remanent magnetization (ARM, median: 0.1612 A/m), and isothermal remanent magnetization (IRM, median: 2.5367 A/m) intensity, which allow for the determination of two common environmental magnetic ratios (ARM/χ and ARM/IRM, medians: 1051 and 0.068 respectively) that are often used to approximate magnetic grain size. The data were analyzed using robust EDA methods for classification, correlation, and signal extraction. Using these techniques, it becomes evident that a good correspondence exists between the geophysical data and the geologic model (stratigraphy). For example, the cross plots showed that the magnetic data segregate into clusters corresponding to stratigraphy. Smoothing of the magnetic ratio data produces an oscillatory signal that may correspond to climate cyclicity. Additionally the smoothed models show a noticeable change in periodicity, where the ARM, IRM and χ values in the uppermost section exhibit a much higher amplitude and lower frequency than the bottom part of the section (with the reverse being true for the ratios). When comparing the data to the geologic model this change appears to correlate with

  15. Prediction of Fracture Behavior in Rock and Rock-like Materials Using Discrete Element Models

    Science.gov (United States)

    Katsaga, T.; Young, P.

    2009-05-01

    The study of fracture initiation and propagation in heterogeneous materials such as rock and rock-like materials are of principal interest in the field of rock mechanics and rock engineering. It is crucial to study and investigate failure prediction and safety measures in civil and mining structures. Our work offers a practical approach to predict fracture behaviour using discrete element models. In this approach, the microstructures of materials are presented through the combination of clusters of bonded particles with different inter-cluster particle and bond properties, and intra-cluster bond properties. The geometry of clusters is transferred from information available from thin sections, computed tomography (CT) images and other visual presentation of the modeled material using customized AutoCAD built-in dialog- based Visual Basic Application. Exact microstructures of the tested sample, including fractures, faults, inclusions and void spaces can be duplicated in the discrete element models. Although the microstructural fabrics of rocks and rock-like structures may have different scale, fracture formation and propagation through these materials are alike and will follow similar mechanics. Synthetic material provides an excellent condition for validating the modelling approaches, as fracture behaviours are known with the well-defined composite's properties. Calibration of the macro-properties of matrix material and inclusions (aggregates), were followed with the overall mechanical material responses calibration by adjusting the interfacial properties. The discrete element model predicted similar fracture propagation features and path as that of the real sample material. The path of the fractures and matrix-inclusion interaction was compared using computed tomography images. Initiation and fracture formation in the model and real material were compared using Acoustic Emission data. Analysing the temporal and spatial evolution of AE events, collected during the

  16. Thermo-hydro-mechanical coupling in long-term sedimentary rock response

    Science.gov (United States)

    Makhnenko, R. Y.; Podladchikov, Y.

    2017-12-01

    Storage of nuclear waste or CO2 affects the state of stress and pore pressure in the subsurface and may induce large thermal gradients in the rock formations. In general, the associated coupled thermo-hydro-mechanical effect on long-term rock deformation and fluid flow have to be studied. Principles behind mathematical models for poroviscoelastic response are reviewed, and poroviscous model parameter, the bulk viscosity, is included in the constitutive equations. Time-dependent response (creep) of fluid-filled sedimentary rocks is experimentally quantified at isotropic stress states. Three poroelastic parameters are measured by drained, undrained, and unjacketed geomechanical tests for quartz-rich Berea sandstone, calcite-rich Apulian limestone, and clay-rich Jurassic shale. The bulk viscosity is calculated from the measurements of pore pressure growth under undrained conditions, which requires time scales 104 s. The bulk viscosity is reported to be on the order of 1015 Pa•s for the sandstone, limestone, and shale. It is found to be decreasing with the increase of pore pressure despite corresponding decrease in the effective stress. Additionally, increase of temperature (from 24 ºC to 40 ºC) enhances creep, where the most pronounced effect is reported for the shale with bulk viscosity decrease by a factor of 3. Viscous compaction of fluid-filled porous media allows a generation of a special type of fluid flow instability that leads to formation of high-porosity, high-permeability domains that are able to self-propagate upwards due to interplay between buoyancy and viscous resistance of the deforming porous matrix. This instability is known as "porosity wave" and its formation is possible under conditions applicable to deep CO2 storage in reservoirs and explains creation of high-porosity channels and chimneys. The reported experiments show that the formation of high-permeability pathways is most likely to occur in low-permeable clay-rich materials (caprock

  17. Corrosion of candidate materials for canister: applications in rock salt formations

    International Nuclear Information System (INIS)

    Azkarate, I.; Madina, V.; Barrio, A. del; Macarro, J.M.

    1994-01-01

    Previous corrosion studies carried out on various metallic materials in typical salt rock environments show that carbon steel and titanium alloys are the most promising candidates for canister applications in this geological formation. Although carbon steels have a low corrosion resistance, they are considered acceptable as corrosion-allowance materials for a thick walled container due to their practical immunity to the localized corrosion phenomena such as stress corrosion cracking, pitting or crevice corrosion. Aiming to improve the performances of these materials, studies on the effect of small additions of Ni and V on the general corrosion are in process. The improvement in the resistance to general corrosion should not be accompanied by a sensitivity to stress corrosion cracking. On the contrary, alfa titanium alloys are considered the most resistant materials to general corrosion in salt brines. However, pitting, are potential deficiencies of this corrosion-resistant materials for a thin walled container. (Author)

  18. Biological Communities in Desert Varnish and Potential Implications for Varnish Formation Mechanisms

    Science.gov (United States)

    Lang-Yona, Naama; Maier, Stefanie; Macholdt, Dorothea; Rodriguez-Caballero, Emilio; Müller-Germann, Isabell; Yordanova, Petya; Jochum, Klaus-Peter; Andreae, Meinrat O.; Pöschl, Ulrich; Weber, Bettina; Fröhlich-Nowoisky, Janine

    2017-04-01

    Desert varnishes are thin, orange to black coatings found on rocks in arid and semi-arid environments on Earth. The formation mechanisms of rock varnish are still under debate and the involvement of microorganisms in this process remains unclear. In this work we aimed to identify the microbial community occurring in rock varnish to potentially gain insights into the varnish formation mechanism. For this purpose, rocks coated with desert varnish were collected from the Anza-Borrego Desert, California, USA, as well as soils from underneath the rocks. DNA from both varnish coatings and soil samples was extracted and subsequently used for metagenomic analysis, as well as for q-PCR analyses for specific species quantification. The element composition of the varnish coatings was analyzed and compared to the soil samples. Rock varnish shows similar depleted elements, compared to soil, but Mn and Pb are 50-60 times enriched compared to the soil samples, and about 100 times enriched compared to the upper continental crust. Our genomic analyses suggest unique populations and different protein functional groups occurring in the varnish compared to soil samples. We discuss these differences and try to shed light on the mechanism of Mn oxyhydroxide production in desert varnish formation.

  19. Analysis of volcano rock from Canary islands

    International Nuclear Information System (INIS)

    Sitek, J.; Sedlackova, K.; Dekan, J.

    2013-01-01

    In this work we have analyzed the basalt rock from Lanzarote, which is the easternmost island of the Canary Islands lying in the Atlantic Ocean and has a volcanic origin. It was born through fiery eruptions and has solidified lava streams as well as extravagant rock formations. We compared our results with composition of basalt rocks from some other places on the Earth. Different iron oxides created on the volcanic rocks during their weathering on the Earth surface has been also analyzed. (authors)

  20. Development of in-situ rock shear test under low compressive to tensile normal stress

    International Nuclear Information System (INIS)

    Nozaki, Takashi; Shin, Koichi

    2003-01-01

    The purpose of this study is to develop an in-situ rock shear testing method to evaluate the shear strength under low normal stress condition including tensile stress, which is usually ignored in the assessment of safety factor of the foundations for nuclear power plants against sliding. The results are as follows. (1) A new in-situ rock shear testing method is devised, in which tensile normal stress can be applied on the shear plane of a specimen by directly pulling up a steel box bonded to the specimen. By applying the counter shear load to cancel the moment induced by the main shear load, it can obtain shear strength under low normal stress. (2) Some model tests on Oya tuff and diatomaceous mudstone have been performed using the developed test method. The shear strength changed smoothly from low values at tensile normal stresses to higher values at compressive normal stresses. The failure criterion has been found to be bi-linear on the shear stress vs normal stress plane. (author)

  1. Frost formation under different gaseous atmospheres

    International Nuclear Information System (INIS)

    Fukada, Satoshi; Tsuru, Hisanori; Nishikawa, Masabumi

    1995-01-01

    Rates of water frost growth in a vessel with a cooled horizontal plate were experimentally determined under reduced pressure atmospheres of hydrogen, helium, methane and nitrogen. The mass deposited on the cooled surface under each of the atmospheres was almost in proportion to time. The Sherwood number under the condition of no mist formation, Sh 0 , in the atmospheres of methane and nitrogen was in good agreement with Catton's equation for natural convection between horizontal parallel plates. Sh 0 in a hydrogen atmosphere was unity, which corresponds to control by molecular diffusion in the stagnant gas. The tendency of the decrease in Sh due to mist formation could be evaluated well by multiplying Sh 0 by a factor ζ CSM . The ζ CSM value was calculated based on the critical supersaturation model as a function of the two interface temperatures and the total pressure. Frost growth rates under each atmosphere were in proportion to [(T S1 -T W1 )t/(1+1/A S1 )] 0.5 . The proportional constant for hydrogen was greater than that for any other tested gas. Agreement and disagreement of the frost effective thermal conductivity with previous models were discussed. (author)

  2. The three-dimension model for the rock-breaking mechanism of disc cutter and analysis of rock-breaking forces

    Science.gov (United States)

    Zhang, Zhao-Huang; Sun, Fei

    2012-06-01

    To study the rock deformation with three-dimensional model under rolling forces of disc cutter, by carrying out the circular-grooving test with disc cutter rolling around on the rock, the rock mechanical behavior under rolling disc cutter is studied, the mechanical model of disc cutter rolling around the groove is established, and the theory of single-point and double-angle variables is proposed. Based on this theory, the physics equations and geometric equations of rock mechanical behavior under disc cutters of tunnel boring machine (TBM) are studied, and then the balance equations of interactive forces between disc cutter and rock are established. Accordingly, formulas about normal force, rolling force and side force of a disc cutter are derived, and their validity is studied by tests. Therefore, a new method and theory is proposed to study rock-breaking mechanism of disc cutters.

  3. Sliding rocks on Racetrack Playa, Death Valley National Park: first observation of rocks in motion.

    Directory of Open Access Journals (Sweden)

    Richard D Norris

    Full Text Available The engraved trails of rocks on the nearly flat, dry mud surface of Racetrack Playa, Death Valley National Park, have excited speculation about the movement mechanism since the 1940s. Rock movement has been variously attributed to high winds, liquid water, ice, or ice flotation, but has not been previously observed in action. We recorded the first direct scientific observation of rock movements using GPS-instrumented rocks and photography, in conjunction with a weather station and time-lapse cameras. The largest observed rock movement involved > 60 rocks on December 20, 2013 and some instrumented rocks moved up to 224 m between December 2013 and January 2014 in multiple move events. In contrast with previous hypotheses of powerful winds or thick ice floating rocks off the playa surface, the process of rock movement that we have observed occurs when the thin, 3 to 6 mm, "windowpane" ice sheet covering the playa pool begins to melt in late morning sun and breaks up under light winds of -4-5 m/s. Floating ice panels 10 s of meters in size push multiple rocks at low speeds of 2-5 m/min. along trajectories determined by the direction and velocity of the wind as well as that of the water flowing under the ice.

  4. Numerical Simulation on Zonal Disintegration in Deep Surrounding Rock Mass

    OpenAIRE

    Xuguang Chen; Yuan Wang; Yu Mei; Xin Zhang

    2014-01-01

    Zonal disintegration have been discovered in many underground tunnels with the increasing of embedded depth. The formation mechanism of such phenomenon is difficult to explain under the framework of traditional rock mechanics, and the fractured shape and forming conditions are unclear. The numerical simulation was carried out to research the generating condition and forming process of zonal disintegration. Via comparing the results with the geomechanical model test, the zonal disintegration p...

  5. Hydrogeochemical studies of the Rustler Formation and related rocks in the Waste Isolation Pilot Plant Area, Southeastern New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Siegel, M.D.; Lambert, S.J.; Robinson, K.L. (eds.)

    1991-08-01

    Chemical, mineralogical, isotopic, and hydrological studies of the Culebra dolomite member of the Rustler Formation and related rocks are used to delineate hydrochemical facies and form the basis for a conceptual model for post-Pleistocene groundwater flow and chemical evolution. Modern flow within the Culebra in the Waste Isolation Pilot Plant (WIPP) area appears to be largely north-to-south; however, these flow directions under confined conditions are not consistent with the salinity distribution in the region surrounding the WIPP Site. Isotopic, mineralogical, and hydrological data suggest that vertical recharge to the Culebra in the WIPP area and to the immediate east and south has not occurred for several thousand years. Eastward increasing {sup 234}U/{sup 238}U activity ratios suggest recharge from a near-surface Pleistocene infiltration zone flowing from the west-northwest and imply a change in flow direction in the last 30,000 to 12,000 years. 49 refs., 34 figs., 4 tabs.

  6. Hydrogeochemical studies of the Rustler Formation and related rocks in the Waste Isolation Pilot Plant Area, Southeastern New Mexico

    International Nuclear Information System (INIS)

    Siegel, M.D.; Lambert, S.J.; Robinson, K.L.

    1991-08-01

    Chemical, mineralogical, isotopic, and hydrological studies of the Culebra dolomite member of the Rustler Formation and related rocks are used to delineate hydrochemical facies and form the basis for a conceptual model for post-Pleistocene groundwater flow and chemical evolution. Modern flow within the Culebra in the Waste Isolation Pilot Plant (WIPP) area appears to be largely north-to-south; however, these flow directions under confined conditions are not consistent with the salinity distribution in the region surrounding the WIPP Site. Isotopic, mineralogical, and hydrological data suggest that vertical recharge to the Culebra in the WIPP area and to the immediate east and south has not occurred for several thousand years. Eastward increasing 234 U/ 238 U activity ratios suggest recharge from a near-surface Pleistocene infiltration zone flowing from the west-northwest and imply a change in flow direction in the last 30,000 to 12,000 years. 49 refs., 34 figs., 4 tabs

  7. Hydrogeology of the carbonate rocks of the Lebanon Valley, Pennsylvania

    Science.gov (United States)

    Meisler, Harold

    1963-01-01

    The Lebanon Valley, which is part of the Great Valley in southeastern Pennsylvania, is underlain by carbonate rocks in the southern part and by shale in the northern part. The carbonate rocks consist of alternating beds of limestone and dolomite of Cambrian and Ordovician age. Although the beds generally dip to the south, progressively younger beds crop out to the north, because the rocks are overturned. The stratigraphic units, from oldest to youngest, are: the Buffalo Springs Formation, Snitz Creek, Schaefferstown, Millbach, and Richland Formations of the Conococheague Group; the Stonehenge, Rickenbach, Epler, and Ontelaunee Formations of the Beekmantown Group; and the Annville, Myerstown, and Hershey Limestones.

  8. Burial history of two potential clay host formations in Belgium

    International Nuclear Information System (INIS)

    Mertens, J.; Wouters, L.; Van Marcke, Ph.

    2004-01-01

    When dealing with long term stability of repository host rocks, it is important to consider and learn from all past geological events since the deposition of the formations. The burial history of the Boom Clay and Ypresian Clays, both considered as potential host rocks in Belgium, illustrates that the North Belgian region was tectonically relatively stable since deposition. In Northern Belgium, where both formations are located at a few hundreds meters of depth, tectonic movements were relatively small and no significant uplifts took place. The burial history of the Boom Clay in Mol, where the HADES underground research facility is located illustrates this. On the poster, the burial history for both formations is presented at two locations each: one location in the outcrop region and one research site location, where the formation is currently buried under a few 100 metres of sediment. (authors)

  9. Dynamic properties of anhydrites, marls and salts of the Gachsaran evaporitic formation, Iran

    International Nuclear Information System (INIS)

    Gorjian, M; Memarian, H; Moosavi, M; Mehrgini, B

    2013-01-01

    A large carbonate oil field in Iran is suffering from severe casing collapses and related operational problems in anhydrite, marl and salt sequences of the Gachsaran cap rock formation. To investigate the causes and cures of operational problems, specifically casing collapse, knowing geomechanical properties of anhydrite, marl and salt of this formation is a prerequisite. However, taking cores in this formation is virtually impossible due to high solubility and weakness of the rocks. Moreover, there are insufficient well log data in this formation and the only available running well log is V p . In this paper, in order to obtain the dynamic parameters of the Gachsaran formation, V p , V s and ρ b in anhydrite, marl and salt cores, which had been taken from depths up to 300 m, were measured. Moreover, V p and V s in salt cores under different triaxial and hydrostatic stress conditions were obtained. The V p –V s, (V p /V s )–V p and V p –ρ b relations in anhydrite, marl and salt were investigated. The established relations in these anhydrite samples were verified by the data derived from limited cores which were taken from 3600 m depth. The relations between dynamic properties of salt with lateral and hydrostatic stresses were investigated. In conclusion, V s , ρ b and the ratio of V p /V s in anhydrite and marl can be estimated through the established relations and having V p logs in the Gachsaran formation. As a result, the dynamic properties of these rocks can be calculated in different depths of this evaporitic formation. Furthermore, the dynamic properties of salt rock seem to be constant in various depths and under differing triaxial and hydrostatic stress conditions. (paper)

  10. Fractal Characteristics of Rock Fracture Surface under Triaxial Compression after High Temperature

    Directory of Open Access Journals (Sweden)

    X. L. Xu

    2016-01-01

    Full Text Available Scanning Electron Microscopy (SEM test on 30 pieces of fractured granite has been researched by using S250MK III SEM under triaxial compression of different temperature (25~1000°C and confining pressure (0~40 MPa. Research results show that (1 the change of fractal dimension (FD of rock fracture with temperature is closely related to confining pressure, which can be divided into two categories. In the first category, when confining pressure is in 0~30 MPa, FD fits cubic polynomial fitting curve with temperature, reaching the maximum at 600°C. In the second category, when confining pressure is in 30~40 MPa, FD has volatility with temperature. (2 The FD of rock fracture varies with confining pressure and is also closely related to the temperature, which can be divided into three categories. In the first category, FD has volatility with confining pressure at 25°C, 400°C, and 800°C. In the second category, it increases exponentially at 200°C and 1000°C. In the third category, it decreases exponentially at 600°C. (3 It is found that 600°C is the critical temperature and 30 MPa is the critical confining pressure of granite. The rock transfers from brittle to plastic phase transition when temperature exceeds 600°C and confining pressure exceeds 30 MPa.

  11. Subsurface Rock Physical Properties by Downhole Loggings - Case Studies of Continental Deep Drilling in Kanto Distinct, Japan

    Science.gov (United States)

    Omura, K.

    2014-12-01

    In recent years, many examples of physical logging have been carried out in deep boreholes. The loggings are direct in-situ measurements of rock physical properties under the ground. They provide significant basic data for the geological, geophysical and geotechnical investigations, e.g., tectonic history, seismic wave propagation, and ground motion prediction. Since about 1980's, Natl. Res. Inst. for Earth Sci. and Disast. Prev. (NIED) dug deep boreholes (from 200m to 3000m depth) in sedimentary basin of Kanto distinct, Japan, for purposes of installing seismographs and hydrological instruments, and in-situ stress and pore pressure measurements. At that time, downhole physical loggings were conducted in the boreholes: spontaneous potential, electrical resistance, elastic wave velocity, formation density, neutron porosity, total gamma ray, caliper, temperature loggings. In many cases, digital data values were provided every 2m or 1m or 0.1m. In other cases, we read printed graphs of logging plots and got digital data values. Data from about 30 boreholes are compiled. Especially, particular change of logging data at the depth of an interface between a shallow part (soft sedimentary rock) and a base rock (equivalent to hard pre-Neogene rock) is examined. In this presentation, the correlations among physical properties of rock (especially, formation density, elastic wave velocity and electrical resistance) are introduced and the relation to the lithology is discussed. Formation density, elastic wave velocity and electric resistance data indicate the data are divide in two groups that are higher or lower than 2.5g/cm3: the one correspond to a shallow part and the other correspond to a base rock part. In each group, the elastic wave velocity and electric resistance increase with increase of formation density. However the rates of increases in the shallow part are smaller than in the base rock part. The shallow part has lower degree of solidification and higher porosity

  12. Aquifer Characterization and Groundwater Potential Evaluation in Sedimentary Rock Formation

    Science.gov (United States)

    Ashraf, M. A. M.; Yusoh, R.; Sazalil, M. A.; Abidin, M. H. Z.

    2018-04-01

    This study was conducted to characterize the aquifer and evaluate the ground water potential in the formation of sedimentary rocks. Electrical resistivity and drilling methods were used to develop subsurface soil profile for determining suitable location for tube well construction. The electrical resistivity method was used to infer the subsurface soil layer by use of three types of arrays, namely, the pole–dipole, Wenner, and Schlumberger arrays. The surveys were conducted using ABEM Terrameter LS System, and the results were analyzed using 2D resistivity inversion program (RES2DINV) software. The survey alignments were performed with maximum electrode spreads of 400 and 800 m by employing two different resistivity survey lines at the targeted zone. The images were presented in the form of 2D resistivity profiles to provide a clear view of the distribution of interbedded sandstone, siltstone, and shale as well as the potential groundwater zones. The potential groundwater zones identified from the resistivity results were confirmed using pumping, step drawdown, and recovery tests. The combination among the three arrays and the correlation between the well log and pumping test are reliable and successful in identifying potential favorable zones for obtaining groundwater in the study area.

  13. Experimental Investigation of the Influence of Joint Geometric Configurations on the Mechanical Properties of Intermittent Jointed Rock Models Under Cyclic Uniaxial Compression

    Science.gov (United States)

    Liu, Yi; Dai, Feng; Fan, Pengxian; Xu, Nuwen; Dong, Lu

    2017-06-01

    Intermittent joints in rock mass are quite sensitive to cyclic loading conditions. Understanding the fatigue mechanical properties of jointed rocks is beneficial for rational design and stability analysis of rock engineering projects. This study experimentally investigated the influences of joint geometry (i.e., dip angle, persistency, density and spacing) on the fatigue mechanism of synthetic jointed rock models. Our results revealed that the stress-strain curve of jointed rock under cyclic loadings is dominated by its curve under monotonic uniaxial loadings; the terminal strain in fatigue curve is equal to the post-peak strain corresponding to the maximum cyclic stress in the monotonic stress-strain curve. The four joint geometrical parameters studied significantly affect the fatigue properties of jointed rocks, including the irreversible strains, the fatigue deformation modulus, the energy evolution, the damage variable and the crack coalescence patterns. The higher the values of the geometrical parameters, the lower the elastic energy stores in this jointed rock, the higher the fatigue damage accumulates in the first few cycles, and the lower the fatigue life. The elastic energy has certain storage limitation, at which the fatigue failure occurs. Two basic micro-cracks, i.e., tensile wing crack and shear crack, are observed in cyclic loading and unloading tests, which are controlled principally by joint dip angle and persistency. In general, shear cracks only occur in the jointed rock with higher dip angle or higher persistency, and the jointed rock is characterized by lower fatigue strength, larger damage variable and lower fatigue life.

  14. A theoretical and numerical consideration of rock mass behaviour under thermal loading of radioactive waste repository

    International Nuclear Information System (INIS)

    Reivinen, M.; Freund, J.; Eloranta, E.

    1996-08-01

    The aim of the study is to model the geodynamic response of a ground rock block under horizontal stresses and also consider the thermal fields and deformations, especially on the ground surface, caused by the heat produced by nuclear waste. (12 refs.)

  15. Evaluation of radiological safety assessment of a repository in a clay rock formation

    International Nuclear Information System (INIS)

    1999-01-01

    This report presents a comprehensive description of the post-closure radiological safety assessment of a repository for the spent fuel arisings resulting from the Spanish nuclear program excavated in a clay host rock formation. In this report three scenarios have been analysed in detail. The first scenario represents the normal in detail. The first scenario represents the normal evolution of the repository (Reference Scenario); and includes a set of variants to investigate the relative importance of the various repository components and examine the sensitivity of the performance to parameters variations. Two altered scenarios have also been considered: deep well construction and poor sealing of the repository. This document contains a detailed description of the repository system, the methodology adopted for the scenarios generation, the process modelling approach and the results of the consequences analysis. (Author)

  16. 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.

  17. Fissures in rock under water pressure, implications on stability : 3 unusual cases

    Energy Technology Data Exchange (ETDEWEB)

    Helwig, P.C. [Helwig Hydrotechnique Ltd., St. John' s, NL (Canada)

    2006-07-01

    The presence of water in rock joints has important implications on the stability of rock foundations. Appropriate analyses are needed to assess the stability of dam foundations, abutments and rock walls. This paper presented 3 case studies in which the freezing of seepage flows in rock joints and transient pressure in rock walls were investigated: (1) an assessment of the effects of freezing water in rock joints at the Paradise River arch dam in Newfoundland; (2) stability of rock walls in the unlined power tunnel of the Cat Arm hydroelectric development in Newfoundland due to transient pressures; and (3) assessing the influence of fluctuating water pressures in a stilling basin excavated in rock. After an investigation of the Paradise River canyon walls, a drainage system comprised of peripheral drain holes was drilled into the foundation and walls at regular intervals to intercept seepage flows and to relieve uplift water pressures. However, no special treatment was found for the potential freezing of water in the joints of the dam walls and foundation. The Cat Arm tunnel was used to study the depth at which significant transient pressures can be used to assess rock stability. Rock properties, typical fracture apertures and spacing were assumed and joint deformability was taken into account. An axisymmetric solution was obtained by considering the continuity and flow through an annular element of the rock wall. A finite difference method was used to solve the resulting nonlinear differential equation. In the final case study, blast-damaged rock was undermining the toe of a spillway. A cut-off wall was constructed as a series of drilled, cast-in-place concrete caisson piles. Criteria for the design included extending the cut-off wall to a depth beyond the effects of fluctuating surface pressures. Depth was assessed by considering the transient behaviour of water penetrating a sub-vertical joint subject exposed to fluctuating pressures. Results of the calculations

  18. Numerical Study on Dynamic Response of a Horizontal Layered-Structure Rock Slope under a Normally Incident Sv Wave

    Directory of Open Access Journals (Sweden)

    Zhifa Zhan

    2017-07-01

    Full Text Available Several post-earthquake investigations have indicated that the slope structure plays a leading role in the stability of rock slopes under dynamic loads. In this paper, the dynamic response of a horizontal layered-structure rock slope under harmonic Sv wave is studied by making use of the Fast Lagrangian Analysis of Continua method (FLAC. The suitability of FLAC for studying wave transmission across rock joints is validated through comparison with analytical solutions. After parametric studies on Sv wave transmission across the horizontal layered-structure rock slope, it is found that the acceleration amplification coefficient η, which is defined as the ratio of the acceleration at the monitoring point to the value at the toe, wavily increases with an increase of the height along the slope surface. Meanwhile, the fluctuation weakens with normalized joint stiffness K increasing and enhances with normalized joint spacing ξ increasing. The acceleration amplification coefficient of the slope crest ηcrest does not monotonously increase with the increase of ξ, but decreases with the increase of K. Additionally, ηcrest is more sensitive to ξ compared to K. From the contour figures, it can also be found that the contour figures of η take on rhythm, and the effects of ξ on the acceleration amplification coefficient are more obvious compared to the effects on K.

  19. A Percolation Study of Wettability Effect on the Electrical Properties of Reservoir Rocks

    DEFF Research Database (Denmark)

    Zhou, Dengen; Arbabi, Sepehr; Stenby, Erling Halfdan

    1997-01-01

    Measurements of the electrical resistivity of oil reservoirs are commonly used to estimate other properties of reservoirs, such as porosity and hydrocarbon reserves. However, the interpretation of the measurements is based on empirical correlations, because the underlying mechanisms that control...... the electrical properties of oil bearing rocks have not been well understood. In this paper, we employ percolation concepts to investigate the effect of wettability on the electrical conductivity of a reservoir formation. A three-dimensional simple cubic network is used to represent an ideal reservoir formation...

  20. Heat production in granitic rocks

    DEFF Research Database (Denmark)

    Artemieva, Irina; Thybo, Hans; Jakobsen, Kiki

    2017-01-01

    Granitic rocks play special role in the dynamics and evolution of the Earth and its thermal regime. First, their compositional variability, reflected in the distribution of concentrations of radiogenic elements, provides constraints on global differentiation processes and large scale planetary...... evolution, where emplacement of granites is considered a particularly important process for the formation of continental crust. Second, heat production by radioactive decay is among the main heat sources in the Earth. Therefore knowledge of heat production in granitic rocks is pivotal for thermal modelling...... of the continental lithosphere, given that most radiogenic elements are concentrated in granitic rocks of the upper continental crust whereas heat production in rocks of the lower crust and lithospheric mantle is negligible. We present and analyze a new global database GRANITE2017 (with about 500 entries...

  1. Clonal diversity and clone formation in the parthenogenetic Caucasian rock Lizard Darevskia dahli [corrected].

    Science.gov (United States)

    Vergun, Andrey A; Martirosyan, Irena A; Semyenova, Seraphima K; Omelchenko, Andrey V; Petrosyan, Varos G; Lazebny, Oleg E; Tokarskaya, Olga N; Korchagin, Vitaly I; Ryskov, Alexey P

    2014-01-01

    The all-female Caucasian rock lizard species Darevskia dahli and other parthenogenetic species of this genus reproduce normally via true parthenogenesis. Previously, the genetic diversity of this species was analyzed using allozymes, mitochondrial DNA, and DNA fingerprint markers. In the present study, variation at three microsatellite loci was studied in 111 specimens of D. dahli from five populations from Armenia, and new information regarding clonal diversity and clone formation in D. dahli was obtained that suggests a multiple hybridization origin. All individuals but one were heterozygous at the loci studied. Based on specific allele combinations, 11 genotypes were identified among the individuals studied. Individuals with the same genotypes formed distinct clonal lineages: one major clone was represented by 72 individuals, an intermediate clone was represented by 21 individuals, and nine other clones were rare and represented by one or several individuals. A new approach based on the detection and comparison of genotype-specific markers formed by combinations of parental-specific markers was developed and used to identify at least three hybridization founder events that resulted in the initial formation of one major and two rare clones. All other clones, including the intermediate and seven rare clones, probably arose through postformation microsatellite mutations of the major clone. This approach can be used to identify hybridization founder events and to study clone formation in other unisexual taxa.

  2. Microhyla laterite sp. nov., A New Species of Microhyla Tschudi, 1838 (Amphibia: Anura: Microhylidae from a Laterite Rock Formation in South West India.

    Directory of Open Access Journals (Sweden)

    K S Seshadri

    Full Text Available In recent times, several new species of amphibians have been described from India. Many of these discoveries are from biodiversity hotspots or from within protected areas. We undertook amphibian surveys in human dominated landscapes outside of protected areas in south western region of India between years 2013-2015. We encountered a new species of Microhyla which is described here as Microhyla laterite sp. nov. It was delimited using molecular, morphometric and bioacoustics comparisons. Microhyla laterite sp. nov. appears to be restricted to areas of the West coast of India dominated by laterite rock formations. The laterite rock formations date as far back as the Cretaceous-Tertiary boundary and are considered to be wastelands in-spite of their intriguing geological history. We identify knowledge gaps in our understanding of the genus Microhyla from the Indian subcontinent and suggest ways to bridge them.

  3. Stratigraphy of the Kapalga Formation north of Pine Creek and its relationship to base metal mineralization

    International Nuclear Information System (INIS)

    Goulevitch, J.

    1980-01-01

    The lithology, stratigraphy and mineralization of the Kapalga Formation (South Alligator Group) is described from the Margaret Syncline in the Pine Creek area of the Northern Territory of Australia. An interdigitation of carbonaceous siltstones and mudstones, chert, ashstones and tuffaceous chert, greywacke, siltstone, mudstone and minor banded iron formation (b.i.f.) characterises the Formation. These rocks define a vertical facies transition between low energy sediments of the underlying Koolpin Formation, and high energy sediments of the overlying Burrell Creek Formation. This transition is interlayered with numerous ashstone-tuffaceous chert horizons which were deposited during the waning stage of Gerowie Tuff sedimentation. The boundary between the Kapalga Formation of the South Alligator Group and the Burrell Creek Formation of the Finniss River Group is strictly conformable in this part of the Pine Creek 'Geosyncline'. Relict devitrified shards have been recognised in the Gerowie Tuff in the Margaret Syncline and these observations along with whole-rock chemical analyses conclusively support claims by previous investigators that these rocks are volcanic derivatives. Base metal mineralization at Iron Blow and Mt. Bonnie occurs as massive, stratiform, sulphide-silicate-carbonate lodes. The deposits are at the same stratigraphic level towards the base of the Kapalga Formation and minor stratification parallel with bedding has been observed. These features, and the association of the lodes with mud-flow breccias, lead to the conclusion that the lodes are syngenetic in origin. Thermochemical consideration of the sulphide assemblages together with the temporal relationship between the mineralization and Gerowie Tuff point to diagenetic devitrification of the underlying tuffaceous rocks as the source of the mineralization. Recent publications of experimental data from reaction of seawater and volcanic glass provide information which supports this thesis, and

  4. Structure analysis - chiromancy of the rock

    International Nuclear Information System (INIS)

    Huber, A.; Huber, M.

    1989-01-01

    The reader may initially be surprised by a comparison between structure analysis and palmistry which is, in effect, a comparison between a scientific research method on the one hand and art which is equated with magical powers on the other. In the figurative sense, however, these two fields have some points in common which should help us to obtain a first impression of the nature of geological structure analysis. Chiromancy uses the lines and the form of the hand to predict the character and the future of the person in question. In the same way, geologists use rocks and rock forms to obtain information on structure and behaviour of different formations. Structure analysis is a specialised field of geological investigation in which traces of deformation are interpreted as expressions of rockforming forces. This article discusses how and why the character of a rock formation as well as its past, present and even future behaviour can be determined using structure analysis. (author) 11 figs

  5. Rock Formation and Cosmic Radiation Exposure Ages in Gale Crater Mudstones from the Mars Science Laboratory

    Science.gov (United States)

    Mahaffy, Paul; Farley, Ken; Malespin, Charles; Gellert, Ralph; Grotzinger, John

    2014-05-01

    The quadrupole mass spectrometer (QMS) in the Sample Analysis at Mars (SAM) suite of the Mars Science Laboratory (MSL) has been utilized to secure abundances of 3He, 21Ne, 36Ar, and 40Ar thermally evolved from the mudstone in the stratified Yellowknife Bay formation in Gale Crater. As reported by Farley et al. [1] these measurements of cosmogenic and radiogenic noble gases together with Cl and K abundances measured by MSL's alpha particle X-ray spectrometer enable a K-Ar rock formation age of 4.21+0.35 Ga to be established as well as a surface exposure age to cosmic radiation of 78+30 Ma. Understanding surface exposures to cosmic radiation is relevant to the MSL search for organic compounds since even the limited set of studies carried out, to date, indicate that even 10's to 100's of millions of years of near surface (1-3 meter) exposure may transform a significant fraction of the organic compounds exposed to this radiation [2,3,4]. Transformation of potential biosignatures and even loss of molecular structural information in compounds that could point to exogenous or endogenous sources suggests a new paradigm in the search for near surface organics that incorporates a search for the most recently exposed outcrops through erosional processes. The K-Ar rock formation age determination shows promise for more precise in situ measurements that may help calibrate the martian cratering record that currently relies on extrapolation from the lunar record with its ground truth chronology with returned samples. We will discuss the protocol for the in situ noble gas measurements secured with SAM and ongoing studies to optimize these measurements using the SAM testbed. References: [1] Farley, K.A.M Science Magazine, 342, (2013). [2] G. Kminek et al., Earth Planet Sc Lett 245, 1 (2006). [3] Dartnell, L.R., Biogeosciences 4, 545 (2007). [4] Pavlov, A. A., et al. Geophys Res Lett 39, 13202 (2012).

  6. An experimental study of velocities under pressure for ancient oceanic rocks

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, K.V.L.N.S.

    Seismic velocities of Indus suture rock types from Dras-Sanko-Kargil, Kashmir Himalaya, as a function of pressure up to 10 kbar were studied. The high-pressure measurements on the rocks reflect the depthwise increase in velocity, and in general...

  7. Drilling Performance of Rock Drill by High-Pressure Water Jet under Different Configuration Modes

    Directory of Open Access Journals (Sweden)

    Songyong Liu

    2017-01-01

    Full Text Available In the rock drilling progress, the resistant force results in tools failure and the low drilling efficiency; thus, it is necessary to reduce the tools failure and enhance the drilling efficiency. In this paper, different configuration modes of drilling performance assisted with water jet are explored based on the mechanism and experiment analysis of rock drilling assisted with water jet. Moreover, the rotary sealing device with high pressure is designed to achieve the axial and rotation movement simultaneously as well as good sealing effect under high-pressure water jet. The results indicate that the NDB and NFB have better effects on drilling performance compared with that of NSB. Moreover, the high-pressure water jet is helpful not only to reduce the drill rod deflection, but also to reduce the probability of drill rod bending and improve the drill rod service life.

  8. Rock engineering in Finland

    Energy Technology Data Exchange (ETDEWEB)

    1986-01-01

    Contains a large collection of short articles concerned with tunnels and underground caverns and their construction and use. The articles are grouped under the following headings: use of the subsurface space; water supply; waste water services; energy management (includes articles on power stations, district heating and oil storage and an article on coal storage); multipurpose tunnels; waste disposal; transport; shelters; sporting and recreational amenities located in rock caverns; storage facilities; industrial, laboratory, and service facilities; rock foundations; tourism and culture; utilization of rock masses; research on the disposal of nuclear waste; training and research in the field of rock engineering; site investigation techniques; design of structures in rock; construction; the environment and occupational safety; modern equipment technology; underground space in Helsinki.

  9. Theoretical and numerical studies of crack initiation and propagation in rock masses under freezing pressure and far-field stress

    Directory of Open Access Journals (Sweden)

    Yongshui Kang

    2014-10-01

    Full Text Available Water-bearing rocks exposed to freezing temperature can be subjected to freeze–thaw cycles leading to crack initiation and propagation, which are the main causes of frost damage to rocks. Based on the Griffith theory of brittle fracture mechanics, the crack initiation criterion, propagation direction, and crack length under freezing pressure and far-field stress are analyzed. Furthermore, a calculation method is proposed for the stress intensity factor (SIF of the crack tip under non-uniformly distributed freezing pressure. The formulae for the crack/fracture propagation direction and length of the wing crack under freezing pressure are obtained, and the mechanism for coalescence of adjacent cracks is investigated. In addition, the necessary conditions for different coalescence modes of cracks are studied. Using the topology theory, a new algorithm for frost crack propagation is proposed, which has the capability to define the crack growth path and identify and update the cracked elements. A model that incorporates multiple cracks is built by ANSYS and then imported into FLAC3D. The SIFs are then calculated using a FISH procedure, and the growth path of the freezing cracks after several calculation steps is demonstrated using the new algorithm. The proposed method can be applied to rocks containing fillings such as detritus and slurry.

  10. Mapping the productive sands of Lower Goru Formation by using seismic stratigraphy and rock physical studies in Sawan area, southern Pakistan: A case study

    KAUST Repository

    Munir, K.; Iqbal, M.A.; Farid, A.; Shabih, S.M.

    2011-01-01

    This study has been conducted in the Sawan gas field located in southern Pakistan. The aim of the study is to map the productive sands of the Lower Goru Formation of the study area. Rock physics parameters (bulk modulus, Poisson's ratio

  11. Stages of weathering mantle formation from carbonate rocks in the light of rare earth elements (REE) and Sr-Nd-Pb isotopes

    Science.gov (United States)

    Hissler, Christophe; Stille, Peter

    2015-04-01

    Weathering mantles are widespread and include lateritic, sandy and kaolinite-rich saprolites and residuals of partially dissolved rocks. These old regolith systems have a complex history of formation and may present a polycyclic evolution due to successive geological and pedogenetic processes that affected the profile. Until now, only few studies highlighted the unusual high content of associated trace elements in weathering mantles originating from carbonate rocks, which have been poorly studied, compared to those developing on magmatic bedrocks. For instance, these enrichments can be up to five times the content of the underlying carbonate rocks. However, these studies also showed that the carbonate bedrock content only partially explains the soil enrichment for all the considered major and trace elements. Up to now, neither soil, nor saprolite formation has to our knowledge been geochemically elucidated. Therefore, the aim of this study was to examine more closely the soil forming dynamics and the relationship of the chemical soil composition to potential sources. REE distribution patterns and Sr-Nd-Pb isotope ratios have been used because they are particularly well suited to identify trace element migration, to recognize origin and mixing processes and, in addition, to decipher possible anthropogenic and/or "natural" atmosphere-derived contributions to the soil. Moreover, leaching experiments have been applied to identify mobile phases in the soil system and to yield information on the stability of trace elements and especially on their behaviour in these Fe-enriched carbonate systems. All these geochemical informations indicate that the cambisol developing on such a typical weathering mantle ("terra fusca") has been formed through weathering of a condensed Bajocian limestone-marl facies. This facies shows compared to average world carbonates important trace element enrichments. Their trace element distribution patterns are similar to those of the soil

  12. Basic rocks in Finland

    International Nuclear Information System (INIS)

    Piirainen, T.; Gehoer, S.; Iljina, M.; Kaerki, A.; Paakkola, J.; Vuollo, J.

    1992-10-01

    Basic igneous rocks, containing less than 52% SiO 2 , constitute an important part of the Finnish Archaean and Proterozoic crust. In the Archaean crust exist two units which contain the majority of the basic rocks. The Arcaean basic rocks are metavolcanics and situated in the Greenstone Belts of Eastern Finland. They are divided into two units. The greenstones of the lower one are tholeiites, komatiites and basaltic komatiites. The upper consists of bimodal series of volcanics and the basic rocks of which are Fe-tholeiites, basaltic komatiites and komatiites. Proterozoic basic rocks are divided into seven groups according to their ages. The Proterozoic igneous activity started by the volominous basic magmatism 2.44 Ga ago. During this stage formed the layered intrusions and related dykes in the Northern Finland. 2.2 Ga old basic rocks are situated at the margins of Karelian formations. 2.1 Ga aged Fe-tholeiitic magmatic activity is widespread in Eastern and Northern Finland. The basic rocks of 1.97 Ga age group are met within the Karelian Schist Belts as obducted ophiolite complexes but they occur also as tholeiitic diabase dykes cutting the Karelian schists and Archean basement. The intrusions and the volcanics of the 1.9 Ga old basic igneous activity are mostly encountered around the Granitoid Complex of Central Finland. Subjotnian, 1.6 Ga aged tholeiitic diabases are situated around the Rapakivi massifs of Southern Finland, and postjotnian, 1.2 Ga diabases in Western Finland where they form dykes cutting Svecofennian rocks

  13. Experimental study on influence of carbon dioxide on porous structure and mechanical properties of shale rock

    Directory of Open Access Journals (Sweden)

    Danuta Miedzińska

    2017-12-01

    Full Text Available Shale rocks are geological formations which can be unconventional gas reservoirs. During their interaction with carbon dioxide, which can be used as a fracturing fluid in shale gas recovery process, many phenomena take place that can influence rock structure and mechanical properties. The research on changes in rock structure under super critical carbon dioxide interaction and their influence of shale properties were presented in the paper. The structural tests were carried out with the use of microscopic techniques with different resolutions of visualization. The uniaxial compression test was applied as a mechanical properties’ assessment experiment. As a result of research, some dependence was observed. The bigger decrease was in porosity after infiltration in lower zooms, the bigger increase in porosity in high zooms and mechanical properties was noticed. Keywords: geomechanics, shale rock, carbon dioxide

  14. Depositional environments, provenance and paleoclimatic implications of Ordovician siliciclastic rocks of the Thango Formation, Spiti Valley, Tethys Himalaya, northern India

    Science.gov (United States)

    Rashid, Shaik A.; Ganai, Javid A.

    2018-05-01

    Recently published findings indicate that the Ordovician period has been much more dynamic than previously anticipated thus making this period significant in geological time. The Ordovician of India can best be studied in the Spiti region because the Spiti basin records the complete uninterrupted history of excellent marine sedimentary rocks starting from Cambrian to Paleogene which were deposited along the northern margin of India. Due to these reasons the geochemical data on the Ordovician rocks from the Spiti region is uncommon. The present geochemical study on the Ordovician Thango Formation (Sanugba Group) is mainly aimed to understand the provenance and the paleoclimatic conditions. The sandstones are the dominant lithology of the Thango Formation with intercalations of minor amount of shales. Detailed petrographic and sedimentological analysis of these rocks suggest that three major depositional environments, viz., fluvial, transitional and marine prevailed in the basin representing transgressive and regressive phases. The major and trace element ratios such as SiO2/Al2O3, K2O/Na2O and La-Th- Sc discrimination diagram suggest that these rocks were deposited in passive margin tectonic settings. Various geochemical discriminants and elemental ratios such as K2O/Na2O, Al2O3/TiO2, La/Sc, Th/Sc, Cr/Th, Zr/Sc, (Gd/Yb)N and pronounced negative Eu anomalies indicate the rocks to be the product of weathering of post-Archean granites. The striking similarities of the multi-elemental spider diagrams of the studied sediments and the Himalayan granitoids indicate that sediments are sourced from the Proterozoic orogenic belts of the Himalayan region. Chemical index of alteration (CIA) values of the studied sediments (55-72) suggest that the source rocks underwent low to moderate degree of chemical weathering. The span of the CIA values (55-72) recorded in the sediments from the Spiti region may have resulted from varying degrees of weathering conditions in the source area

  15. Hematite Spherules in Basaltic Tephra Altered Under Aqueous, Acid-Sulfate Conditions on Mauna Kea Volcano, Hawaii: Possible Clues for the Occurrence of Hematite-Rich Spherules in the Burns Formation at Meridiani Planum, Mars

    Science.gov (United States)

    Morris, R. V.; Ming, D. W.; Graff, T. G.; Arvidson, R. E.; Bell, J. F., III; Squyres, S. W.; Mertzman, S. A.; Gruener, J. E.; Golden, D. C.; Robinson, G. A.

    2005-01-01

    Iron-rich spherules (>90% Fe2O3 from electron microprobe analyses) approx.10-100 microns in diameter are found within sulfate-rich rocks formed by aqueous, acid-sulfate alteration of basaltic tephra on Mauna Kea volcano, Hawaii. Although some spherules are nearly pure Fe, most have two concentric compositional zones, with the core having a higher Fe/Al ratio than the rim. Oxide totals less than 100% (93-99%) suggest structural H2O and/or /OH. The transmission Moessbauer spectrum of a spherule-rich separate is dominated by a hematite (alpha-Fe2O3) sextet whose peaks are skewed toward zero velocity. Skewing is consistent with Al(3+) for Fe(3+) substitution and structural H2O and/or /OH. The grey color of the spherules implies specular hematite. Whole-rock powder X-ray diffraction spectra are dominated by peaks from smectite and the hydroxy sulfate mineral natroalunite as alteration products and plagioclase feldspar that was present in the precursor basaltic tephra. Whether spherule formation proceeded directly from basaltic material in one event (dissolution of basaltic material and precipitation of hematite spherules) or whether spherule formation required more than one event (formation of Fe-bearing sulfate rock and subsequent hydrolysis to hematite) is not currently constrained. By analogy, a formation pathway for the hematite spherules in sulfate-rich outcrops at Meridiani Planum on Mars (the Burns formation) is aqueous alteration of basaltic precursor material under acid-sulfate conditions. Although hydrothermal conditions are present on Mauna Kea, such conditions may not be required for spherule formation on Mars if the time interval for hydrolysis at lower temperatures is sufficiently long.

  16. Fracture Dissolution of Carbonate Rock: An Innovative Process for Gas Storage

    Energy Technology Data Exchange (ETDEWEB)

    James W. Castle; Ronald W. Falta; David Bruce; Larry Murdoch; Scott E. Brame; Donald Brooks

    2006-10-31

    The goal of the project is to develop and assess the feasibility and economic viability of an innovative concept that may lead to commercialization of new gas-storage capacity near major markets. The investigation involves a new approach to developing underground gas storage in carbonate rock, which is present near major markets in many areas of the United States. Because of the lack of conventional gas storage and the projected growth in demand for storage capacity, many of these areas are likely to experience shortfalls in gas deliverability. Since depleted gas reservoirs and salt formations are nearly non-existent in many areas, alternatives to conventional methods of gas storage are required. The need for improved methods of gas storage, particularly for ways to meet peak demand, is increasing. Gas-market conditions are driving the need for higher deliverability and more flexibility in injection/withdrawal cycling. In order to meet these needs, the project involves an innovative approach to developing underground storage capacity by creating caverns in carbonate rock formations by acid dissolution. The basic concept of the acid-dissolution method is to drill to depth, fracture the carbonate rock layer as needed, and then create a cavern using an aqueous acid to dissolve the carbonate rock. Assessing feasibility of the acid-dissolution method included a regional geologic investigation. Data were compiled and analyzed from carbonate formations in six states: Indiana, Ohio, Kentucky, West Virginia, Pennsylvania, and New York. To analyze the requirements for creating storage volume, the following aspects of the dissolution process were examined: weight and volume of rock to be dissolved; gas storage pressure, temperature, and volume at depth; rock solubility; and acid costs. Hydrochloric acid was determined to be the best acid to use because of low cost, high acid solubility, fast reaction rates with carbonate rock, and highly soluble products (calcium chloride

  17. Synthetic Rock Analogue for Permeability Studies of Rock Salt with Mudstone

    Directory of Open Access Journals (Sweden)

    Hongwu Yin

    2017-09-01

    Full Text Available Knowledge about the permeability of surrounding rock (salt rock and mudstone interlayer is an important topic, which acts as a key parameter to characterize the tightness of gas storage. The goal of experiments that test the permeability of gas storage facilities in rock salt is to develop a synthetic analogue to use as a permeability model. To address the permeability of a mudstone/salt layered and mixed rock mass in Jintan, Jiangsu Province, synthetic mixed and layered specimens using the mudstone and the salt were fabricated for permeability testing. Because of the gas “slippage effect”, test results are corrected by the Klinkenberg method, and the permeability of specimens is obtained by regression fitting. The results show that the permeability of synthetic pure rock salt is 6.9 × 10−20 m2, and its porosity is 3.8%. The permeability of synthetic mudstone rock is 2.97 × 10−18 m2, with a porosity 17.8%. These results are close to those obtained from intact natural specimens. We also find that with the same mudstone content, the permeability of mixed specimens is about 40% higher than for the layered specimens, and with an increase in the mudstone content, the Klinkenberg permeability increases for both types of specimens. The permeability and mudstone content have a strong exponential relationship. When the mudstone content is below 40%, the permeability increases only slightly with mudstone content, whereas above this threshold, the permeability increases rapidly with mudstone content. The results of the study are of use in the assessment of the tightness of natural gas storage facilities in mudstone-rich rock salt formations in China.

  18. Development of rock segment for reduction of amount of cement use

    International Nuclear Information System (INIS)

    Tada, Hiroyuki; Kumasaka, Hiroo; Saito, Akira; Nakaya, Atsushi; Ishii, Takashi; Sanada, Masanori; Noguchi, Akira; Kishi, Hirokazu; Nakama, Shigeo; Fujita, Tomoo

    2013-01-01

    The authors have been developing methods for constructing tunnels using the minimum quantities of cement-type support materials in high-level radioactive waste disposal facilities and advancing research and development about the technical formation of rock segment using low alkali mortar. In this study, the mechanical characteristic values concerning the rock segment and backfill materials were examined. The stability analysis of drift supported by the rock segment and backfilling with gravel were performed. Technical formation and effectiveness of the support planned for further reduction in cement influence was confirmed from the study result. (author)

  19. Modeling fluid-rock interaction at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Viani, B.E.; Bruton, C.J.

    1992-08-01

    Volcanic rocks at Yucca Mountain, Nevada aie being assessed for their suitability as a potential repository for high-level nuclear waste. Recent progress in modeling fluid-rock interactions, in particular the mineralogical and chemical changes that may accompany waste disposal at Yucca Mountain, will be reviewed in this publication. In Part 1 of this publication, ''Geochemical Modeling of Clinoptilolite-Water Interactions,'' solid-solution and cation-exchange models for the zeolite clinoptilolite are developed and compared to experimental and field observations. At Yucca Mountain, clinoptilolite which is found lining fractures and as a major component of zeolitized tuffs, is expected to play an important role in sequestering radionuclides that may escape from a potential nuclear waste repository. The solid-solution and ion-exchange models were evaluated by comparing predicted stabilities and exchangeable cation distributions of clinoptilolites with: (1) published binary exchange data; (2) compositions of coexisting clinoptilolites and formation waters at Yucca Mountain; (3) experimental sorption isotherms of Cs and Sr on zeolitized tuff, and (4) high temperature experimental data. Good agreement was found between predictions and expertmental data, especially for binary exchange and Cs and Sr sorption on clinoptilolite. Part 2 of this publication, ''Geochemical Simulation of Fluid-Rock Interactions at Yucca Mountain,'' describes preliminary numerical simulations of fluid-rock interactions at Yucca Mountain. The solid-solution model developed in the first part of the paper is used to evaluate the stability and composition of clinciptilolite and other minerals in the host rock under ambient conditions and after waste emplacement

  20. Source rock potential of middle cretaceous rocks in Southwestern Montana

    Science.gov (United States)

    Dyman, T.S.; Palacas, J.G.; Tysdal, R.G.; Perry, W.J.; Pawlewicz, M.J.

    1996-01-01

    The middle Cretaceous in southwestern Montana is composed of a marine and nonmarine succession of predominantly clastic rocks that were deposited along the western margin of the Western Interior Seaway. In places, middle Cretaceous rocks contain appreciable total organic carbon (TOC), such as 5.59% for the Mowry Shale and 8.11% for the Frontier Formation in the Madison Range. Most samples, however, exhibit less than 1.0% TOC. The genetic or hydrocarbon potential (S1+S2) of all the samples analyzed, except one, yield less than 1 mg HC/g rock, strongly indicating poor potential for generating commercial amounts of hydrocarbons. Out of 51 samples analyzed, only one (a Thermopolis Shale sample from the Snowcrest Range) showed a moderate petroleum potential of 3.1 mg HC/g rock. Most of the middle Cretaceous samples are thermally immature to marginally mature, with vitrinite reflectance ranging from about 0.4 to 0.6% Ro. Maturity is high in the Pioneer Mountains, where vitrinite reflectance averages 3.4% Ro, and at Big Sky Montana, where vitrinite reflectance averages 2.5% Ro. At both localities, high Ro values are due to local heat sources, such as the Pioneer batholith in the Pioneer Mountains.

  1. Experimental investigation of incipient shear failure in foliated rock

    NARCIS (Netherlands)

    Ikari, Matt J.; Niemeijer, André R.; Marone, Chris

    It has long been known that rock fabric plays a key role in dictating rock strength and rheology throughout Earth's crust; however the processes and conditions under which rock fabric impacts brittle failure and frictional strength are still under investigation. Here, we report on laboratory

  2. Brine migrations in the Athabasca Basin platform, alteration and associated fluid-rock exchanges

    International Nuclear Information System (INIS)

    Mercadier, J.; Cathelineau, M.; Richard, A.; Boiron, M.Ch.; Cuney, M.; Milesi, J.P.

    2009-01-01

    Uranium deposits of Athabasca Basin (Saskatchewan, Canada) are considered as the richest in the world. They result from massive percolation of basin brines in the underlying platform. The authors describe the brine movements and how structures and micro-fractures promoted this percolation until very important depths (hundreds of meters under the discordance), and their chemical modifications as they interacted with platform rocks, thus promoting the transformation of an initially sodic brine into a uranium-enriched calcic brine which is essential to the formation of discordance-type deposit

  3. Microscale experimental investigation of deformation and damage of argillaceous rocks under cyclic hydric and mechanical loads

    International Nuclear Information System (INIS)

    Wang, Linlin; Yang, Diansen; Heripre, Eva; Chanchole, Serge; Bornert, Michel; Pouya, Ahmad; Halphen, Bernard

    2012-01-01

    Document available in abstract form only. Argillaceous rocks are possible host rocks for underground nuclear waste repositories. They exhibit complex coupled thermo-hydro-chemo-mechanical behavior, the description of which would strongly benefit from an improved experimental insight on their deformation and damage mechanisms at microscale. We present some recent observations of the evolution of these rocks at the scale of their composite microstructure, essentially made of a clay matrix with embedded carbonates and quartz particles with sizes ranging from a few to several tens of micrometers, when they are subjected to cyclic variations of relative humidity and mechanical loading. They are based on the combination of high definition and high resolution imaging in an environmental scanning electron microscope (ESEM), in situ hydro-mechanical loading of the samples, and digital image correlation techniques. Samples, several millimeters in diameter, are held at a constant temperature of 2 deg. Celsius while the vapor pressure in the ESEM chamber is varied from a few to several hundreds of Pascals, generating a relative humidity ranging from about 10% up to 90%. Results show a strongly heterogeneous deformation field at microscale, which is the result of complex hydro-mechanical interactions. In particular, it can be shown that local swelling incompatibilities can generate irreversible deformations in the clay matrix, even if the overall hydric deformations seem reversible. In addition, local damage can be generated, in the form of a network of microcracks, located in the bulk of the clay matrix and/or at the interface between clay and other mineral particles. The morphology of this network, described in terms of crack length, orientation and preferred location, has been observed to be dependent on the speed of the variation of the relative humidity, and is different in a saturation or desaturation process. Besides studying the deformation and damage under hydric

  4. Research on Formation Mechanisms of Hot Dry Rock Resources in China

    Science.gov (United States)

    Wang, G.; Xi, Y.

    2017-12-01

    As an important geothermal resource, hot dry rock(HDR) reserves have been studied in many countries. HDR resources in China have huge capacity and have become one of the most important resources for the potential replacement of fossil fuels. However, HDR resources are difficult to develop and utilise. Technologies for use with HDR, such as high-temperature drilling, reservoir characterisation, reservoir fracturing, microseismic monitoring and high-temperature power stations, originate from the field of oil and drilling. Addressing how to take advantage of these developed technologies is a key factor in the development of HDR reserves. Based on the thermal crustal structure in China, HDR resources can be divided into four types: high radioactive heat production, sedimentary basin, modern volcano and the inner-plate active tectonic belt. The prospective regions of HDR resources are located in South Tibet, West Yunnan, the southeast coast of China, Bohai Rim, Songliao Basin and Guanzhong Basin. The related essential technologies are relatively mature, and the prospect of HDR power generation is promising. Therefore, analysing the formation mechanisms of HDR resources and promoting the transformation of technological achievements, large-scale development and the utilisation of HDR resources can be achieved in China.

  5. Geology and Geochemistry of Magmatic Rocks from the Southern Part of the Kyushu-Palau Ridge in the Philippine Sea

    Science.gov (United States)

    Lelikov, E. P.; Sedin, V. T.; Pugachev, A. A.

    2018-03-01

    The paper reports the results of a geochemical study of volcanogenic rocks from the southern part of the Kyushu-Palau Ridge. Volcanic structures, such as plateaulike rises, mountain massifs, and single volcanoes, are the major relief-forming elements of the southern part of the Kyushu-Palau Ridge. They are divided into three types according to the features of the relief and geological structure: shield, cone-shaped, and dome-shaped volcanoes. The ridge was formed on oceanic crust in the Late Mesozoic and underwent several stages of evolution with different significance and application of forces (tension and compression). Change in the geodynamic conditions during the geological evolution of the ridge mostly determined the composition of volcanic rocks of deep-mantle nature. Most of the ridge was formed by the Early Paleogene under geodynamic conditions close to the formation of oceanic islands (shield volcanoes) under tension. The island arc formed on the oceanic basement in the compression mode in the Late Eocene-Early Oligocene. Dome-shaped volcanic edifices composed of alkaline volcanic rocks were formed in the Late Oligocene-Early Miocene under tension. Based on the new geochemical data, detailed characteristics of volcanic rocks making up the shield, cone-shape, and dome-shape stratovolcanoes resulting in the features of these volcanic edifices are given for the first time. Continuous volcanism (with an age from the Cretaceous to the Late Miocene and composition from oceanic tholeiite to calc-alkaline volcanites of the island arc type) resulting in growth of the Earth's crust beneath the Kyushu-Palau Ridge was the major factor in the formation this ridge.

  6. Sociality Affects REM Sleep Episode Duration Under Controlled Laboratory Conditions in the Rock Hyrax, Procavia capensis

    Directory of Open Access Journals (Sweden)

    Nadine Gravett

    2017-11-01

    Full Text Available The rock hyrax, Procavia capensis, is a highly social, diurnal mammal. In the current study several physiologically measurable parameters of sleep, as well as the accompanying behavior, were recorded continuously from five rock hyraxes, for 72 h under solitary (experimental animal alone in the recording chamber, and social conditions (experimental animal with 1 or 2 additional, non-implanted animals in the recording chamber. The results revealed no significant differences between solitary and social conditions for total sleep times, number of episodes, episode duration or slow wave activity (SWA for all states examined. The only significant difference observed between social and solitary conditions was the average duration of rapid eye movement (REM sleep episodes. REM sleep episode duration was on average 20 s and 40 s longer under social conditions daily and during the dark period, respectively. It is hypothesized that the increase in REM sleep episode duration under social conditions could possibly be attributed to improved thermoregulation strategies, however considering the limited sample size and design of the current study further investigations are needed to confirm this finding. Whether the conclusions and the observations made in this study can be generalized to all naturally socially sleeping mammals remains an open question.

  7. Evolution of the Petrophysical and Mineralogical Properties of Two Reservoir Rocks Under Thermodynamic Conditions Relevant for CO2 Geological Storage at 3 km Depth

    International Nuclear Information System (INIS)

    Rimmel, G.; Barlet-Gouedard, V.; Renard, F.

    2010-01-01

    Injection of carbon dioxide (CO 2 ) underground, for long-term geological storage purposes, is considered as an economically viable option to reduce greenhouse gas emissions in the atmosphere. The chemical interactions between supercritical CO 2 and the potential reservoir rock need to be thoroughly investigated under thermodynamic conditions relevant for geological storage. In the present study, 40 samples of Lavoux limestone and Adamswiller sandstone, both collected from reservoir rocks in the Paris basin, were experimentally exposed to CO 2 in laboratory autoclaves specially built to simulate CO 2 -storage-reservoir conditions. The two types of rock were exposed to wet supercritical CO 2 and CO 2 -saturated water for one month, at 28 MPa and 90 C, corresponding to conditions for a burial depth approximating 3 km. The changes in mineralogy and micro-texture of the samples were measured using X-ray diffraction analyses, Raman spectroscopy, scanning-electron microscopy, and energy-dispersion spectroscopy microanalysis. The petrophysical properties were monitored by measuring the weight, density, mechanical properties, permeability, global porosity, and local porosity gradients through the samples. Both rocks maintained their mechanical and mineralogical properties after CO 2 exposure despite an increase of porosity and permeability. Microscopic zones of calcite dissolution observed in the limestone are more likely to be responsible for such increase. In the sandstone, an alteration of the petro-fabric is assumed to have occurred due to clay minerals reacting with CO 2 . All samples of Lavoux limestone and Adamswiller sandstone showed a measurable alteration when immersed either in wet supercritical CO 2 or in CO 2 -saturated water. These batch experiments were performed using distilled water and thus simulate more severe conditions than using formation water (brine). (authors)

  8. Natural analogue studies in crystalline rock: the influence of water-bearing fractures on radionuclide immobilisation in a granitic rock repository

    International Nuclear Information System (INIS)

    Alexander, W.R.; MacKenzie, A.B.; Scott, R.D.; McKinley, I.G.

    1990-06-01

    Current Swiss concepts for the disposal of radioactive waste involve disposal in deep mined repositories to ensure that only insignificant quantities of radionuclides will ever reach the surface and so enter the biosphere. The rock formations presently considered as potential candidates for hosting radwaste repositories have thus been selected on the basis of their capacity to isolate radionuclides from the biosphere. An important factor in ensuring such containment is a very low solute transport rate through the host formation. However, it is considered likely that, in the formations of interest in the Swiss programme (eg. granites, argillaceous sediments, anhydrite), the rocks will be fractured to some extent even at repository depth. In the instance of the cumulative failure of near-field barriers in the repository, these hydraulically connected fractures in the host formation could be very important far-field routes of migration (and possible sites of retardation) of radionuclides dissolved in the groundwaters. In this context, the so-called 'matrix diffusion' mechanism is potentially very important for radionuclide retardation. This report is the culmination of a programme which has attempted to assess the potential influence of these water-bearing fractures on radionuclide transport in a crystalline rock radwaste repository. 162 refs., 36 figs., 16 tabs

  9. Detrital zircon without detritus: a result of 496-Ma-old fluid-rock interaction during the gold-lode formation of Passagem, Minas Gerais, Brazil

    Science.gov (United States)

    Cabral, Alexandre Raphael; Zeh, Armin

    2015-01-01

    Zircon and xenotime occur in tourmaline-rich hydrothermal pockets in the auriferous lode of Passagem de Mariana, a world-class gold deposit. Zircon grains show pristine oscillatory zoning, but many of them are altered, exhibiting porous domains filled with graphite. Uranium-Pb dating of zircon, using in-situ laser ablation-inductively coupled plasma-mass spectrometry, yields ages between 3.2 and 2.65 Ga, which match those for detrital zircon of the footwall quartzite of the > 2.65-Ga-old Moeda Formation. Discordant analyses point to zircon-age resetting during the Brasiliano orogeny at ca. 500 Ma. This interpretation is supported by U-Pb dating of euhedral xenotime immediately adjacent to altered zircon within the same tourmaline pocket. The xenotime grains give a Concordia age of 496.3 ± 2.0 Ma, which is identical to that determined for monazite of a quartz-hematite vein-type deposit (i.e., jacutinga lode) in the region (Itabira), another important mineralisation style of gold. The occurrence of relatively abundant inherited detrital zircon, but absence of rock fragments in the tourmaline pocket investigated here, implies that detrital material was completely replaced by tourmaline. The graphite overprint on the altered detrital zircon attests to a reducing fluid, which was likely formed by fluid-rock interaction with carbonaceous phyllite of the Batatal Formation, the host rock of the Passagem lode.

  10. ROCK1 and ROCK2 are Required for Non-Small Cell Lung Cancer Anchorage-Independent Growth and Invasion

    OpenAIRE

    Vigil, Dominico; Kim, Tai Young; Plachco, Ana; Garton, Andrew J.; Castaldo, Linda; Pachter, Jonathan A.; Dong, Hanqing; Chen, Xin; Tokar, Brianna; Campbell, Sharon L.; Der, Channing J.

    2012-01-01

    Evidence is emerging that the closely related ROCK1 and ROCK2 serine/threonine kinases support the invasive and metastatic growth of a spectrum of human cancer types. Therefore, inhibitors of ROCK are under preclinical development. However, a key step in their development involves the identification of genetic biomarkers that will predict ROCK inhibitor anti-tumor activity. One identified mechanism for ROCK activation in cancer involves the loss of function of the DLC1 tumor suppressor gene, ...

  11. Studies about strength recovery and generalized relaxation behavior of rock (4)

    International Nuclear Information System (INIS)

    Sanada, Masanori; Kishi, Hirokazu; Hayashi, Katsuhiko; Takebe, Atsuji; Okubo, Seisuke

    2011-11-01

    Surrounding rock failure occurs due to the increasing stress with tunnel excavation and extent of the failure depends on rock strength and rock stress. The NATM (New Austrian Tunneling Method) assumes that supporting effects by shotcrete and rock bolt prevent rock failure maximizing the potential capability of rock mass. Recently, it was found that failed rock just behind tunnel support recovers its strength. This phenomenon should take into account in evaluation of tunnel stability and long-term mechanical behavior of rock mass after closure of a repository for high-level radioactive waste (HLW). Visco-elastic behavior of rock is frequently studied by creep testing, but creep occasionally occurs together with relaxation in-situ due to the effect of various supports and rock heterogeneity. Therefore generalized stress relaxation in which both load and displacement are controlled is proper to study such behavior under the complicated conditions. It is also important to understand rock behavior in tensile stress field which may be developed in the surrounding rock of deposition hole or tunnel by swelling of bentonite or volume expansion of overpack with corrosion after the repository closure. Cores sampled at 'Horonobe Underground Research Laboratory' has been tested to reveal the above-mentioned behavior. Quantitative evaluation and modeling of the rock behavior, however, have not been established mainly because of large scatter of data. As a factor of the large scatter of data, it was expected that the evaporation of moisture from the surface of the test piece influences the test outcome because it tested in the nature. In this study, strength recovery, generalized stress relaxation and two tensile strength tests were carried out using shale sampled in the Wakkanai-formation. As the results, recovery of failed rocks in strength and hydraulic conductivity were observed under a certain condition. We believe this result is very important for the stability evaluation

  12. Interpretation of Oil Seepage of Source Rock Based Magnetic Survey in Cipari Cilacap District

    Directory of Open Access Journals (Sweden)

    Sukmaji Anom Raharjo

    2015-12-01

    Full Text Available The magnetic survey had been conducted in Village of Cipari, District of Cipari, Region of  Cilacap to interpret to the location of the oil seepage source rock. Boundary of the research area is 108.75675°E – 108.77611°E and 7.42319°S – 7.43761°S. The observed total magnetic data is corrected and reducted to obtain the local magnetic anomaly data. The local magnetic anomaly data is applied to model the subsurface bodies anomalies based on the Mag2DC for Windows software. With be supported the geological information, the some bodies anomalies are interpreted as the basaltic igneous rock (c = 0.0051, the alternately of sandstone and claystone and insert of marl from Halang Formation (c = 0.0014, the breccia from Kumbang Formation (c = 0.0035, the alternately of sandstones and claystone with insert of marl and breccia from Halang Formation (c = 0.0036, the claystone from Tapak Formation (c = 0.0015, the alternately of sandstones and claystone with insert of marl and compacted breccia from Halang Formation (c = 0.0030, and the alternately of sandstone and claystone from   Halang Formation (c = 0.0020. The plantonic foraminifer fossils as resources of oil seepage are estimated in the sedimentaries rocks, where the oil flows from those rocks into the         reservoir (source rock. Based on the interpretation results, the source rock is above basaltic igneous rock with the approximate position is 108.76164°W and 7.43089°S; and the depth is 132.09 meters below the average topographic.

  13. United States National Waste Terminal Storage argillaceous rock studies

    International Nuclear Information System (INIS)

    Brunton, G.D.

    1981-01-01

    The past and present argillaceous rock studies for the US National Waste Terminal Storage Program consist of: (1) evaluation of the geological characteristics of several widespread argillaceous formations in the United States; (2) laboratory studies of the physical and chemical properties of selected argillaceous rock samples; and (3) two full-scale in situ surface heater experiments that simulate the emplacement of heat-generating radioactive waste in argillaceous rock

  14. United States National Waste Terminal Storage argillaceous rock studies

    International Nuclear Information System (INIS)

    Brunton, G.D.

    1979-01-01

    The past and present argillaceous rock studies for the US National Waste Terminal Storage Program consist of: (1) evaluation of the geological characteristics of several widespread argillaceous formations in the United States; (2) laboratory studies of the physical and chemical properties of selected argillaceous rock samples; and (3) two full-scale in-situ surface heater experiments that simulate the emplacement of heat-generating radioactive waste in argillaceous rock

  15. Experimental Study and Numerical Modeling of Fracture Propagation in Shale Rocks During Brazilian Disk Test

    Science.gov (United States)

    Mousavi Nezhad, Mohaddeseh; Fisher, Quentin J.; Gironacci, Elia; Rezania, Mohammad

    2018-06-01

    Reliable prediction of fracture process in shale-gas rocks remains one of the most significant challenges for establishing sustained economic oil and gas production. This paper presents a modeling framework for simulation of crack propagation in heterogeneous shale rocks. The framework is on the basis of a variational approach, consistent with Griffith's theory. The modeling framework is used to reproduce the fracture propagation process in shale rock samples under standard Brazilian disk test conditions. Data collected from the experiments are employed to determine the testing specimens' tensile strength and fracture toughness. To incorporate the effects of shale formation heterogeneity in the simulation of crack paths, fracture properties of the specimens are defined as spatially random fields. A computational strategy on the basis of stochastic finite element theory is developed that allows to incorporate the effects of heterogeneity of shale rocks on the fracture evolution. A parametric study has been carried out to better understand how anisotropy and heterogeneity of the mechanical properties affect both direction of cracks and rock strength.

  16. Regulation of ROCK Activity in Cancer

    DEFF Research Database (Denmark)

    Morgan-Fisher, Marie; Wewer, Ulla M; Yoneda, Atsuko

    2013-01-01

    , these findings demonstrate additional modes to regulate ROCK activity. This review describes the molecular mechanisms of ROCK activity regulation in cancer, with emphasis on ROCK isoform-specific regulation and interaction partners, and discusses the potential of ROCKs as therapeutic targets in cancer.......Cancer-associated changes in cellular behavior, such as modified cell-cell contact, increased migratory potential, and generation of cellular force, all require alteration of the cytoskeleton. Two homologous mammalian serine/threonine kinases, Rho-associated protein kinases (ROCK I and II), are key...... regulators of the actin cytoskeleton acting downstream of the small GTPase Rho. ROCK is associated with cancer progression, and ROCK protein expression is elevated in several types of cancer. ROCKs exist in a closed, inactive conformation under quiescent conditions, which is changed to an open, active...

  17. Influence of different geological structures on stress–strain state of hard rock mass

    Science.gov (United States)

    Kuznetzov, NN; Fedotova, YuV

    2018-03-01

    The results of numerical simulation of stress–strain state in a hard rock mass area with the complex geological structures are presented. The variants of the stress value change are considered depending on the boundary conditions and physical properties of the model blocks. Furthermore, the possibility of in-situ stress formation under the influence of energy coming from the deeper Earth’s layers is demonstrated in terms of the Khibiny Massif.

  18. Theoretical analysis and design of hydro-hammer with a jet actuator: An engineering application to improve the penetration rate of directional well drilling in hard rock formations.

    Science.gov (United States)

    He, Jiang-Fu; Liang, Yun-Pei; Li, Li-Jia; Luo, Yong-Jiang

    2018-01-01

    Rapid horizontal directional well drilling in hard or fractured formations requires efficient drilling technology. The penetration rate of conventional hard rock drilling technology in horizontal directional well excavations is relatively low, resulting in multiple overgrinding of drill cuttings in bottom boreholes. Conventional drilling techniques with reamer or diamond drill bit face difficulties due to the long construction periods, low penetration rates, and high engineering costs in the directional well drilling of hard rock. To improve the impact energy and penetration rate of directional well drilling in hard formations, a new drilling system with a percussive and rotary drilling technology has been proposed, and a hydro-hammer with a jet actuator has also been theoretically designed on the basis of the impulse hydro-turbine pressure model. In addition, the performance parameters of the hydro-hammer with a jet actuator have been numerically and experimentally analyzed, and the influence of impact stroke and pumped flow rate on the motion velocity and impact energy of the hydro-hammer has been obtained. Moreover, the designed hydro-hammer with a jet actuator has been applied to hard rock drilling in a trenchless drilling program. The motion velocity of the hydro-hammer ranges from 1.2 m/s to 3.19 m/s with diverse flow rates and impact strokes, and the motion frequency ranges from 10 Hz to 22 Hz. Moreover, the maximum impact energy of the hydro-hammer is 407 J, and the pumped flow rate is 2.3 m3/min. Thus, the average penetration rate of the optimized hydro-hammer improves by over 30% compared to conventional directional drilling in hard rock formations.

  19. micro-mechanical experimental investigation and modelling of strain and damage of argillaceous rocks under combined hydric and mechanical loads

    International Nuclear Information System (INIS)

    Wang, L.

    2012-01-01

    The hydro-mechanical behavior of argillaceous rocks, which are possible host rocks for underground radioactive nuclear waste storage, is investigated by means of micro-mechanical experimental investigations and modellings. Strain fields at the micrometric scale of the composite structure of this rock, are measured by the combination of environmental scanning electron microscopy, in situ testing and digital image correlation technique. The evolution of argillaceous rocks under pure hydric loading is first investigated. The strain field is strongly heterogeneous and manifests anisotropy. The observed nonlinear deformation at high relative humidity (RH) is related not only to damage, but also to the nonlinear swelling of the clay mineral itself, controlled by different local mechanisms depending on RH. Irreversible deformations are observed during hydric cycles, as well as a network of microcracks located in the bulk of the clay matrix and/or at the inclusion-matrix interface. Second, the local deformation field of the material under combined hydric and mechanical loadings is quantified. Three types of deformation bands are evidenced under mechanical loading, either normal to stress direction (compaction), parallel (microcracking) or inclined (shear). Moreover, they are strongly controlled by the water content of the material: shear bands are in particular prone to appear at high RH states. In view of understanding the mechanical interactions a local scale, the material is modeled as a composite made of non-swelling elastic inclusions embedded in an elastic swelling clay matrix. The internal stress field induced by swelling strain incompatibilities between inclusions and matrix, as well as the overall deformation, is numerically computed at equilibrium but also during the transient stage associated with a moisture gradient. An analytical micro-mechanical model based on Eshelby's solution is proposed. In addition, 2D finite element computations are performed. Results

  20. Case Studies of Rock Bursts Under Complicated Geological Conditions During Multi-seam Mining at a Depth of 800 m

    Science.gov (United States)

    Zhao, Tong-bin; Guo, Wei-yao; Tan, Yun-liang; Yin, Yan-chun; Cai, Lai-sheng; Pan, Jun-feng

    2018-05-01

    A serious rock burst ("4.19" event) occurred on 19 April 2016 in the No. 4 working face of the No. 10 coal seam in Da'anshan Coal Mine, Jingxi Coalfield. According to the China National Seismological Network, a 2.7 magnitude earthquake was simultaneously recorded in this area. The "4.19" event resulted in damage to the entire longwall face and two gateways that were 105 m in long. In addition, several precursor bursts and mine earthquakes had occurred between October 2014 and April 2016 in the two uphill roadways and the No. 4 working face. In this paper, the engineering geological characteristics and in situ stress field are provided, and then the rock burst distributions are introduced. Next, the temporal and spatial characteristics, geological and mining conditions, and other related essential information are reviewed in detail. The available evidence and possible explanations for the rock burst mechanisms are also presented and discussed. Based on the description and analysis of these bursts, a detailed classification system of rock burst mechanisms is established. According to the main causes and different disturbance stresses (i.e., high/low disturbance stresses and far-field/near-field high disturbance stresses), there are a total of nine types of rock bursts. Thus, some guidelines for controlling or mitigating different types of rock bursts are provided. These experiences and strategies not only provide an essential reference for understanding the different rock burst mechanisms, but also build a critical foundation for selecting mitigation measures and optimizing the related technical parameters during mining or tunnelling under similar conditions.

  1. WIPP air-intake shaft disturbed-rock zone study

    International Nuclear Information System (INIS)

    Dale, T.; Hurtado, L.D.

    1996-01-01

    The disturbed-rock zone surrounding the air-intake shaft at the Waste Isolation Pilot Plant (WIPP) site was investigated to determine the extent and the permeability of the disturbed-rock zone as a function of radial distance from the 6.1 m diameter shaft, at different elevations within the Salado. Gas- and brine-permeability tests were performed in the bedded halite of the Salado formation at two levels within the air-intake shaft. The gas- and brine-permeability test results demonstrated that the radial distance to an undisturbed formation permeability of 1 x 10 -21 m 2 was less than 3.0 m

  2. Colloid and radionuclide retention mechanisms in fractured rock under near-natural flow conditions

    International Nuclear Information System (INIS)

    Delos, A.; Schaefer, T.; Geckeis, H.; Guimera, J.; Carrera, J.; Fanghaenel, T.

    2005-01-01

    Full text of publication follows: Experiments in fractured host rock (Grimsel Test Site, GTS, Switzerland) revealed that the colloid relevance for actinide migration is high due to the specific geochemical groundwater conditions [1]. However, even under such conditions it is found that retention of colloids and colloid-borne actinides becomes significant under near-natural groundwater flow rates (1-10 m/a) [2]. Underlying mechanisms of colloid and radionuclide retention are not well understood up to now. The present study co-funded by the NoE ACTINET-6 focuses on (i) the kinetics of actinide-colloid interactions and (ii) the relevance of matrix diffusion as a competition process to other retention mechanisms which affect the actinides behavior in fractured rock systems such as the Grimsel granodiorite. Colloid migration is studied with well defined model colloids as e.g. fluorescence dyed carboxylated polystyrene particles, and natural colloids extracted from bentonite (FEBEX) and from fracture filling material (GTS). In order to study the influence of matrix porosity on actinides migration, those experiments are performed in columns of well defined geometry filled with microporous unmodified silica spheres, porous ceramic material and natural fracture filling material from the GTS. The behaviour of actinides (Pu(IV) and Am(III)) sorbed onto bentonite colloids is investigated in column and batch experiments. All experiments are performed under anoxic conditions. Colloid characterization methods used in this study include the combination of photon correlation spectroscopy (PCS), laser-induced breakdown detection (LIBD), fluorimetry and field flow fractionation (FFF). Experimental results and their application to the parametrisation of reactive colloid transport models are discussed. [1] Geckeis H, Schaefer T, Hauser W, Rabung T, Missana T, Degueldre C, Moeri A, Eikenberg J, Fierz T, Alexander WR (2004) Results of the Colloid and Radionuclide Retention experiment

  3. Aqueous Alteration of Endeavour Crater Rim Apron Rocks

    Science.gov (United States)

    Ming, D. W.; Mittlefehldt, D. W.; Gellert, R.; Clark, B. C.; Morris, R. V.; Yen, A. S.; Arvidson, R. E.; Crumpler, L. S.; Farrand, W. H.; Grant, J. A., III; Jolliff, B. L.; Parker, T. J.; Peretyazhko, T.

    2014-12-01

    Mars Exploration Rover Opportunity is exploring Noachian age rocks of the rim of 22 km diameter Endeavour crater. Overlying the pre-impact lithologies and rim breccias is a thin apron of fine-grained sediments, the Grasberg fm, forming annuli on the lower slopes of rim segments. Hesperian Burns fm sandstones overly the Grasberg fm. Grasberg rocks have major element compositions that are distinct from Burns fm sandstones, especially when comparing interior compositions exposed by the Rock Abrasion Tool. Grasberg rocks are also different from Endeavour rim breccias, but have general compositional similarities to them. Grasberg sediments are plausibly fine-grained materials derived from the impact breccias. Veins of CaSO4 transect Grasberg fm rocks demonstrating post-formation aqueous alteration. Minor/trace elements show variations consistent with mobilization by aqueous fluids. Grasberg fm rocks have low Mn and high Fe/Mn ratios compared to the other lithologies. Manganese likely was mobilized and removed from the Grasberg host rock by redox reactions. We posit that Fe2+ from acidic solutions associated with formation of the Burns sulfate-rich sandstones acted as an electron donor to reduce more oxidized Mn to Mn2+. The Fe contents of Grasberg rocks are slightly higher than in other rocks suggesting precipitation of Fe phases in Grasberg materials. Pancam spectra show that Grasberg rocks have a higher fraction of ferric oxide minerals than other Endeavour rim rocks. Solutions transported Mn2+ into the Endeavour rim materials and oxidized and/or precipitated it in them. Grasberg has higher contents of the mobile elements K, Zn, Cl, and Br compared to the rim materials. Similar enrichments of mobile elements were measured by the Spirit APXS on West Spur and around Home Plate in Gusev crater. Enhancements in these elements are attributed to interactions of hydrothermal acidic fluids with the host rocks. Interactions of fluids with the Grasberg fm postdate the genesis

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

    Science.gov (United States)

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

    2003-04-01

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

  5. Dating oxalate minerals in rock surface deposits

    International Nuclear Information System (INIS)

    Watchman, A.

    2001-01-01

    Oxalate minerals are found associated with rocks, mineral coatings, micro-organisms, plants and animals. They are important in archaeology because they have been found intimately associated with organic binders in prehistoric paints. Oxalate minerals also accumulate in the coatings on rock shelter walls and fallen ceiling slabs where they form the natural backing supports for painting and opaque laminates covering engravings. Though the relationship between anthropogenic activity in a rock shelter and oxalate formation is often uncertain, the radiocarbon age of the oxalate may provide the only means for determining the antiquity of a rock painting or engraving. This paper examines the history of dating oxalate minerals at archaeological sites and provides insights into achieving reliable age estimates. (author). 37 refs., 1 fig., 2 tabs

  6. Maximization of permanent trapping of CO{sub 2} and co-contaminants in the highest-porosity formations of the Rock Springs Uplift (Southwest Wyoming): experimentation and multi-scale modeling

    Energy Technology Data Exchange (ETDEWEB)

    Piri, Mohammad

    2014-03-31

    Under this project, a multidisciplinary team of researchers at the University of Wyoming combined state-of-the-art experimental studies, numerical pore- and reservoir-scale modeling, and high performance computing to investigate trapping mechanisms relevant to geologic storage of mixed scCO{sub 2} in deep saline aquifers. The research included investigations in three fundamental areas: (i) the experimental determination of two-phase flow relative permeability functions, relative permeability hysteresis, and residual trapping under reservoir conditions for mixed scCO{sub 2}-­brine systems; (ii) improved understanding of permanent trapping mechanisms; (iii) scientifically correct, fine grid numerical simulations of CO{sub 2} storage in deep saline aquifers taking into account the underlying rock heterogeneity. The specific activities included: (1) Measurement of reservoir-­conditions drainage and imbibition relative permeabilities, irreducible brine and residual mixed scCO{sub 2} saturations, and relative permeability scanning curves (hysteresis) in rock samples from RSU; (2) Characterization of wettability through measurements of contact angles and interfacial tensions under reservoir conditions; (3) Development of physically-­based dynamic core-­scale pore network model; (4) Development of new, improved high-­performance modules for the UW-­team simulator to provide new capabilities to the existing model to include hysteresis in the relative permeability functions, geomechanical deformation and an equilibrium calculation (Both pore-­ and core-­scale models were rigorously validated against well-­characterized core-­ flooding experiments); and (5) An analysis of long term permanent trapping of mixed scCO{sub 2} through high-­resolution numerical experiments and analytical solutions. The analysis takes into account formation heterogeneity, capillary trapping, and relative permeability hysteresis.

  7. Deformation style of the Mesozoic sedimentary rocks in southern Thailand

    Science.gov (United States)

    Kanjanapayont, Pitsanupong

    2014-10-01

    Mesozoic sedimentary rocks in southern Thailand are widespread from NNE-SSW and N-S in Chumphon and Trang provinces. The Mesozoic stratigraphic units are the marine Triassic Sai Bon Formation and the non-marine Jurassic-Cretaceous Thung Yai Group, the latter subdivided into Khlong Min, Lam Thap, Sam Chom, and Phun Phin Formations. These units overlie Permian carbonate rocks with an angular unconformity, and are overlain unconformably by Cenozoic units and the Quaternary sediments. The Mesozoic rocks have been folded to form two huge first-ordered syncline or synclinoria, the Chumphon and Surat Thani-Krabi-Trang synclinoria. These synclinoria are elongated in NNE-SSW to N-S direction, and incorporate asymmetric lower-order parasitic folds. The folds have moderately to steeply dipping eastward limbs and more gently dipping westward limbs. These folds were transected by brittle fractures in four major directions. These geologic structures indicate WNW-ESE to E-W contraction with top-to-the-east simple shear at some time before the deposition of the Cenozoic sedimentary units. No major deformation has affected the rocks subsequently, apart from the formation of the fault-controlled Cenozoic basins.

  8. Groundwater characteristics and problems in volcanic rock terrains

    International Nuclear Information System (INIS)

    Custodio, E.

    1989-01-01

    Volcanic rock formations, each with their own particular hydrogeological characteristics, occur in circumstances that cover a multiplicity of situations. These range from permeable porous rock formations to permeable fissured formations and include all types of intermediate situation between the two. The type of volcanism, distance from the source of emission, age, alteration processes and tectonics are all factors which determine their behaviour. Volcanic formations usually constitute a single aquifer system, even though this may be very heterogeneous and may locally be separated into clearly defined subunits. At times, formations may be hundreds of metres thick and are fairly permeable almost throughout. As a rule, volcanic material does not yield directly soluble salts to the water that flows through it. Mineralization of the water is due to the concentration of rainfall and the hydrolysis of silicates as a result of CO 2 being absorbed from the atmosphere and the ground, or as a result of volcanism itself. Cationic grouping is usually closely correlated to that of the rock formation in which the chemical composition is formed. Most environmental isotope and radioisotope techniques may be used, and at times are of unquestionable value. However, the existence of evaporation in the soil with possible isotopic fractionation, the effects of marked relief, the dilution of dissolved carbon by volcanic carbon and isotopic exchange brought about by volcanic carbon, etc., should be taken into account before valid conclusions are drawn. The paper uses examples taken from existing studies, mainly those being carried out in the Canary Islands (Spain). (author). 98 refs, 18 figs, 4 tabs

  9. Multivariate statistics application in development of blast fragmentation charts for different rock formations in quarries

    Directory of Open Access Journals (Sweden)

    Birol Elevli

    2012-12-01

    Full Text Available Rock fragmentation is considered to be one of the most important aspects of quarrying because of its direct effect on the costsof drilling, which include blasting, loading, hauling and crushing. Thus, it is essential to consider fragmentation size in blasting design.Fragmentation depends on many variables, such as rock properties, geological structures, and blasting parameters. Although empiricalmodels for the estimation of the size distribution of rock fragmentation have been developed by considering these parameters,no complete empirical prediction model for fragmentation exists since rock properties and geological structures vary from site to site.However, these models regard rock properties as constant. In this study, a step–wise multiple linear regression analysis has beencarried out to determine the degree of dominance of various influencing parameters on fragmentation and to develop a fragmentationprediction model. The results showed that the rock mass properties, burden width and specific charge are the main parameters affectingfragmentation. The relations among those parameters were used to develop guideline charts to determine blast layouts for desiredfragmentation on the basis of rock characteristics.

  10. Study on acoustic-electric-heat effect of coal and rock failure processes under uniaxial compression

    Science.gov (United States)

    Li, Zhong-Hui; Lou, Quan; Wang, En-Yuan; Liu, Shuai-Jie; Niu, Yue

    2018-02-01

    In recent years, coal and rock dynamic disasters are becoming more and more severe, which seriously threatens the safety of coal mining. It is necessary to carry out an depth study on the various geophysical precursor information in the process of coal and rock failure. In this paper, with the established acoustic-electric-heat multi-parameter experimental system of coal and rock, the acoustic emission (AE), surface potential and thermal infrared radiation (TIR) signals were tested and analyzed in the failure processes of coal and rock under the uniaxial compression. The results show that: (1) AE, surface potential and TIR have different response characteristics to the failure process of the sample. AE and surface potential signals have the obvious responses to the occurrence, extension and coalescence of cracks. The abnormal TIR signals occur at the peak and valley points of the TIR temperature curve, and are coincident with the abnormities of AE and surface potential to a certain extent. (2) The damage precursor points and the critical precursor points were defined to analyze the precursor characteristics reflected by AE, surface potential and TIR signals, and the different signals have the different precursor characteristics. (3) The increment of the maximum TIR temperature after the main rupture of the sample is significantly higher than that of the average TIR temperature. Compared with the maximum TIR temperature, the average TIR temperature has significant hysteresis in reaching the first peak value after the main rapture. (4) The TIR temperature contour plots at different times well show the evolution process of the surface temperature field of the sample, and indicate that the sample failure originates from the local destruction.

  11. Measurements of the Suitability of Large Rock Salt Formations for Radio Detection of High-Energy Neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Odian, Allen C.

    2001-09-14

    We have investigated the possibility that large rock salt formations might be suitable as target masses for detection of neutrinos of energies about 10 PeV and above. In neutrino interactions at these energies, the secondary electromagnetic cascade produces a coherent radio pulse well above ambient thermal noise via the Askaryan effect. We describe measurements of radio-frequency attenuation lengths and ambient thermal noise in two salt formations. Measurements in the Waste Isolation Pilot Plant (WIPP), located in an evaporite salt bed in Carlsbad, NM yielded short attenuation lengths, 3-7 m over 150-300 MHz. However, measurements at United Salt's Hockley mine, located in a salt dome near Houston, Texas yielded attenuation lengths in excess of 250 m at similar frequencies. We have also analyzed early ground-penetrating radar data at Hockley mine and have found additional evidence for attenuation lengths in excess of several hundred meters at 440 MHz. We conclude that salt domes, which may individually contain several hundred cubic kilometer water-equivalent mass, provide attractive sites for next-generation high-energy neutrino detectors.

  12. Measurements of the suitability of large rock salt formations for radio detection of high-energy neutrinos

    International Nuclear Information System (INIS)

    Gorham, Peter; Saltzberg, David; Odian, Allen; Williams, Dawn; Besson, David; Frichter, George; Tantawi, Sami

    2002-01-01

    We have investigated the possibility that large rock salt formations might be suitable as target masses for detection of neutrinos of energies about 10 PeV and above. In neutrino interactions at these energies, the secondary electromagnetic cascade produces a coherent radio pulse well above ambient thermal noise via the Askaryan effect. We describe measurements of radio-frequency attenuation lengths and ambient thermal noise in two salt formations. Measurements in the Waste Isolation Pilot Plant, located in an evaporite salt bed in Carlsbad, NM yielded short attenuation lengths, 3-7 m over 150-300 MHz. However, measurements at United Salt's Hockley mine, located in a salt dome near Houston, Texas yielded attenuation lengths in excess of 250 m at similar frequencies. We have also analyzed early ground-penetrating radar data at Hockley mine and have found additional evidence for attenuation lengths in excess of several hundred meters at 440 MHz. We conclude that salt domes, which may individually contain several hundred cubic kilometer water-equivalent mass, provide attractive sites for next-generation high-energy neutrino detectors

  13. Incarvine C suppresses proliferation and vasculogenic mimicry of hepatocellular carcinoma cells via targeting ROCK inhibition

    International Nuclear Information System (INIS)

    Zhang, Ji-Gang; Zhang, Dan-Dan; Wu, Xin; Wang, Yu-Zhu; Gu, Sheng-Ying; Zhu, Guan-Hua; Li, Xiao-Yu; Li, Qin; Liu, Gao-Lin

    2015-01-01

    Studies have described vasculogenic mimicry (VM) as an alternative circulatory system to blood vessels in multiple malignant tumor types, including hepatocellular carcinoma (HCC). In the current study, we aimed to seek novel and more efficient treatment strategies by targeting VM and explore the underlying mechanisms in HCC cells. Cell counting kit-8 (CCK-8) assay and colony survival assay were performed to explore the inhibitory effect of incarvine C (IVC) on human cancer cell proliferation. Flow cytometry was performed to analyze the cell cycle distribution after DNA staining and cell apoptosis by the Annexin V-PE and 7-AAD assay. The effect of IVC on Rho-associated, coiled-coil-containing protein kinase (ROCK) was determined by western blotting and stress fiber formation assay. The inhibitory role of IVC on MHCC97H cell VM formation was determined by formation of tubular network structures on Matrigel in vitro, real time-qPCR, confocal microscopy and western blotting techniques. We explored an anti-metastatic HCC agent, IVC, derived from traditional Chinese medicinal herbs, and found that IVC dose-dependently inhibited the growth of MHCC97H cells. IVC induced MHCC97H cell cycle arrest at G1 transition, which was associated with cyclin-dependent kinase 2 (CDK-2)/cyclin-E1 degradation and p21/p53 up-regulation. In addition, IVC induced apoptotic death of MHCC97H cells. Furthermore, IVC strongly suppressed the phosphorylation of the ROCK substrate myosin phosphatase target subunit-1 (MYPT-1) and ROCK-mediated actin fiber formation. Finally, IVC inhibited cell-dominant tube formation in vitro, which was accompanied with the down-regulation of VM-key factors as detected by real time-qPCR and immunofluorescence. Taken together, the effective inhibitory effect of IVC on MHCC97H cell proliferation and neovascularization was associated with ROCK inhibition, suggesting that IVC may be a new potential drug candidate for the treatment of HCC

  14. First Observation of Rock Motion on Racetrack Playa, Death Valley National Park—Role of a Persistent Pool, Sun, Zephyrs, Windowpane Ice, and Tugboats

    Science.gov (United States)

    Norris, R. D.; Norris, J. M.

    2014-12-01

    Trails in the mud-cracked surface of Racetrack Playa have been scored by hundreds of rocks up to 320 kg, but the mechanism of movement is debated. In Winter 2013-2014, we observed rocks in motion associated with a transient pool formed by winter precipitation. The pond was 7 cm deep on the southern edge of the playa, tapering to a mud flat to the north. Freezing during cold winter nights formed floating "windowpane" ice 3-5 mm thick. Rocks repeatedly moved on sunny days under light winds of 3-5 m/second, as the ice broke up near midday and was set into motion by wind stress on melt pools and the ice surface. Ice panels shoved rocks along the mud like a tugboat, sometimes forming moving imbricated ice piles upstream of the rocks and in other cases moving faster than the rocks and forming brash-filled leads downstream. GPS units mounted in experimental rocks recorded a creeping pace of 2-6 m/minute, a speed that made it difficult to observe trail formation visually. The 2013-2014 pond formed on November 20-24 and persisted through early February 2014. During this time rocks were observed moving at least five times, and studies of "stiz marks" formed by rocks at the ends of trail segments show that there were likely 3-5 additional move events. Observed travel times ranged from a few seconds to 16 minutes. In one event, two experimental rocks 153 m apart began moving simultaneously and traveled 64.1 and 65.6 m respectively, ultimately moving 157-162 m in subsequent events. Rock motion depends on the creation of winter pools sufficiently deep to allow the formation of floating ice and exposed to the light winds and sun needed for ice breakup. The combination of these events is extremely rare, leading to highly episodic trail formation. Our observations differ from previous hypotheses in that the rocks were moved by thinner ice, at slower speeds, and by lighter winds than predicted.

  15. Alteration of Basaltic Glass to Mg/Fe-Smectite under Acidic Conditions: A Potential Smectite Formation Mechanism on Mars

    Science.gov (United States)

    Peretyazhko, Tanya; Sutter, Brad; Ming, Douglas W.

    2014-01-01

    Phyllosilicates of the smectite group including Mg- and Fe-saponite and Fe(III)-rich nontronite have been identified on Mars. Smectites are believed to be formed under neutral to alkaline conditions that prevailed on early Mars. This hypothesis is supported by the observation of smectite and carbonate deposits in Noachian terrain on Mars. However, smectite may have formed under mildly acidic conditions. Abundant smectite formations have been detected as layered deposits hundreds of meters thick in intracrater depositional fans and plains sediments, while no large deposits of carbonates are found. Development of mildly acidic conditions at early Mars might allow formation of smectite but inhibit widespread carbonate precipitation. Little is known regarding the mechanisms of smectite formation from basaltic glass under acidic conditions. The objective of this study was to test a hypothesis that Mars-analogue basaltic glass alters to smectite minerals under acidic conditions (pH 4). The effects of Mg and Fe concentrations and temperature on smectite formation from basaltic glass were evaluated. Phyllosilicate synthesis was performed in batch reactors (Parr acid digestion vessel) under reducing hydrothermal conditions at 200 C and 100 C. Synthetic basaltic glass with a composition similar to that of the Gusev crater rock Adirondack (Ground surface APXS measurement) was used in these experiments. Basaltic glass was prepared by melting and quenching procedures. X-ray diffraction (XRD) analysis indicated that the synthesized glass was composed of olivine, magnetite and X-ray amorphous phase. Samples were prepared by mixing 250 mg Adirondack with 0.1 M acetic acid (final pH 4). In order to study influence of Mg concentration on smectite formation, experiments were performed with addition of 0, 1 and 10 mM MgCl2. After 1, 7 and 14 day incubations the solution composition was analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and the altered glass and formed

  16. Interim rock mass properties and conditions for analyses of a repository in crystalline rock

    International Nuclear Information System (INIS)

    Tammemagi, H.Y.; Chieslar, J.D.

    1985-03-01

    A summary of rock properties for generic crystalline rock is compiled from literature sources to provide the input data for analyses of a conceptual repository in crystalline rock. Frequency histograms, mean values and ranges of physical, mechanical, thermal, and thermomechanical properties, and the dependence of these properties on temperature are described. A description of the hydrogeologic properties of a crystalline rock mass and their dependence on depth is provided. In addition, the temperature gradients, mean annual surface temperature, and in situ stress conditions are summarized for the three regions of the United States currently under consideration to host a crystalline repository; i.e., the North Central, Northeastern, and Southeastern. Brief descriptions of the regional geology are also presented. Large-scale underground experiments in crystalline rock at Stripa, Sweden, and in Climax Stock in Nevada, are reviewed to assess whether the rock properties presented in this report are representative of in situ conditions. The suitability of each rock property and the sufficiency of its data base are described. 110 refs., 27 figs., 4 tabs

  17. Demonstration of a Fractured Rock Geophysical Toolbox (FRGT) for Characterization and Monitoring of DNAPL Biodegradation in Fractured Rock Aquifers

    Science.gov (United States)

    2015-09-29

    is characterized by dark gray slate or phyllite, alternating with thin layers of light gray siltstone or sandstone . Table 1 summarizes the primary...sedimentary rocks of the Newark Basin. Competent rocks are primarily mudstones and sandstones of the Lockatong and Stockton Formations. Fill, weathered silt... sandstone , and characterized by water bearing bedding plane fractures. An array of open boreholes in the source area that were drilled for the 2002

  18. Dome-shaped PDC cutters drill harder rock effectively

    International Nuclear Information System (INIS)

    Moran, D.P.

    1992-01-01

    This paper reports that rock mechanics and sonic travel time log data indicate that bits with convex-shaped polycrystalline diamond compact (PDC) cutters can drill harder rock formations than comparable bits with flat PDC cutters. The Dome-shaped cutters have drilled carbonate formations with sonic travel times as small as 50 μsec/ft, compared to the standard cutoff of 75 μsec/ft for flat PCD cutters. Recent field data from slim hole wells drilled in the Permian basin have shown successful applications of the 3/8-in. Dome cutter in the Grayburg dolomite with its sonic travel times as low as 50-55 μsec/ft and compressive strengths significantly greater than the standard operating range for PDC bit applications. These field data indicate that the Dome cutters can successfully drill hard rock. The convex cutter shape as good impact resistance, cuttings removal, heat dissipation, and wear resistance

  19. Location-Related Differences in Weathering Behaviors and Populations of Culturable Rock-Weathering Bacteria Along a Hillside of a Rock Mountain.

    Science.gov (United States)

    Wang, Qi; Wang, Rongrong; He, Linyan; Sheng, Xiafang

    2017-05-01

    Bacteria play important roles in rock weathering, elemental cycling, and soil formation. However, little is known about the weathering potential and population of bacteria inhabiting surfaces of rocks. In this study, we isolated bacteria from the top, middle, and bottom rock samples along a hillside of a rock (trachyte) mountain as well as adjacent soils and characterized rock-weathering behaviors and populations of the bacteria. Per gram of rock or surface soil, 10 6 -10 7 colony forming units were obtained and total 192 bacteria were isolated. Laboratory rock dissolution experiments indicated that the proportions of the highly effective Fe (ranging from 67 to 92 %), Al (ranging from 40 to 48 %), and Cu (ranging from 54 to 81 %) solubilizers were significantly higher in the top rock and soil samples, while the proportion of the highly effective Si (56 %) solubilizers was significantly higher in the middle rock samples. Furthermore, 78, 96, and 6 % of bacteria from the top rocks, soils, and middle rocks, respectively, significantly acidified the culture medium (pH bacteria (79 %) from the rocks were different to those from the soils and most of them (species level) have not been previously reported. Furthermore, location-specific rock-weathering bacterial populations were found and Bacillus species were the most (66 %) frequently isolated rock-weathering bacteria in the rocks based on cultivation methods. Notably, the top rocks and soils had the highest and lowest diversity of rock-weathering bacterial populations, respectively. The results suggested location-related differences in element (Si, Al, Fe, and Cu) releasing effectiveness and communities of rock-weathering bacteria along the hillside of the rock mountain.

  20. Radiogeochemical features of hydrothermal metasomatic formations

    International Nuclear Information System (INIS)

    Plyushchev, E.V.; Ryabova, L.A.; Shatov, V.V.

    1978-01-01

    Considered are the most general peculiarities of uranium and thorium distributions in hydrothermal-metasomatic formations of three levels of substance formation: 1) in hydrothermal minerals; 2) in natural associations of these minerals (in the altered rocks, metasomatites, ores, etc.); 3) ordened series of zonally and in stage conjugated hydrothermal-metasomatic formations. Statistically stable recurrence of natural combinations of hydrothermal-metasomatic formations points out conjugation of their formation in the directed evolution in the general hydrothermal process. Series of metasomatic formations, the initial members of which are potassium metasomatites, mostly result in accumulation up to industrial concentrations of radioactive elements in final members of these formations. Development of midlow-temperature propylitic alterations in highly radiative rocks causes the same accumulation

  1. Proceedings of a technical session on rock mechanics ''Advance in laboratory sample testing''

    International Nuclear Information System (INIS)

    Come, B.

    1984-01-01

    This report brings together a series of papers about rock mechanics. The meeting was divided into three sessions, which dealt with the three main types of rock formation currently considered in the CEC Programme: granite, clay and salt. Safe disposal of high-level radioactive waste involves the proper design of deep underground repositories. This necessitates an in-depth knowledge of the mechanical properties of the rock mass. The behaviour of the rock mass must be known both for the construction and the operation (heating effects) of the repository. Usually, the dominant factor for designing an underground structure is the fracturing of the rock mass. In the present case, the rock is chosen with a very low fracturing. Therefore, the mechanical properties of the formation are mainly those of the rock matrix. These properties are obtained, at least in a first exploratory step, by laboratory testing of rock samples obtained by core-drilling from surface. This aspect of rock characterization was thought to deserve a special technical meeting, in order to bring together most of the results obtained in this field by contracting partners of the CEC for the years 1980-82

  2. Study on Mechanical Characteristics of Fully Grouted Rock Bolts for Underground Caverns under Seismic Loads

    Directory of Open Access Journals (Sweden)

    Guoqing Liu

    2017-01-01

    Full Text Available This study establishes an analytical model for the interaction between the bolt and surrounding rock based on the bearing mechanism of fully grouted rock bolts. The corresponding controlled differential equation for load transfer is deduced. The stress distributions of the anchorage body are obtained by solving the equations. A dynamic algorithm for the bolt considering shear damage on the anchoring interface is proposed based on the dynamic finite element method. The rationality of the algorithm is verified by a pull-out test and excavation simulation of a rounded tunnel. Then, a case study on the mechanical characteristics of the bolts in underground caverns under seismic loads is conducted. The results indicate that the seismic load may lead to stress originating from the bolts and damage on the anchoring interface. The key positions of the antiseismic support can be determined using the numerical simulation. The calculated results can serve as a reference for the antiseismic optimal design of bolts in underground caverns.

  3. Two-phase flow visualization under reservoir conditions for highly heterogeneous conglomerate rock: A core-scale study for geologic carbon storage.

    Science.gov (United States)

    Kim, Kue-Young; Oh, Junho; Han, Weon Shik; Park, Kwon Gyu; Shinn, Young Jae; Park, Eungyu

    2018-03-20

    Geologic storage of carbon dioxide (CO 2 ) is considered a viable strategy for significantly reducing anthropogenic CO 2 emissions into the atmosphere; however, understanding the flow mechanisms in various geological formations is essential for safe storage using this technique. This study presents, for the first time, a two-phase (CO 2 and brine) flow visualization under reservoir conditions (10 MPa, 50 °C) for a highly heterogeneous conglomerate core obtained from a real CO 2 storage site. Rock heterogeneity and the porosity variation characteristics were evaluated using X-ray computed tomography (CT). Multiphase flow tests with an in-situ imaging technology revealed three distinct CO 2 saturation distributions (from homogeneous to non-uniform) dependent on compositional complexity. Dense discontinuity networks within clasts provided well-connected pathways for CO 2 flow, potentially helping to reduce overpressure. Two flow tests, one under capillary-dominated conditions and the other in a transition regime between the capillary and viscous limits, indicated that greater injection rates (potential causes of reservoir overpressure) could be significantly reduced without substantially altering the total stored CO 2 mass. Finally, the capillary storage capacity of the reservoir was calculated. Capacity ranged between 0.5 and 4.5%, depending on the initial CO 2 saturation.

  4. Screening methodology for site selection of a nuclear waste repository in shale formations in Germany

    International Nuclear Information System (INIS)

    Hoth, P.; Krull, P.; Wirth, H.

    2004-01-01

    The radioactive waste disposal policy in the Federal Republic of Germany is based on the principle that all types of radioactive waste must be disposed of in deep geological formations. Because of the favourable properties of rock salt and the existence of thick rock salt formations in Germany, so far most of the research in the field of radioactive waste disposal sites was focused on the study of the use of rock salt. In addition, German research organisations have also conducted generic research and development projects in alternative geological formations (Wanner and Brauer, 2001), but a comprehensive evaluation of their utilisation has been only done for parts of the crystalline rocks in Germany. Research projects on argillaceous rocks started relatively late, so that German experience is mainly connected to German research work with the corresponding European Underground Research Laboratories and the exploration of the former Konrad iron mine as a potential repository site for radioactive waste with negligible heat generation. The German Federal Government has signed in 2001 an agreement with national utility companies to end electricity generation by nuclear power. This decision affected the entire German radioactive waste isolation strategy and especially the repository projects. The utility companies agreed upon standstill of exploration at the Gorleben site and the Federal Ministry for the Environment tries to establish a new comprehensive procedure for the selection of a repository site, built upon well-founded criteria incorporating public participation. Step 3 of the planning includes the examination of further sites in Germany and the comparison with existing sites and concepts. Under these circumstances, argillaceous rock (clay and shale) formations are now a special area of interest in Germany and the development of a screening methodology was required for the evaluation of shales as host and barrier rocks for nuclear waste repositories. (author)

  5. Clay club catalogue of characteristics of argillaceous rocks

    International Nuclear Information System (INIS)

    2005-01-01

    The OECD/NEA Working Group on the Characterisation, the Understanding and the Performance of Argillaceous Rocks as Repository Host Formations, namely the Clay Club, examines the various argillaceous rocks that are being considered for the deep geological disposal of radioactive waste, i.e. from plastic, soft, poorly indurated clays to brittle, hard mud-stones or shales. The Clay Club considered it necessary and timely to provide a catalogue to gather in a structured way the key geo-scientific characteristics of the various argillaceous formations that are - or were - studied in NEA member countries with regard to radioactive waste disposal. The present catalogue represents the outcomes of this Clay Club initiative. (author)

  6. Professional users handbook for rock bolting

    Energy Technology Data Exchange (ETDEWEB)

    Stillborg, B.

    1986-01-01

    The paper is a practical handbook which reviews the basic principles of rock bolting and sets out the design considerations used for most types of rockbolts in current use. It discusses the characteristics of these bolts and gives information on installation procedures and the observations and measurement of rockbolt performance. Rockbolting is considered under the following chapter headings: review of typical rockbolt systems; rockbolt installation; testing of rockbolts; design considerations; design of rock reinforcement; monitoring; cost of rock bolting; and Atlas Lopco auxillary equipment for rock bolting. 45 refs.

  7. Study on flow and mass transport through fractured soft sedimentary rocks (Contact research)

    International Nuclear Information System (INIS)

    Shimo, Michito; Kumamoto, Sou; Maekawa, Keisuke

    2007-03-01

    It is important for safety assessment of HLW geological disposal to evaluate groundwater flow and mass transport in deep underground accurately. Though it is considered that the mass transport in sedimentary rock occurs in pores between grains mainly, fractures of sedimentary rock can be main paths. The objective of this study is to establish a conceptual model for flow and mass transport in fractured soft sedimentary rock. In previous study, a series of laboratory hydraulic and tracer tests and numerical analyses were carried out using sedimentary rock specimens obtained from Koetoi and Wakkanai formation. Single natural fractured cores and rock block specimen were used for the tests and analyses. The results indicated that the matrix diffusion played an important role for mass transport in the fractured soft sedimentary rocks. In this study, the following two tasks were carried out: (1) laboratory hydraulic and tracer experiments of rock cores of Koetoi and Wakkanai formation obtained at HDB-9, HDB-10 and HDB-11 boreholes and a rock block specimen, Wakkanai formation, obtained at an outcrop in the Horonobe area, (2) a numerical study on the conceptual model of flow and mass transport through fractured soft sedimentary rocks. Non-sorbing tracer experiments using naturally fractured cores and rock block specimens were carried out. Pottasium iodide was used as a tracer. The obtained breakthrough curves were interpreted and fitted by using a numerical simulator, and mass transport parameters, such as longitudinal dispersivity, matrix diffusion coefficient, transport aperture, were obtained. Mass transport simulations using a fracture network model, a continuum model and a double porosity model were performed to study the applicability of continuum model and double porosity model for transport in fractured sedimentary rock. (author)

  8. Golovkinskii law for prediction of distribution of rock lithotypes of Permian deposits (east part of Russian plate)

    Science.gov (United States)

    Sitdikova, Lyalya; Izotov, Victor; Berthault, Gi; Lalomov, Alexander

    2010-05-01

    Zone of development of upper-permian-kazanian deposits in Volga-Kama petroleum province is the region of facies interrelations law identification. This law is known as the rule of Golovkinskii-Valter. Many details of geological formations relationship in change zones are still discussed. Efforts of analytic expression of Golovkinskii rule for specific regions of its development are very important. We analyzed width of horizons of the Kazanian Stage. They are in zone of facies change of marine gray and red formations of the east part of Russian plate. Results of this analysis were principle for analytic expression of Golovkinskii rule. Percent proportion of main lithological types of these rock formations was also used. We used profile which was based on data from 75 wells. This profile crosses region of development of kazanian deposits from the river Volga to Urals territory. It overpasses main structural and tectonic units of the region: Kazan-Kirov downfold, system of lifted blocks of Tatar Arch and Upper-Kama depression. Kazanian deposits of Kazan-Kirov downfold are represented by typical marine gray carbonate-terrigenous formation. Red formation is deposed within Upper-Kama depression. Zone of these formations relationship is limited to central parts of Tatar Arch. Abrupt fluctuations of content of one rock type in insignificant distance are common. Every rock type has unique features in its distribution on profile. That's why it is possible to study function of dependence of certain rock type content from distance as a sum of regular and chance components. Intensively rising change of proportions of different rock types is presented in the zone of transition from typical marine deposits to red deposits. So trends of variation of percent content (y) of main rock lithotypes depending on distance (x) can be described by simple difference equations: dy = -kdx, for rocks of marine gray formation. dy = k(M-y)dx, for rocks of red formation. M - mathematical

  9. Requirements of actual final repository concepts for different host rock formations. Final report; Anforderungen an aktuelle Endlagerkonzepte fuer unterschiedliche Wirtsgesteinsformationen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Fass, Thorsten; Hartwig-Thurat, Eva; Krischer, Angelika; Lambers, Ludger; Larue, Juergen; Uhlmann, Stephan; Weyand, Torben

    2017-08-15

    In the frame of the research project the basic requirements and technical safety specifications with respect to the retrievability of stored radioactive wastes for the different final repository concepts based on the host rock formations occurring in Germany are presented. Existing international disposal concepts for clay/claystone, granite and salt are described and compared to the actual German regulatory requirements. The safety engineering relations between stock piling and possible retrieval are described and evaluated.

  10. Initial settlements of rock fills on soft clay

    OpenAIRE

    Pedersen, Truls Martens

    2012-01-01

    Rock fills that hit the seabed will remold the underlying material. If this material is a clay with sufficiently low shear strength, it will adopt rheological properties, causing flow through the rock fill, and contributing to the initial settlements of the rock fill in addition to conventional consolidation theory. The settlements of the rocks depend upon the height of the rock fill and how the rocks have been laid out. This is due to the viscosity of the clay, and the fact that clay is thix...

  11. Litho- and biostratigraphy of the Opalinus Clay and bounding formations in the Mont Terri rock laboratory (Switzerland)

    International Nuclear Information System (INIS)

    Hostettler, B.; Reisdorf, A. G.; Jaeggi, D.

    2017-01-01

    A 250 m-deep inclined well, the Mont Terri BDB-1, was drilled through the Jurassic Opalinus Clay and its bounding formations at the Mont Terri rock laboratory (NW Switzerland). For the first time, a continuous section from (oldest to youngest) the topmost members of the Staffelegg Formation to the basal layers of the Hauptrogenstein Formation is now available in the Mont Terri area. We extensively studied the drill core for lithostratigraphy and biostratigraphy, drawing upon three sections from the Mont Terri area. The macropaleontological, micropaleontological, and palynostratigraphical data are complementary, not only spatially but they also cover almost all biozones from the Late Toarcian to the Early Bajocian. We ran a suite of geophysical logs to determine formational and intraformational boundaries based on clay content in the BDB-1 well. In the framework of an interdisciplinary study, analysis of the above-mentioned formations permitted us to process and derive new and substantial data for the Mont Terri area in a straightforward way. Some parts of the lithologic inventory, stratigraphic architecture, thickness variations, and biostratigraphic classification of the studied formations deviate considerably from occurrences in northern Switzerland that crop out further to the east. For instance, with the exception of the Sissach Member, no further lithostratigraphic subdivision in members is proposed for the Passwang Formation. Also noteworthy is that the ca. 130 m-thick Opalinus Clay in the BDB-1 core is 20 m thinner than that equivalent section found in the Mont Terri tunnel. The lowermost 38 m of the Opalinus Clay can be attributed chronostratigraphically solely to the Aalensis Zone (Late Toarcian). Deposition of the Opalinus Clay began at the same time farther east in northern Switzerland (Aalensis Subzone, Aalensis Zone), but in the Mont Terri area the sedimentation rate was two or three orders of magnitude higher. (authors)

  12. Litho- and biostratigraphy of the Opalinus Clay and bounding formations in the Mont Terri rock laboratory (Switzerland)

    Energy Technology Data Exchange (ETDEWEB)

    Hostettler, B. [Naturhistorisches Museum der Burgergemeinde Berne, Berne (Switzerland); Reisdorf, A. G. [Geologisch-Paläontologisches InstitutUniversität Basle, Basle (Switzerland); Jaeggi, D. [Swisstopo, Federal Office of Topography, Wabern (Switzerland); and others

    2017-04-15

    A 250 m-deep inclined well, the Mont Terri BDB-1, was drilled through the Jurassic Opalinus Clay and its bounding formations at the Mont Terri rock laboratory (NW Switzerland). For the first time, a continuous section from (oldest to youngest) the topmost members of the Staffelegg Formation to the basal layers of the Hauptrogenstein Formation is now available in the Mont Terri area. We extensively studied the drill core for lithostratigraphy and biostratigraphy, drawing upon three sections from the Mont Terri area. The macropaleontological, micropaleontological, and palynostratigraphical data are complementary, not only spatially but they also cover almost all biozones from the Late Toarcian to the Early Bajocian. We ran a suite of geophysical logs to determine formational and intraformational boundaries based on clay content in the BDB-1 well. In the framework of an interdisciplinary study, analysis of the above-mentioned formations permitted us to process and derive new and substantial data for the Mont Terri area in a straightforward way. Some parts of the lithologic inventory, stratigraphic architecture, thickness variations, and biostratigraphic classification of the studied formations deviate considerably from occurrences in northern Switzerland that crop out further to the east. For instance, with the exception of the Sissach Member, no further lithostratigraphic subdivision in members is proposed for the Passwang Formation. Also noteworthy is that the ca. 130 m-thick Opalinus Clay in the BDB-1 core is 20 m thinner than that equivalent section found in the Mont Terri tunnel. The lowermost 38 m of the Opalinus Clay can be attributed chronostratigraphically solely to the Aalensis Zone (Late Toarcian). Deposition of the Opalinus Clay began at the same time farther east in northern Switzerland (Aalensis Subzone, Aalensis Zone), but in the Mont Terri area the sedimentation rate was two or three orders of magnitude higher. (authors)

  13. 3D pore-type digital rock modeling of natural gas hydrate for permafrost and numerical simulation of electrical properties

    Science.gov (United States)

    Dong, Huaimin; Sun, Jianmeng; Lin, Zhenzhou; Fang, Hui; Li, Yafen; Cui, Likai; Yan, Weichao

    2018-02-01

    Natural gas hydrate is being considered as an alternative energy source for sustainable development and has become a focus of research throughout the world. In this paper, based on CT scanning images of hydrate reservoir rocks, combined with the microscopic distribution of hydrate, a diffusion limited aggregation (DLA) model was used to construct 3D hydrate digital rocks of different distribution types, and the finite-element method was used to simulate their electrical characteristics in order to study the influence of different hydrate distribution types, hydrate saturation and formation of water salinity on electrical properties. The results show that the hydrate digital rocks constructed using the DLA model can be used to characterize the microscopic distribution of different types of hydrates. Under the same conditions, the resistivity of the adhesive hydrate digital rock is higher than the cemented and scattered type digital rocks, and the resistivity of the scattered hydrate digital rock is the smallest among the three types. Besides, the difference in the resistivity of the different types of hydrate digital rocks increases with an increase in hydrate saturation, especially when the saturation is larger than 55%, and the rate of increase of each of the hydrate types is quite different. Similarly, the resistivity of the three hydrate types decreases with an increase in the formation of water salinity. The single distribution hydrate digital rock constructed, combined with the law of microscopic distribution and influence of saturation on the electrical properties, can effectively improve the accuracy of logging identification of hydrate reservoirs and is of great significance for the estimation of hydrate reserves.

  14. Qualitative and Quantitative Changes of Carbonate Rocks Exposed to SC CO2 (Basque-Cantabrian Basin, Northern Spain

    Directory of Open Access Journals (Sweden)

    Edgar Berrezueta

    2017-11-01

    Full Text Available This study aims at the qualitative and quantitative determination of porosity, mineralogical and textural changes in carbonate rock samples after injection of (i supercritical CO2-rich brine and (ii dry supercritical CO2, under similar experimental conditions (P ≈ 75 bar, T ≈ 35 °C, 970 h exposure time and no CO2 flow. The studied rocks were sampled in the western Basque-Cantabrian Basin, North Spain, and consist of vuggy carbonates (“Carniolas” of the Puerto de la Palombera formation (Hettangian. Mineralogical and pore space characterization is completed using optical microscopy, scanning electron microscopy and optical image analysis. In addition, X-ray fluorescence analyses are performed to refine the mineralogical information and to obtain whole rock geochemical data and the brine composition is analysed before and after the experiment. Mineralogical and chemical results indicate that the carbonate rocks exposed to supercritical CO2 in dry conditions do not suffer significant changes. However, the injection of supercritical CO2-rich brine induces chemical and physical changes in the rock due to the high reactivity of calcite at the low pH conditions produced by the acidified brine. Numerical modelling validates the experimental observations. These results can be used to characterize the behaviour of carbonate rocks under conditions similar to the vicinity of a CO2 injection well. The results should be considered only at the scale of the studied samples and not at reservoir scale.

  15. Drilling and coring methods that minimize the disturbance of cuttings, core, and rock formation in the unsaturated zone, Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Hammermeister, D.P.; Blout, D.O.; McDaniel, J.C.

    1985-01-01

    A drilling-and-casing method (Odex 115 system) utilizing air as a drilling fluid was used successfully to drill through various rock types within the unsaturated zone at Yucca Mountain, Nevada. This paper describes this method and the equipment used to rapidly penetrate bouldery alluvial-colluvial deposits, poorly consolidated bedded and nonwelded tuff, and fractured, densely welded tuff to depths of about 130 meters. A comparison of water-content and water-potential data from drill cuttings with similar measurements on rock cores indicates that drill cuttings were only slightly disturbed for several of the rock types penetrated. Coring, sampling, and handling methods were devised to obtain minimally disturbed drive core from bouldery alluvial-colluvial deposits. Bulk-density values obtained from bulk samples dug from nearby trenches were compared to bulk-density values obtained from drive core to determine the effects of drive coring on the porosity of the core. Rotary coring methods utilizing a triple-tube core barrel and air as the drilling fluid were used to obtain core from welded and nonwelded tuff. Results indicate that the disturbance of the water content of the core was minimal. Water-content distributions in alluvium-colluvium were determined before drilling occurred by drive-core methods. After drilling, water-content distributions were determined by nuclear-logging methods. A comparison of the water-content distributions made before and after drilling indicates that Odex 115 drilling minimally disturbs the water content of the formation rock. 10 refs., 12 figs., 4 tabs

  16. Pressure-temperature evolution of Neoproterozoic metamorphism in the Welayati Formation (Kabul Block), Afghanistan

    Science.gov (United States)

    Collett, Stephen; Faryad, Shah Wali

    2015-11-01

    The Welayati Formation, consisting of alternating layers of mica-schist and quartzite with lenses of amphibolite, unconformably overlies the Neoarchean Sherdarwaza Formation of the Kabul Block that underwent Paleoproterozoic granulite-facies and Neoproterozoic amphibolite-facies metamorphic events. To analyze metamorphic history of the Welayati Formation and its relations to the underlying Sherdarwaza Formation, petrographic study and pressure-temperature (P-T) pseudosection modeling were applied to staurolite- and kyanite-bearing mica-schists, which crop out to the south of Kabul City. Prograde metamorphism, identified by inclusion trails and chemical zonation in garnet from the micaschists indicates that the rocks underwent burial from around 6.2 kbar at 525 °C to maximum pressure conditions of around 9.5 kbar at temperatures of around 650 °C. Decompression from peak pressures under isothermal or moderate heating conditions are indicated by formation of biotite and plagioclase porphyroblasts which cross-cut and overgrow the dominant foliation. The lack of sillimanite and/or andalusite suggests that cooling and further decompression occurred in the kyanite stability field. The results of this study indicate a single amphibolite-facies metamorphism that based on P-T conditions and age dating correlates well with the Neoproterozoic metamorphism in the underlying Sherdarwaza Formation. The rocks lack any paragenetic evidence for a preceding granulite-facies overprint or subsequent Paleozoic metamorphism. Owing to the position of the Kabul Block, within the India-Eurasia collision zone, partial replacement of the amphibolite-facies minerals in the micaschist could, in addition to retrogression of the Neoproterozoic metamorphism, relate to deformation associated with the Alpine orogeny.

  17. Radiogeochemical characteristic of rocks of the Crimea peninsula and some principles of sedimentation

    International Nuclear Information System (INIS)

    Gherasimov, Yu.G.

    1983-01-01

    Radiogeochemical mapping with rock sampling of profiles, crossing all main structural facies zones of the Crimea peninsula was conducted. 1000 samples were taken. Uranium determination in samples was performed by fluorescence method (2 g/t threshold sensitivity). The distributions of U and Th background contents in rocks of the Crimea were tabulated. Maps of sampling of geological formations and distribution of U and Th background contents in rocks are given. It is shown that radioelement content in Crimea rocks is for the most part lower than clark one: 1.3-2.1 g/t contents prevail for U, Th contents don't exceed 12 g/t. Closeness of some radiogeochemical parameters points to the formation of terrigenous Crimea rocks due to removal of the material from the Ukrainian shield. Reworking of initial terrigenous material by hypergene processes led to U and Th separation, as well as to enrichment of younger sedimentary rocks with uranium

  18. Introduction to numerical modeling of thermohydrologic flow in fractured rock masses

    International Nuclear Information System (INIS)

    Wang, J.S.Y.

    1980-01-01

    More attention is being given to the possibility of nuclear waste isolation in hard rock formations. The waste will generate heat which raises the temperature of the surrounding fractured rock masses and induces buoyancy flow and pressure change in the fluid. These effects introduce the potential hazard of radionuclides being carried to the biosphere, and affect the structure of a repository by stress changes in the rock formation. The thermohydrological and thermomechanical responses are determined by the fractures as well as the intact rock blocks. The capability of modeling fractured rock masses is essential to site characterization and repository evaluation. The fractures can be modeled either as a discrete system, taking into account the detailed fracture distributions, or as a continuum representing the spatial average of the fractures. A numerical model is characterized by the governing equations, the numerical methods, the computer codes, the validations, and the applications. These elements of the thermohydrological models are discussed. Along with the general review, some of the considerations in modeling fractures are also discussed. Some remarks on the research needs in modeling fractured rock mass conclude the paper

  19. Design of experimental system for supercritical CO2 fracturing under confining pressure conditions

    Science.gov (United States)

    Wang, H.; Lu, Q.; Li, X.; Yang, B.; Zheng, Y.; Shi, L.; Shi, X.

    2018-03-01

    Supercritical CO2 has the characteristics of low viscosity, high diffusion and zero surface tension, and it is considered as a new fluid for non-polluting and non-aqueous fracturing which can be used for shale gas development. Fracturing refers to a method of utilizing the high-pressure fluid to generate fractures in the rock formation so as to improve the oil and gas flow conditions and increase the oil and gas production. In this article, a new type of experimental system for supercritical CO2 fracturing under confining pressure conditions is designed, which is based on characteristics of supercritical CO2, shale reservoir and down-hole environment. The experimental system consists of three sub-systems, including supercritical CO2 generation system, supercritical CO2 fracturing system and data analysis system. It can be used to simulate supercritical CO2 fracturing under geo-stress conditions, thus to study the rock initiation pressure, the formation of the rock fractures, fractured surface morphology and so on. The experimental system has successfully carried out a series of supercritical CO2 fracturing experiments. The experimental results confirm the feasibility of the experimental system and the high efficiency of supercritical CO2 in fracturing tight rocks.

  20. Regulation of ROCK Activity in Cancer

    Science.gov (United States)

    Morgan-Fisher, Marie; Wewer, Ulla M.

    2013-01-01

    Cancer-associated changes in cellular behavior, such as modified cell-cell contact, increased migratory potential, and generation of cellular force, all require alteration of the cytoskeleton. Two homologous mammalian serine/threonine kinases, Rho-associated protein kinases (ROCK I and II), are key regulators of the actin cytoskeleton acting downstream of the small GTPase Rho. ROCK is associated with cancer progression, and ROCK protein expression is elevated in several types of cancer. ROCKs exist in a closed, inactive conformation under quiescent conditions, which is changed to an open, active conformation by the direct binding of guanosine triphosphate (GTP)–loaded Rho. In recent years, a number of ROCK isoform-specific binding partners have been found to modulate the kinase activity through direct interactions with the catalytic domain or via altered cellular localization of the kinases. Thus, these findings demonstrate additional modes to regulate ROCK activity. This review describes the molecular mechanisms of ROCK activity regulation in cancer, with emphasis on ROCK isoform-specific regulation and interaction partners, and discusses the potential of ROCKs as therapeutic targets in cancer. PMID:23204112

  1. In-situ experiments for the determination of rock properties and behaviour at the Meuse/Haute Marne Centre

    Directory of Open Access Journals (Sweden)

    Conil N.

    2010-06-01

    Full Text Available Andra is in charge of studying the feasibility of a disposal facility for longlived high-level nuclear waste (LL-HLW in a deep geological environment. With this aim, dedicated experiments have been carried out for several years at the Meuse/Haute Marne Underground Research Laboratory excavated in a 500 m deep argillaceous rock formation. These experiments include determining the feasibility of the excavation of disposal cells for LL-HLW, consisting of 40 meter long, 70 cm in diameter, horizontal cased micro tunnels. The hydro mechanical impact of the excavation of such openings on the rock mass behaviour is continuously monitored as well as their mean term mechanical behaviour. Since LL-HLW produce heat, the impact of temperature on the surrounding rock mass and on the micro tunnel steel casing will also be studied. Specific instrumentation has been developed to study this impact. The first step of the microtunnel excavation tests, carried out in 2009, has led to improving the excavation method and the drilling machine. These improvements will be tested in the next step of the excavation tests planned for 2010. The THM experiment dedicated to studying the behaviour of the rock mass under thermal solicitation started early 2010. The behaviour of a steel casing in contact with the rock mass and under thermal solicitation will be studied in an experiment scheduled to start in September 2010.

  2. Strength and deformation properties of volcanic rocks in Iceland

    DEFF Research Database (Denmark)

    Foged, Niels Nielsen; Andreassen, Katrine Alling

    2016-01-01

    rock from Iceland has been the topic for rock mechanical studies carried out by Ice-landic guest students at the Department of Civil Engineering at the Technical University of Den-mark over a number of years in cooperation with University of Iceland, Vegagerðin (The Icelandic Road Directorate......) and Landsvirkjun (The National Power Company of Iceland). These projects involve engineering geological properties of volcanic rock in Iceland, rock mechanical testing and parameter evaluation. Upscaling to rock mass properties and modelling using Q- or GSI-methods have been studied by the students......Tunnelling work and preinvestigations for road traces require knowledge of the strength and de-formation properties of the rock material involved. This paper presents results related to tunnel-ling for Icelandic water power plants and road tunnels from a number of regions in Iceland. The volcanic...

  3. Assessment of rock mass decay in artificial slopes

    NARCIS (Netherlands)

    Huisman, M.

    2006-01-01

    This research investigates the decay of rock masses underlying slopes, and seeks to quantify the relations of such decay with time and geotechnical parameters of the slope and rock mass. Decay can greatly affect the geotechnical properties of rocks within engineering timescales, and may induce a

  4. Sorptivity of rocks and soils of the van Genuchten-Mualem type

    Energy Technology Data Exchange (ETDEWEB)

    Zimmerman, R.W.; Bodvarsson, G.S. [Lawrence Berkeley Lab., CA (United States)

    1991-06-01

    One hydrological process that will have great relevance to the performance of the proposed underground radioactive waste repository at Yucca Mountain, Nevada, is that of the absorption of water from a water-filled fracture into the adjacent unsaturated rock formation. The rate at which water is imbibed by a rock depends on the hydrological properties of the rock and on the initial saturation (or initial capillary suction) of the formation. The hydrological properties that affect imbibition are the relative permeability function and the capillary pressure function. These functions are often collectively referred to as the `characteristic functions` of the porous medium. For one-dimensional absorption, it can be shown that, regardless of the details of the characteristic functions, the total amount of water imbibed by the formation, per unit surface area, will be proportional to the square root of the elapsed time. Hence the ability of a rock or soil to imbibe water can be quantified by a parameter known as the sorptivity S, which is defined such that the cumulative volumetric liquid influx per unit area is given by Q = S{radical}t. The paper discusses the simplification of these characteristic functions of porous medium.

  5. Experimental Study on Mechanical and Acoustic Emission Characteristics of Rock-Like Material Under Non-uniformly Distributed Loads

    Science.gov (United States)

    Wang, Xiao; Wen, Zhijie; Jiang, Yujing; Huang, Hao

    2018-03-01

    The mechanical and acoustic emission characteristics of rock-like materials under non-uniform loads were investigated by means of a self-developed mining-induced stress testing system and acoustic emission monitoring system. In the experiments, the specimens were divided into three regions and different initial vertical stresses and stress loading rates were used to simulate different mining conditions. The mechanical and acoustic emission characteristics between regions were compared, and the effects of different initial vertical stresses and different stress loading rates were analysed. The results showed that the mechanical properties and acoustic emission characteristics of rock-like materials can be notably localized. When the initial vertical stress and stress loading rate are fixed, the peak strength of region B is approximately two times that of region A, and the maximum acoustic emission hit value of region A is approximately 1-2 times that of region B. The effects of the initial vertical stress and stress loading rate on the peck strain, maximum hit value, and occurrence time of the maximum hit are similar in that when either of the former increase, the latter all decrease. However, peck strength will increase with the increase in loading rate and decrease with the increase in initial vertical stress. The acoustic emission hits can be used to analyse the damage in rock material, but the number of acoustic emission hits cannot be used alone to determine the degree of rock damage directly.

  6. On the crack propagation analysis of rock like Brazilian disc specimens containing cracks under compressive line loading

    Directory of Open Access Journals (Sweden)

    Hadi Haeri

    Full Text Available The pre-existing cracks in the brittle substances seem to be the main cause of their failure under various loading conditions. In this study, a simultaneous analytical, experimental and numerical analysis of crack propagation, cracks coalescence and failure process of brittle materials has been performed. Brazilian disc tests are being carried out to evaluate the cracks propagation paths in rock-like Brazilian disc specimens containing single and double cracks (using rock-like specimens which are specially prepared from Portland Pozzolana Cement (PPC, fine sands and water in a rock mechanics laboratory. The failure load of the pre-cracked disc specimens are measured showing the decreasing effects of the cracks and their orientation on the final failure load. The same specimens are numerically simulated by a higher order indirect boundary element method known as displacement discontinuity method. These numerical results are compared with the existing analytical and experimental results proving the accuracy and validity of the proposed numerical method. The numerical and experimental results obtained from the tested specimens are in good agreement and demonstrate the accuracy and effectiveness of the proposed approach.

  7. Geochronology of the basement rocks, Amazonas Territory, Venezuela and the tectonic evolution of the western Guiana Shield

    Energy Technology Data Exchange (ETDEWEB)

    Gaudette, H E; Olszewski, Jr, W J

    1985-01-01

    The Amazonas Territory of Venezuela is a large area of Precambrian basement rocks overlain in some locales by the supracrustal sedimentary and volcanic rocks of the Roraima Formation. The basement rocks are medium to high grade gneisses with both igneous and sedimentary protoliths, plutonic rocks ranging in composition from granite to tonalite, and meta-volcanic rocks. Rb-Sr whole rock, and U-Pb isotopic analyses of zircons indicate a period of medium to high grade metamorphism and intrusion from 1860 to 1760 Ma. Post-tectonic plutonic activity continued to 1550 Ma. The volcanic rocks of the Roraima Formation in Venezuela give an age of 1746 Ma comparable to volcanic rocks of the Roraima Formation in other parts of the Guiana Shield. The ages and distribution of the basement rocks suggest the presence of a tectonic zone, approximately coincident with the Venezuelan-Colombian border, representing an active orogenic boundary between distinct tectonic provinces. The rocks to the northeast of this zone are part of the Trans-Amazonian of the Guiana Shield, while to the southwest and in adjacent Brazil and Colombia, new younger continental crust has been developed and cratonized. We suggest a model of collision and subduction followed by a chan0140n tectonic style to extensional-vertical to produce the basement rocks of the western Guiana Shield in the Amazonas Territory. (Auth.). 20 refs.; 13 figs.; 2 tabs.

  8. Time-Dependent Damage Investigation of Rock Mass in an In Situ Experimental Tunnel

    Science.gov (United States)

    Jiang, Quan; Cui, Jie; Chen, Jing

    2012-01-01

    In underground tunnels or caverns, time-dependent deformation or failure of rock mass, such as extending cracks, gradual rock falls, etc., are a costly irritant and a major safety concern if the time-dependent damage of surrounding rock is serious. To understand the damage evolution of rock mass in underground engineering, an in situ experimental testing was carried out in a large belowground tunnel with a scale of 28.5 m in width, 21 m in height and 352 m in length. The time-dependent damage of rock mass was detected in succession by an ultrasonic wave test after excavation. The testing results showed that the time-dependent damage of rock mass could last a long time, i.e., nearly 30 days. Regression analysis of damage factors defined by wave velocity, resulted in the time-dependent evolutional damage equation of rock mass, which corresponded with logarithmic format. A damage viscoelastic-plastic model was developed to describe the exposed time-dependent deterioration of rock mass by field test, such as convergence of time-dependent damage, deterioration of elastic modules and logarithmic format of damage factor. Furthermore, the remedial measures for damaged surrounding rock were discussed based on the measured results and the conception of damage compensation, which provides new clues for underground engineering design.

  9. Corrosion testing of selected packaging materials for disposal of high-level waste glass in rock salt formations

    International Nuclear Information System (INIS)

    Smailos, E.; Schwarzkopf, W.; Koester, R.; Fiehn, B.; Halm, G.

    1990-05-01

    In previous corrosion studies performed in salt brines, unalloyed steels, Ti 99.8-Pd and Hastelloy C4 have proved to be the most promising materials for long-term resistant packagings to be used in heat-generating waste (vitrified HLW, spent fuel) disposal in rock-salt formations. To characterise the corrosion behaviour of these materials in more detail, further in-depth laboratory-scale and in-situ corrosion studies have been performed in the present study. Besides the above-mentioned materials, also some in-situ investigations of the iron-base materials Ni-Resist D2 and D4, cast iron and Si-cast iron have been carried out in order to complete the results available to date. (orig.) [de

  10. The origin of volcanic rock fragments in Upper Pliocene Grad Member of the Mura Formation, North-Eastern Slovenia

    Directory of Open Access Journals (Sweden)

    Polona Kralj

    2006-12-01

    Full Text Available Fresh-water, coarse-grained and detritus-dominated Mura Formation in North Eastern Slovenia includes pyroclastic and volcaniclastic deposits originating from Upper Pliocene volcanic activity of basaltic geochemical character. Although localized in occurrence at the hamlet Grad, these pyroclastic and volcaniclastic sediments forma distinctive depositional unit, for which the term “Grad Member” is proposed and introduced in this paper.In the Grad area no lavas or cinder cones are preserved, and the origin of volcaniclastic fragments still uncertain. For this reason, chemical composition of basaltic rock fragments from the Grad Member volcaniclastics has been studied and compared with basaltic rocks from the neighboring locations at Klöch, Kindsberg, Dölling and Neuhaus. The Grad Member pyroclastic and volcaniclastic deposits seem to be fed from the same source which is different from the occurrences in Austria. That supports the idea about the existence of a local volcanic centre in the present Grad area. The old volcanic edificeswerepossiblydestroyed by the late-stage hydrovolcanic eruptions, and pyroclastic and volcaniclastic deposits subjected to constant reworking by fluvial currents in a dynamic sedimentary environment of alluvial fan and braided river systems.

  11. Analysis of the potential formation of a Breccia chimney beneath the WIPP repository

    International Nuclear Information System (INIS)

    Spiegler, P.

    1982-05-01

    This report evaluates the potential formation of a Breccia pipe beginning at the Bell Canyon aquifer beneath the WIPP repository and the resulting release of radioactivity to the surface. Rock mechanics considerations indicate that the formation of a Breccia pipe by collapse of a cavern is not reasonable. Even if rock mechanics is ignored, the overlying strata act as a barrier and would prevent the release of radioactivity to the biosphere. Gradual formation of a Breccia pipe is so slow that the plutonium-239 in the waste (one of the most important long-lived components) would decay during formation. If Bell Lake and San Simon Sinks are the surface manifestation of a regional deep dissolution wedge, such a wedge is too far removed to represent pipe forming activity near the WIPP site. The formation of a Breccia pipe under the WIPP repository is highly unlikely. If it did occur, the concentration of plutonium-239 in brine reaching the surface would be less than the maximum permissible concentration in water specified in the Code of Federal Regulation Title 10, part 20

  12. Facies and age of the Oso Ridge Member (new), Abo Formation, Zuni Mountains, New Mexico

    Science.gov (United States)

    Armstrong, A.K.; Stamm, R.G.; Kottlowski, F.E.; Mamet, B.L.; Dutro, J.T.; Weary, D.J.

    1994-01-01

    The Oso Ridge Member (new), at the base of the Abo Formation, nonconformably overlies Proterozoic rocks. The member consists of some 9m of conglomerate and arkose composed principally of fragments of the underlying Proterozoic metamorphic rocks; thin, fossiliferous limestone lenses are interbedded with the arkose. Biota from the lenses include a phylloid alga, foraminifers, conodonts, brachiopods, and molluscs. The age of the Oso Ridge Member is Virgilian Late Pennsylvanian) to Wolfcampian (Early Permian). -from Authors

  13. North Slope, Alaska: Source rock distribution, richness, thermal maturity, and petroleum charge

    Science.gov (United States)

    Peters, K.E.; Magoon, L.B.; Bird, K.J.; Valin, Z.C.; Keller, M.A.

    2006-01-01

    Four key marine petroleum source rock units were identified, characterized, and mapped in the subsurface to better understand the origin and distribution of petroleum on the North Slope of Alaska. These marine source rocks, from oldest to youngest, include four intervals: (1) Middle-Upper Triassic Shublik Formation, (2) basal condensed section in the Jurassic-Lower Cretaceous Kingak Shale, (3) Cretaceous pebble shale unit, and (4) Cretaceous Hue Shale. Well logs for more than 60 wells and total organic carbon (TOC) and Rock-Eval pyrolysis analyses for 1183 samples in 125 well penetrations of the source rocks were used to map the present-day thickness of each source rock and the quantity (TOC), quality (hydrogen index), and thermal maturity (Tmax) of the organic matter. Based on assumptions related to carbon mass balance and regional distributions of TOC, the present-day source rock quantity and quality maps were used to determine the extent of fractional conversion of the kerogen to petroleum and to map the original TOC (TOCo) and the original hydrogen index (HIo) prior to thermal maturation. The quantity and quality of oil-prone organic matter in Shublik Formation source rock generally exceeded that of the other units prior to thermal maturation (commonly TOCo > 4 wt.% and HIo > 600 mg hydrocarbon/g TOC), although all are likely sources for at least some petroleum on the North Slope. We used Rock-Eval and hydrous pyrolysis methods to calculate expulsion factors and petroleum charge for each of the four source rocks in the study area. Without attempting to identify the correct methods, we conclude that calculations based on Rock-Eval pyrolysis overestimate expulsion factors and petroleum charge because low pressure and rapid removal of thermally cracked products by the carrier gas retards cross-linking and pyrobitumen formation that is otherwise favored by natural burial maturation. Expulsion factors and petroleum charge based on hydrous pyrolysis may also be high

  14. Stochastic calculus of protein filament formation under spatial confinement

    Science.gov (United States)

    Michaels, Thomas C. T.; Dear, Alexander J.; Knowles, Tuomas P. J.

    2018-05-01

    The growth of filamentous aggregates from precursor proteins is a process of central importance to both normal and aberrant biology, for instance as the driver of devastating human disorders such as Alzheimer's and Parkinson's diseases. The conventional theoretical framework for describing this class of phenomena in bulk is based upon the mean-field limit of the law of mass action, which implicitly assumes deterministic dynamics. However, protein filament formation processes under spatial confinement, such as in microdroplets or in the cellular environment, show intrinsic variability due to the molecular noise associated with small-volume effects. To account for this effect, in this paper we introduce a stochastic differential equation approach for investigating protein filament formation processes under spatial confinement. Using this framework, we study the statistical properties of stochastic aggregation curves, as well as the distribution of reaction lag-times. Moreover, we establish the gradual breakdown of the correlation between lag-time and normalized growth rate under spatial confinement. Our results establish the key role of spatial confinement in determining the onset of stochasticity in protein filament formation and offer a formalism for studying protein aggregation kinetics in small volumes in terms of the kinetic parameters describing the aggregation dynamics in bulk.

  15. Studies on the radiation absorption characteristics of various rocks

    International Nuclear Information System (INIS)

    Rahman, K.N.; Abdullah, S.A.; Gazzaz, M.A.

    1984-05-01

    Radiation absorption characteristics of nine different rocks, namely, ferrugenous quartz, metabasalt, larvikite, coarse grained diorite, coarse grained granite, coarse grained alkali granite, marble, quartz mica schist, and metamorphosed rock are studied. The rocks were collected from Jeddah, Makkah, Mina and Taif areas. Special attention was given on the availability, compactness, physical formation and uniform composition in selecting the rocks. The rocks were identified by optical method and their elemental composition determined by chemical analysis. The data were used to calculate the effective atomic numbers, half value layers mass and linear attenuation coefficients. The half value layers and the linear attenuation coefficientsof these rocks were determined experimentally using Am-241, Cs-137,and Co-60 sources. The results are compared with those obtained by theoretical calculations and agrre within 10%. Most of the rocks show much higher radiation attenuation characteristics than the standard concrete. Rocks containing higher percentage of Fe, Ca, Ti, and Mn show much higher radiation absorption characteristics than concrete. Only granites are found to be almost equivalent to concrete. 12 Ref

  16. System and method for investigating sub-surface features and 3D imaging of non-linear property, compressional velocity VP, shear velocity VS and velocity ratio VP/VS of a rock formation

    Science.gov (United States)

    Vu, Cung Khac; Skelt, Christopher; Nihei, Kurt; Johnson, Paul A.; Guyer, Robert; Ten Cate, James A.; Le Bas, Pierre-Yves; Larmat, Carene S.

    2015-06-02

    A system and a method for generating a three-dimensional image of a rock formation, compressional velocity VP, shear velocity VS and velocity ratio VP/VS of a rock formation are provided. A first acoustic signal includes a first plurality of pulses. A second acoustic signal from a second source includes a second plurality of pulses. A detected signal returning to the borehole includes a signal generated by a non-linear mixing process from the first and second acoustic signals in a non-linear mixing zone within an intersection volume. The received signal is processed to extract the signal over noise and/or signals resulting from linear interaction and the three dimensional image of is generated.

  17. Formation of Intermediate Plutonic Rocks by Magma Mixing: the Shoshonite Suite of Timna, Southern Israel.

    Science.gov (United States)

    Fox, S.; Katzir, Y.

    2017-12-01

    In magmatic series considered to form by crystal fractionation intermediate rocks are usually much less abundant than expected. Yet, intermediate plutonic rocks, predominantly monzodiorites, are very abundant in the Neoproterozoic Timna igneous complex, S. Israel. A previously unnoticed plutonic shoshonitic suite was recently defined and mapped in Timna (Litvinovsky et al., 2015). It mostly comprises intermediate rocks in a seemingly 'continuous' trend from monzodiorite through monzonite to quartz syenite. Macroscale textures including gradational boundaries of mafic and felsic rocks and MME suggest that magma mixing is central in forming intermediate rocks in Timna. Our petrographic, microtextural and mineral chemistry study delineates the mode of incipient mixing, ultimate mingling and crystal equilibration in hybrid melts. An EMP study of plagioclase from rocks across the suite provides a quantitative evaluation of textures indicative of magma mixing/mingling, including recurrent/patchy zoning, Ca spike, boxy/sponge cellular texture and anti-Rapakivi texture. Each texture has an affinity to a particular mixing region. A modal count of these textures leads to a kinetic mixing model involving multi temporal and spatial scales necessary to form the hybrid intermediate rocks. A `shell'-like model for varying degrees of mixing is developed with the more intensive mixing at the core and more abundant felsic and mafic end-members towards the outer layer. REE patterns in zircon shows that it originated from both mafic and felsic parent melts. Whole rock Fe vs Sr plot suggests a two-stage mixing between the monzogabbro and quartz-syenite producing first mesocratic syenite, and subsequent mixing with a fractionating monzogabbro resulting in monzonitic compositions. A fractionating monzogabbro intruded into a syenitic melt sequentially. While slowly cooling, the monzogabbro heated the immediate syenitic melt, lowering the viscosity and rheological obstruction to overturn

  18. Change in cap rock porosity triggered by pressure and temperature dependent CO2–water–rock interactions in CO2 storage systems

    Directory of Open Access Journals (Sweden)

    Christina Hemme

    2017-03-01

    Full Text Available Carbon capture and storage in deep geological formations is a method to reduce greenhouse gas emissions. Supercritical CO2 is injected into a reservoir and dissolves in the brine. Under the impact of pressure and temperature (P–T the aqueous species of the CO2-acidified brine diffuse through the cap rock where they trigger CO2–water–rock interactions. These geochemical reactions result in mineral dissolution and precipitation along the CO2 migration path and are responsible for a change in porosity and therefore for the sealing capacity of the cap rock. This study focuses on the diffusive mass transport of CO2 along a gradient of decreasing P–T conditions. The process is retraced with a one-dimensional hydrogeochemical reactive mass transport model. The semi-generic hydrogeochemical model is based on chemical equilibrium thermodynamics. Based on a broad variety of scenarios, including different initial mineralogical, chemical and physical parameters, the hydrogeochemical parameters that are most sensitive for safe long-term CO2 storage are identified. The results demonstrate that P–T conditions have the strongest effect on the change in porosity and the effect of both is stronger at high P–T conditions because the solubility of the mineral phases involved depends on P–T conditions. Furthermore, modeling results indicate that the change in porosity depends strongly on the initial mineralogical composition of the reservoir and cap rock as well as on the brine compositions. Nevertheless, a wide range of conditions for safe CO2 storage is identified.

  19. X-Ray Computed Tomography of Tranquility Base Moon Rock

    Science.gov (United States)

    Jones, Justin S.; Garvin, Jim; Viens, Mike; Kent, Ryan; Munoz, Bruno

    2016-01-01

    X-ray Computed Tomography (CT) was used for the first time on the Apollo 11 Lunar Sample number 10057.30, which had been previously maintained by the White House, then transferred back to NASA under the care of Goddard Space Flight Center. Results from this analysis show detailed images of the internal structure of the moon rock, including vesicles (pores), crystal needles, and crystal bundles. These crystals, possibly the common mineral ilmenite, are found in abundance and with random orientation. Future work, in particular a greater understanding of these crystals and their formation, may lead to a more in-depth understanding of the lunar surface evolution and mineral content.

  20. Study on epigenetic alterations of ore-enclosing sedimentary rocks

    International Nuclear Information System (INIS)

    Kondrat'eva, I.A.; Komarova, G.V.

    1985-01-01

    Epigenetic alterations of sedimentary rocks under effect of exogenous undeground waters of various types: near-surface, ground, stratum, and deep circulation waters, are considered. Association to postsedimentary tectonic structures, confinement of neogenesis to areas of high permeability (porous or crack one), geochemical contradictions between mineral neogenis and facial outlook of deposits, noncoincidence of variability gradient of authigenous mineral associations with variability of primary facial signs of deposits, regular position of mineral formations and ore concentrations in epigenetic mineralogo-geochemical zonation are referred to epigenetic criteria. The complex of epigenetic alterations accompanying mineralization is frequently used as a search sign of uranium deposit of a certain type

  1. Mass transport in low permeability rocks under the influence of coupled thermomechanical and hydrochemical effects - an overview

    International Nuclear Information System (INIS)

    Tsang, C.F.

    1984-10-01

    The present paper gives a general overview of mass transport in low permeability rocks under the coupled thermomechanical and hydrochemical effects associated with a nuclear waste repository. A classification of coupled processes is given. Then an ess is presented. example of a coupled process is presented. Discussions of coupled processes based on a recent LBL Panel meeting are summarized. 5 references, 3 figures, 4 tables

  2. Deformation and damage modes of deep argillaceous rocks under hydro-mechanical stresses

    International Nuclear Information System (INIS)

    Vales, F.

    2008-12-01

    An experimental identification of the hydro-mechanical behaviour of an argillite rock is proposed within a multi-scale approach. In particular, interest is focused on the spatial and temporal localization of strain and damage in a specimen during hydro-mechanical loading. Firstly, we describe the techniques used to follow the rock evolutions under loading, and in particular Digital Images Correlation (DIC), Acoustic Emission, microscopy and mercury intrusion porosimetry. Measurement errors and device limitations are discussed. The studied material is the Callovo-Oxfordian indurated argillaceous rock (or argillite) of the Bure site where ANDRA has built an underground research laboratory to study the radioactive waste storage. Petrophysical characterizations and microstructural observations by optical and scanning electron microscopy provide an identification of the constitutive phase and a characterization of their spatial distribution and typical sizes. Argillite can be described as a composite structure with a continuous clay matrix and embedded mineral particles, essentially quartz and carbonates. The typical size of these particles ranges from a few micrometers to a few hundreds micrometers, with an average close to 50 μ.m. The general experimental procedure combines two steps: in a fist time, imposed suctions bring samples to a given degree of water saturation, and, in a second time, uniaxial mechanical compression tests are performed. To understand the evolutions of the material under hydric and mechanical loading, samples are instrumented with standard measurement techniques, but also with Digital Image Correlation, at both the global scale of the sample and the local scale of the composite microstructure, and with Acoustic Emissions recording. Moisture transfers are imposed by controlled suctions on the range of 150 to 2.8 MPa, corresponding to the relative humidity range of 32 to 98%RH. During pure hydric solicitation, the changes in physical parameters

  3. Dolomitization and sedimentary cyclicity of the Ordovician, Silurian, and Devonian rocks in South Estonia

    Directory of Open Access Journals (Sweden)

    Kallaste, Toivo

    2006-03-01

    Full Text Available The distribution and composition of dolomitized rocks and stoichiometry of dolomite in southern Estonia in the Ordovician, Silurian, and Devonian were studied on the background of the facies, sedimentary cyclicity (nine shallowing-up cycles, and evolution of the palaeobasins. The composition of rocks and lattice parameters of dolomite were investigated using the X-ray diffraction, X-ray fluorescence, titration and gravimetric analyses, and porosity measurements. The formation of dolostones is directly determined by the cyclic evolution of palaeobasins. Dolomitized rocks belong to the shallow-water inner shelf or tidal/lagoonal facies belt of regressive phases of sedimentary cycles. Sediments of the deep shelf/transitional environment and transgressive phases are not dolomitized. The most stoichiometric is secondary replacive dolomite of Silurian and upper Ordovician dolostones, formed during the early diagenesis of normal-marine (saline shallow-shelf calcitic sediments. The content of insoluble residue does not affect the stoichiometry. The changes in lattice parameters are induced by the Ca/Mg ratio in the dolomite lattice. The dolomite of the dolostones contacting limestone or containing calcite has an expanded lattice. The primary (syngenetic dolostone of the lagoonal or tidal flat belt has also an expanded lattice. No dolomitizing effect of the waters of the Devonian palaeobasin on the underlying rocks was revealed. The whole data set of the studied dolostones is consistent with the marine water environment in the palaeobasin at the corresponding time and shows no sign of the inflow of external fluids. It suggests that the microbial model of dolomite formation may characterize the Ordovician, Silurian, and Devonian in southern Estonia. The occurrence of dolostones between undolomitized rocks limits the time of dolomitization to the early diagenetic stage.

  4. Microscopic study of rock for estimating long-term behavior

    International Nuclear Information System (INIS)

    Ichikawa, Yasuaki

    2002-03-01

    Micro-structure of rock plays a essential role for their long-term behavior. For elucidating long-term characteristics of granite we here present the followings: 1) Conforcal Laser Scanning Microscope (LSM) observation of joint surfaces of granite and Fourier analysis, 2) characterization of the mechanism of microcrack initiation and propagation observed by stereoscopic microscope under uniaxial/triaxial compression and relaxation tests, 3) observation of microcrack initiation and propagation by LSM under uniaxial compression, and 4) a viscoelastic homogenization theory to predict the long-term behavior of micro/macro-level stress for granite. Rock image processing and analysis become a fundamental procedure to determine rock surface discontinuities. But the complexity of rock surface discontinuities seems beyond the manual image processing method. In Chapter 2 a Conforcal Laser Scanning Microscope that can acquire three-dimensional images is introduced to observe the rock roughness of a discontinuity. Then, scanning three-dimensional images are changed its data form in order to adapt various image analysis programs, and granitic rock roughness of discontinuities are displayed by graphic images. For example, these datas are analyzed by Discrete Fourier Transformation (DFT) program and Inverse Discrete Fourier Transformation (IDFT) program. Microcrack generation and propagation play an essential role to predict the long-term behavior of rock. In Chapter 3 a progressive development of cracking in granite is revealed by using stereoscopic microscope under triaxial compression condition and by using LSM under uniaxial compression condition. With a viscoelastic theory applied in homogenization method, we can calculate macro behavior of medium influenced by its micro structure by analyse the long-term time-dependent behavior of granite under the same condition to the relaxation experiment. (author)

  5. Geochemistry of coal-measure source rocks and natural gases in deep formations in Songliao Basin, NE China

    Energy Technology Data Exchange (ETDEWEB)

    Mi, Jingkui; Zhang, Shuichang; Hu, Guoyi; He, Kun [State Key Laboratory for Enhanced Oil Recovery, Beijing (China); Petroleum Geology Research and Laboratory Center, Research Institute of Petroleum Exploration and Development, PetroChina (China); Key Laboratory for Petroleum Geochemistry, China National Petroleum Corp. (China)

    2010-12-01

    The natural gases developed in deep volcanic rock reservoirs of the Songliao Basin, NE China are characterized by enriched {delta}{sup 13}C value for methane and frequently reversal carbon isotopic distribution pattern. Although many researchers consider such gas type as an abiogenic origin, we believe the natural gases have a biogenic origin mainly except little inorganic gases and the reversal carbon isotopic distribution pattern of gases is caused by mixing of different origin gases. Methane carbon isotopic values for majority samples fall in the range from - 24 permille to - 32 permille, which is heavier than typical coal-type gases in other Chinese basins. There are several reasons caused heavy carbon isotope of methane: (1) Carbon isotopic values of source kerogen are 3-5 permille heavier than these from other basins; (2) Source rocks are at extremely high maturity stage with vitrinite reflectance mostly above 3.0%; (3) Portion of gas is derived from basement mudrock or slate with higher maturity. The observation on the organic from deep formation reveals that there is a relatively high content for liptinite, which reaches approximately 8 to 10%. The macerals component of source rock shows that the source rocks have some ability to generate oil. Small portion of oil was generated from high hydrogen content macerals in coals and shales as proof by oil found in microcrack and in micropore of coal and oil-bearing fluid inclusions grown in volcanic reservoir. The occurrence of pyrobitumen in volcanic reservoir indicates preexisted oil had been cracked into wet gas, and this kind of gas had also been found in gas pools. Heavy isotopic methane is derived from coal at extremely high maturity stage. There may be little inorganic alkane gases in deep layers for their geochemistry and special geological setting of Songliao Basin. Artificial mixing experiments of different origins gases confirm that inorganic gas such as gas from well FS1 mixed with other end members

  6. Alteration of submarine volcanic rocks in oxygenated Archean oceans

    Science.gov (United States)

    Ohmoto, H.; Bevacqua, D.; Watanabe, Y.

    2009-12-01

    Most submarine volcanic rocks, including basalts in diverging plate boundaries and andesites/dacites in converging plate boundaries, have been altered by low-temperature seawater and/or hydrothermal fluids (up to ~400°C) under deep oceans; the hydrothermal fluids evolved from shallow/deep circulations of seawater through the underlying hot igneous rocks. Volcanogenic massive sulfide deposits (VMSDs) and banded iron formations (BIFs) were formed by mixing of submarine hydrothermal fluids with local seawater. Therefore, the behaviors of various elements, especially of redox-sensitive elements, in altered submarine volcanic rocks, VMSDs and BIFs can be used to decipher the chemical evolution of the oceans and atmosphere. We have investigated the mineralogy and geochemistry of >500 samples of basalts from a 260m-long drill core section of Hole #1 of the Archean Biosphere Drilling Project (ABDP #1) in the Pilbara Craton, Western Australia. The core section is comprised of ~160 m thick Marble Bar Chert/Jasper Unit (3.46 Ga) and underlying, inter-bedded, and overlying submarine basalts. Losses/gains of 65 elements were quantitatively evaluated on the basis of their concentration ratios against the least mobile elements (Ti, Zr and Nb). We have recognized that mineralogical and geochemical characteristics of many of these samples are essentially the same as those of hydrothermally-altered modern submarine basalts and also those of altered volcanic rocks that underlie Phanerozoic VMSDs. The similarities include, but are not restricted to: (1) the alteration mineralogy (chlorite ± sericite ± pyrophyllite ± carbonates ± hematite ± pyrite ± rutile); (2) the characteristics of whole-rock δ18O and δ34S values; (3) the ranges of depletion and enrichment of Si, Al, Mg, Ca, K, Na, Fe, Mn, and P; (4) the enrichment of Ba (as sulfate); (5) the increases in Fe3+/Fe2+ ratios; (6) the enrichment of U; (7) the depletion of Cr; and (8) the negative Ce anomalies. Literature data

  7. Diffusion in the matrix of granitic rock

    International Nuclear Information System (INIS)

    Birgersson, L.; Neretnieks, I.

    1982-07-01

    A migration experiment in the rock matrix is presented. The experiment has been carried out in undisturbed rock, that is rock under its natural stress environment. Since the experiment was performed at the 360 m-level (in the Stripa mine), the rock had nearly the same conditions as the rock surrounding a nuclear waste storage. The results show that all three tracers (Uranine, Cr-EDTA and I - ) have passed the disturbed zone from the injection hole and migrated into undisturbed rock. At the distance of 11 cm from the injection hole 5-10 percent of the injection concentration was found. The results also indicate that the tracer have passed through fissure filling material. These results indicate that it is possible for tracers (and therefore radionuclides) to migrate from a fissure, through fissure filling material, and into the undisturbed rock matrix. (Authors)

  8. Analysis of the effect of pore geometry in the physical properties of rocks

    Directory of Open Access Journals (Sweden)

    Luiz Alberto Oliveira Lima Roque

    2012-12-01

    Full Text Available Pore geometry is one of the main factors influencing the flow of reservoir fluids under pressure. Pores with narrower formats are more easily compressed when subject to pressure. Pressure modifies pore geometry by opening or closing cracks, causing increase or decrease in the elastic modulus, porosity, permeability, and other parameters. Rock physical properties depend on the size and shape of pores. Thus, in order to analyze changes on the physical properties behavior according to the pores geometry, it is necessary to study and improve mathematical models of the porous media by taking into account the pore shape factor for estimating rock elastic properties. Differential effective medium model (DEM, Hertz-Mindlin theory and coherent potential approximation (CPA are some of the theoretical paradigms that take into account pore geometry in changes in elastic moduli. Given the importance of the pore structure effect on the behavior of physical parameters, this article proposes an analysis of some mathematical models that consider the influence of pore shapes in the physical properties of rocks.

  9. In situ investigations on the impact of heat production and gamma radiation with regard to high-level radioactive waste disposal in rock salt formations

    International Nuclear Information System (INIS)

    Rothfuchs, T.

    1986-01-01

    Deep geological formations especially rock salt formations, are considered worldwide as suitable media for the final disposal of radioactive high-level waste (HLW). In the Federal Republic of Germany, the Institut fur Tieflagerung of the Gesellschaft fur Strahlen- und Umweltforschung mbH Munchen operates the Asse Salt Mine as a pilot facility for testing the behavior of an underground nuclear waste repository. The tests are performed using heat and radiation sources to simulate disposed HLW canisters. The measured data obtained since 1965 show that the thermomechanical response of the salt formation and the physical/chemical changes in the vicinity of disposal boreholes are not a serious concern and that their long-term consequences can be estimated based on theoretical considerations and in-situ investigations

  10. 预掘底板岩巷卸压增透方法∗%Methods of destressing and increasing penetration at pre-excavated rock roadway under floor

    Institute of Scientific and Technical Information of China (English)

    王中华

    2016-01-01

    针对难抽采煤层,提出了预掘底板岩巷卸压增透方法,理论分析了底板岩巷卸压影响范围一般为巷道半径r 的2~6倍.现场考察了曲江煤矿702底板岩巷围岩位移量最大为38 mm,钻孔瓦斯流量、煤层透气性系数分别为原始煤层的11.1倍、43.2倍,实践表明曲江煤矿702底板岩巷布置在待掘煤巷正下方8~10 m处增透效果显著.%Proposing methods of destressing and increasing penetration at pre-excavated rock road-way under floor for coal seams which are difficult to be drained;theoretically analyzing that the influen-tial incidence of destressing at rock roadway under floor is generally as 2 to 6 times of roadway radius r. In-situ measurements show that the maximum surrounding rock displacement of rock roadway under 702 floor of Qujiang Mine is 38 mm;gas flow rate in borehole and permeability coefficient of coal seam is 1 1.1 and 43.2 times of those of the original coal seam,respectively. The practice shows that rock road-way under 702 floor of Qujiang Mine could make significantly increasing penetration effect when it is placed 8-1 0 meters directly below coal lanes to be excavated.

  11. ROCK inhibitors in ocular disease

    Directory of Open Access Journals (Sweden)

    Eva Halasz

    2016-12-01

    Full Text Available Rho kinases (ROCKs have a crucial role in actin-cytoskeletal reorganization and thus are involved in broad aspects of cell motility, from smooth muscle contraction to neurite outgrowth. The first marketed ROCK inhibitor, called fasudil, has been used safely for treatment of cerebral vasospasm since 1995 in Japan. During the succeeding decades ROCK inhibitors have been applied in many pathological conditions from central nervous system disorders to cardiovascular disease as potential therapeutic agents or experimental tools to help understand the underlying (pathomechanisms. In 2014, a fasudil derivate named ripasudil was accepted for clinical use in glaucoma and ocular hypertension. Since ROCK kinases are widely expressed in ocular tissues, they have been implicated in the pathology of many ocular conditions such as corneal dysfunction, glaucoma, cataract, diabetic retinopathy, age-related macular degeneration, and retinal detachment. This paper aims to provide an overview of the most recent status/application of ROCK inhibitors in the field of eye disease.

  12. Laboratory tests to study the influence of rock stress confinement on the performances of TBM discs in tunnels

    Science.gov (United States)

    Innaurato, N.; Oggeri, C.; Oreste, P.; Vinai, R.

    2011-06-01

    To clarify some aspects of rock destruction with a disc acting on a high confined tunnel face, a series of tests were carried out to examine fracture mechanisms under an indenter that simulates the tunnel boring machine (TBM) tool action, in the presence of an adjacent groove, when a state of stress (lateral confinement) is imposed on a rock sample. These tests proved the importance of carefully establishing the optimal distance of grooves produced by discs acting on a confined surface, and the value (as a mere order of magnitude) of the increase of the thrust to produce the initiation of chip formation, as long as the confinement pressure becomes greater.

  13. The Stability of Metasedimentary Rock in Ranau, Sabah, Malaysia

    Directory of Open Access Journals (Sweden)

    Ismail Abd Rahim

    2018-01-01

    Full Text Available DOI: 10.17014/ijog.5.1.23-31The aim of this paper is to determine the stability of slopes and to propose preliminary rock cut slope protection and stabilization measures for Paleocene to Middle Eocene Trusmadi Formation along Marakau-Kigiok in Ranau, Sabah, Malaysia. The rock of Trusmadi Formation is slightly metamorphosed and dominated by interbeds of sandstone with quartz vein (metagreywacke, metamudstone, shale, slate, sheared sandstone, and mudstone. The rock unit can be divided into four geotechnical units namely arenaceous unit, argillaceous unit, interbedded unit, and sheared unit. Twelve slopes were selected for this study. Geological mapping, discontinuity survey, kinematic analysis, and prescriptive measure were used in this study. Results of this study conclude that the potential modes of failures are planar and wedge. Terrace, surface drainage, weep holes, horizontal drain, vegetation cover, wire mesh, slope reprofiling, and retaining structure were proposed protection and stabilization measures for the slopes in the studied area.

  14. Organic geochemical characterization of potential hydrocarbon source rocks in the upper Benue Trough

    International Nuclear Information System (INIS)

    Obaje, N. G.; Pearson, M. J.; Suh, C. E.; Dada, S. S.

    1999-01-01

    The Upper Benue Trough of Nigeria is the northeastern most portion of the Benue rift structure that extends from the northern limit of the Niger Delta in the south to the southern limit of the Chad basin int he northeast. this portion of the trough is made up of two arms: the Gongola Arm and the Yola Arm. Stratigraphic sequence in the Gongola Arm comprises the continental Albian Bima Sandstone, the transitional Cenomanian Yolde Formation and the marine Turonian - Santonian Gongila, Pindiga, and Fika Formations. Overlying these are the continental Campane - Maastrichtian Gombe Sandstone and the Tertiary Kerri - Kerri Formation. In the Yola Arm, the Turonian - Santonian sequence is replaced by the equally marine Dukul, Jessu, Sekuliye Formations, Numanha Shale, and the Lamja Sandstone. Organic geochemical studies have been carried on outcrop sample form the Gongila, Pindiga, Dukul Formations, the Fika shale and the shaly units of the Gombe Sandstone, with the aim of assessing their source rock potential. Gas Chromatography (GC), Gas Chromatography - Mass Spectrometry (C - MS), and Rock Eval Pyrolysis were the major organic geochemical tools employed. Biomaker hydrocarbon signatures obtained from the GC - MS and the Rock Eval Pyrolysis results indicate that all he formations studied, except the Dukul formation, are immature and are all lean in organic matter

  15. Analysis of the potential impact of capillarity on long-term geochemical processes in sulphidic waste-rock dumps

    International Nuclear Information System (INIS)

    Pedretti, Daniele; Lassin, Arnault; Beckie, Roger D.

    2015-01-01

    Highlights: • Capillarity may affect geochemical reactions generating acid-rock drainage. • We studied its impact in a simplified, synthetic WRD. • Capillarity mainly affects the formation of secondary minerals. • It can strongly control long-term formation of gypsum and in turn sulfate release. • Capillarity can be also important for the analysis of calcite passivation. - Abstract: Assessing long-term production of acid rock drainage (ARD) from waste-rock dumps (WRDs) requires a careful analysis of the processes controlling acid-generating geochemical reactions under unsaturated conditions. In this work, we focus on the potential control of capillarity on these reactions, as previous studies showed that capillarity affects the activity of water and solutes in the unsaturated zone through the pore water pressure. We used capillarity-corrected thermodynamic databases and compared calculated speciation and solubility results with those from databases that do not account for capillarity. We developed a simple dynamic model with reduced geochemical components to analyze in detail the effect of capillarity. Results indicate that under low pH conditions simulations with capillarity-controlled reactions generate relatively larger dissolved sulfate concentrations from the WRDs over longer time scales, when compared against simulations without capillarity control. This occurs because capillarity strongly controls the formation of secondary sulfate-bearing minerals such as gypsum. When sufficient oxygen and carbon dioxide partial pressures are maintained within WRDs (such as in well-ventilated systems) and calcite content is insufficient to buffer acidity, the amount of secondary gypsum was calculated to be much larger in capillarity-corrected models. No appreciable effects of capillarity were observed under conditions where gypsum was not generated. Model results are also insensitive to temperature changes in typical climatic ranges. These results indicate some of

  16. Fine-grained sheet silicate rocks

    International Nuclear Information System (INIS)

    Weaver, C.E.

    1977-09-01

    Considerable interest has been shown in the possibility of using shales as repositories for radioactive waste and a variety of other waste products, and it appears that over the next few years much money and effort will be expended to investigate and test a wide variety of shales. If shales are to be studied in detail by a large number of investigators, it is important that all concerned have the same concept of what constitutes a shale. The term shale and other terms for fine-grained rocks have been used for many years and have been continually redefined. Most definitions predate the development of modern instrumentation and are based on field observations and intuition; however, the main problem is the diversity of definitions. An attempt is made here to develop a simple, rational classification of fine-grained sediments, and it is hoped that this classification will eliminate some of the present ambiguity. In order that the classification be pertinent, mineral composition and textural data were compiled and evaluated. The data on unconsolidated and consolidated sediments were contrasted and the effects of burial diagenesis assessed. It was found necessary to introduce a new term, physil, to describe all sheet silicate minerals. In contrast to the term clay mineral, the term physil has no size connotation. A simple classification is proposed that is based on the percentage of physils and grain size. In Part II the fine-grained physil rocks are classified on the basis of physil type, non-physil minerals, and texture. Formations are listed which have the mineral and textural characteristics of the most important rock types volumetrically. Selected rock types, and the formations in which they can be found, are recommended for laboratory study to determine their suitability for the storage of high-level radioactive waste

  17. Fifteen years of microbiological investigation in Opalinus Clay at the Mont Terri rock laboratory (Switzerland)

    Energy Technology Data Exchange (ETDEWEB)

    Leupin, O.X. [National Cooperative for the Disposal of Radioactive Waste (NAGRA), Wettingen (Switzerland); Bernier-Latmani, R.; Bagnoud, A. [Swiss Federal Office of Technology EPFL, Lausanne (Switzerland); Moors, H.; Leys, N.; Wouters, K. [Belgian Nuclear Research Centre SCK-CEN, Mol (Belgium); Stroes-Gascoyne, S. [University of Saskatchewan, Saskatoon (Canada)

    2017-04-15

    Microbiological studies related to the geological disposal of radioactive waste have been conducted at the Mont Terri rock laboratory in Opalinus Clay, a potential host rock for a deep geologic repository, since 2002. The metabolic potential of microorganisms and their response to excavation-induced effects have been investigated in undisturbed and disturbed claystone cores and in pore- (borehole) water. Results from nearly 15 years of research at the Mont Terri rock laboratory have shown that microorganisms can potentially affect the environment of a repository by influencing redox conditions, metal corrosion and gas production and consumption under favourable conditions. However, the activity of microorganisms in undisturbed Opalinus Clay is limited by the very low porosity, the low water activity, and the largely recalcitrant nature of organic matter in the claystone formation. The presence of microorganisms in numerous experiments at the Mont Terri rock laboratory has suggested that excavation activities and perturbation of the host rock combined with additional contamination during the installation of experiments in boreholes create favourable conditions for microbial activity by providing increased space, water and substrates. Thus effects resulting from microbial activity might be expected in the proximity of a geological repository i.e., in the excavation damaged zone, the engineered barriers, and first containments (the containers). (authors)

  18. Fifteen years of microbiological investigation in Opalinus Clay at the Mont Terri rock laboratory (Switzerland)

    International Nuclear Information System (INIS)

    Leupin, O.X.; Bernier-Latmani, R.; Bagnoud, A.; Moors, H.; Leys, N.; Wouters, K.; Stroes-Gascoyne, S.

    2017-01-01

    Microbiological studies related to the geological disposal of radioactive waste have been conducted at the Mont Terri rock laboratory in Opalinus Clay, a potential host rock for a deep geologic repository, since 2002. The metabolic potential of microorganisms and their response to excavation-induced effects have been investigated in undisturbed and disturbed claystone cores and in pore- (borehole) water. Results from nearly 15 years of research at the Mont Terri rock laboratory have shown that microorganisms can potentially affect the environment of a repository by influencing redox conditions, metal corrosion and gas production and consumption under favourable conditions. However, the activity of microorganisms in undisturbed Opalinus Clay is limited by the very low porosity, the low water activity, and the largely recalcitrant nature of organic matter in the claystone formation. The presence of microorganisms in numerous experiments at the Mont Terri rock laboratory has suggested that excavation activities and perturbation of the host rock combined with additional contamination during the installation of experiments in boreholes create favourable conditions for microbial activity by providing increased space, water and substrates. Thus effects resulting from microbial activity might be expected in the proximity of a geological repository i.e., in the excavation damaged zone, the engineered barriers, and first containments (the containers). (authors)

  19. Isolation and characterization of dissolved organic matter from the Callovo-Oxfordian formation

    International Nuclear Information System (INIS)

    Courdouan, Amandine; Christl, Iso; Meylan, Sebastien; Wersin, Paul; Kretzschmar, Ruben

    2007-01-01

    Characterizing dissolved organic matter (DOM) in the pore water of the Callovo-Oxfordian formation, a potential host rock for the disposal of radioactive waste, is important to estimate its potential influence on the mobility of radionuclides in the rock. To isolate DOM, crushed rock material was extracted under anoxic conditions with deionized water, 0.1 M NaOH and synthetic pore water (SPW, water containing all major ions at pore water concentrations but no organic matter), respectively. The effects of extraction parameters on the extracted DOM including the solid-to-liquid ratio, extraction time, exposure to O 2 and acid pretreatment of the rock material prior to the anoxic extraction were evaluated. In addition, DOM in one of the first pore water samples collected in the underground rock laboratory at Bure (France) was characterized for comparison. The size distribution and the low molecular weight organic acid contents of the extracts and pore water DOM were determined by liquid chromatography coupled with an organic C detector (LC-OCD) and by ion chromatography. The results revealed that only a fraction of less than 1.2% of the total organic C present in the rock was extractable. Maximum dissolved organic C (DOC) concentrations in the anoxic extracts ranged from 5.5 ± 0.3 mg/L for SPW extracts to 14.2 ± 1.1 mg/L for 0.1 M NaOH extracts. The major portion of the DOC in the anoxic extracts consisted of hydrophilic compounds (48-78%) having a molecular weight of less than 500 Da. Up to 21% of DOC in the anoxic extracts was identified as acetate, formate, lactate and malate. The short-term exposure of rock material to O 2 during rock crushing strongly increased DOC concentrations and led to a shift towards smaller molecular weight compounds and to a higher low molecular weight organic acid (LMWOA) content as compared to the strictly anoxic extraction. The pore water sampled from a packed-off borehole exhibited a higher DOC concentration (56.7 mg/L) than the

  20. Comparing crack damage evolution in rocks deformed under conventional and true triaxial loading

    Science.gov (United States)

    Browning, J.; Meredith, P. G.; Stuart, C.; Healy, D.; Harland, S. R.; Mitchell, T. M.

    2017-12-01

    The vast majority of experimental studies investigate damage evolution using conventional triaxial stress states (σ1 > σ2 = σ3, CTA), whereas in nature the stress state is generally truly triaxial (σ1 > σ2 > σ3, TTA). We present a comparative study of crack damage evolution during CTA vs. TTA stress conditions using results from measurements made on cubic samples of sandstone deformed in three orthogonal directions with independently controlled stress paths. We have measured, simultaneously with stress and strain, changes in wave velocities in the three principal directions, together with acoustic emission (AE) output. Changes in wave velocities are associated with both elastic closure and opening of pre-existing cracks, and the inelastic formation of new cracks. By contrast, AE is associated only with the inelastic growth of new crack damage. The onset of new damage is shown to be a function of differential stress regardless of the magnitude of mean stress. Hence, we show that damage can form due to a decrease in the minimum principal stress, which reduces mean stress but increases the differential stress. We find an approximately fivefold decrease in the number of AE events in the TTA case in comparison to the CTA case. In essence, we create two end-member crack distributions; one displaying cylindrical transverse isotropy and the other planar transverse isotropy. Taken together, the AE data, the velocities and the crack densities indicate that the intermediate principal stress plays a key role in suppressing the total amount of crack growth and concentrating it in planes sub-parallel to the minimum stress. However, the size of individual cracks remains constant. Hence, the differential stress at which rocks fail (i.e. strength) will be significantly higher under TTA stress (where σ2 > σ3) than under CTA stress (where σ2 = σ3). Cyclic loading tests show that while individual stress states are important, the stress path by which these stress states are

  1. [Secondary metabolites accumulating and geoherbs formation under enviromental stress].

    Science.gov (United States)

    Huang, Lu-Qi; Guo, Lan-Ping

    2007-02-01

    This paper analyzed how habitat affected the formation of geoherbs after summarizing the influences of environmental stress on plants growth, especially on theirs secondary metabolites accumulating, and introducing 4 kinds hypothesis about environmental stress affects plants. It was then pointed out that environmental stress may have advantage on the formation of geoherbs. The stress effect hypothesis on forming geoherbs was brought forward, and the ways and methods on study the geoherbs under environmental stress was discussed.

  2. Cracking and Failure in Rock Specimen Containing Combined Flaw and Hole under Uniaxial Compression

    Directory of Open Access Journals (Sweden)

    Xiang Fan

    2018-01-01

    Full Text Available Flaw is a key factor influencing failure behavior of a fractured specimen. In the present study, rectangular-flawed specimens were prepared using sandstone to investigate the effect of flaw on failure behavior of rock. Open flaw and cylindrical hole were simultaneously precut within rock specimens using high-pressure water jet cutting technology. Five series of specimens including intact, single-hole-alone, two-hole-alone, single-hole and two-flaw, and two-hole and single-flaw blocks were prepared. Uniaxial compressive tests using a rigid servo control instrument were carried out to investigate the fracture processes of these flawed specimens. It is observed that during loading, internal stress always intensively distributed at both sidewalls of open hole, especially at midpoint of sidewalls, so rock crumb flaking was firstly observed among all sandstone specimens containing single hole or two holes. Cracking around open hole is associated with the flaw inclination angle which was observed in Series III and V. Crack easily initiated at the tips of flaw with inclination angles of 0°, 30°, and 60° but hard for 90° in Series III and V. Rock burst was the major failure mode among most tested specimens, which generally induced new cracks and finally created crater shape. Additionally, due to extrusion between blocks, new shear or tensile cracks were generated and the rock specimen surface spalled. Eventually, four typical failure processes including rock crumb flaking, crack initiation and propagation, rock burst, and second rupture, were summarized.

  3. Heterogeneity of uranium host rocks in Zhiluo formation in Dongsheng area and its relation to uranium mineralization

    International Nuclear Information System (INIS)

    Yi Chao; Zheng Yunlong; Wang Mingtai

    2013-01-01

    Numbers of uranium deposits have be found in Dongsheng area. The major ore-bearing layer is the sub member of the lower member of the Zhiluo Formation, the heterogeneity of host rocks plays an important role during the process of uranium mineralization. This paper sorted and counted up the data of sand body and the impermeable bed in Dongsheng area to study the heterogeneity characteristic of host rock and its relationship to uranium mineralization in horizontal and vertical directions. The thickness of sand body in Dongsheng area decreases gradually from northwest to southeast. The uranium mineralization is mainly distributed in the place where the thickness of sand body changed from the thick to the thin. Statistics shows that the best uranium mineralization occurred in sand body thickness between 20 m to 40 m and the sand rate over 60% in the eastern part of Dongsheng area. And the best uranium mineralization in the western part occurred in area of sand body thickness between 60 m to 70 m and the sand rate over 70%. In vertical direction, the numbers and the thickness of the impermeable beds have negative relation to sand rate. Moreover, uranium deposits generally exist in the area of less number impermeable bed and small thickness. The uranium mineralization grade decreased with the increase of number and thickness of the impermeable beds. (authors)

  4. Planning of the in-situ creep test in sedimentary soft rocks under high temperature

    International Nuclear Information System (INIS)

    Takakura, Nozomu; Yoshikawa, Kazuo; Okada, Tetsuji; Sawada, Masataka; Tani, Kazuo; Takeda, Kayo

    2007-01-01

    Research has been conducted on underground facilities for energy storage and waste disposal in sedimentary soft rocks. One of the research topics is that the long-term mechanical behaviors of sedimentary soft rocks can be affected by various environmental factors such as temperatures or hydraulic conditions. Therefore, it is necessary to develop a method for evaluating the long-term stability of caverns in sedimentary soft rocks as influenced by changes in the external environment. This report presents the plan of field creep test for the purpose to establish the evaluation method of long-term stability of caverns in soft rocks. A series of field creep test is performed to study the influence of high temperature in an underground facility at a depth of 50 meters. (author)

  5. A study about the long-term stability of sedimentary rock

    International Nuclear Information System (INIS)

    Yoshino, Naoto; Miyanomae, Shun-ichi; Inoue, Hiroyuki; Nashimoto, Yutaka

    2005-02-01

    In this paper, following two issues were examined and estimated, (1) the influence of near field condition factor to the dynamical behavior of sedimentary soft rock, (2) the long term estimation of the dynamical behavior considering the condition of Horonobe area. As the study about the influence of near field condition factor to the dynamical behavior of sedimentary soft rock, the thermal factor was focused on and the laboratory tests using test pieces which were sampled in Horonobe area were carried out under the water temperature were 20 degrees and 80 degrees. As a result, the time dependence parameter in variable-compliance-type constitutive-equation could be obtained. And comparison between creep property under 20 degrees and 80 degrees was conducted. In addition, the general properties of sedimentary soft rock under several conditions were identified by the survey of the literature. And the way how to confirm the dynamical properties of sedimentary soft rock with in-situ test were presented. For the study on the short-term and long-term stability of rock surrounding buffer materials, numerical simulations were carried out assuming several conditions. The direction of disposal tunnels and the ratio of rock strength by initial stress were estimated to be the main factor affecting the short-term stability of rock. Time dependency of rock and the stiffness of buffer material were estimated to be the main factor affecting the long-term stability of rock. (author)

  6. Study on the Reinforcement Measures and Control Effect of the Surrounding Rock Stability Based on the Shield Tunneling Under Overpass Structure

    Directory of Open Access Journals (Sweden)

    Qian-cheng Fang

    2016-04-01

    Full Text Available To study the stability of surrounding rocks for shield tunneling under overpass structures and the safety of existing bridge structures, a practical example of the method was cited through a shield tunneling project under the overpass structure between K1+110 and K1+700 on Line 2 of Shenyang Subway, China. The sub-area reinforcement was proposed according to surrounding rock deformation characteristics during shield tunnel excavation. The bridge foundation (i.e., the clear spacing to the shield tunnel is less than 2 m was reinforced by steel support, the bridge foundation (the clear spacing is about 2~7m used “jet grouting pile” reinforcement, whereas the bridge foundation (the clear spacing is greater than 7 m did not adopt any reinforcement measures for the moment. For this study, the mean value and material heterogeneity models were established to evaluate the reinforcement effect from several aspects, such as surrounding rock deformation, plastic zone development, and safety factor. The simulation results were consistent with those of field monitoring. After reinforcement, the maximum deformation values of the surrounding rock were reduced by 4.9%, 12.2%, and 48.46%, and the maximum values of surface subsidence were decreased by 5.6%, 72.2%, and 88.64%. By contrast, the overall safety factor was increased by 4.1%, 55.46%, and 55.46%. This study posited that this reinforcement method can be adopted to solve tunnel construction problems in engineering-geological conditions effectively. References for evaluating similar projects are provided.

  7. Strength Assessment of Broken Rock Postgrouting Reinforcement Based on Initial Broken Rock Quality and Grouting Quality

    Directory of Open Access Journals (Sweden)

    Hongfa Xu

    2017-01-01

    Full Text Available To estimate postgrouting rock mass strength growth is important for engineering design. In this paper, using self-developed indoor pressure-grouting devices, 19 groups of test cubic blocks were made of the different water cement ratio grouting into the broken rock of three kinds of particle sizes. The shear strength parameters of each group under different conditions were tested. Then this paper presents a quantitative calculation method for predicting the strength growth of grouted broken rock. Relational equations were developed to investigate the relationship between the growth rates of uniaxial compressive strength (UCS, absolute value of uniaxial tensile strength (AUTS, internal friction angle, and cohesion for post- to pregrouting broken rock based on Mohr-Coulomb strength criterion. From previous test data, the empirical equation between the growth rate of UCS and the ratio of the initial rock mass UCS to the grout concretion UCS has been determined. The equations of the growth rates of the internal friction coefficient and UCS for grouting broken rock with rock mass rating (RMR and its increment have been established. The calculated results are consistent with the experimental results. These observations are important for engineered design of grouting reinforcement for broken rock mass.

  8. Water - rock interaction in different rock environments

    International Nuclear Information System (INIS)

    Lamminen, S.

    1995-01-01

    The study assesses the groundwater geochemistry and geological environment of 44 study sites for radioactive waste disposal. Initially, the study sites were divided by rock type into 5 groups: (1) acid - intermediate rocks, (2) mafic - ultramafic rocks, (3) gabbros, amphibolites and gneisses that contain calc-silicate (skarn) rocks, (4) carbonates and (5) sandstones. Separate assessments are made of acid - intermediate plutonic rocks and of a subgroup that comprises migmatites, granite and mica gneiss. These all belong to the group of acid - intermediate rocks. Within the mafic -ultramafic rock group, a subgroup that comprises mafic - ultramafic plutonic rocks, serpentinites, mafic - ultramafic volcanic rocks and volcanic - sedimentary schists is also evaluated separately. Bedrock groundwaters are classified by their concentration of total dissolved solids as fresh, brackish, saline, strongly saline and brine-class groundwaters. (75 refs., 24 figs., 3 tabs.)

  9. Competition on the rocks: community growth and tessellation.

    Directory of Open Access Journals (Sweden)

    Espen Jettestuen

    Full Text Available Crustose lichen communities on rocks exhibit fascinating spatial mosaics resembling political maps of nations or municipalities. Although the establishment and development of biological populations are important themes in ecology, our understanding of the formation of such patterns on the rocks is still in its infancy. Here, we present a novel model of the concurrent growth, establishment and interaction of lichens. We introduce an inverse technique based on Monte Carlo simulations to test our model on field samples of lichen communities. We derive an expression for the time needed for a community to cover a surface and predict the historical spatial dynamics of field samples. Lichens are frequently used for dating the time of exposure of rocks in glacial deposits, lake retreats or rock falls. We suggest our method as a way to improve the dating.

  10. Composition of the Rex Chert and associated rocks of the Permian Phosphoria Formation: Soda Springs area, SE Idaho

    Science.gov (United States)

    Hein, James R.; McIntyre, Brandie; Perkins, Robert B.; Piper, David Z.; Evans, James

    2002-01-01

    This study, one in a series, reports bulk chemical and mineralogical compositions, as well as petrographic and outcrop descriptions of rocks collected from three measured outcrop sections of the Rex Chert member of the Phosphoria Formation in SE Idaho. The three measured sections were chosen from ten outcrops of Rex Chert that were described in the field. The Rex Chert overlies the Meade Peak Phosphatic Shale Member of the Phosphoria Formation, the source of phosphate ore in the region. Rex Chert removed as overburden comprises part of the material disposed in waste-rock piles during phosphate mining. It has been proposed that the chert be used to cap and isolate waste piles, thereby inhibiting the leaching of potentially toxic elements into the environment. It is also used to surface roads in the mining district. The rock samples studied here constitute a set of individual chert beds that are representative of each stratigraphic section sampled. The informally named cherty shale member that overlies the Rex Chert in measured section 1 was also described and sampled. The upper Meade Peak and the transition zone to the Rex Chert were described and sampled in section 7. The cherts are predominantly spicularite composed of granular and mosaic quartz, and sponge spicules, with various but minor amounts of other fossils and detrital grains. The cherty shale member and transition rocks between the Meade Peak and Rex Chert are siliceous siltstones and argillaceous cherts with ghosts of sponge spicules and somewhat more detrital grains than the chert. The overwhelmingly dominant mineral is quartz, although carbonate beds are rare in each section and are composed predominantly of calcite and dolomite in addition to quartz. Feldspar, mica, clay minerals, calcite, dolomite, and carbonate fluorapatite are minor to trace minerals in the chert. The mean concentrations of oxides and elements in the Rex Chert and the cherty shale member are dominated by SiO2, which averages 94

  11. Stress Wave Propagation in Viscoelastic-Plastic Rock-Like Materials

    Directory of Open Access Journals (Sweden)

    Liu Lang

    2016-05-01

    Full Text Available Rock-like materials are composites that can be regarded as a mixture composed of elastic, plastic, and viscous components. They exhibit viscoelastic-plastic behavior under a high-strain-rate loading according to element model theory. This paper presents an analytical solution for stress wave propagation in viscoelastic-plastic rock-like materials under a high-strain-rate loading and verifies the solution through an experimental test. A constitutive equation of viscoelastic-plastic rock-like materials was first established, and then kinematic and kinetic equations were then solved to derive the analytic solution for stress wave propagation in viscoelastic-plastic rock-like materials. An experimental test using the SHPB (Split Hopkinson Pressure Bar for a concrete specimen was conducted to obtain a stress-strain curve under a high-strain-rate loading. Inverse analysis based on differential evolution was conducted to estimate undetermined variables for constitutive equations. Finally, the relationship between the attenuation factor and the strain rate in viscoelastic-plastic rock-like materials was investigated. According to the results, the frequency of the stress wave, viscosity coefficient, modulus of elasticity, and density play dominant roles in the attenuation of the stress wave. The attenuation decreases with increasing strain rate, demonstrating strongly strain-dependent attenuation in viscoelastic-plastic rock-like materials.

  12. Bibliography for acid-rock drainage and selected acid-mine drainage issues related to acid-rock drainage from transportation activities

    Science.gov (United States)

    Bradley, Michael W.; Worland, Scott C.

    2015-01-01

    Acid-rock drainage occurs through the interaction of rainfall on pyrite-bearing formations. When pyrite (FeS2) is exposed to oxygen and water in mine workings or roadcuts, the mineral decomposes and sulfur may react to form sulfuric acid, which often results in environmental problems and potential damage to the transportation infrastructure. The accelerated oxidation of pyrite and other sulfidic minerals generates low pH water with potentially high concentrations of trace metals. Much attention has been given to contamination arising from acid mine drainage, but studies related to acid-rock drainage from road construction are relatively limited. The U.S. Geological Survey, in cooperation with the Tennessee Department of Transportation, is conducting an investigation to evaluate the occurrence and processes controlling acid-rock drainage and contaminant transport from roadcuts in Tennessee. The basic components of acid-rock drainage resulting from transportation activities are described and a bibliography, organized by relevant categories (remediation, geochemical, microbial, biological impact, and secondary mineralization) is presented.

  13. Porosity, permeability and 3D fracture network characterisation of dolomite reservoir rock samples.

    Science.gov (United States)

    Voorn, Maarten; Exner, Ulrike; Barnhoorn, Auke; Baud, Patrick; Reuschlé, Thierry

    2015-03-01

    With fractured rocks making up an important part of hydrocarbon reservoirs worldwide, detailed analysis of fractures and fracture networks is essential. However, common analyses on drill core and plug samples taken from such reservoirs (including hand specimen analysis, thin section analysis and laboratory porosity and permeability determination) however suffer from various problems, such as having a limited resolution, providing only 2D and no internal structure information, being destructive on the samples and/or not being representative for full fracture networks. In this paper, we therefore explore the use of an additional method - non-destructive 3D X-ray micro-Computed Tomography (μCT) - to obtain more information on such fractured samples. Seven plug-sized samples were selected from narrowly fractured rocks of the Hauptdolomit formation, taken from wellbores in the Vienna basin, Austria. These samples span a range of different fault rocks in a fault zone interpretation, from damage zone to fault core. We process the 3D μCT data in this study by a Hessian-based fracture filtering routine and can successfully extract porosity, fracture aperture, fracture density and fracture orientations - in bulk as well as locally. Additionally, thin sections made from selected plug samples provide 2D information with a much higher detail than the μCT data. Finally, gas- and water permeability measurements under confining pressure provide an important link (at least in order of magnitude) towards more realistic reservoir conditions. This study shows that 3D μCT can be applied efficiently on plug-sized samples of naturally fractured rocks, and that although there are limitations, several important parameters can be extracted. μCT can therefore be a useful addition to studies on such reservoir rocks, and provide valuable input for modelling and simulations. Also permeability experiments under confining pressure provide important additional insights. Combining these and

  14. Radiation effects in rock salt. A status report

    International Nuclear Information System (INIS)

    Gies, H.; Hild, W.; Kuehle, T.; Moenig, J.

    1994-01-01

    Knowledge of the irradiation defects and the accompanying energy storage in rock salt resulting from the absorption of ionizing radiation emitted by vitrified high level radioactive waste (HLW) disposed off in geological rock salt formations in an important prerequisite for a realistic assessment of possible consequences. Based on a critical review of the scientific status this report attempts to evaluate whether the available database is satisfactory and sufficiently reliable for the performance of such an assessment. Apart from a brief description of the radiation-and temperature-conditions prevailing in a HLW-repository, a detailed presentation is given of both the interaction of radiation with rock salt and the theories and models developed for their quantification

  15. Heterogeneous Rock Simulation Using DIP-Micromechanics-Statistical Methods

    Directory of Open Access Journals (Sweden)

    H. Molladavoodi

    2018-01-01

    Full Text Available Rock as a natural material is heterogeneous. Rock material consists of minerals, crystals, cement, grains, and microcracks. Each component of rock has a different mechanical behavior under applied loading condition. Therefore, rock component distribution has an important effect on rock mechanical behavior, especially in the postpeak region. In this paper, the rock sample was studied by digital image processing (DIP, micromechanics, and statistical methods. Using image processing, volume fractions of the rock minerals composing the rock sample were evaluated precisely. The mechanical properties of the rock matrix were determined based on upscaling micromechanics. In order to consider the rock heterogeneities effect on mechanical behavior, the heterogeneity index was calculated in a framework of statistical method. A Weibull distribution function was fitted to the Young modulus distribution of minerals. Finally, statistical and Mohr–Coulomb strain-softening models were used simultaneously as a constitutive model in DEM code. The acoustic emission, strain energy release, and the effect of rock heterogeneities on the postpeak behavior process were investigated. The numerical results are in good agreement with experimental data.

  16. Methods for the risk assessment of rock bursts under the condition of the Upper Silesian coal basin; Methoden zur Bewertung des Risikos von Gebirgsschlaegen unter Bedingungen des oberschlesischen Kohlebeckens

    Energy Technology Data Exchange (ETDEWEB)

    Myszkowski, Jacek [Forschungsanstalt fuer Gebirgsschlaege und Gebirgsmechanik BT, Katowice (Poland). Hauptinst. fuer Bergbau

    2013-06-15

    The assessment of the risk of rock burst in underground coal mines is associated with the forecasting, assessment and management of risks. The contribution under consideration presents methods for the risk assessment and prevention of rock bursts.

  17. Shale characterization in mass transport complex as a potential source rock: An example from onshore West Java Basin, Indonesia

    Science.gov (United States)

    Nugraha, A. M. S.; Widiarti, R.; Kusumah, E. P.

    2017-12-01

    This study describes a deep-water slump facies shale of the Early Miocene Jatiluhur/Cibulakan Formation to understand its potential as a source rock in an active tectonic region, the onshore West Java. The formation is equivalent with the Gumai Formation, which has been well-known as another prolific source rock besides the Oligocene Talang Akar Formation in North West Java Basin, Indonesia. The equivalent shale formation is expected to have same potential source rock towards the onshore of Central Java. The shale samples were taken onshore, 150 km away from the basin. The shale must be rich of organic matter, have good quality of kerogen, and thermally matured to be categorized as a potential source rock. Investigations from petrography, X-Ray diffractions (XRD), and backscattered electron show heterogeneous mineralogy in the shales. The mineralogy consists of clay minerals, minor quartz, muscovite, calcite, chlorite, clinopyroxene, and other weathered minerals. This composition makes the shale more brittle. Scanning Electron Microscope (SEM) analysis indicate secondary porosities and microstructures. Total Organic Carbon (TOC) shows 0.8-1.1 wt%, compared to the basinal shale 1.5-8 wt%. The shale properties from this outcropped formation indicate a good potential source rock that can be found in the subsurface area with better quality and maturity.

  18. The global rock art database: developing a rock art reference model for the RADB system using the CIDOC CRM and Australian heritage examples

    Science.gov (United States)

    Haubt, R. A.

    2015-08-01

    The Rock Art Database (RADB) is a virtual organisation that aims to build a global rock art community. It brings together rock art enthusiasts and professionals from around the world in one centralized location through the deployed publicly available RADB Management System. This online platform allows users to share, manage and discuss rock art information and offers a new look at rock art data through the use of new technologies in rich media formats. Full access to the growing platform is currently only available for a selected group of users but it already links over 200 rock art projects around the globe. This paper forms a part of the larger Rock Art Database (RADB) project. It discusses the design stage of the RADB System and the development of a conceptual RADB Reference Model (RARM) that is used to inform the design of the Rock Art Database Management System. It examines the success and failure of international and national systems and uses the Australian heritage sector and Australian rock art as a test model to develop a method for the RADB System design. The system aims to help improve rock art management by introducing the CIDOC CRM in conjunction with a rock art specific domain model. It seeks to improve data compatibility and data sharing to help with the integration of a variety of resources to create the global Rock Art Database Management System.

  19. On the CO2 Wettability of Reservoir Rocks: Addressing Conflicting Information

    Science.gov (United States)

    Garing, C.; Wang, S.; Tokunaga, T. K.; Wan, J.; Benson, S. M.

    2017-12-01

    Conventional wisdom is that siliclastic rocks are strongly water wet for the CO2-brine system, leading to high irreducible water saturation, moderate residual gas trapping and implying that tight rocks provide efficient seals for buoyant CO2. If the wetting properties become intermediate or CO2 wet, the conclusions regarding CO2 flow and trapping could be very different. Addressing the CO2 wettability of seal and reservoir rocks is therefore essential to predict CO2 storage in geologic formation. Although a substantial amount of work has been dedicated to the topic, contact angle data show a large variability and experiments on plates, micromodels and cores report conflicting results regarding the influence of supercritical CO2 (scCO2) exposure on wetting properties: whereas some experimental studies suggest dewetting upon reaction with scCO2, some others observe no wettability alteration under reservoir scCO2 conditions. After reviewing evidences for and against wettability changes associated with scCO2, we discuss potential causes for differences in experimental results. They include the presence of organic matter and impact of sample treatment, the type of media (non consolidated versus real rock), experimental time and exposure to scCO2, and difference in measurement system (porous plate versus stationary fluid method). In order to address these points, new scCO2/brine drainage-imbibition experiments were conducted on a same Berea sandstone rock core, first untreated, then fired and finally exposed to scCO2 for three weeks, using the stationary fluid method. The results are compared to similar experiments performed on quartz sands, untreated and then baked, using the porous plate method. In addition, a comparative experiment using the same Idaho gray sandstone rock core was performed with both the porous plate and the stationary fluid methods to investigate possible method-dependent results.

  20. Petrology, Magnetic susceptibility, Tectonic setting and mineralization associated with Plutonic and Volcanic Rocks, Eastern Bajestan and Taherabad, Iran

    Directory of Open Access Journals (Sweden)

    Malihe Ghoorchi

    2009-09-01

    Full Text Available Study area is located in district of Bajestan and Ferdows cities, NE of Iran. Structurally, this area is part of Lut block. The oldest exposed rocks, to the north of intrusive rocks and in Eastern Bajestan, are meta-chert, slate, quartzite, thin-bedded crystalline limestone and meta-argillite. The sedimentary units are: Sardar Formation (Carboniferous, Jamal Formation (Permian, Sorkh Shale and Shotori Formations (Triassic, carbonateous rocks (Cretaceous and lithostratigraphically equivalent to Kerman conglomerate (Cretaceous-Paleocene are exposed in this area. Based on relative age, magmatism in eastern Bajestan and Taherabad started after Late Cretaceous and it has been active and repeated during Tertiary time. At least, three episodes of volcanic activities are recognized in this area. The first stage was mainly volcanic flow with mafic composition and minor intermediate. The second episode was mainly intermediate in composition. The third stage was changed to acid-intermediate in composition. Since the plutonic rocks intruded the volcanic rocks, therefore they may be Oligo-Miocene age. Bajestan intrusive rocks are granite-granodiorite-quartz monzonite. Taherabad intrusive rocks are diorite-quartz diorite- monzonite-latite. Bajestan intrusive rocks are reduced type (ilmenite series and Taherabad intrusive rocks are oxidized type (magnetite series.Based on geochemical analysis including trace elements, REE and isotopic data, Bajestan intrusive rocks formed in continental collision zone and the magma has crustal origin. Taherabad intrusive rocks were formed in subduction zone and magma originated from oceanic crust. Taherabad intrusive rock has exploration potential for Cu-Au and pb.

  1. The potential for methane hydrate formation in deep repositories of spent nuclear fuel in granitic rocks

    International Nuclear Information System (INIS)

    Tohidi, Bahman; Chapoy, Antonin; Smellie, John; Puigdomenech, Ignasi

    2010-12-01

    The main aim of this work was to establish whether the pertaining pressure and temperature conditions and dissolved gas concentration in groundwater is conducive to gas hydrate formation using a modelling approach. The hydrate stability pressure-temperature zone of dissolved methane in the presence of salt has been obtained through calculations which show that a decrease in the system pressure and/or an increase in salt concentration favours hydrate formation, as both factors reduce equilibrium gas solubility in the aqueous phase. This behaviour is unlike that of the system including a gas phase, where the water phase is always saturated with methane, and hence the methane solubility in water is not a limiting factor. The main conclusion is that hydrate formation is not possible at the reported methane concentrations and water salinities for the Forsmark and Laxemar sites in Sweden and Olkiluoto in Finland. At the highest salinities and methane concentrations encountered, namely ∼0.00073 mole fraction methane and ∼10 mass % NaCl at a depth of 1,000 m in Olkiluoto, Finland, hydrates could form if the system temperatures and pressures are below 2.5 deg C and 60 bar, respectively, i.e. values that are much lower than those prevailing at that depth (∼20 deg C and ∼100 bar, respectively). Furthermore, the calculated results provide the necessary data to estimate the effect of increase in dissolved methane concentration on potential hydrate formation, as well as two phase flow. The available depth dependency of methane concentration at the sites studied in Sweden and Finland was used in another study to estimate the diffusive flow of methane in the rock volumes. These diffusion rates, which are highest at Olkiluoto, indicate that even if the conditions were to become favourable to methane hydrate formation, then it would take several millions of years before a thin layer of hydrates could be formed, a condition which is outside the required period of satisfactory

  2. The potential for methane hydrate formation in deep repositories of spent nuclear fuel in granitic rocks

    Energy Technology Data Exchange (ETDEWEB)

    Tohidi, Bahman; Chapoy, Antonin (Hydrafact Ltd, Inst. of Petroleum Engineering, Heriot-Watt Univ., Edinburgh (United Kingdom)); Smellie, John (Conterra AB, Uppsala (Sweden)); Puigdomenech, Ignasi (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden))

    2010-12-15

    The main aim of this work was to establish whether the pertaining pressure and temperature conditions and dissolved gas concentration in groundwater is conducive to gas hydrate formation using a modelling approach. The hydrate stability pressure-temperature zone of dissolved methane in the presence of salt has been obtained through calculations which show that a decrease in the system pressure and/or an increase in salt concentration favours hydrate formation, as both factors reduce equilibrium gas solubility in the aqueous phase. This behaviour is unlike that of the system including a gas phase, where the water phase is always saturated with methane, and hence the methane solubility in water is not a limiting factor. The main conclusion is that hydrate formation is not possible at the reported methane concentrations and water salinities for the Forsmark and Laxemar sites in Sweden and Olkiluoto in Finland. At the highest salinities and methane concentrations encountered, namely approx0.00073 mole fraction methane and approx10 mass % NaCl at a depth of 1,000 m in Olkiluoto, Finland, hydrates could form if the system temperatures and pressures are below 2.5 deg C and 60 bar, respectively, i.e. values that are much lower than those prevailing at that depth (approx20 deg C and approx100 bar, respectively). Furthermore, the calculated results provide the necessary data to estimate the effect of increase in dissolved methane concentration on potential hydrate formation, as well as two phase flow. The available depth dependency of methane concentration at the sites studied in Sweden and Finland was used in another study to estimate the diffusive flow of methane in the rock volumes. These diffusion rates, which are highest at Olkiluoto, indicate that even if the conditions were to become favourable to methane hydrate formation, then it would take several millions of years before a thin layer of hydrates could be formed, a condition which is outside the required period of

  3. Summary of United States Geological Survey investigations of fluid-rock-waste reactions in evaporite environments under repository conditions

    International Nuclear Information System (INIS)

    Stewart, D.B.; Jones, B.F.; Roedder, E.; Potter, R.W. II

    1980-01-01

    The interstitial and inclusion fluids contained in rock salt and anhydrite, though present in amounts less than 1 weight per cent, are chemically aggressive and may react with canisters or wastes. The three basic types of fluids are: (1) bitterns residual from saline mineral precipitation including later recrystallization reactions; (2) brines containing residual solutes from the formation of evaporite that have been extensively modified by reactions with contiguous carbonate of clastic rocks; and (3) re-solution brines resulting from secondary dehydration of evaporite minerals or solution of saline minerals by undersaturated infiltrating waters. Fluid composition can indicate that meteoric flow systems have contacted evaporites or that fluids from evaporites have migrated into other formations. The movement of fluids trapped in fluid inclusions in salt from southeast New Mexico is most sensitive to ambient temperature and to inclusion size, although several other factors such as thermal gradient and vapour/liquid ratio are also important. There is no evidence of a threshold temperature for movement of inclusions. Empirical data are given for determining the amount of brine reaching the heat source if the temperature, approximate amount of total dissolved solids, and Ca:Mg ratio in the brine are known. SrCl 2 and CsCl can reach high concentrations in saturated NaCl solutions and greatly depress the liquidus. The possibility that such fluids, if generated, could migrate from a high-level waste repository must be minimized because the fluid would contain its own radiogenic energy source in the first decades after repository closure, thus changing the thermal evolution of the repository from designed values. (author)

  4. Studying physical properties of deformed intact and fractured rocks by micro-scale hydro-mechanical-seismicity model

    Science.gov (United States)

    Raziperchikolaee, Samin

    The pore pressure variation in an underground formation during hydraulic stimulation of low permeability formations or CO2 sequestration into saline aquifers can induce microseismicity due to fracture generation or pre-existing fracture activation. While the analysis of microseismic data mainly focuses on mapping the location of fractures, the seismic waves generated by the microseismic events also contain information for understanding of fracture mechanisms based on microseismic source analysis. We developed a micro-scale geomechanics, fluid-flow and seismic model that can predict transport and seismic source behavior during rock failure. This model features the incorporation of microseismic source analysis in fractured and intact rock transport properties during possible rock damage and failure. The modeling method considers comprehensive grains and cements interaction through a bonded-particle-model. As a result of grain deformation and microcrack development in the rock sample, forces and displacements in the grains involved in the bond breakage are measured to determine seismic moment tensor. In addition, geometric description of the complex pore structure is regenerated to predict fluid flow behavior of fractured samples. Numerical experiments are conducted for different intact and fractured digital rock samples, representing various mechanical behaviors of rocks and fracture surface properties, to consider their roles on seismic and transport properties of rocks during deformation. Studying rock deformation in detail provides an opportunity to understand the relationship between source mechanism of microseismic events and transport properties of damaged rocks to have a better characterizing of fluid flow behavior in subsurface formations.

  5. Development of micro-scale joints in volcanic rocks under thermal ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging Solutions)

    Petrographic studies of samples of the Rajmahal basalt reveal a variety of microscopic joints ... To study the micro-scale joints in rock systems, ..... fiber-like crystal habit of the material chosen for ... stress, Y is the numerical modification factor to.

  6. Pore water colloid properties in argillaceous sedimentary rocks.

    Science.gov (United States)

    Degueldre, Claude; Cloet, Veerle

    2016-11-01

    The focus of this work is to evaluate the colloid nature, concentration and size distribution in the pore water of Opalinus Clay and other sedimentary host rocks identified for a potential radioactive waste repository in Switzerland. Because colloids could not be measured in representative undisturbed porewater of these host rocks, predictive modelling based on data from field and laboratory studies is applied. This approach allowed estimating the nature, concentration and size distributions of the colloids in the pore water of these host rocks. As a result of field campaigns, groundwater colloid concentrations are investigated on the basis of their size distribution quantified experimentally using single particle counting techniques. The colloid properties are estimated considering data gained from analogue hydrogeochemical systems ranging from mylonite features in crystalline fissures to sedimentary formations. The colloid concentrations were analysed as a function of the alkaline and alkaline earth element concentrations. Laboratory batch results on clay colloid generation from compacted pellets in quasi-stagnant water are also reported. Experiments with colloids in batch containers indicate that the size distribution of a colloidal suspension evolves toward a common particle size distribution independently of initial conditions. The final suspension size distribution was found to be a function of the attachment factor of the colloids. Finally, calculations were performed using a novel colloid distribution model based on colloid generation, aggregation and sedimentation rates to predict under in-situ conditions what makes colloid concentrations and size distributions batch- or fracture-size dependent. The data presented so far are compared with the field and laboratory data. The colloid occurrence, stability and mobility have been evaluated for the water of the considered potential host rocks. In the pore water of the considered sedimentary host rocks, the clay

  7. Formation process of Malaysian modern architecture under influence of nationalism

    OpenAIRE

    宇高, 雄志; 山崎, 大智

    2001-01-01

    This paper examines the Formation Process of Malaysian Modern Architecture under Influence of Nationalism,through the process of independence of Malaysia. The national style as "Malaysian national architecture" which hasengaged on background of political environment under the post colonial situation. Malaysian urban design is alsodetermined under the balance of both of ethnic culture and the national culture. In Malaysia, they decided to choosethe Malay ethnic culture as the national culture....

  8. Organic tissues, graphite, and hydrocarbons in host rocks of the Rum Jungle Uranium Field, northern Australia

    Science.gov (United States)

    Foster, C.B.; Robbins, E.I.; Bone, Y.

    1990-01-01

    The Rum Jungle Uranium field consists of at least six early Proterozoic deposits that have been mined either for uranium and/or the associated base and precious metals. Organic matter in the host rocks of the Whites Formation and Coomalie Dolomite is now predominantly graphite, consistent with the metamorphic history of these rocks. For nine samples, the mean total organic carbon content is high (3.9 wt%) and ranged from 0.33 to 10.44 wt%. Palynological extracts from the host rocks include black, filamentous, stellate (Eoastrion-like), and spherical morphotypes, which are typical of early Proterozoic microbiota. The colour, abundance, and shapes of these morphotypes reflect the thermal history, organic richness, and probable lacustrine biofacies of the host rocks. Routine analysis of rock thin sections and of palynological residues shows that mineral grains in some of the host rocks are coated with graphitized organic matter. The grain coating is presumed to result from ultimate thermal degradation of a petroleum phase that existed prior to metamorphism. Hydrocarbons are, however, still present in fluid inclusions within carbonates of the Coomalie Dolomite and lower Whites Formation. The fluid inclusions fluoresce dull orange in blue-light excitation and their hydrocarbon content is confirmed by gas chromatography of whole-rock extracts. Preliminary analysis of the oil suggests that it is migrated, and because it has escaped graphitization through metamorphism it is probably not of early Proterozoic age. The presence of live oil is consistent with fluid inclusion data that suggest subsequent, low-temperature brine migration through the rocks. The present observations support earlier suggestions that organic matter in the host formations trapped uranium to form protore. Subsequent fluid migrations probably brought additional uranium and other metals to these formations, and the organic matter provided a reducing environment for entrapment. ?? 1990.

  9. Respirable dust measured downwind during rock dust application.

    Science.gov (United States)

    Harris, M L; Organiscak, J; Klima, S; Perera, I E

    2017-05-01

    The Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health (NIOSH) conducted underground evaluations in an attempt to quantify respirable rock dust generation when using untreated rock dust and rock dust treated with an anticaking additive. Using personal dust monitors, these evaluations measured respirable rock dust levels arising from a flinger-type application of rock dust on rib and roof surfaces. Rock dust with a majority of the respirable component removed was also applied in NIOSH's Bruceton Experimental Mine using a bantam duster. The respirable dust measurements obtained downwind from both of these tests are presented and discussed. This testing did not measure miners' exposure to respirable coal mine dust under acceptable mining practices, but indicates the need for effective continuous administrative controls to be exercised when rock dusting to minimize the measured amount of rock dust in the sampling device.

  10. Pore water colloid properties in argillaceous sedimentary rocks

    Energy Technology Data Exchange (ETDEWEB)

    Degueldre, Claude, E-mail: c.degueldre@lancaster.ac.uk [Engineering Department, University of Lancaster, LA1 4YW Lancaster (United Kingdom); ChiAM & Institute of Environment, University of Geneva, 1211 Genève 4, Swizerland (Switzerland); Earlier, NES, Paul Scherrer Institute, 5232 Villigen (Switzerland); Cloet, Veerle [NAGRA, Hardstrasse 73, 5430 Wettingen (Switzerland)

    2016-11-01

    The focus of this work is to evaluate the colloid nature, concentration and size distribution in the pore water of Opalinus Clay and other sedimentary host rocks identified for a potential radioactive waste repository in Switzerland. Because colloids could not be measured in representative undisturbed porewater of these host rocks, predictive modelling based on data from field and laboratory studies is applied. This approach allowed estimating the nature, concentration and size distributions of the colloids in the pore water of these host rocks. As a result of field campaigns, groundwater colloid concentrations are investigated on the basis of their size distribution quantified experimentally using single particle counting techniques. The colloid properties are estimated considering data gained from analogue hydrogeochemical systems ranging from mylonite features in crystalline fissures to sedimentary formations. The colloid concentrations were analysed as a function of the alkaline and alkaline earth element concentrations. Laboratory batch results on clay colloid generation from compacted pellets in quasi-stagnant water are also reported. Experiments with colloids in batch containers indicate that the size distribution of a colloidal suspension evolves toward a common particle size distribution independently of initial conditions. The final suspension size distribution was found to be a function of the attachment factor of the colloids. Finally, calculations were performed using a novel colloid distribution model based on colloid generation, aggregation and sedimentation rates to predict under in-situ conditions what makes colloid concentrations and size distributions batch- or fracture-size dependent. The data presented so far are compared with the field and laboratory data. The colloid occurrence, stability and mobility have been evaluated for the water of the considered potential host rocks. In the pore water of the considered sedimentary host rocks, the clay

  11. Hydrological and thermal issues concerning a nuclear waste repository in fractured rocks

    International Nuclear Information System (INIS)

    Wang, J.S.Y.

    1991-12-01

    The characterization of the ambient conditions of a potential site and the assessment of the perturbations induced by a nuclear waste repository require hydrological and thermal investigations of the geological formations at different spatial and temporal scales. For high-level wastes, the near-field impacts depend on the heat power of waste packages and the far-field long-term perturbations depend on the cumulative heat released by the emplaced wastes. Surface interim storage of wastes for several decades could lower the near-field impacts but would have relatively small long-term effects if spent fuels were the waste forms for the repository. One major uncertainty in the assessment of repository impacts is from the variation of hydrological properties in heterogeneous media, including the effects of fractures as high-permeability flow paths for containment migration. Under stress, a natural fracture cannot be represented by the parallel plate model. The rock surface roughness, the contact area, and the saturation state in the rock matrix could significantly change the fracture flow. In recent years, the concern of fast flow through fractures in saturated media has extended to the unsaturated zones. The interactions at different scales between fractures and matrix, between fractured matrix unites and porous units, and between formations and faults are discussed

  12. Phosphatic Permian rocks of the Adobe Range, Nevada, and their environment of deposition

    Science.gov (United States)

    Ketner, Keith Brindley

    1979-01-01

    Permian sedimentary rocks in the Adobe range, northern Nevada, are phosphatic, and although the particles of phosphate are relatively more disseminated, they closely resemble the rocks of the Phosphoria Formation. In the northern Adobe Range, where the entire Permian sequence is approximately correlative with the Phosphoria Formation, it is 200 m thick and averages 1.7 percent P2O5 . In the southern Adobe Range, the Permian sequence is more than 1,700 m thick, and the upper half which is roughly correlative with the Phosphoria Formation averages more than 2 percent P2O5. Some thin beds in rocks of Permian age contain more than 20 percent P2O5. Phosphatic rocks of the Adobe Range were deposited in shallow water among islands in the western part of the epicontinental Phosphoria sea. The continental margin and the open ocean lay far to the west. At the same time, the Phosphoria Formation was being deposited in the eastern and central parts of the Phosphoria sea. Theories based on the work of Kasakov done in 1937 relating phosphate deposition directly to sites of upwelling oceanic waters are questioned. Nondeposition of diluent materials such as detritus and carbonate is probably of more importance in producing phosphate in economic concentrations than is geographic position with respect to upwelling waters.

  13. Comparative sound velocity measurements between porous rock and fully-dense material under crustal condition: The cases of Darley Dale sandstone and copper block

    Science.gov (United States)

    Kung, J.; Chien, Y. V.; Wu, W.; Dong, J.; Chang, Y.; Tsai, C.; Yang, M.; Wang, K.

    2012-12-01

    Previous studies showed that the voids and their geometry in the sedimentary rocks have great influence on the compressibility of rock, which reflects on its elastic velocities. Some models were developed to discuss the relations among velocity, porosity and void geometry. Therefore, the information of porosity, and void geometry and its distribution in rock is essential for understanding how the elastic properties of porous rocks affected by their poregeometry. In this study, we revisited a well-studied porous rock, Darley Dale sandstone, which has been studied by different groups with different purposes. Most of them are the deformation experiments. Different from previous studies, we measured the sound velocity of Darley dale sandstone under hydrostatic conditions. Also, we employed different techniques to investigate the pore geometry and porosity of Darley Dale sandstone to gain the insight of velocity changing behavior under the crustal conditions. Here, we measured a fully-dense copper block for a comparison. We performed X-ray CT scanning (XCT) to image the pore space of sandstone to construct the 3-D image of pore geometry, distribution and the pore size. The CT image data are allowed us to estimate the porosity of sandstone, too. One the other hand, the porosity of sample was measured using imbibitions method at ambient conditions and helium porosimeter at high pressure (up to 150 MPa). A set of specimens were cored from Darley Dale sandstone block. P and S wave velocities of specimens were measured at ambient conditions. We also performed high pressure velocity measurements on a selected rock specimen and a copper block up to 150 MPa under dry condition. Porosity of a set of rock specimens measured by imbibitions method was spanned from 6% to 15%, largely distributed within a range of 8%-11%. Compared the porosity obtained from three different techniques, imbibitions method, helium porosimeter and XCT, values from those measurements are in good agreement

  14. ENSI - Evaluation of NAGRA’s planned investigation of Brown Dogger host rock - Expert report

    International Nuclear Information System (INIS)

    Bitterli-Dreher, P; Burkhalter, R.

    2011-06-01

    This report published by the Swiss National Safety Inspectorate ENSI discusses the reports published on the Brown Dogger host rock formations and the investigations planned as part of Phase 2 of the planning process for deep repositories for low and medium-active nuclear wastes. After a review of the tasks to be carried out, two expert reports are introduced. In the first report, Dr. Peter Bitterli-Dreher looks at the geological situation in central Europe and rock conditions in northern Switzerland. The situation in the Dogger formations with their calcium carbonate and clay-like components in various locations in northern Switzerland are discussed, including water flow in the rocks. The second report from Dr. Reto Burkhalter also discusses the Brown Dogger formations and comments on the investigations proposed by NAGRA in detail. Work yet to be planned is looked at

  15. Organic richness and organic matter quality studies of source rocks ...

    African Journals Online (AJOL)

    The hydrocarbon potential of the Upper Cretaceous units (Maastrichtian Mamu Formation) exposed at Imiegba and environs of the Benin Flank, Western Anambra Basin was assessed by Total Organic Carbon (TOC) and Rock-Eval Pyrolysis Analyses. The investigated sections of the Mamu Formation consist of dark grey to ...

  16. Favorability for uranium in tertiary sedimentary rocks, southwestern Montana

    International Nuclear Information System (INIS)

    Wopat, M.A.; Curry, W.E.; Robins, J.W.; Marjaniemi, D.K.

    1977-10-01

    Tertiary sedimentary rocks in the basins of southwestern Montana were studied to determine their favorability for potential uranium resources. Uranium in the Tertiary sedimentary rocks was probably derived from the Boulder batholith and from silicic volcanic material. The batholith contains numerous uranium occurrences and is the most favorable plutonic source for uranium in the study area. Subjective favorability categories of good, moderate, and poor, based on the number and type of favorable criteria present, were used to classify the rock sequences studied. Rocks judged to have good favorability for uranium deposits are (1) Eocene and Oligocene strata and undifferentiated Tertiary rocks in the western Three Forks basin and (2) Oligocene rocks in the Helena basin. Rocks having moderate favorability consist of (1) Eocene and Oligocene strata in the Jefferson River, Beaverhead River, and lower Ruby River basins, (2) Oligocene rocks in the Townsend and Clarkston basins, (3) Miocene and Pliocene rocks in the Upper Ruby River basin, and (4) all Tertiary sedimentary formations in the eastern Three Forks basin, and in the Grasshopper Creek, Horse Prairie, Medicine Lodge Creek, Big Sheep Creek, Deer Lodge, Big Hole River, and Bull Creek basins. The following have poor favorability: (1) the Beaverhead Conglomerate in the Red Rock and Centennial basins, (2) Eocene and Oligocene rocks in the Upper Ruby River basin, (3) Miocene and Pliocene rocks in the Townsend, Clarkston, Smith River, and Divide Creek basins, (4) Miocene through Pleistocene rocks in the Jefferson River, Beaverhead River, and Lower Ruby River basins, and (5) all Tertiary sedimentary rocks in the Boulder River, Sage Creek, Muddy Creek, Madison River, Flint Creek, Gold Creek, and Bitterroot basins

  17. Uranium favorability of tertiary sedimentary rocks of the Pend Oreille River valley, Washington

    International Nuclear Information System (INIS)

    Marjaniemi, D.K.; Robins, J.W.

    1975-08-01

    Tertiary sedimentary rocks in the Pend Oreille River valley were investigated in a regional study to determine the favorability for potential uranium resources of northeastern Washington. This project involved measurement and sampling of surface sections, collection of samples from isolated outcrops, chemical and mineralogical analyses of samples, and examination of available water well logs. The Box Canyon Dam area north of Ione is judged to have very high favorability. Thick-bedded conglomerates interbedded with sandstones and silty sandstones compose the Tiger Formation in this area, and high radioactivity levels are found near the base of the formation. Uranophane is found along fracture surfaces or in veins. Carbonaceous material is present throughout the Tiger Formation in the area. Part of the broad Pend Oreille valley surrounding Cusick, Washington, is an area of high favorability. Potential host rocks in the Tiger Formation, consisting of arkosic sandstones interbedded with radioactive shales, probably extend throughout the subsurface part of this area. Carbonaceous material is present and some samples contain high concentrations of uranium. In addition, several other possible chemical indicators were found. The Tiger-Lost Creek area is rated as having medium favorability. The Tiger Formation contains very hard, poorly sorted granite conglomerate with some beds of arkosic sandstone and silty sandstone. The granite conglomerate was apparently derived from source rocks having relatively high uranium content. The lower part of the formation is more favorable than the upper part because of the presence of carbonaceous material, anomalously high concentrations of uranium, and other possible chemical indicators. The area west of Ione is judged to have low favorability, because of the very low permeability of the rocks and the very low uranium content

  18. Palynofacies characterization for hydrocarbon source rock ...

    Indian Academy of Sciences (India)

    source rock potential of the Subathu Formation in the area. Petroleum geologists are well aware of the fact that the dispersed organic matter derived either from marine or non-marine sediments on reach- ing its maturation level over extended period of time contributes as source material for the produc- tion of hydrocarbons.

  19. The crazy hollow formation (Eocene) of central Utah

    Science.gov (United States)

    Weiss, M.P.; Warner, K.N.

    2001-01-01

    the Crazy Hollow beds dip beneath Quaternary sediments that fill the two valleys. The Crazy Hollow Formation ranges from 0 to 1,307 feet (0-398 m) thick in the region, but is usually much thinner than the maximum value. At most outcrops it is only a few scores of feet (12-50 m) thick. Its age is middle Eocene, for it is only a little younger than the underlying Green River Formation. The unit developed by the washing of detritus into the basin of the southwest arm of Lake Uinta from the various source rocks in the highlands surrounding the basin. The limestone beds and lenses formed in ponds and small lakes that developed in the basin from time to time during and following the draining and evaporation of Lake Uinta. The qualities of the Crazy Hollow Formation are described in detail for 10 different areas of outcrops in the Sanpete and Sevier Valleys and vicinity.

  20. Fluid-Rock Characterization and Interactions in NMR Well Logging

    Energy Technology Data Exchange (ETDEWEB)

    Hirasaki, George J.; Mohanty, Kishore K.

    2003-02-10

    The objective of this project was to characterize the fluid properties and fluid-rock interactions which are needed for formation evaluation by NMR well logging. NMR well logging is finding wide use in formation evaluation. The formation parameters commonly estimated were porosity, permeability, and capillary bound water. Special cases include estimation of oil viscosity, residual oil saturation, location of oil/water contact, and interpretation on whether the hydrocarbon is oil or gas.

  1. The Behaviour of Chromium Isotopes during the Oxidative Weathering of Ultramafic Rocks

    DEFF Research Database (Denmark)

    Paulukat, Cora Stefanie; Døssing, Lasse Nørbye; Mondal, Sisir K.

    The chromium isotope system has been proven to be a redox-sensitve proxy in ancient and modern environmental studies (e.g. [1], [2]). In this study we investigated Cr isotope fractionation during soil formation from Archean (3.1-3.3 Ga) ultramafic rocks, intruded into metamorphic rocks of the Iron...

  2. Weathering of rock 'Ginger'

    Science.gov (United States)

    1997-01-01

    One of the more unusual rocks at the site is Ginger, located southeast of the lander. Parts of it have the reddest color of any material in view, whereas its rounded lobes are gray and relatively unweathered. These color differences are brought out in the inset, enhanced at the upper right. In the false color image at the lower right, the shape of the visible-wavelength spectrum (related to the abundance of weathered ferric iron minerals) is indicated by the hue of the rocks. Blue indicates relatively unweathered rocks. Typical soils and drift, which are heavily weathered, are shown in green and flesh tones. The very red color in the creases in the rock surface correspond to a crust of ferric minerals. The origin of the rock is uncertain; the ferric crust may have grown underneath the rock, or it may cement pebbles together into a conglomerate. Ginger will be a target of future super-resolution studies to better constrain its origin.Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator. JPL is an operating division of the California Institute of Technology (Caltech).

  3. Rock melting technology and geothermal drilling

    Science.gov (United States)

    Rowley, J. C.

    1974-01-01

    National awareness of the potential future shortages in energy resources has heightened interest in exploration and utilization of a variety of geothermal energy (GTE) reservoirs. The status of conventional drilling of GTE wells is reviewed briefly and problem areas which lead to higher drilling costs are identified and R and D directions toward solution are suggested. In the immediate future, an expanded program of drilling in GTE formations can benefit from improvements in drilling equipment and technology normally associated with oil or gas wells. Over a longer time period, the new rock-melting drill bits being developed as a part of the Los Alamos Scientific Laboratory's Subterrene Program offer new solutions to a number of problems which frequently hamper GTE drilling, including the most basic problem - high temperature. Two of the most favorable characteristics of rock-melting penetrators are their ability to operate effectively in hot rock and produce glass linings around the hole as an integral part of the drilling process. The technical advantages to be gained by use of rock-melting penetrators are discussed in relation to the basic needs for GTE wells.

  4. Microscopic study of rock for estimating long-term behavior

    International Nuclear Information System (INIS)

    Ichikawa, Yasuaki

    1997-03-01

    One must consider micro-structures of rock and rock mass in order to predict the long-term behavior for more than ten thousand years. First we observe the micro-crack distribution of granite which is commonly distributed in Japan, and is widely used for several structures. The creep under constant load and the relaxation under constant displacement are typical time dependent phenomena, and we performed a series of relaxation tests under microscope observation in laboratory. The specimen that is preserved in water is granite as mentioned above. The aim of this experiment is to observe the sequential propagation of micro-cracks and its affect to the macroscopic response of the rock material under relaxation state. Next, a viscoelastic homogenization method is applied for analyzing the behavior of granite that is composed of several kinds of minerals (i.e., a polycrystalline material). The homogenization method developed for analyzing mechanics of composite materials is a mathematical theory that can describe the macroscopic behavior accounting for the microscopic characteristics with periodic microstructures. In this study, it is applied to a polycrystalline rock which involves a few minerals and micro-cracks. Furthermore, it is required to apply the homogenization analysis for rock materials which show a nonlinear time dependent behavior, so we develop a new elasto-visco-plastic homogenization theory, and its validity is checked for some ground structures made by clay. (author)

  5. Developing two-phase flow modelling concepts for rock fractures

    Energy Technology Data Exchange (ETDEWEB)

    Keto, V. (Fortum Nuclear Services Oy, Espoo (Finland))

    2010-01-15

    The Finnish nuclear waste disposal company, Posiva Oy, is planning an underground repository for spent nuclear fuel to be constructed on the island of Olkiluoto on the south-west coast of Finland. One element of the site investigations conducted at Olkiluoto is the excavation of the underground rock characterisation facility (ONKALO) that will be extended to the final disposal depth (approximately -400 m). The bedrock around the excavated tunnel volume is fully saturated with groundwater, which water commonly contains a mixture of dissolved gases. These gases remain dissolved due to the high hydrostatic pressure. During tunnel excavation work the natural hydrostatic pressure field is disturbed and the water pressure will decrease close to the atmospheric pressure in the immediate vicinity of the tunnel. During this pressure drop two-phase flow conditions (combined flow of both water and gas) may develop in the vicinity of the underground opening, as the dissolved gas is exsoluted under the low pressure (the term exsolution refers here to release of the dissolved gas molecules from the water phase into a separate gas phase). This report steers towards concept development for numerical two-phase flow modeling for fractured rock. The focus is on the description of gas phase formation process under disturbed hydraulic conditions by exsolution of dissolved gases from groundwater, and on understanding the effects of a possibly formed gas phase on groundwater flow conditions in rock fractures. A mathematical model of three mutually coupled nonlinear partial differential equations for two-phase flow is presented and corresponding constitutional relationships are introduced and discussed. Illustrative numerical simulations are performed in a simplified setting using COMSOL Multiphysics 3.5a - software package. Shortcomings and conceptual problems are discussed. (orig.)

  6. Developing two-phase flow modelling concepts for rock fractures

    International Nuclear Information System (INIS)

    Keto, V.

    2010-01-01

    The Finnish nuclear waste disposal company, Posiva Oy, is planning an underground repository for spent nuclear fuel to be constructed on the island of Olkiluoto on the south-west coast of Finland. One element of the site investigations conducted at Olkiluoto is the excavation of the underground rock characterisation facility (ONKALO) that will be extended to the final disposal depth (approximately -400 m). The bedrock around the excavated tunnel volume is fully saturated with groundwater, which water commonly contains a mixture of dissolved gases. These gases remain dissolved due to the high hydrostatic pressure. During tunnel excavation work the natural hydrostatic pressure field is disturbed and the water pressure will decrease close to the atmospheric pressure in the immediate vicinity of the tunnel. During this pressure drop two-phase flow conditions (combined flow of both water and gas) may develop in the vicinity of the underground opening, as the dissolved gas is exsoluted under the low pressure (the term exsolution refers here to release of the dissolved gas molecules from the water phase into a separate gas phase). This report steers towards concept development for numerical two-phase flow modeling for fractured rock. The focus is on the description of gas phase formation process under disturbed hydraulic conditions by exsolution of dissolved gases from groundwater, and on understanding the effects of a possibly formed gas phase on groundwater flow conditions in rock fractures. A mathematical model of three mutually coupled nonlinear partial differential equations for two-phase flow is presented and corresponding constitutional relationships are introduced and discussed. Illustrative numerical simulations are performed in a simplified setting using COMSOL Multiphysics 3.5a - software package. Shortcomings and conceptual problems are discussed. (orig.)

  7. Characterization of the rock joint surface. A contribution to DECOVALEX II Task 3 'Constitutive relationships of rock joints'

    International Nuclear Information System (INIS)

    Vuopio, J.; Poellae, J.

    1997-12-01

    In order to understand the effects of spent fuel on the hydraulical behaviour of the rock mass it is necessary to have knowledge about the relationship between the stresses and hydraulical properties of the fractures. The roughness of a fracture surface governs the dilatation of the fracture and the displacement of the fracture surface under shear stress. The peak shear strength and hydraulic flow properties of fractures depend very much on the surface roughness. This report describes different methods and techniques used in the characterization of rock joint surfaces and their applications in rock mechanics

  8. Impact of weathering on slope stability in soft rock mass

    Directory of Open Access Journals (Sweden)

    Predrag Miščević

    2014-06-01

    Full Text Available Weathering of soft rocks is usually considered as an important factor in various fields such as geology, engineering geology, mineralogy, soil and rock mechanics, and geomorphology. The problem of stability over time should be considered for slopes excavated in soft rocks, in case they are not protected against weathering processes. In addition to disintegration of material on slope surface, the weathering also results in shear strength reduction in the interior of the slope. Principal processes in association with weathering are discussed with the examples of marl hosted on flysch formations near Split, Croatia.

  9. Thermal Inertia of Rocks and Rock Populations

    Science.gov (United States)

    Golombek, M. P.; Jakosky, B. M.; Mellon, M. T.

    2001-01-01

    The effective thermal inertia of rock populations on Mars and Earth is derived from a model of effective inertia versus rock diameter. Results allow a parameterization of the effective rock inertia versus rock abundance and bulk and fine component inertia. Additional information is contained in the original extended abstract.

  10. Impact of solid second phases on deformation mechanisms of naturally deformed salt rocks (Kuh-e-Namak, Dashti, Iran) and rheological stratification of the Hormuz Salt Formation

    Science.gov (United States)

    Závada, P.; Desbois, G.; Urai, J. L.; Schulmann, K.; Rahmati, M.; Lexa, O.; Wollenberg, U.

    2015-05-01

    Viscosity contrasts displayed in flow structures of a mountain namakier (Kuh-e-Namak - Dashti), between 'weak' second phase bearing rock salt and 'strong' pure rock salt types are studied for deformation mechanisms using detailed quantitative microstructural study. While the solid inclusions rich ("dirty") rock salts contain disaggregated siltstone and dolomite interlayers, "clean" salts reveal microscopic hematite and remnants of abundant fluid inclusions in non-recrystallized cores of porphyroclasts. Although the flow in both, the recrystallized "dirty" and "clean" salt types is accommodated by combined mechanisms of pressure-solution creep (PS), grain boundary sliding (GBS), transgranular microcracking and dislocation creep accommodated grain boundary migration (GBM), their viscosity contrasts observed in the field outcrops are explained by: 1) enhanced ductility of "dirty" salts due to increased diffusion rates along the solid inclusion-halite contacts than along halite-halite contacts, and 2) slow rates of intergranular diffusion due to dissolved iron and inhibited dislocation creep due to hematite inclusions for "clean" salt types Rheological contrasts inferred by microstructural analysis between both salt rock classes apply in general for the "dirty" salt forming Lower Hormuz and the "clean" salt forming the Upper Hormuz of the Hormuz Formation and imply strain rate gradients or decoupling along horizons of mobilized salt types of different composition and microstructure.

  11. Behaviour of rock-like oxide fuels under reactivity-initiated accident conditions

    International Nuclear Information System (INIS)

    Kazuyuki, Kusagaya; Takehiko, Nakamura; Makio, Yoshinaga; Hiroshi, Akie; Toshiyuki, Yamashita; Hiroshi, Uetsuka

    2002-01-01

    Pulse irradiation tests of three types of un-irradiated rock-like oxide (ROX) fuel - yttria-stabilised zirconia (YSZ) single phase, YSZ and spinel (MgAl 2 O 4 ) homogeneous mixture and particle-dispersed YSZ/spinel - were conducted in the Nuclear Safety Research Reactor to investigate the fuel behaviour under reactivity-initiated accident conditions. The ROX fuels failed at fuel volumetric enthalpies above 10 GJ/m 3 , which was comparable to that of un-irradiated UO 2 fuel. The failure mode of the ROX fuels, however, was quite different from that of the UO 2 fuel. The ROX fuels failed with fuel pellet melting and a part of the molten fuel was released out to the surrounding coolant water. In spite of the release, no significant mechanical energy generation due to fuel/coolant thermal interaction was observed in the tested enthalpy range below∼12 GJ/m 3 . The YSZ type and homogenous YSZ/spinel type ROX fuels failed by cladding burst when their temperatures peaked, while the particle-dispersed YSZ/spinel type ROX fuel seemed to have failed by cladding local melting. (author)

  12. Geological assessment of crystalline rock formations with a view to radioactive waste disposal

    International Nuclear Information System (INIS)

    Mather, J.D.

    1984-01-01

    Field work has been concentrated at the Altnabreac Research Site on north-east Scotland, where three deep boreholes to approximately 300 m and 24 shallow boreholes to approximately 40 m were drilled. The movement of groundwater within 300 m of the surface was investigated using a specially developed straddle packer system. Geochemical studies have demonstrated that most groundwater is dominated by recent recharge but one borehole yielded water with an age of around 10 4 years. Geophysical borehole logging has shown that the full wave train sonic logs and the acoustic logs show most promise for the assessment of crystalline rocks. In the laboratory the interaction of rocks and groundwater at the temperature/pressure conditions to be expected in a repository has established the geochemical environment to which waste canisters and backfill materials would be subjected. Other generic studies reported include the characterization of geotechnical properties of rocks at elevated temperatures and pressures, the development of a new cross-hole sinusoidal pressure test for the measurement of hydraulic properties and the use of thermal infra-red imagery to detect groundwater discharge zones

  13. Metamorphic rocks in the deep boreholes near Maribor

    Directory of Open Access Journals (Sweden)

    Mirka Trajanova

    2002-12-01

    Full Text Available Six research-captive boreholes for thermal water passed through a pile of metamorphic rocks near Maribor (Eastern Slovenia that is on average about 1000 m thick. The succession of metamorphic rocks is characteristic for the Pohorje Mt. and eastern Kobansko region. In the area of the boreholes two tectonic zones are more pronounced: the upper one, at a depth of about 510 to 550 m at the contact of the Štelenska Gora and Phyllite formations and the deeper one at a depth of about 460 to 590 m, indicating the reverse fault junction of the Phyllite and Kobansko formations. They belong to the second andthe third thrust unit of the accretionary wedge formed at the collision of the European and African plates. Four Alpine nappe units are proven in the Slovenian part of the Eastern Alps.

  14. Large-Scale True Triaxial Apparatus for Geophysical Studies in Fractured Rock

    KAUST Repository

    Garcia, A. V.

    2018-05-12

    The study of fractured rock masses in the laboratory remains challenging because of the large specimen sizes and bulky loading systems that are required. This article presents the design, structural analysis, and operation of a compact and self-reacting true triaxial device for fractured rock. The frame subjects a 50 cm by 50 cm by 50 cm fractured rock specimen to a maximum stress of 3 MPa along three independent axes. Concurrent measurements include long-wavelength P-wave propagation, passive acoustic emission monitoring, deformations, and thermal measurements. The device can accommodate diverse research, from rock mass properties and geophysical fractured rock characterizations, to coupled hydro-chemo-thermo-mechanical processes, drilling, and grouting. Preliminary wave propagation data gathered under isotropic and anisotropic stress conditions for an assembly of 4,000 rock blocks demonstrate the system’s versatility and provide unprecedented information related to long-wavelength propagation in fractured rock under various stress anisotropies.

  15. Large-Scale True Triaxial Apparatus for Geophysical Studies in Fractured Rock

    KAUST Repository

    Garcia, A. V.; Rached, R. M.; Santamarina, Carlos

    2018-01-01

    The study of fractured rock masses in the laboratory remains challenging because of the large specimen sizes and bulky loading systems that are required. This article presents the design, structural analysis, and operation of a compact and self-reacting true triaxial device for fractured rock. The frame subjects a 50 cm by 50 cm by 50 cm fractured rock specimen to a maximum stress of 3 MPa along three independent axes. Concurrent measurements include long-wavelength P-wave propagation, passive acoustic emission monitoring, deformations, and thermal measurements. The device can accommodate diverse research, from rock mass properties and geophysical fractured rock characterizations, to coupled hydro-chemo-thermo-mechanical processes, drilling, and grouting. Preliminary wave propagation data gathered under isotropic and anisotropic stress conditions for an assembly of 4,000 rock blocks demonstrate the system’s versatility and provide unprecedented information related to long-wavelength propagation in fractured rock under various stress anisotropies.

  16. Determining the specific electric resistance of rock

    Energy Technology Data Exchange (ETDEWEB)

    Persad' ko, V.Ia.

    1982-01-01

    Data are presented on perfecting the method of laboratory determination of the specific electric resistance of a rock formation. The average error in determining the specific electric resistance of the core at various locations is no more than two percent with low resistance values (2-5 ohms).

  17. Predicting hydrocarbon potential of an earth formation underlying water

    International Nuclear Information System (INIS)

    Damaison, G.J.; Kaplan, I.R.

    1981-01-01

    A method for the on-site collection and examination of small concentrations of a carbonaceous gas, e.g. methane, dissolved in a body of water overlying an earth formation to predict hydrocarbon potential of the earth formation under the body of water, the formation being a source of carbonaceous gas, comprises at a known geographic location sampling the water at a selected flow rate and at a selected depth; continuously vacuum separating the water into liquid and gas phases; separating a selected carbonaceous gas from interfering gas species in the presence of an air carrier vented to atmosphere at a known flow rate; and quantitatively oxidizing the selected gas and then cryogenically trapping an oxidant thereof in the presence of said air carrier to provide for an accurate isotopic examination. (author)

  18. Investigations on THM effects in buffer, EDZ and argillaceous host rock. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Jobmann, M.; Breustedt, M.; Li, S.; Polster, M.; Schirmer, S.

    2013-11-15

    In the Federal Republic of Germany the final disposal of heat-generating radioactive waste in clay formations is investigated as an alternative to the reference concept in a salt formation. The main concern when switching to a clay host rock is the high amount of heat released from the canisters into the clay rock over a long period of time. It is still an open question to what extent the host rock formation is affected by the released heat and if this is a threat to safety. The released heat from the canisters is a load on the whole barrier system, which consists of the geotechnical barriers (buffer and plugs) and the geological barrier. The temperature has a direct impact on the buffer, the excavative damaged zone (EDZ) and the surrounding host rock. The buffer has specific thermo-physical properties that significantly influence the temperature evolution in the near field so that a temperature load on the buffer is of special concern. Thus, with regard to thermal criteria, the buffer plays a significant role for the design of the emplacement fields. An open question is whether the use of admixtures could enhance the thermo-physical properties so that the heat release into the host rock would be more efficient. Due to the permanent heat release and the continuous emplacement of additional canisters, the in-situ stress state in the vicinity of the emplacement boreholes continuously varies during the operational period and beyond. It is an open question how the EDZ of emplacement boreholes evolves in the long term with regard to its fissure system and mainly its permeability. A closure of the EDZ and a corresponding decrease in its permeability are necessary to enhance the tightness of the barrier system, especially to avoid a preferential pathway through the EDZ around the openings. The host rock has specific properties that are necessary to ensure a safe enclosure of the waste. A change in the host rock temperature may change these properties irreversibly. This is

  19. K-Ar ages of the Neogene volcanic rocks from the Oshamambe district, southwestern Hokkaido

    International Nuclear Information System (INIS)

    Kubo, Kazuya; Shibata, Ken; Ishida, Masao

    1988-01-01

    Oshamanbe district is on the northern extension of the so-called green tuff district in northeastern Japan, and the sedimentary rocks in a sea area and volcanic rocks from Miocene to Pleistocene widely distribute. The authors carried out the geological survey of this district, and published the results as the geological features in Oshamanbe district. The volcanic rocks distributing in this district range from andesite to dacite and rhyolite. Their lithofacies are mostly volcanic breccia and tuff breccia, accompanied by lava and dikes. This time, the measurement of the age of these volcanic rocks was carried out, and the stratigraphical table made by the authors was investigated. It is considered that those age values offer important information for determining the age of the Setana formation. The outline of the geological features, the samples for the measurement, the method of measurement of Ar isotopic ratio and K, and the results of measurement are reported. As the results, 4.38 - 4.47 Ma were obtained for Garogawa volcanic rocks, and 2.59 Ma for Shamanbesan volcanic rocks. The period of sedimentation of the Setana formation was from the latter period of Pliocene to pleistocene. (Kako, I.)

  20. Evaluation of salt and mine rock disposal. Project No. 76-283

    International Nuclear Information System (INIS)

    1976-11-01

    Studies are being performed on the isolation of nuclear waste in geological formations; this would entail constructing an underground mine in selected rock strata for waste storage. Rocks removed from the mine during construction must be either disposed of permanently or temporarily stored for later backfill into the mine. Several methods of storing or disposing of the mined rock are discussed in this report. The technical feasibility, cost, advantages and disadvantages of each method are presented and the ranking of methods based on currently available data is discussed. Salt, shale, granite, and limestone are covered

  1. An improved method for predicting brittleness of rocks via well logs in tight oil reservoirs

    Science.gov (United States)

    Wang, Zhenlin; Sun, Ting; Feng, Cheng; Wang, Wei; Han, Chuang

    2018-06-01

    There can be no industrial oil production in tight oil reservoirs until fracturing is undertaken. Under such conditions, the brittleness of the rocks is a very important factor. However, it has so far been difficult to predict. In this paper, the selected study area is the tight oil reservoirs in Lucaogou formation, Permian, Jimusaer sag, Junggar basin. According to the transformation of dynamic and static rock mechanics parameters and the correction of confining pressure, an improved method is proposed for quantitatively predicting the brittleness of rocks via well logs in tight oil reservoirs. First, 19 typical tight oil core samples are selected in the study area. Their static Young’s modulus, static Poisson’s ratio and petrophysical parameters are measured. In addition, the static brittleness indices of four other tight oil cores are measured under different confining pressure conditions. Second, the dynamic Young’s modulus, Poisson’s ratio and brittleness index are calculated using the compressional and shear wave velocity. With combination of the measured and calculated results, the transformation model of dynamic and static brittleness index is built based on the influence of porosity and clay content. The comparison of the predicted brittleness indices and measured results shows that the model has high accuracy. Third, on the basis of the experimental data under different confining pressure conditions, the amplifying factor of brittleness index is proposed to correct for the influence of confining pressure on the brittleness index. Finally, the above improved models are applied to formation evaluation via well logs. Compared with the results before correction, the results of the improved models agree better with the experimental data, which indicates that the improved models have better application effects. The brittleness index prediction method of tight oil reservoirs is improved in this research. It is of great importance in the optimization of

  2. The Shublik Formation and adjacent strata in northeastern Alaska description, minor elements, depositional environments and diagenesis

    Science.gov (United States)

    Tourtelot, Harry Allison; Tailleur, Irvin L.

    1971-01-01

    The Shublik Formation (Middle and Late Triassic) is widespread in the surface and subsurface of northern Alaska. Four stratigraphic sections along about 70 miles of the front of the northeastern Brooks Range east of the Canning giver were examined and sampled in detail in 1968. These sections and six-step spectrographic and carbon analyses of the samples combined with other data to provide a preliminary local description of the highly organic unit and of the paleoenvironments. Thicknesses measured between the overlying Kingak Shale of Jurassic age and the underlying Sadlerochit Formation of Permian and Triassic age range from 400 to more than 800 feet but the 400 feet, obtained from the most completely exposed section, may be closer to the real thickness across the region. The sections consist of organic-rich, phosphatic, and fossiliferous muddy, silty, or carbonate rocks. The general sequence consists, from the bottom up, of a lower unit of phosphatic siltstone, a middle unit of phosphatic carbonate rocks, and an upper unit of shale and carbonate rocks near the Canning River and shale, carbonate rocks, and sandstone to the east. Although previously designated a basal member of the Kingak Shale (Jurassic), the upper unit is here included with the Shublik on the basis of its regional lithologic relation. The minor element compositions of the samples of the Shublik Formation are consistent with their carbonaceous and phosphatic natures in that relatively large amounts of copper, molybdenum, nickel, vanadium and rare earths are present. The predominantly sandy rocks of the underlying Sadlerochit Formation (Permian and Triassic) have low contents of most minor elements. The compositions of samples of Kingak Shale have a wide range not readily explicable by the nature of the rock: an efflorescent sulfate salt contains 1,500 ppm nickel and 1,500 ppm zinc and large amounts of other metals derived from weathering of pyrite and leaching of local shale. The only recorded

  3. Effect of rock rheology on fluid leak- off during hydraulic fracturing

    Science.gov (United States)

    Yarushina, V. M.; Bercovici, D.; Oristaglio, M. L.

    2012-04-01

    In this communication, we evaluate the effect of rock rheology on fluid leak­off during hydraulic fracturing of reservoirs. Fluid leak-off in hydraulic fracturing is often nonlinear. The simple linear model developed by Carter (1957) for flow of fracturing fluid into a reservoir has three different regions in the fractured zone: a filter cake on the fracture face, formed by solid additives from the fracturing fluid; a filtrate zone affected by invasion of the fracturing fluid; and a reservoir zone with the original formation fluid. The width of each zone, as well as its permeability and pressure drop, is assumed to remain constant. Physical intuition suggests some straightforward corrections to this classical theory to take into account the pressure dependence of permeability, the compressibility or non-Newtonian rheology of fracturing fluid, and the radial (versus linear) geometry of fluid leak­off from the borehole. All of these refinements, however, still assume that the reservoir rock adjacent to the fracture face is non­deformable. Although the effect of poroelastic stress changes on leak-off is usually thought to be negligible, at the very high fluid pressures used in hydraulic fracturing, where the stresses exceed the rock strength, elastic rheology may not be the best choice. For example, calculations show that perfectly elastic rock formations do not undergo the degree of compaction typically seen in sedimentary basins. Therefore, pseudo-elastic or elastoplastic models are used to fit observed porosity profiles with depth. Starting from balance equations for mass and momentum for fluid and rock, we derive a hydraulic flow equation coupled with a porosity equation describing rock compaction. The result resembles a pressure diffusion equation with the total compressibility being a sum of fluid, rock and pore-space compressibilities. With linear elastic rheology, the bulk formation compressibility is dominated by fluid compressibility. But the possibility

  4. Uranium deposits in granitic rocks

    International Nuclear Information System (INIS)

    Nishimori, R.K.; Ragland, P.C.; Rogers, J.J.W.; Greenberg, J.K.

    1977-01-01

    This report is a review of published data bearing on the geology and origin of uranium deposits in granitic, pegmatitic and migmatitic rocks with the aim of assisting in the development of predictive criteria for the search for similar deposits in the U.S. Efforts were concentrated on the so-called ''porphyry'' uranium deposits. Two types of uranium deposits are primarily considered: deposits in pegmatites and alaskites in gneiss terrains, and disseminations of uranium in high-level granites. In Chapter 1 of this report, the general data on the distribution of uranium in igneous and metamorphic rocks are reviewed. Chapter 2 contains some comments on the classification of uranium deposits associated with igneous rocks and a summary of the main features of the geology of uranium deposits in granites. General concepts of the behavior of uranium in granites during crustal evolution are reviewed in Chapter 3. Also included is a discussion of the relationship of uranium mineralization in granites to the general evolution of mobile belts, plus the influence of magmatic and post-magmatic processes on the distribution of uranium in igneous rocks and related ore deposits. Chapter 4 relates the results of experimental studies on the crystallization of granites to some of the geologic features of uranium deposits in pegmatites and alaskites in high-grade metamorphic terrains. Potential or favorable areas for igneous uranium deposits in the U.S.A. are delineated in Chapter 5. Data on the geology of specific uranium deposits in granitic rocks are contained in Appendix 1. A compilation of igneous rock formations containing greater than 10 ppM uranium is included in Appendix 2. Appendix 3 is a report on the results of a visit to the Roessing area. Appendix 4 is a report on a field excursion to eastern Canada

  5. The earliest Paleoproterozoic supracrustal rocks in Koillismaa, northern Finland – their petrographic and geochemical characteristics and lithostratigraphy

    Directory of Open Access Journals (Sweden)

    Laura S. Lauri

    2003-01-01

    Full Text Available The 2.44 Ga Koillismaa layered igneous complex (KLIC in northern Finland is interpreted to have formed as a consequence of early Paleoproterozoic continental rifting. Associated with the mafic layered intrusions are felsic to intermediate volcanic and plutonic rocks of approximately the same age. The supracrustal rocks on top of the KLIC have been divided into three stratigraphic groups. The lowermost of these, the Sirniö Group, is thought to predate the KLIC and thus to represent the original roof. The overlying Kynsijärvi andHautavaara Groups are somewhat younger than the layered intrusions. The Sirniö Group comprises two formations of felsic and intermediate volcanic rocks. The Sirniövaara Formation, also called as the Koillismaa granophyre, consists of a thick rhyodacitic unit withgranophyric groundmass and some breccia interlayers. The Sirniövaara rhyodacite consists of plagioclase, quartz and biotite. Minor and accessory phases include ilmenite, magnetite, apatite, titanite, zircon and fluorite. Low-grade metamorphic minerals such as chlorite, epidote, carbonate and sericite are also commonly present. The granophyric texture is considered to have formed as a consequence of contact metamorphism and hydrothermal alteration associated with the emplacement of the KLIC. Above the Sirniövaara Formation is the Unijoki Formation, a heterogeneous group of felsic to intermediate volcanic rocks. The felsic rocks of the Unijoki Formation resemble the Sirniövaara rhyodacite whereas the intermediate rocks generally contain amphibole, instead of biotite, as the predominant mafic mineral. The rocks of the Sirniö Group show A-type geochemical character, e.g., high alkali content, Fe/Mg, 10000*Ga/Al, LREE, Y and Zr. In addition to primary compositional variation, metamorphic, and possibly hydrothermal, disturbance are recorded in the Sirniö Group lithologies. We consider them to be an example of early Paleoproterozoic rift-related volcanic rocks

  6. Hot dry rock heat mining

    International Nuclear Information System (INIS)

    Duchane, D.V.

    1992-01-01

    Geothermal energy utilizing fluids from natural sources is currently exploited on a commercial scale at sites around the world. A much greater geothermal resource exists, however, in the form of hot rock at depth which is essentially dry. This hot dry rock (HDR) resource is found almost everywhere, but the depth at which usefully high temperatures are reached varies from place to place. The technology to mine the thermal energy from HDR has been under development for a number of years. Using techniques adapted from the petroleum industry, water is pumped at high pressure down an injection well to a region of usefully hot rock. The pressure forces open natural joints to form a reservoir consisting of a small amount of water dispensed in a large volume of hot rock. This reservoir is tapped by second well located at some distance from the first, and the heated water is brought to the surface where its thermal energy is extracted. The same water is then recirculated to mine more heat. Economic studies have indicated that it may be possible to produce electricity at competitive prices today in regions where hot rock is found relatively close to the surface

  7. The peculiarities of structurizing enclosing rock massif while developing a coal seam

    Science.gov (United States)

    Kozyreva, E. N.; Shinkevich, M. V.

    2017-09-01

    Different concepts of the development of geo-mechanical processes during longwall mining of a seam which are fundamentally different from the conventional ones are introduced in the article. Fundamental principles of the model for structurizing enclosing rock mass while longwall mining along the strike are described. The model was developed on the bases of non-linear geomechanical laws. According to the model, rock mass in the area of mining operation is organized as rock geomechanical layers with shifting arches. And the formation period of shifting arches in disintegrated rock mass is divisible by the length of the stope. Undulate characteristic of a massif as a peculiarity of man-made structurization of a massif is defined. It is shown that structuring the broken massif causes the formation of block-structured system and it can be detected while monitoring the ground pressure in powered support props. The results of the research allow decreasing the negative influence of a ground pressure and can be applied to specify parameters for controlling the roof, defining geometrical dimensions of a mining section and positioning of holing chute (face entry).

  8. Stratigraphy of Slick Rock district and vicinity, San Miguel and Dolores Counties, Colorado

    Science.gov (United States)

    Shawe, Daniel R.; Simmons, George C.; Archbold, Norbert L.

    1968-01-01

    The Slick Rock district covers about 570 square miles in western San Miguel and Dolores Counties, in southwestern Colorado. It is at the south edge of the salt-anticline region of southwestern Colorado and southeastern Utah and of the Uravan mineral belt.Deposition of Paleozoic sedimentary rocks in the district and vicinity was principally controlled by development of the Paradox Basin, and of Mesozoic rocks by development of a depositional basin farther west. The Paleozoic rocks generally are thickest at the northeast side of the Paradox Basin in a northwest- trending trough which seems to be a wide graben in Precambrian igneous and metamorphic basement rocks; Mesozoic rocks generally thicken westward and southwestward from the district.Sedimentary rocks rest on a Precambrian basement consisting of a variety of rocks, including granite and amphibolite. The surface of the Precambrian rocks is irregular and generally more than 2,000 feet below sea level and 7,000-11,000 feet below the ground surface. In the northern part of the district the Precambrian surface plunges abruptly northeastward into the trough occupying the northeast side of the Paradox Basin, and in the southern part it sags in a narrow northeasterly oriented trough. Deepening of both troughs, or crustal deformation in their vicinity, influenced sedimentation during much of late Paleozoic and Mesozoic time.The maximum total thickness of sedimentary rocks underlying the district is 13,000 feet, and prior to extensive erosion in the late Tertiary and the Quaternary it may have been as much as about 18,000 feet. The lower 5,000 feet or more of the sequence of sedimentary rocks consists of arenaceous strata of early Paleozoic age overlain by dominantly marine carbonate rocks and evaporite beds interbedded with lesser amounts of clastic sediments of late Paleozoic age. Overlying these rocks is about 4,500 feet of terrestrial clastic sediments, dominantly sandstone with lesser amounts of shale, mudstone

  9. Radionuclide fixation mechanisms in rocks

    International Nuclear Information System (INIS)

    Nakashima, S.

    1991-01-01

    In the safety evaluation of the radioactive waste disposal in geological environment, the mass balance equation for radionuclide migration is given. The sorption of radionuclides by geological formations is conventionally represented by the retardation of the radionuclides as compared with water movement. In order to quantify the sorption of radionuclides by rocks and sediments, the distribution ratio is used. In order to study quantitatively the long term behavior of waste radionuclides in geological environment, besides the distribution ratio concept in short term, slower radionuclide retention reaction involving mineral transformation should be considered. The development of microspectroscopic method for long term reaction path modeling, the behavior of iron during granite and water interaction, the reduction precipitation of radionuclides, radionuclide migration pathways, and the representative scheme of radionuclide migration and fixation in rocks are discussed. (K.I.)

  10. Thermo-mechanical ratcheting in jointed rock masses

    KAUST Repository

    Pasten, C.

    2015-09-01

    Thermo-mechanical coupling takes place in jointed rock masses subjected to large thermal oscillations. Examples range from exposed surfaces under daily and seasonal thermal fluctuations to subsurface rock masses affected by engineered systems such as geothermal operations. Experimental, numerical and analytical results show that thermo-mechanical coupling can lead to wedging and ratcheting mechanisms that result in deformation accumulation when the rock mass is subjected to a biased static-force condition. Analytical and numerical models help in identifying the parameter domain where thermo-mechanical ratcheting can take place.

  11. Thermo-mechanical ratcheting in jointed rock masses

    KAUST Repository

    Pasten, C.; Garcí a, M.; Santamarina, Carlos

    2015-01-01

    Thermo-mechanical coupling takes place in jointed rock masses subjected to large thermal oscillations. Examples range from exposed surfaces under daily and seasonal thermal fluctuations to subsurface rock masses affected by engineered systems such as geothermal operations. Experimental, numerical and analytical results show that thermo-mechanical coupling can lead to wedging and ratcheting mechanisms that result in deformation accumulation when the rock mass is subjected to a biased static-force condition. Analytical and numerical models help in identifying the parameter domain where thermo-mechanical ratcheting can take place.

  12. Hydrological and geochemical investigation on the volcanic rock and gneissic rock area

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Yong Kwon; Jeong, Chan Ho; Ryu, Kun Seok; Kim, Byoung Yeop; Park, Hyung Kun; Yu, Sang Woo; Jang, Hyu Kun; Lee, Suk Chi; Choi, Ki Young; Jeon, Hyu Woong; Kim, Do Hyoung [Daejong University, Daejeon (Korea, Republic of)

    2010-01-15

    The purpose of this study is to supply the basic data and optimum study site among volcanic rock area and gneissic rock area for high-level radioactive waste disposal. For this purpose, geological, hydrogeological and geochemical data from previously published literatures were collected and analyzed. In this study, we selected 36 volcanic rock sites and 26 gneissic sites as the candidate sites for high level radwaste disposal. Finally, for four sites(M-1, M-13, V-1 and V-13 sites) were selected as the study sites. The geochemical characteristics of groundwaters of each study site were statistically analyzed. The nitrate contamination and the sea water mixing will be important factors on the assessment of behaviour of radionuclides under groundwater environment. From the deep geothermal study, alkaline and sodium-bicarbonate chemical environment, and sea water mixing should be considered as the key factors for the deep disposal of high-level radioactive waste

  13. Experimental Investigation of the Influence of Confining Stress on Hard Rock Fragmentation Using a Conical Pick

    Science.gov (United States)

    Li, Xibing; Wang, Shaofeng; Wang, Shanyong

    2018-01-01

    High geostress is a prominent condition in deep excavations and affects the cuttability of deep hard rock. This study aims to determine the influence of confining stress on hard rock fragmentation as applied by a conical pick. Using a true triaxial test apparatus, static and coupled static and dynamic loadings from pick forces were applied to end faces of cubic rock specimens to break them under biaxial, uniaxial and stress-free confining stress conditions. The cuttability indices (peak pick force, insertion depth and disturbance duration), failure patterns and fragment sizes were measured and compared to estimate the effects of confining stress. The results show that the rock cuttabilities decreased in order from rock breakages under stress-free conditions to uniaxial confining stress and then to biaxial confining stress. Under biaxial confining stress, only flake-shaped fragments were stripped from the rock surfaces under the requirements of large pick forces or disturbance durations. As the level of uniaxial confining stress increased, the peak pick force and the insertion depth initially increased and then decreased, and the failure patterns varied from splitting to partial splitting and then to rock bursts with decreasing average fragment sizes. Rock bursts will occur under elastic compression via ultra-high uniaxial confining stresses. There are two critical uniaxial confining stress levels, namely stress values at which peak pick forces begin to decrease and improve rock cuttability, and those at which rock bursts initially occur and cutting safety decreases. In particular, hard rock is easiest to split safely and efficiently under stress-free conditions. Moreover, coupled static preloading and dynamic disturbance can increase the efficiency of rock fragmentation with increasing preloading levels and disturbance amplitudes. The concluding remarks confirm hard rock cuttability using conical pick, which can improve the applicability of mechanical excavation in

  14. Elastic properties of granulite facies rocks of Mahabalipuram, Tamil ...

    Indian Academy of Sciences (India)

    the granulite facies rocks have helped us to under- stand the metamorphic ... imperative need to make new and accurate lab- .... the driving side and a digital storage oscilloscope ..... propagation in rocks and other lossy media: An experi-.

  15. Processes of cation migration in clay-rocks: Final Scientific Report of the CatClay European Project

    International Nuclear Information System (INIS)

    Altmann, S.; Aertsens, M.; Appelo, T.; Bruggeman, C.; Gaboreau, S.; Glaus, M.; Jacquier, P.; Kupcik, T.; Maes, N.; Montoya, V.; Rabung, T.; Robinet, J.-C.; Savoye, S.; Schaefer, T.; Tournassat, C.; Van Laer, L.; Van Loon, L.

    2015-07-01

    In the framework of the feasibility studies on the radioactive waste disposal in deep argillaceous formations, it is now well established that the transport properties of solutes in clay rocks, i.e. parameter values for Fick's law, are mainly governed by the negatively charged clay mineral surface. While a good understanding of the diffusive behaviour of non-reactive anionic and neutral species is now achieved, much effort has to be placed on improving understanding of coupled sorption/diffusion phenomena for sorbing cations. Indeed, several cations known to form highly stable surface complexes with sites on mineral surfaces migrate more deeply into clay rock than expected. Therefore, the overall objective of the EC CatClay project is to address this issue, using a 'bottom-up' approach, in which simpler, analogous systems (here a compacted clay, 'pure' illite) are experimentally studied and modelled, and then the transferability of these results to more complex materials, i.e. the clay rocks under consideration in France, Switzerland and Belgium for hosting radioactive waste disposal facilities, is verified. The cations of interest were chosen for covering a representative range of cations families: from a moderately sorbing cation, the strontium, to three strongly sorbing cations, Co(II), Zn(II) and Eu(III). For the 4 years of this project, much effort was devoted to developing and applying specific experimental methods needed for acquiring the high precision, reliable data needed to test the alternative hypotheses represented by different conceptual-numerical models. The enhanced diffusion of the sorbing cations of interest was confirmed both in the simpler analogous illite system for Sr 2+ , Co(II) and Zn(II), but also in the natural clay rocks, except for Eu(III). First modelling approach including diffusion in the diffuse double layer (DDL) promisingly succeeded in reproducing the experimental data under the various conditions both in

  16. In situ determination of the dynamic properties of thinly-layered rock to evaluate rock-structure interaction at a nuclear power plant site

    International Nuclear Information System (INIS)

    Johnson, William J.; Rizzo, Paul C.

    1988-01-01

    The presence of layers of weak sedimentary rock in a column of otherwise competent rock can significantly affect the seismic response of nuclear power plant structures due to rock-structure interaction effects. The determination of the dynamic properties of thinly-layered rock is, however, difficult. When borings are placed close enough to allow for a characterization of refracted waves, other potential problems such as the identification of clear P- and S-wave arrivals, extremely short duration of records, near-field waves, instrumental stability, and overall record resolution become magnified. Other problems such as cultural noise and signal amplitude can become critical when high resolution is required. Conventional storage oscilloscopes and seismographs are inadequate under these conditions, but modern digital recording systems with the application of stringent calibration and recording procedures can yield successful results. A case history of a high-precision cross-hole survey to a depth of 150 meters in thinly-bedded sedimentary rock at a nuclear power plant site is presented in order to illustrate the systems and procedures necessary to obtain successful results under adverse conditions. (author)

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

    Science.gov (United States)

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

    2016-01-01

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

  18. Proteins involved in flor yeast carbon metabolism under biofilm formation conditions.

    Science.gov (United States)

    Moreno-García, Jaime; García-Martínez, Teresa; Moreno, Juan; Mauricio, Juan Carlos

    2015-04-01

    A lack of sugars during the production of biologically aged wines after fermentation of grape must causes flor yeasts to metabolize other carbon molecules formed during fermentation (ethanol and glycerol, mainly). In this work, a proteome analysis involving OFFGEL fractionation prior to LC/MS detection was used to elucidate the carbon metabolism of a flor yeast strain under biofilm formation conditions (BFC). The results were compared with those obtained under non-biofilm formation conditions (NBFC). Proteins associated to processes such as non-fermentable carbon uptake, the glyoxylate and TCA cycles, cellular respiration and inositol metabolism were detected at higher concentrations under BFC than under the reference conditions (NBFC). This study constitutes the first attempt at identifying the flor yeast proteins responsible for the peculiar sensory profile of biologically aged wines. A better metabolic knowledge of flor yeasts might facilitate the development of effective strategies for improved production of these special wines. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Terminal storage of radioactive waste in geologic formations

    International Nuclear Information System (INIS)

    Lomenick, T.F.

    1976-01-01

    The principal aim of the National Waste Terminal Storage (NWTS) program is to develop pilot plants and, ultimately, repositories in several different rock formations in various parts of the country. Rocks such as salt, shale, limestone, granite, schists, and serpentinite may all qualify as host media for the disposition of radioactive wastes in the proper environments. In general, the only requirement for any rock formation or storage site is that it contain any emplaced wastes for so long as it takes for the radioactive materials to decay to innocuous levels. This requirement, though, is a formidable one as some of the wastes will remain active for periods of hundreds of thousands of years and the physical and chemical properties of rocks that govern circulating groundwater and hence containment, are difficult to determine and define. Nevertheless, there are many rock types and a host of areas throughout the country where conditions are promising for the development of waste repositories. Some of these are discussed below

  20. Role of Lithology and Rock Structure in Drainage Development in ...

    African Journals Online (AJOL)

    Lithology and Rock structure play a vital role in the development of Drainage Network in any drainage basin. The drainage patterns upon land surface develop as directed by the underlying lithology and rock structure. In fact, lithology and rock structure together shape the basin and are decisive parameters of nature and ...

  1. Microelements containing in rock of the Aral region. Agrochemical problems

    International Nuclear Information System (INIS)

    Zhumamuratov, A.

    2004-01-01

    Lately chemization of agriculture has been done not only by mineral nitrification and pesticides but also by melioration with rocks and industrial waste. However, increase in soil fertility and the related efficiency of production requires systematic control and analysis of the chemization so as not to disturb the existing balance in ecosystem. The experiment on bringing mountain rocks up 30 ton/hectare in soil shows that the socks have variable element contents (up a few orders of value) and under this condition the soil may be poisoned with undesirable toxic elements. Thus, it becomes actual to analyse the total element contents of soil and the inserted meliorants (rocks and other resources available in the region) used in agriculture production. Besides, the obtained information about element contents of mountain rocks allows to solve not only geochemical problems but also to evaluate soil formation process. Choose of a mountain rock having soil. Lack of microelements in soil can be made up by fitting optimal doses of meliorants consisting of mineral (NPK) and local fertilizers, mountain rocks or industrial waste. We proved earlier, that the soils of cotton planting area of Uzbekistan are exhausted with the nutrient elements (Co, Fe, Zn, Cu, Mn, Mo, Rb, Cs, K and rarer P). Besides, the soil are polluted with As, Sb, Br, U, Th, REE and the Republics. Owing to pollution of the region soil with toxic elements, deficit of the nutritious in the environment, one can expect progressing of several diseases (sick ratr) in the population. Relating to the update agro-state of the soil of cotton planting region of Karakalpakstan, one can observe similar agrogeochemical processes complicated by a sharp accumulation on Na and Cl in subsurface layers of the soil. On the territory of the South Aral at different depths of many chinks and paleogenic terrigenic thick being opened in hills of Krantau, Khoja-Kul, Beshtube, Khojeily and also in the South-East Sultanuezdag, there are

  2. Microelements containing in rock of the Aral region. Agrogeochemical problems

    International Nuclear Information System (INIS)

    Zhumamuratov, A.

    2004-01-01

    Full text: Lately chemization of agriculture has been done not only by mineral nutrification and pesticides but also by melioration with rocks and industrial waste. However, increase in soil fertility and the related efficiency of production requires systematic control and analysis of the chemization so as not to disturb the existing balance in ecosystem. The experiment on bringing mountain rocks up 30ton/hectare in soil shows that the socks have variable element contents (up a few orders of value) and under this condition the soil may be poisoned with undesirable toxic elements. Thus, it becomes actual to analyse the total element contents of soil and the inserted meliorants (rocks and other resources available in the region) used in agriculture production. Besides, the obtained information about element contents of mountain rocks allows to solve not only geochemical problems but also to evaluate soil formation process. Choose of a mountain rock having soil. Lack of microelements in soil can be made up by fitting optimal doses of meliorants consisting of mineral (NPK) and local fertilizers, mountain rocks or industrial waste. We proved earlier, that the soils of cotton planting area of Uzbekistan are exhausted with the nutrient elements (Co, Fe, Zn, Cu, Mn, Mo, Rb, Cs, K and rarer P). Besides, the soil are polluted with As, Sb, Br, U, Th, REE and the Republics. Owing to pollution of the region soil with toxic elements, deficit of the nutritious in the environment, one can expect progressing of several diseases (sick ratr) in the population. Relating to the update agro-state of the soil of cotton planting region of Karakalpakstan, one can observe similar agrogeochemical processes complicated by a sharp accumulation on Na and Cl in subsurface layers of the soil. On the territory of the South Aral at different depths of many chinks and paleogenic terrigenic thick being opened in hills of Krantau, Khoja-Kul, Beshtube, Khojeily and also in the South-East Sultanuezdag

  3. Exploring How Weathering Related Stresses and Subcritical Crack Growth May Influence the Size of Sediment Produced From Different Rock Types.

    Science.gov (United States)

    Eppes, M. C.; Hallet, B.; Hancock, G. S.; Mackenzie-Helnwein, P.; Keanini, R.

    2016-12-01

    The formation and diminution of rock debris, sediment and soil at and near Earth's surface is driven in large part by in situ, non-transport related, rock cracking. Given the relatively low magnitude stresses that arise in surface and near-surface settings, this production and diminution of granular material is likely strongly influenced and/or driven by subcritical crack growth (Eppes et al., 2016), cracking that occurs under stress loading conditions much lower than a rock's strength as typically measured in the laboratory under rapid loading. Despite a relatively sound understanding of subcritical crack growth through engineering and geophysical studies, its geomorphic and sedimentologic implications have only been minimally explored. Here, based on existing studies, we formulate several hypotheses to predict how weathering-induced stresses combined with the subcritical crack growth properties of rock may influence sediment size distribution. For example, subcritical crack growth velocity (v) can be described by v = CKIn where KI is the mode I (simple opening mode) stress intensity factor, a function of tensile stress at the crack tip and crack length; C is a rock- and environment-dependent constant; and n is material constant, the subcritical crack growth index. Fracture length and spacing in rock is strongly dependent on n, where higher n values result in fewer, more distally spaced cracks (e.g. Olsen, 1993). Thus, coarser sediment might be expected from rocks with higher n values. Weathering-related stresses such as thermal stresses and mineral hydration, however, can disproportionally stress boundaries between minerals with contrasting thermal or chemical properties and orientation, resulting in granular disintegration. Thus, rocks with properties favorable to inducing these stresses might produce sediment whose size is reflective of its constituent grains. We begin to test these hypotheses through a detailed examination of crack and rock characteristics in

  4. The results of the investigations on rock mechanics in HDB-9-11 boreholes and update of the rock mechanical model around the Horonobe URL construction area

    International Nuclear Information System (INIS)

    Sanada, Hiroyuki; Niunoya, Sumio; Matsui, Hiroya

    2008-09-01

    Horonobe URL (Underground Research Laboratory) Project is conducted at Horonobe-cho, Teshio-gun, Hokkaido. This research report shows the result of the rock mechanical investigations which have been carried out from 2004 to 2005 as a part of the project. The objectives of the rock mechanical investigation are as follows: To obtain the data which were necessary for construction design of URL. To confirm the distribution of rock mechanical properties in and around URL construction area. The results of the investigations are summarized as follows: 1) Variation and values of depth direction of physical and mechanical properties in the laboratory construction area corresponded approximately to the results obtained from the rock mechanical investigations of HDB-1-8. 2) The major redesign had been not had about physical and mechanical properties in the laboratory construction area being able to divide into three zones and length of its own zone in updating rock mechanical model. 3) From the results of initial stress measured by hydraulic fracturing, the results that the direction of the maximum principle stress is E-W was no different from results obtained from the investigations of HDB-1-8, but the magnitude correlation among maximum, minimum principle stress and overburden pressure measured around G.L.-927 m showed different trends compared with the results of HDB-1-8. 4) Diatomaceous mudstone was yielded under isotropic compression. Cam-clay model as constitutive law of diatomaceous mudstone should be used for tunnel excavation analysis. 5) Uniaxial compression strength of rock saturated under saline water is larger than that of saturated under freshwater. Poisson's ratio of rock saturated under saline water is smaller than that of saturated under saline water. 6) The effective confining pressure increases with the equivalent opening width and permeability decreases. 7) The value of principle stress obtained from DSCA method is larger than that obtained from hydraulic

  5. Chemistry and texture of the rocks at Rocknest, Gale Crater: Evidence for sedimentary origin and diagenetic alteration

    Science.gov (United States)

    Blaney, Diana L.; Wiens, R.C.; Maurice, S.; Clegg, S.M.; Anderson, Ryan; Kah, L.C.; Le Mouélic, S.; Ollila, A.; Bridges, N.; Tokar, R.; Berger, G.; Bridges, J.C.; Cousin, A.; Clark, B.; Dyar, M.D.; King, P.L.; Lanza, N.; Mangold, N.; Meslin, P.-Y.; Newsom, H.; Schroder, S.; Rowland, S.; Johnson, J.; Edgar, L.; Gasnault, O.; Forni, O.; Schmidt, M.; Goetz, W.; Stack, K.; Sumner, D.; Fisk, M.; Madsen, M.B.

    2014-01-01

    A suite of eight rocks analyzed by the Curiosity Rover while it was stopped at the Rocknest sand ripple shows the greatest chemical divergence of any potentially sedimentary rocks analyzed in the early part of the mission. Relative to average Martian soil and to the stratigraphically lower units encountered as part of the Yellowknife Bay formation, these rocks are significantly depleted in MgO, with a mean of 1.3 wt %, and high in Fe, averaging over 20 wt % FeOT, with values between 15 and 26 wt % FeOT. The variable iron and low magnesium and rock texture make it unlikely that these are igneous rocks. Rock surface textures range from rough to smooth, can be pitted or grooved, and show various degrees of wind erosion. Some rocks display poorly defined layering while others seem to show possible fractures. Narrow vertical voids are present in Rocknest 3, one of the rocks showing the strongest layering. Rocks in the vicinity of Rocknest may have undergone some diagenesis similar to other rocks in the Yellowknife Bay Formation as indicated by the presence of soluble calcium phases. The most reasonable scenario is that fine-grained sediments, potentially a mixture of feldspar-rich rocks from Bradbury Rise and normal Martian soil, were lithified together by an iron-rich cement.

  6. Review of and contribution to the Stratigraphy of the Cenozoic Igneous Rocks in the Republic of Yemen

    International Nuclear Information System (INIS)

    El-Nakhal, H.A.

    2002-01-01

    In Yemen the Cenozoic igneous rocks consists of intrusive and extrusive rocks with interlayered sediments, all of which are included within the Manakha Group (latest Cretaceous-Holocene). This group is subdivided into the Haraz Formation which includes the latest Cretaceous-Tertiary volcanics and the interlayered sediments, the Aden Formation which includes the Late Tertiary-Holocene volcanics, and the Bura Formations are introduced here as new units. The Haraz Formation replaces the informal names: Trap Series, Yemen Volcanics and Aden Trap Series, Yemen Volcanics and Adan Trap Series.The Adan Formation are a readaptation of the term Aden Vocanic Series. A startotype for the Aden Formation is designated in the Shuqra-Ahwar area. (author)

  7. Poisson's Ratio and Auxetic Properties of Natural Rocks

    Science.gov (United States)

    Ji, Shaocheng; Li, Le; Motra, Hem Bahadur; Wuttke, Frank; Sun, Shengsi; Michibayashi, Katsuyoshi; Salisbury, Matthew H.

    2018-02-01

    Here we provide an appraisal of the Poisson's ratios (υ) for natural elements, common oxides, silicate minerals, and rocks with the purpose of searching for naturally auxetic materials. The Poisson's ratios of equivalently isotropic polycrystalline aggregates were calculated from dynamically measured elastic properties. Alpha-cristobalite is currently the only known naturally occurring mineral that has exclusively negative υ values at 20-1,500°C. Quartz and potentially berlinite (AlPO4) display auxetic behavior in the vicinity of their α-β structure transition. None of the crystalline igneous and metamorphic rocks (e.g., amphibolite, gabbro, granite, peridotite, and schist) display auxetic behavior at pressures of >5 MPa and room temperature. Our experimental measurements showed that quartz-rich sedimentary rocks (i.e., sandstone and siltstone) are most likely to be the only rocks with negative Poisson's ratios at low confining pressures (≤200 MPa) because their main constituent mineral, α-quartz, already has extremely low Poisson's ratio (υ = 0.08) and they contain microcracks, micropores, and secondary minerals. This finding may provide a new explanation for formation of dome-and-basin structures in quartz-rich sedimentary rocks in response to a horizontal compressional stress in the upper crust.

  8. Agronomic behavior of phosphoric rock from Bahia Inglesa using isotopic techniques. 1. Field trial with concentrated and non concentrated rock

    International Nuclear Information System (INIS)

    Pino N, I.; Casa G, L.

    1989-01-01

    With the aim to assess the agronomic behaviour of the phosphoric rock from Bahia Inglesa, a field trial was carried out with concentrated and non concentrated 100 mesh sieved rock. The method of isotopic dilution was used with TSP labeled P32 (TSP-P32) as standard fertilizer. Total dry matter, total P by colorimetry and P32 by liquid scintillation using the Cerenkov effect were measured. Both agronomic and isotope parameters were analyzed. The concentrated phosphoric rock was 3.7 times better than the same non concentrated rock. These also was a positive effect from non concentrated at 400 kg P205/ha dose. This effect was attributed to a higher saturation in the points of P sorption. The TSP showed a better behaviour than the phosphoric rock under study. (author)

  9. Theoretical Modeling of Rock Breakage by Hydraulic and Mechanical Tool

    Directory of Open Access Journals (Sweden)

    Hongxiang Jiang

    2014-01-01

    Full Text Available Rock breakage by coupled mechanical and hydraulic action has been developed over the past several decades, but theoretical study on rock fragmentation by mechanical tool with water pressure assistance was still lacking. The theoretical model of rock breakage by mechanical tool was developed based on the rock fracture mechanics and the solution of Boussinesq’s problem, and it could explain the process of rock fragmentation as well as predicating the peak reacting force. The theoretical model of rock breakage by coupled mechanical and hydraulic action was developed according to the superposition principle of intensity factors at the crack tip, and the reacting force of mechanical tool assisted by hydraulic action could be reduced obviously if the crack with a critical length could be produced by mechanical or hydraulic impact. The experimental results indicated that the peak reacting force could be reduced about 15% assisted by medium water pressure, and quick reduction of reacting force after peak value decreased the specific energy consumption of rock fragmentation by mechanical tool. The crack formation by mechanical or hydraulic impact was the prerequisite to improvement of the ability of combined breakage.

  10. Hydromechanical modeling of clay rock including fracture damage

    Science.gov (United States)

    Asahina, D.; Houseworth, J. E.; Birkholzer, J. T.

    2012-12-01

    Argillaceous rock typically acts as a flow barrier, but under certain conditions significant and potentially conductive fractures may be present. Fracture formation is well-known to occur in the vicinity of underground excavations in a region known as the excavation disturbed zone. Such problems are of particular importance for low-permeability, mechanically weak rock such as clays and shales because fractures can be relatively transient as a result of fracture self-sealing processes. Perhaps not as well appreciated is the fact that natural fractures can form in argillaceous rock as a result of hydraulic overpressure caused by phenomena such as disequlibrium compaction, changes in tectonic stress, and mineral dehydration. Overpressure conditions can cause hydraulic fracturing if the fluid pressure leads to tensile effective stresses that exceed the tensile strength of the material. Quantitative modeling of this type of process requires coupling between hydrogeologic processes and geomechanical processes including fracture initiation and propagation. Here we present a computational method for three-dimensional, hydromechanical coupled processes including fracture damage. Fractures are represented as discrete features in a fracture network that interact with a porous rock matrix. Fracture configurations are mapped onto an unstructured, three-dimensonal, Voronoi grid, which is based on a random set of spatial points. Discrete fracture networks (DFN) are represented by the connections of the edges of a Voronoi cells. This methodology has the advantage that fractures can be more easily introduced in response to coupled hydro-mechanical processes and generally eliminates several potential issues associated with the geometry of DFN and numerical gridding. A geomechanical and fracture-damage model is developed here using the Rigid-Body-Spring-Network (RBSN) numerical method. The hydrogelogic and geomechanical models share the same geometrical information from a 3D Voronoi

  11. 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)

  12. THE STUDY OF GAS MIGRATION IN CRYSTALLINE ROCK USING INJECTION TESTS

    Directory of Open Access Journals (Sweden)

    Jiří Svoboda

    2012-07-01

    Full Text Available The study of gas migration in crystalline rock using injection tests is being carried out in the frame of the FORGE (Fate of Repository Gases project. The Czech Technical University in Prague (CTU, Centre of Experimental Geotechnics (CEG is participating in WP4 which is focused on disturbed host rock formations with respect to radioactive waste deep repositories. A series of in-situ tests is being conducted at the Josef Underground Laboratory. The aim of the testing is to simulate and study phenomena that might lead to gas-driven radionuclide transport in fractured crystalline rock. The in-situ tests combine migration and large-scale gas injection measurements; gas injection tests are being employed for the study of gas transport. For the purposes of comparison of the behaviour of the rock mass with regard to air and water a series of water pressure tests are also being carried out. The quality of the rock mass is assessed using rock mass classification systems.

  13. Geochemistry of silicate-rich rocks can curtail spreading of carbon dioxide in subsurface aquifers.

    Science.gov (United States)

    Cardoso, S S S; Andres, J T H

    2014-12-11

    Pools of carbon dioxide are found in natural geological accumulations and in engineered storage in saline aquifers. It has been thought that once this CO2 dissolves in the formation water, making it denser, convection streams will transport it efficiently to depth, but this may not be so. Here, we assess theoretically and experimentally the impact of natural chemical reactions between the dissolved CO2 and the rock formation on the convection streams in the subsurface. We show that, while in carbonate rocks the streaming of dissolved carbon dioxide persists, the chemical interactions in silicate-rich rocks may curb this transport drastically and even inhibit it altogether. These results challenge our view of carbon sequestration and dissolution rates in the subsurface, suggesting that pooled carbon dioxide may remain in the shallower regions of the formation for hundreds to thousands of years. The deeper regions of the reservoir can remain virtually carbon free.

  14. Improved microstructure of cement-based composites through the addition of rock wool particles

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Wei-Ting [Dept. of Civil Engineering, National Ilan University, Ilan 26047, Taiwan (China); Institute of Nuclear Energy Research, Atomic Energy Council, Taoyuan 32546, Taiwan (China); Cheng, An, E-mail: ancheng@niu.edu.tw [Dept. of Civil Engineering, National Ilan University, Ilan 26047, Taiwan (China); Huang, Ran; Zou, Si-Yu [Dept. of Harbor and River Engineering, National Taiwan Ocean University, Keelung 20224, Taiwan (China)

    2013-10-15

    Rock wool is an inorganic fibrous substance produced by steam blasting and cooling molten glass. As with other industrial by-products, rock wool particles can be used as cementitious materials or ultra fine fillers in cement-based composites. This study investigated the microstructure of mortar specimens produced with cement-based composites that include various forms of rock wool particles. It conducted compressive strength testing, rapid chloride penetration tests, X-ray diffraction analysis, thermo-gravimetric analysis, and scanning electronic microscopy to evaluate the macro- and micro-properties of the cement-based composites. Test results indicate that inclusion of rock wool particles in composites improved compressive strength and reduced chloride ion penetration at the age of 91 days due to the reduction of calcium hydroxide content. Microscopic analysis confirms that the use of rock wool particles contributed to the formation of a denser, more compact microstructure within the hardened paste. In addition, X-ray diffraction analysis shows few changes in formation of pozzolanic reaction products and no new hydrations are formed with incorporating rock wool particles. - Highlights: • We report the microstructural characterization of cement-based composites. • Different mixes produced with various rock wool particles have been tested. • The influence of different mixes on macro and micro properties has been discussed. • The macro properties are included compressive strength and permeability. • XRD and SEM observations confirm the pozzolanic reaction in the resulting pastes.

  15. Experimental study of chemical-mechanical coupling during percolation of reactive fluid through rocks under stress, in the context of the CO2 geological sequestration

    International Nuclear Information System (INIS)

    Le Guen, Y.

    2006-10-01

    CO 2 injection into geological repositories will induce chemical and mechanical instabilities. The study of these instabilities is based on experimental deformation of natural rock samples under stress, in the presence of fluids containing, or not, dissolved CO 2 . Triaxial cells used for the experiments permitted an independent control and measurement of stress, temperature, fluid pressure and composition. Vertical strains were measured during several months, with a resolution of 1.10 -12 s -1 on the strain rate. Simultaneously, fluids were analysed in order to quantify fluid-rock interactions. For limestone samples, percolation of CO 2 -rich fluids increases strain rate by a factor 1.7 up to 5; on the other hand, sandstone deformation remained almost the same. Increase in strain rate with limestone samples was explained by injected water acidification by the CO 2 which increases rock solubility and reaction kinetics. On the opposite, small effect of CO 2 on quartz explains the absence of deformation. X-ray observations confirmed the importance of rock composition and structure on the porosity evolution. Numerical simulations of rock elastic properties showed increasing shear stress into the sample. Measured deformation showed an evolution of reservoir rocks mechanical properties. It was interpreted as the consequence of pressure solution mechanisms both at grains contacts and on grain free surfaces. (author)

  16. Formation and fate of gases in the caverns of a repository in salt rock

    International Nuclear Information System (INIS)

    Mueller, W.; Morlock, G.; Gronemeyer, C.

    1992-01-01

    The report summarizes the knowledge avaible today of the mechanisms governing the formation and transport of gases in a salt mine repository for radioactive wastes. The work under review deals with the formation of gases-by way of radiolysis, corrosion, microbial degradation, thermally induced or primary gas generation - and analyses the efficiency of predicting and modelling the gas generation mechanisms in terms of the role of parameters involved, and accuracy. Existing gaps in available knowledge are shown and defined in terms of significance, leading to an analysis of interdependencies between the various mechanisms and to a statement concerning the necessity of establishing materials balances. (orig./EF) [de

  17. Formative flow in bedrock canyons

    Science.gov (United States)

    Venditti, J. G.; Kwoll, E.; Rennie, C. D.; Church, M. A.

    2017-12-01

    In alluvial channels, it is widely accepted that river channel configuration is set by a formative flow that represents a balance between the magnitude and frequency of flood flows. The formative flow is often considered to be one that is just capable of filling a river channel to the top of its banks. Flows much above this formative flow are thought to cause substantial sediment transport and rearrange the channel morphology to accommodate the larger flow. This idea has recently been extended to semi-alluvial channels where it has been shown that even with bedrock exposed, the flows rarely exceed that required to entrain the local sediment cover. What constitutes a formative flow in a bedrock canyon is not clear. By definition, canyons have rock walls and are typically incised vertically, removing the possibility of the walls being overtopped, as can occur in an alluvial channel at high flows. Canyons are laterally constrained, have deep scour pools and often have width to maximum depth ratios approaching 1, an order of magnitude lower than alluvial channels. In many canyons, there are a sequence of irregularly spaced scour pools. The bed may have intermittent or seasonal sediment cover, but during flood flows the sediment bed is entrained leaving a bare bedrock channel. It has been suggested that canyons cut into weak, well-jointed rock may adjust their morphology to the threshold for block plucking because the rock bed is labile during exceptionally large magnitude flows. However, this hypothesis does not apply to canyons cut into massive crystalline rock where abrasion is the dominant erosion process. Here, we argue that bedrock canyon morphology is adjusted to a characteristic flow structure developed in bedrock canyons. We show that the deeply scoured canyon floor is adjusted to a velocity inversion that is present at low flows, but gets stronger at high flows. The effect is to increase boundary shear stresses along the scour pool that forms in constricted

  18. Subtask 1.8 - Investigation of Improved Conductivity and Proppant Applications in the Bakken Formation

    Energy Technology Data Exchange (ETDEWEB)

    Bethany Kurz; Darren Schmidt; Steven Smith Christopher Beddoe; Corey Lindeman; Blaise Mibeck

    2012-07-31

    Given the importance of hydraulic fracturing and proppant performance for development of the Bakken and Three Forks Formations within the Williston Basin, a study was conducted to evaluate the key factors that may result in conductivity loss within the reservoirs. Various proppants and reservoir rock cores were exposed to several different fracturing and formation fluids at reservoir conditions. The hardness of the rock cores and the strength of the proppants were evaluated prior to and following fluid exposure. In addition, the conductivity of various proppants, as well as formation embedment and spalling, was evaluated at reservoir temperatures and pressures using actual reservoir rock cores. The results of this work suggest that certain fluids may affect both rock and proppant strength, and therefore, fluid exposure needs to be considered in the field. In addition, conductivity decreases within the Bakken Formation appear to be a function of a variety of factors, including proppant and rock strength, as well as formation embedment and spalling. The results of this study highlight the need for advanced conductivity testing, coupled with quantification of formation embedment and spalling. Given the importance of proppant performance on conductivity loss and, ultimately, oil recovery, better understanding the effects of these various factors on proppant and rock strength in the field is vital for more efficient production within unconventional oil and gas reservoirs.

  19. Tectonic implications of the contrasting geochemistry of Damaran mafic volcanic rocks, South West Africa

    International Nuclear Information System (INIS)

    Miller, R.McG.

    1983-01-01

    Ortho-amphibolites occur in the southern and central parts of the north-east-trending branch of the Damara Orogen. The Matchless Member amphibolites are interbedded with quartzose mica schist. Mobility of Si, ΣFe, Mn, Mg, Ca, Na, K, P, CO 2 , H 2 O, Rb, Ba, Sr and possibly LREE and immobility of Co, V, Sc, Ga, Zr, Nb, Y and HREE are indicated during metamorphism and reaction with country rock. Central Zone amphibolites are alkaline. The stratigraphically lower amphibolites have a within-plate chemistry; their distribution and associated rock types indicate a continental origin. The Matchless amphibolites have an ocean-floor chemistry. The Damaran sedimentary and orogenic cycle was initiated by continental rifting in three parallel zones in which alkaline acid volcanics occur locally. Widespread subsidence of the rift zones and the intervening areas followed and led to deposition of carbonate and clastic rocks under shallow marine conditions. During renewed rifting, submarine, alkaline basic lavas were extruded. The Southern Margin Zone amphibolites are interbedded with continental slope mixtites and continental rise deep-water fans. Spreading led to continental breakup and the formation of oceanic crust

  20. Radionuclide migration in geological formations

    International Nuclear Information System (INIS)

    Barbreau, A.; Heremans, R.; Skytte Jensen, B.

    1980-01-01

    Radioactive waste disposal into geological formation is based on the capacity of rocks to confine radioactivity for a long period of time. Radionuclide migration from the repository to the environment depends on different mechanisms and phenomena whose two main ones are groundwater flow and the retention and ion-exchange property of rocks. Many studies are underway presently in EEC countries concerning hydrodynamic characteristics of deep geological formations as well as in radionuclide retention capacity and modelling. Important results have already been achieved which show the complexity of some phenomena and further studies shall principally be developed taking into account real conditions of the repository and its environment

  1. The biodegradation of layered silicates under the influence of cyanobacterial-actinomycetes associations

    Science.gov (United States)

    Ivanova, Ekaterina

    2013-04-01

    The weathering of sheet silicates is well known to be related to local and global geochemical cycles. Content and composition of clay minerals in soil determine the sorption properties of the soil horizons, water-holding capacity of the soil, stickiness, plasticity, etc. Microorganisms have a diverse range of mechanisms of minerals' structure transformation (acid- and alkali formation, biosorption, complexing, etc). One of the methods is an ability of exopolysaccharide-formation, in particular the formation of mucus, common to many bacteria, including cyanobacteria. Mucous covers cyanobacteria are the specific econiches for other bacteria, including actinomycetes. The objective was to analyze the structural changes of clay minerals under the influence of the cyanobacterial-actinomycetes associative growth. The objects of the study were: 1) the experimental symbiotic association, consisting of free-living heterocyst-formative cyanobacterium Anabaena variabilis Kutz. ATCC 294132 and actinomycete Streptomyces cyaneofuscatus FR837630, 2) rock samples obtained from the Museum of the Soil Science Department of the Lomonosov Moscow State University: kaolinite, consisting of kaolin (96%) Al4 (OH) 8 [Si4O10]; mixed with hydromica, chlorite and quartz; vermiculite, consisting of vermiculite (Ca, Mg, ...)*(Mg, Fe)3(OH)2[(Si, Al)4O10]*4H2O and trioctahedral mica (biotite). The mineralogical compositions of the rocks were determined by the universal X-ray Diffractometer Carl Zeiss Yena. The operationg regime was kept constant (30 kv, 40 mA). The cultivation of the association of actinomycete S. cyanoefuscatus and cyanobacterium A. variabilis caused a reduction in the intensity of kaolinite and hydromica reflexes. However, since both (mica and kaolinite) components have a rigid structure, the significant structural transformation of the minerals was not revealed. Another pattern was observed in the experiment, where the rock sample of vermiculite was used as the mineral

  2. Analysis of hydraulic gradients across the host rock at the proposed Texas Panhandle nuclear-waste repository site

    International Nuclear Information System (INIS)

    Bair, E.S.

    1987-01-01

    Analysis of the direction of ground-water flow across the host rock at the proposed high-level nuclear-waste repository site in Deaf Smith County, Texas, is complicated by vertical and lateral changes in the density of formation fluids in the various hydrogeologic units that overlie and underlie the proposed host rock. Because the concept of hydraulic head is not valid when evaluating vertical hydraulic gradients in a variably-density flow system, other methods were used to determine the direction and magnitude of vertical hydraulic gradients at the proposed site where the specific gravity of formation fluids varies between 1.00 and 1.28. The direction of ground-water flow across the proposed host rock, an 80-foot-thick salt bed in the Lower San Andres Formation, was determined by calculating vertical hydraulic gradients based on formation pressure and fluid density data, and by analysis of pressure-depth diagrams. Based on data from the vicinity of the proposed site, both methods indicate the potential for downflow across the host rock. Downflow or predominantly horizontal flow is considered a favorable prewaste emplacement condition because it prolongs the travel time to the biosphere of any naturally or accidentally released radionuclides

  3. The Rustler Formation at the WIPP [Waste Isolations Pilot Plant] site: Report of a workshop on the geology and hydrology of the Rustler Formation as it relates to the WIPP Project

    International Nuclear Information System (INIS)

    Chaturvedi, L.

    1987-02-01

    This workshop contained eight papers characterizing the Rustler Formation at the WIPP site in New Mexico. Four of these reports were processed separately for the data bases. Information contained in the four remaining papers is available in journal articles or in the reports of other conferences and included discussions of ground water flow through the Rustler Formation, the potential migration of leached radionuclides in this rock, the effects of mineral dissolution on the removal of underlying salt deposits, and a possible pathway for radionuclide migration into the biosphere

  4. Geophysical testing of rock and its relationships to physical properties

    Science.gov (United States)

    2011-02-01

    Testing techniques were designed to characterize spatial variability in geotechnical engineering physical parameters of : rock formations. Standard methods using seismic waves, which are routinely used for shallow subsurface : investigation, have lim...

  5. Study on investigation and evaluation methods of deep seated sedimentary rocks. Chemical weathering, pore water squeezing and relationships of physical properties of sedimentary rocks

    International Nuclear Information System (INIS)

    Oyama, Takahiro; Suzuki, Koichi

    2006-01-01

    Chemical weathering, porewater squeezing and physical properties for the sedimentary rocks were examined. Chemical weathering potential of rocks was described by the sulfur as a acceleration factor of weathering and carbonate contents as a neutralization factor of it. The carbonate contents in the rocks were measured accurately by the gas pressure measurement method. Pore water squeezing method was applied for the semi-hard sedimentary rocks (Opalinusclay). The chemical change of extracted pore water under high pressure conditions was estimated. Physical property of sedimentary rocks have relationship among the porosity and permeability and resistivity coefficient in the same rock types. It is possible to estimate the water permeability from the geophysical tests. (author)

  6. A pore-scale study of fracture dynamics in rock using X-ray micro-CT under ambient freeze-thaw cycling.

    Science.gov (United States)

    De Kock, Tim; Boone, Marijn A; De Schryver, Thomas; Van Stappen, Jeroen; Derluyn, Hannelore; Masschaele, Bert; De Schutter, Geert; Cnudde, Veerle

    2015-03-03

    Freeze-thaw cycling stresses many environments which include porous media such as soil, rock and concrete. Climate change can expose new regions and subject others to a changing freeze-thaw frequency. Therefore, understanding and predicting the effect of freeze-thaw cycles is important in environmental science, the built environment and cultural heritage preservation. In this paper, we explore the possibilities of state-of-the-art micro-CT in studying the pore scale dynamics related to freezing and thawing. The experiments show the development of a fracture network in a porous limestone when cooling to -9.7 °C, at which an exothermal temperature peak is a proxy for ice crystallization. The dynamics of the fracture network are visualized with a time frame of 80 s. Theoretical assumptions predict that crystallization in these experiments occurs in pores of 6-20.1 nm under transient conditions. Here, the crystallization-induced stress exceeds rock strength when the local crystal fraction in the pores is 4.3%. The location of fractures is strongly related to preferential water uptake paths and rock texture, which are visually identified. Laboratory, continuous X-ray micro-CT scanning opens new perspectives for the pore-scale study of ice crystallization in porous media as well as for environmental processes related to freeze-thaw fracturing.

  7. Phosphate-rich sedimentary rocks: significance for organic facies and petroleum exploration

    Energy Technology Data Exchange (ETDEWEB)

    Waples, D W

    1982-03-01

    Phosphorus-bearing rocks and sediments can be divided into two genetically distinct classes: phosphatic shales or limestones and phosphorites. Phosphatic shales are primary sediments in which phosphate nodules or micronodules have formed diagenetically by precipitation of calcium phosphates derived mainly from organic phosphorus. The nodules form in reducing environments at shallow depths within the sediments, where loss of phosphate by diffusion to the overlying water column is minimized. Highly biogenic sediments containing large amounts of organic matter and some fine clastic debris provide ideal environments for the formation of phosphate nodules. Phosphorites, in contrast, represent concentrated accumulations of reworked phosphate nodules which originated in phosphatic shales or limestones. Currents, wave action, recrystallization, and erosion and resedimentation are important mechanisms in the concentration process. Phosphatic shales and limestones may become excellent oil source rocks if thermal maturity is achieved. They are useful facies indicators for anoxic or nearly anoxic depositional environments, and are often associated with restricted basins, or, during certain geologic periods, with broad shelves developed during transgressions. Phosphorites, in contrast, are often correlated with sea-level regressions or uplifts. They are modest source rocks because of their low organic carbon contents and the fact that they were reworked under oxidizing conditions. Nevertheless, because phosphorites are derived from, and often grade into, phosphatic shales, they also are of potential utility in the search for oil source beds.

  8. Investigation of Macroscopic Brittle Creep Failure Caused by Microcrack Growth Under Step Loading and Unloading in Rocks

    Science.gov (United States)

    Li, Xiaozhao; Shao, Zhushan

    2016-07-01

    The growth of subcritical cracks plays an important role in the creep of brittle rock. The stress path has a great influence on creep properties. A micromechanics-based model is presented to study the effect of the stress path on creep properties. The microcrack model of Ashby and Sammis, Charles' Law, and a new micro-macro relation are employed in our model. This new micro-macro relation is proposed by using the correlation between the micromechanical and macroscopic definition of damage. A stress path function is also introduced by the relationship between stress and time. Theoretical expressions of the stress-strain relationship and creep behavior are derived. The effects of confining pressure on the stress-strain relationship are studied. Crack initiation stress and peak stress are achieved under different confining pressures. The applied constant stress that could cause creep behavior is predicted. Creep properties are studied under the step loading of axial stress or the unloading of confining pressure. Rationality of the micromechanics-based model is verified by the experimental results of Jinping marble. Furthermore, the effects of model parameters and the unloading rate of confining pressure on creep behavior are analyzed. The coupling effect of step axial stress and confining pressure on creep failure is also discussed. The results provide implications on the deformation behavior and time-delayed rockburst mechanism caused by microcrack growth on surrounding rocks during deep underground excavations.

  9. What is the Emerging Knowledge of the Early Earth from the Oldest (>3.6 Ga) Rocks?

    Science.gov (United States)

    Bennett, V. C.; Nutman, A. P.

    2016-12-01

    Eoarchean to Hadean rocks are direct samples of early Earth chemistry and conditions and provide the ground-truth for models of early Earth formation, environments and evolution. Intensive investigations by many groups reveal rocks of this age comprise only one millionth of Earth's surface and are found in 9 areas of varying extent distributed worldwide. This record is of variable fidelity however, owing to metamorphic overprinting. The majority of the oldest rocks are high grade gneisses with protoliths from mid-crustal levels; the more rare supracrustal assemblages reflect early Earth's surface conditions and processes. First-order observations from supracrustal sequences at several localities and from 3.6 Ga to ≥3.9 Ga in age provide abundant evidence of liquid water at the Earth's surface with pillow basalts and chemical sedimentary rocks in the form of cherts, banded Fe formations and carbonates. Trace element patterns of these sedimentary rocks strongly resemble modern seawater compositions, except for the absence of redox sensitive Ce anomalies. Evidence for early life remains controversial and is mainly in the form of stable isotopic signatures of C and Fe. Our recent work from newly-discovered, exceptionally well-preserved 3.7 Ga sedimentary rocks and the deformed unconformity they rest on has provided the first evidence of Eoarchean intense weathering and shallow water sedimentary processes. Whilst the major and trace element compositions of Eoarchean gneisses have analogs in younger rocks in accord with a continuum of crust formation processes, radiogenic isotopic signatures from both long and short half-life decay schemes record an image of the Earth in transition from early differentiation processes, likely associated with planetary accretion and formation, to more modern styles. Most Eoarchean rocks possess extinct nuclide anomalies in the form of 142Nd and 182W isotopic signatures that are absent in modern terrestrial samples, and developed from

  10. A study about long-term deformation of soft rock. 2

    International Nuclear Information System (INIS)

    Inoue, Hiroyuki; Yoshino, Naoto; Miyanomae, Shunichi; Mizutani, Kazuhiko; Noda, Kenji

    2004-02-01

    In this study, the laboratory mechanical tests of sedimentary soft rock sampled at Horonobe area in Hokkaido prefecture were conducted in order to build the confidence of Okubo model for long term deformation of sedimentary rock. And the stability of rock around tunnel in building under the condition assumed the underground of Horonobe area was examined by numerical simulation using information of boring data obtained before 2002 year. As a result, authors could obtain many values of parameter in Okubo model under various conditions. These conditions have the difference of temperature and water saturation. In addition, the life time in creep predicted by Okubo model could be compared with the real one. And numerical simulations, assuming various conditions such as stiffness of buffer material and yielding of support, had been carried out to evaluate the long-term stability of rock surrounding buffer material. Results show the decreasing tendency of time dependency of rock. (author)

  11. A physico-chemical characterisation technique for determining the pore-water chemistry in argillaceous rocks

    International Nuclear Information System (INIS)

    Baeyens, B.; Bradbury, M.H.

    1991-09-01

    A prerequisite for carrying out credible sorption studies is the definition of an aqueous phase composition which is in equilibrium with the solid phase. Experimental methods and data analysis procedures are described which enable an equilibrium water composition to be produced for argillaceous rocks which is not dependent on liquid to solid (L:S) ratios. Since a Valanginian marl formation is under consideration by Nagra as a potential rock for the disposal of low and short-lived medium level radioactive waste in Switzerland, samples of this material were chosen for this investigation. Aqueous phase and nickel ethylenediamine extraction experiments were carried out at different L:S ratios under controlled atmosphere conditions (P CO 2 =10 -2 bar, O 2 ≤ 5 ppm ). The results from these tests and petrographical examinations were combined to define the system in terms of the physico-chemical characteristics of the clay mineral component (CEC and cation occupancies) and the identities of highly soluble and solubility limited phases in the marl. The geochemical code PHREEQE was used in conjunction with the Gapon equations to calculate the pore water composition. This work clearly showed that pore water chemistries obtained from aqueous extracts alone may lead to an arbitrary water chemistry in argillaceous rock systems, particularly with respect to ionic composition and ionic strength, which may have important consequences for radionuclide speciation and sorption studies. (author) 11 figs., 12 tabs., 25 refs

  12. Mechanical weathering and rock erosion by climate-dependent subcritical cracking

    Science.gov (United States)

    Eppes, Martha-Cary; Keanini, Russell

    2017-06-01

    This work constructs a fracture mechanics framework for conceptualizing mechanical rock breakdown and consequent regolith production and erosion on the surface of Earth and other terrestrial bodies. Here our analysis of fracture mechanics literature explicitly establishes for the first time that all mechanical weathering in most rock types likely progresses by climate-dependent subcritical cracking under virtually all Earth surface and near-surface environmental conditions. We substantiate and quantify this finding through development of physically based subcritical cracking and rock erosion models founded in well-vetted fracture mechanics and mechanical weathering, theory, and observation. The models show that subcritical cracking can culminate in significant rock fracture and erosion under commonly experienced environmental stress magnitudes that are significantly lower than rock critical strength. Our calculations also indicate that climate strongly influences subcritical cracking—and thus rock weathering rates—irrespective of the source of the stress (e.g., freezing, thermal cycling, and unloading). The climate dependence of subcritical cracking rates is due to the chemophysical processes acting to break bonds at crack tips experiencing these low stresses. We find that for any stress or combination of stresses lower than a rock's critical strength, linear increases in humidity lead to exponential acceleration of subcritical cracking and associated rock erosion. Our modeling also shows that these rates are sensitive to numerous other environment, rock, and mineral properties that are currently not well characterized. We propose that confining pressure from overlying soil or rock may serve to suppress subcritical cracking in near-surface environments. These results are applicable to all weathering processes.

  13. Geohydromechanical Processes in the Excavation Damaged Zone in Crystalline Rock, Rock Salt, and Indurated and Plastic Clays

    International Nuclear Information System (INIS)

    Tsang, Chin-Fu; Bernier, Frederic; Davies, Christophe

    2004-01-01

    The creation of an excavation disturbed zone or excavation damaged zone is expected around all man-made openings in geologic formations. Macro- and micro-fracturing, and in general a redistribution of in situ stresses and rearrangement of rock structures, will occur in this zone, resulting in drastic changes of permeability to flow, mainly through the fractures and cracks induced by excavation. Such an EDZ may have significant implications for the operation and long-term performance of an underground nuclear waste repository. Various issues of concern need to be evaluated, such as processes creating fractures in the excavation damaged zone, the degree of permeability increase, and the potential for sealing or healing (with permeability reduction) in the zone. In recent years, efforts along these lines have been made for a potential repository in four rock types-crystalline rock, salt, indurated clay, and plastic clay-and these efforts have involved field, laboratory, and theoretical studies. The present work involves a synthesis of the ideas and issues that emerged from presentations and discussions on EDZ in these four rock types at a CLUSTER Conference and Workshop held in Luxembourg in November, 2003. First, definitions of excavation disturbed and excavation damaged zones are proposed. Then, an approach is suggested for the synthesis and intercomparison of geohydromechanical processes in the EDZ for the four rock types (crystalline rock, salt, indurated clay, and plastic clay). Comparison tables of relevant processes, associated factors, and modeling and testing techniques are developed. A discussion of the general state-of-the-art and outstanding issues are also presented. A substantial bibliography of relevant papers on the subject is supplied at the end of the paper

  14. Hydrologic properties of shale and related argillaceous rocks

    International Nuclear Information System (INIS)

    Moiseyev, A.N.

    1979-01-01

    This report is the result of a bibliographic study designed primarily to collect hydrologic data on American clay-rich rocks. The following information was also sought: stratigraphy, environment of deposition, mineralogic composition, and diagenetic changes. The collected numerical data are presented in tables which contain densities, porosities, and/or hydraulic conductivities of approximately 360 samples. Additional data include hydraulic diffusivities, resistivities, flow rates, and rock strengths. Geologic information suggests that large deposits of shale which may be suited for waste repository belong to all ages and were formed in both marine and continental environments. Of the studied units, the most promising are Paleozoic in the eastern half of the country, Mesozoic in the central part, and Cenozoic in the Gulf Coast area and the West. Less widespread units locally present some additional possibilities. Mineralogic investigations suggest that the smectite content in rocks shows a decrease in time (70% in Recent rocks; 35% in pre-Mesozoic rocks). Because of this predominance of smectite in younger rocks, the modeling of repositories in post-Paleozoic formations might require knowledge of additional and poorly known parameters. Results of investigations into the mathematical relationships between porosity and permeability (or hydralic conductivity) suggest that in situ permeabilities could be estimated from sonic logs and fluid pressure changes at depth. 16 figures, 8 tables

  15. Experimental investigation of creep behavior of clastic rock in Xiangjiaba Hydropower Project

    Directory of Open Access Journals (Sweden)

    Yu Zhang

    2015-01-01

    Full Text Available There are many fracture zones crossing the dam foundation of the Xiangjiaba Hydropower Project in southwestern China. Clastic rock is the main media of the fracture zone and has poor physical and mechanical properties. In order to investigate the creep behavior of clastic rock, triaxial creep tests were conducted using a rock servo-controlling rheological testing machine. The results show that the creep behavior of clastic rock is significant at a high level of deviatoric stress, and less time-dependent deformation occurs at high confining pressure. Based on the creep test results, the relationship between axial strain and time under different confining pressures was investigated, and the relationship between axial strain rate and deviatoric stress was also discussed. The strain rate increases rapidly, and the rock sample fails eventually under high deviatoric stress. Moreover, the creep failure mechanism under different confining pressures was analyzed. The main failure mechanism of clastic rock is plastic shear, accompanied by a significant compression and ductile dilatancy. On the other hand, with the determined parameters, the Burgers creep model was used to fit the creep curves. The results indicate that the Burgers model can exactly describe the creep behavior of clastic rock in the Xiangjiaba Hydropower Project.

  16. New Techniques for Monitoring and Analyzing the Stability of Steep Cliffs against Rock Falls

    OpenAIRE

    Fujii, Yoshiaki; Maeda, S; Sugawara, T; Kodama, N; Miyashita, N

    2016-01-01

    Mechanisms of joint opening leading to the formation of unstable rock blocks, such as thermal deformation, water-mineral reaction, pore pressure, freeze-thaw cycle, intrusion of wood roots etc. have been more or less clarified; however, the triggering mechanisms of rock falls remain to be elucidated. The problems which prevent the understanding of the mechanisms are (1) difficulty in installation of sensors to very unstable rock blocks, (2) thermoelastic deformation of sensors and attachments...

  17. Analysis of Western Australian zebra rock

    International Nuclear Information System (INIS)

    Clark, M.J.; Cashion, J.D.

    2000-01-01

    Full text: Zebra rock is a striking rock from the Ord River area of Western Australia which contains regularly spaced white and red-brown bands or rods. Its ease of working has made it popular for use in ornaments and costume jewellery. However, the mechanism for its formation has been a source of controversy for 75 years and is still not settled. Possible mechanisms proposed include slow sedimentation with regular addition of hydrated iron oxides, leaching of a reddish mudstone, post-depositional mobilisation and subsequent rhythmic precipitation of iron oxides from groundwaters, and accumulation of iron-containing minerals in ripple troughs. Loughnan and Roberts suggested a more detailed explanation and from a detailed mineralogical examination, including XRD, XRF, SEM and TEM, they concluded that the only major difference between the two coloured bands was the presence of hematite, α-Fe 2 O 3 . In an attempt to throw more light on the problem, we have taken 57 Fe Moessbauer spectra of samples from the two different coloured regions. As expected, the white coloured material contained little iron, giving a weak, broad single line spectrum at room temperature. At 78 K, the spectrum has split into a magnetic sextet which has not yet been positively identified. As expected from the XRD, the spectrum of the red part principally consists of a strong sextet due to hematite, although there is also a weak component from the phase in the white material. It is hoped that further analysis will help us to eliminate at least some of the proposed mechanisms for the formation of zebra rock

  18. Formation of lysinoalanine in egg white under alkali treatment.

    Science.gov (United States)

    Zhao, Yan; Luo, Xuying; Li, Jianke; Xu, Mingsheng; Tu, Yonggang

    2016-03-01

    To investigate the formation mechanism of lysinoalanine (LAL) in eggs during the alkali treatment process, NaOH was used for the direct alkali treatment of egg white, ovalbumin, and amino acids; in addition, the amount of LAL formed during the alkali treatment process was measured. The results showed that the alkali treatment resulted in the formation of LAL in the egg white. The LAL content increased with increasing pH and temperature, with the LAL content first increasing and then leveling off with increasing time. The amount of LAL formed in the ovalbumin under the alkali treatment condition accounted for approximately 50.51% to 58.68% of the amount of LAL formed in the egg white. Thus, the LAL formed in the ovalbumin was the main source for the LAL in the egg white during the alkali treatment process. Under the alkali treatment condition, free L-serine, L-cysteine, and L-cystine reacted with L-lysine to form LAL; therefore, they are the precursor amino acids of LAL formed in eggs during the alkali treatment process. © 2016 Poultry Science Association Inc.

  19. Whole rock and discrete pyrite geochemistry as complementary tracers of ancient ocean chemistry: An example from the Neoproterozoic Doushantuo Formation, China

    Science.gov (United States)

    Gregory, Daniel D.; Lyons, Timothy W.; Large, Ross R.; Jiang, Ganqing; Stepanov, Aleksandr S.; Diamond, Charles W.; Figueroa, Maria C.; Olin, Paul

    2017-11-01

    The trace element content of pyrite is a recently developed proxy for metal abundance in paleo-oceans. Previous studies have shown that the results broadly match those of whole rock studies through geologic time. However, no detailed study has evaluated the more traditional proxies for ocean chemistry for comparison to pyrite trace element data from the same samples. In this study we compare pyrite trace element data from 14 samples from the Wuhe section of the Ediacaran-age Doushantuo Formation, south China, measured by laser ablation inductively coupled plasma mass spectrometry with new and existing whole rock trace element concentrations; total organic carbon; Fe mineral speciation; S isotope ratios; and pyrite textural relationships. This approach allows for comparison of data for individual trace elements within the broader environmental context defined by the other chemical parameters. The results for discrete pyrite analyses show that several chalcophile and siderophile elements (Ag, Sb, Se, Pb, Cd, Te, Bi, Mo, Ni, and Au) vary among the samples with patterns that mirror those of the independent whole rock data. A comparison with existing databases for sedimentary and hydrothermal pyrite allows us to discriminate between signatures of changing ocean conditions and those of known hydrothermal sources. In the case of the Wuhe samples, the observed patterns for trace element variation point to primary marine controls rather than higher temperature processes. Specifically, our new data are consistent with previous arguments for pulses of redox sensitive trace elements interpreted to be due to marine oxygenation against a backdrop of mostly O2-poor conditions in the Ediacaran ocean-with important implications for the availability of bioessential elements. The agreement between the pyrite and whole rock data supports the use of trace element content of pyrite as a tracer of ocean chemistry in ways that complement existing approaches, while also opening additional

  20. Isotopic studies of mariposite-bearing rocks from the south- central Mother Lode, California.

    Science.gov (United States)

    Kistler, R.W.; Dodge, F.C.W.; Silberman, M.L.

    1983-01-01

    Gold-bearing vein formation in the Mother Lode belt of the study area apparently occurred during the Early Cretaceous between 127 and 108 m.y. B.P. The hydrothermal fluids that carried the gold precipitated quartz and mariposite at approx 320oC, similar to the T of precipitation of gold-bearing quartz veins in the Allegheny district. The O- and H-isotopic composition calculated for the fluid indicate that it was similar to formation water or was metamorphic in origin. If the carbonate in the veins was in isotopic equilibrium with this same fluid, it apparently precipitated at a higher T of approx 400oC. The Sr in the carbonate is much less radiogenic than that in any known marine carbonate, but is similar in isotopic composition to that in metamorphosed mafic volcanic rocks of the general region. These mafic rocks could have been the source for the Sr in the hydrothermal veins. This observation supports the contention that the gold-mariposite-quartz-carbonate rocks were formed as an alteration product of serpentinite and other mafic igneous rocks.-A.P.

  1. In situ migration experiment in argillaceous formation

    International Nuclear Information System (INIS)

    Yoshida, Hidekazu

    1990-01-01

    International cooperative R and D has been performed within the five years framework of the bilateral agreement between PNC (Power Reactor and Nuclear Fuel Development Corporation) and SCK/CEN (Studiecentrum voor Kernergie/Centre D'etude de L'energie Nucleaire, Mol, Belgium) which is focused on 'The Migration Experiment in argillaceous formation.' This Tertiary argillaceous formation, called Boom clay, is located at about 230m depth in Mol-Dessel area, Belgium. The argillaceous rock is considered to have a high capability for retardation to radionuclides when they migrate in geosphere because of a high content of clay minerals and dissolved carbon-rich pore water. The main purpose of this collaboration work is to characterize the migration phenomena in sedimentary rock through understanding of the behaviour of radionuclides migration in the argillaceous formation. The present report describes the preliminary results of in situ one-dimensional migration experiment with labelled clay core emplaced in borehole under advective condition. In the experiment, radioactive tracer Sr-85 and Eu-152+154 have been used in order to determine the apparent dispersion coefficient and retardation factor of Boom clay. Finally, the following conclusions were obtained by in situ measurement and calculation based on a appropriate migration model; a) From the Sr-85 experiment, diffusive behavior is interpreted to be a dominant phenomena on radionuclides transportation. b) From the Eu-152+154 experiment, very small non-retarded fraction is observed. (author)

  2. Numerical modelling of fluid-rock interactions: Lessons learnt from carbonate rocks diagenesis studies

    Science.gov (United States)

    Nader, Fadi; Bachaud, Pierre; Michel, Anthony

    2015-04-01

    Quantitative assessment of fluid-rock interactions and their impact on carbonate host-rocks has recently become a very attractive research topic within academic and industrial realms. Today, a common operational workflow that aims at predicting the relevant diagenetic processes on the host rocks (i.e. fluid-rock interactions) consists of three main stages: i) constructing a conceptual diagenesis model including inferred preferential fluids pathways; ii) quantifying the resulted diagenetic phases (e.g. depositing cements, dissolved and recrystallized minerals); and iii) numerical modelling of diagenetic processes. Most of the concepts of diagenetic processes operate at the larger, basin-scale, however, the description of the diagenetic phases (products of such processes) and their association with the overall petrophysical evolution of sedimentary rocks remain at reservoir (and even outcrop/ well core) scale. Conceptual models of diagenetic processes are thereafter constructed based on studying surface-exposed rocks and well cores (e.g. petrography, geochemistry, fluid inclusions). We are able to quantify the diagenetic products with various evolving techniques and on varying scales (e.g. point-counting, 2D and 3D image analysis, XRD, micro-CT and pore network models). Geochemical modelling makes use of thermodynamic and kinetic rules as well as data-bases to simulate chemical reactions and fluid-rock interactions. This can be through a 0D model, whereby a certain process is tested (e.g. the likelihood of a certain chemical reaction to operate under specific conditions). Results relate to the fluids and mineral phases involved in the chemical reactions. They could be used as arguments to support or refute proposed outcomes of fluid-rock interactions. Coupling geochemical modelling with transport (reactive transport model; 1D, 2D and 3D) is another possibility, attractive as it provides forward simulations of diagenetic processes and resulting phases. This

  3. Optimum potassium chloride concentration to reduce hydration capacity of clay formations; Concentracao otima de cloreto de potassio para reduzir a capacidade de hidratacao das formacoes argilosas

    Energy Technology Data Exchange (ETDEWEB)

    Machado, Jose Carlos Vieira [PETROBRAS, Salvador, BA (Brazil). Centro de Recursos Humanos Norte-Nordeste. Setor de Programas de Perfuracao; Oliveira, Manoel Martins de [PETROBRAS, BA (Brazil). Distrito de Perfuracao. Div. de Tecnicas de Perfuracao

    1988-12-31

    An experimental method for ascertaining the optimal concentration of potassium chloride for reducing the hydration and dispersion capacity of clayey formations sensitive to water-based fluids is described. Under this method, filtering time for disperse systems prepared from clayey formation samples is measured. A discussion is offered on theoretical aspects of hydration, expansion, and dispersion of clayey rocks in response to the variations in stress equilibrium states produced by these phenomena when a hole (well) is opened in the rock. The state of the art of this technological branch is also described. (author) 10 refs., 5 figs., 4 tabs.

  4. Compaction of porous rock by dissolution on discrete stylolites

    DEFF Research Database (Denmark)

    Angheluta, Luiza; Mathiesen, Joachim; Aharonov, Einat

    2012-01-01

    Compaction of sedimentary porous rock by dissolution and precipitation is a complex deformation mechanism, that is often localized on stylolites and pressure solution seams. We consider a one-dimensional model of compaction near a thin clay-rich stylolite embedded in a porous rock. Under...

  5. Support to other nuclear waste disposal programmes considering clay as a potential host rock

    International Nuclear Information System (INIS)

    Volckaert, G.

    2009-01-01

    SCK-CEN started to study the Boom Clay as potential host rock for nuclear waste disposal in 1974. Since then, SCK-CEN has been involved in other international projects studying clay as potential host rock in order to get a broader support for disposal in clay and to acquire broader insight in clay behaviour. Besides Belgium, France and Switzerland are currently investigating clay formations as potential host rock for the disposal of radioactive waste. In the Netherlands, clay formations have always been considered as an alternative to disposal in salt. The general interest in clays is increasing: in Germany and The United Kingdom, it was decided a few years ago that besides respectively salt and crystalline rock also clays need to be evaluated. In Eastern and Central Europe, the Slovak republic and Lithuania consider both clay and granite as possible host rocks for spent fuel while in Russia recently a project was started to study the possible disposal of low and medium level waste in a clay formation in the Leningrad area. Within the EC research and development framework programs and the OECD/NEA Clay Club, collaborations were developed between countries studying clay and with a strong involvement of SCK-CEN. The collaboration with the Eastern and Central European countries is supported through the support programme of the Belgian Ministry of Economic affairs. The objectives of these co-operations are to deliver expert services to other nuclear waste disposal programs considering clay as host rock; to to acquire broader international recognition of our expertise and support for the development of nuclear waste disposal in clay; to get a broader insight in the properties and behaviour of clays

  6. Hydrogeologic framework of fractured sedimentary rock, Newark Basin, New Jersey

    Science.gov (United States)

    Lacombe, Pierre J.; Burton, William C.

    2010-01-01

    The hydrogeologic framework of fractured sedimentary bedrock at the former Naval Air Warfare Center (NAWC), Trenton, New Jersey, a trichloroethylene (TCE)-contaminated site in the Newark Basin, is developed using an understanding of the geologic history of the strata, gamma-ray logs, and rock cores. NAWC is the newest field research site established as part of the U.S. Geological Survey Toxic Substances Hydrology Program, Department of Defense (DoD) Strategic Environmental Research and Development Program, and DoD Environmental Security Technology Certification Program to investigate contaminant remediation in fractured rock. Sedimentary bedrock at the NAWC research site comprises the Skunk Hollow, Byram, and Ewing Creek Members of the Lockatong Formation and Raven Rock Member of the Stockton Formation. Muds of the Lockatong Formation that were deposited in Van Houten cycles during the Triassic have lithified to form the bedrock that is typical of much of the Newark Basin. Four lithotypes formed from the sediments include black, carbon-rich laminated mudstone, dark-gray laminated mudstone, light-gray massive mudstone, and red massive mudstone. Diagenesis, tectonic compression, off-loading, and weathering have altered the rocks to give some strata greater hydraulic conductivity than other strata. Each stratum in the Lockatong Formation is 0.3 to 8 m thick, strikes N65 degrees E, and dips 25 degrees to 70 degrees NW. The black, carbon-rich laminated mudstone tends to fracture easily, has a relatively high hydraulic conductivity and is associated with high natural gamma-ray count rates. The dark-gray laminated mudstone is less fractured and has a lower hydraulic conductivity than the black carbon-rich laminated mudstone. The light-gray and the red massive mudstones are highly indurated and tend to have the least fractures and a low hydraulic conductivity. The differences in gamma-ray count rates for different mudstones allow gamma-ray logs to be used to correlate and

  7. Clinopyroxene application in petrogenesis identification of volcanic rocks associated with salt domes from Shurab (Southeast Qom

    Directory of Open Access Journals (Sweden)

    Somayeh Falahaty

    2016-07-01

    Full Text Available Introduction The study area is located in the Shurab area that is about 50 Km Southeast of Qom. Volcanic rocks of the Shurab area have basaltic composition that is associated with salt and marl units. Igneous rocks of the Shurab area have not been comprehensively studied thus far. Clinopyroxene composition of volcanic rocks, and especially the phenocrysts show Magma chemistry and can help to identify magma series (Lebas, 1962; Verhooge, 1962; Kushiro, 1960, Leterrier et al., 1982, tectonic setting (Leterrier et al., 1982; Nisbet and Pearce, 1977 as well as temperature formation and pressure of rock formation. Some geologists have estimated temperature of clinopyroxene formation by clinopyroxene composition (Adams and Bishop, 1986 and clinopyroxene-olivine couple. So, clinopyroxene is used in this study in order to identify magma series, tectonic setting, plus the temperature and pressure of volcanic rocks of the Shurab. Material and method Clinopyroxene analyses were conducted by wavelength-dispersive EPMA (JEOL JXA-8800R at the Cooperative Centre of Kanazawa University (Japan. The analyses were performed under an accelerating voltage of 15 kV and a beam current of 20 nA. The ZAF program was used for data corrections. Natural and synthetic minerals of known composition were used as standards. The Fe3+ content in minerals was estimated by Droop method (Droop, 1987. Discussion In the Shurab area, the volcanic rocks area with basaltic composition are located 50 km Southeast of Qom. Their age is the early Oligocene and they are associated with the salty marl units of the Lower Red Formation (LRF. The hand specimens of the studied rocks look green. These rocks are intergranular, microlitic, porphyric, vitrophyric and amygdaloidal and they consist of olivine, pyroxene and plagioclase. Accessory minerals contain sphene, apatite and opaque. According to Wo-En-Fs diagram (Morimoto, 1988, clinopyroxenes indicate diopside composition. Clinopyroxenes are

  8. Petrogenesis of siliceous high-Mg series rocks as exemplified by the Early Paleoproterozoic mafic volcanic rocks of the Eastern Baltic Shield: enriched mantle versus crustal contamination

    Science.gov (United States)

    Bogina, Maria; Zlobin, Valeriy; Sharkov, Evgenii; Chistyakov, Alexeii

    2015-04-01

    The Early Paleoproterozoic stage in the Earth's evolution was marked by the initiation of global rift systems, the tectonic nature of which was determined by plume geodynamics. These processes caused the voluminous emplacement of mantle melts with the formation of dike swarms, mafic-ultramafic layered intrusions, and volcanic rocks. All these rocks are usually considered as derivatives of SHMS (siliceous high-magnesian series). Within the Eastern Baltic Shield, the SHMS volcanic rocks are localized in the domains with different crustal history: in the Vodlozero block of the Karelian craton with the oldest (Middle Archean) crust, in the Central Block of the same craton with the Neoarchean crust, and in the Kola Craton with a heterogeneous crust. At the same time, these rocks are characterized by sufficiently close geochemical characteristics: high REE fractionation ((La/Yb)N = 4.9-11.7, (La/Sm)N=2.3-3.6, (Gd/Yb)N =1.66-2.74)), LILE enrichment, negative Nb anomaly, low to moderate Ti content, and sufficiently narrow variations in Nd isotope composition from -2.0 to -0.4 epsilon units. The tectonomagmatic interpretation of these rocks was ambiguous, because such characteristics may be produced by both crustal contamination of depleted mantle melts, and by generation from a mantle source metasomatized during previous subduction event. Similar REE patterns and overlapping Nd isotope compositions indicate that the studied basaltic rocks were formed from similar sources. If crustal contamination en route to the surface would play a significant role in the formation of the studied basalts, then almost equal amounts of contaminant of similar composition are required to produce the mafic rocks with similar geochemical signatures and close Nd isotopic compositions, which is hardly possible for the rocks spaced far apart in a heterogeneous crust. This conclusion is consistent with analysis of some relations between incompatible elements and their ratios. In particular, the

  9. Research of compression strength of fissured rock mass

    Directory of Open Access Journals (Sweden)

    А. Г. Протосеня

    2017-03-01

    Full Text Available The article examines a method of forecasting strength properties and their scale effect in fissured rock mass using computational modelling with final elements method in ABAQUS software. It shows advantages of this approach for solving tasks of determining mechanical properties of fissured rock mass, main stages of creating computational geomechanic model of rock mass and conducting a numerical experiment. The article presents connections between deformation during loading of numerical model, inclination angle of main fracture system from uniaxial and biaxial compression strength value, size of the sample of fissured rock mass and biaxial compression strength value under conditions of apatite-nepheline rock deposit at Plateau Rasvumchorr OAO «Apatit» in Kirovsky region of Murmanskaya oblast. We have conducted computational modelling of rock mass blocks testing in discontinuities based on real experiment using non-linear shear strength criterion of Barton – Bandis and compared results of computational experiments with data from field studies and laboratory tests. The calculation results have a high-quality match to laboratory results when testing fissured rock mass samples.

  10. Formation of oil-SPM aggregates under various mixing intensities

    International Nuclear Information System (INIS)

    Sun, J.; Zheng, X.

    2009-01-01

    A considerable amount of petroleum products spill into aquatic ecosystems as a result of increased marine transportation of crude oil products. The oil spill response community is therefore seeking an economical and environmentally sound technology to remove oil from shorelines. The formation of oil-suspended particulate matter (SPM) aggregates (OSAs) occurs when oil and SPM are present in a turbulent system. This process is known to enhance natural cleaning of oiled shorelines by increasing oil dispersion into the water column and accelerating the biodegradation of the oil. This paper reported on a laboratory study that was conducted to investigate OSA formation under different mixing energy levels. It presented the results of experiments conducted with Arabian heavy crude oil, standard reference material 1941b, artificial seawater, and 3 shaking rates of the reciprocating shaker. The results are intended to offer insight into the rate and extent of oil sediment interaction following an oil spill in the marine environment under different mixing conditions. Mixing energy is expected to have a considerable control on OSA formation because it controls the splitting of an oil slick into small droplets, the aggregation between the droplets and SPM, and the breakage rate of natural flocs. The concentration of the OSA was measured using the gas chromatography-flame ionization detection (GC-FID) method. Ultraviolet epi-fluorescence image analysis was used to measure the structure of OSAs and the concentration of oil droplets forming OSAs. The results showed that the formation of OSAs increased as the mixing energy increased. A consistent increase in droplet concentration in OSAs was also noted as the mixing energy increased. Both oil droplet size and OSA size decreased as the mixing intensity increased. 38 refs., 4 tabs., 3 figs.

  11. Rock Mass Behavior Under Hydropower Embankment Dams: A Two-Dimensional Numerical Study

    Science.gov (United States)

    Bondarchuk, A.; Ask, M. V. S.; Dahlström, L.-O.; Nordlund, E.

    2012-09-01

    Sweden has more than 190 large hydropower dams, of which about 50 are pure embankment dams and over 100 are concrete/embankment dams. This paper presents results from conceptual analyses of the response of typical Swedish rock mass to the construction of a hydropower embankment dam and its first stages of operation. The aim is to identify locations and magnitudes of displacements that are occurring in the rock foundation and grout curtain after construction of the dam, the first filling of its water reservoir, and after one seasonal variation of the water table. Coupled hydro-mechanical analysis was conducted using the two-dimensional distinct element program UDEC. Series of the simulations have been performed and the results show that the first filling of the reservoir and variation of water table induce largest magnitudes of displacement, with the greatest values obtained from the two models with high differential horizontal stresses and smallest spacing of sub-vertical fractures. These results may help identifying the condition of the dam foundation and contribute to the development of proper maintenance measures, which guarantee the safety and functionality of the dam. Additionally, newly developed dams may use these results for the estimation of the possible response of the rock foundation to the construction.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1977-02-01

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

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

    International Nuclear Information System (INIS)

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

    1977-02-01

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

  14. Integrated analysis of rock mass deformation within shaft protective pillar

    Directory of Open Access Journals (Sweden)

    Ewa Warchala

    2016-01-01

    Full Text Available The paper presents an analysis of the rock mass deformation resulting from mining in the vicinity of the shaft protection pillar. A methodology of deformation prediction is based on a deterministic method using Finite Element Method (FEM. The FEM solution is based on the knowledge of the geomechanical properties of the various geological formations, tectonic faults, types of mining systems, and the complexity of the behaviour of the rock mass. The analysis gave the stress and displacement fields in the rock mass. Results of the analysis will allow for design of an optimal mining system. The analysis is illustrated by an example of the shaft R-VIII Rudna Mine KGHM Polish Copper SA.

  15. Correlations fo Sc, rare earths and other elements in selected rock samples from Arrua-i

    Energy Technology Data Exchange (ETDEWEB)

    Facetti, J F; Prats, M [Asuncion Nacional Univ. (Paraguay). Inst. de Ciencias

    1972-01-01

    The Sc and Eu contents in selected rocks samples from the stock of Arrua-i have been determined and correlations established with other elements and with the relative amount of some rare earths. These correlations suggest metasomatic phenomena for the formation of the rock samples.

  16. Correlations fo Sc, rare earths and other elements in selected rock samples from Arrua-i

    International Nuclear Information System (INIS)

    Facetti, J.F.; Prats, M.

    1972-01-01

    The Sc and Eu contents in selected rocks samples from the stock of Arrua-i have been determined and correlations established with other elements and with the relative amount of some rare earths. These correlations suggest metasomatic phenomena for the formation of the rock samples

  17. The role of major forest fires on rock physical decay in a Mediterranean environment

    Science.gov (United States)

    Shtober-Zisu, Nurit; Tessler, Naama; Tsatskin, Alexander; Greenbaum, Noam

    2017-04-01

    Massive destruction of carbonate rocks occurred on the slopes of Mt. Carmel (Israel), during a severe forest fire in 2010. The bedrock surfaces exhibited extensive exfoliation into flakes and spalls covering up to 80%-100% of the exposed rocks; detached boulders were totally fractured or disintegrated. The fire affected six carbonate units—various types of chalk, limestone, and dolomite. The burned flakes show a consistent tendency towards flatness, in all lithologies, as 85%-95% of the flakes were detached in the form of blades, plates, and slabs. The extent of the physical disruption depends on rock composition: the most severe response was found in the chalk formations which are covered by calcrete (Nari crusts). These rocks reacted by extreme exfoliation, at an average depth of 7.7 to 9.6 cm and a maximum depth of 20 cm. Scorched and blackened faces under the upper layer of spalls provide strong evidence that chalk breakdown took place at an early stage of the fire. The extreme response of the chalks can be explained by the laminar structure of the Nari, which served as planes of weakness for the rock destruction. Three years after the fire, the rocks continue to exfoliate and break down internally. As the harder surface of the Nari was removed, the more brittle underlying chalk is exposed to erosion. These flakes seem to play an important role in reforming the soil after the fire, especially by increasing the coarse particles percentage. These, in spite of the absence of vegetation cover, improve soil infiltration and percolation rates and cause long-term changes to the hydrological regime. It is difficult to estimate the frequency of high-intensity fires in the Carmel region over the past 2-3 million years, as well as the extension and density of the vegetation. It is even harder to assess the frequency of fires (and the destruction) of a single rock outcrop. Our findings show that rock outcrop may lose even 20 cm of its thickness in a single fire. This

  18. Study on Excitation-triggered Damage Mechanism in Perilous Rock

    Science.gov (United States)

    Chen, Hongkai; Wang, Shengjuan

    2017-12-01

    Chain collapse is easy to happen for perilous rock aggregate locating on steep high slope, and one of the key scientific problems is the damage mechanism of perilous rock under excitation action at perilous rock rupture. This paper studies excitation-triggered damage mechanism in perilous rock by wave mechanics, which gives three conclusions. Firstly, when only the normal incidence attenuation spread of excitation wave is considered, while the energy loss is ignored for excitation wave to spread in perilous rock aggregate, the paper establishes one method to calculate peak velocity when excitation wave passes through boundary between any two perilous rock blocks in perilous rock aggregate. Secondly, following by Sweden and Canmet criteria, the paper provides one wave velocity criterion for excitation-triggered damage in the aggregate. Thirdly, assuming double parameters of volume strain of cracks or fissures in rock meet the Weibull distribution, one method to estimate micro-fissure in excitation-triggered damage zone in perilous rock aggregate is established. The studies solve the mechanical description problem for excitation-triggered damage in perilous rock, which is valuable in studies on profoundly rupture mechanism.

  19. Model test of anchoring effect on zonal disintegration in deep surrounding rock masses.

    Science.gov (United States)

    Chen, Xu-Guang; Zhang, Qiang-Yong; Wang, Yuan; Liu, De-Jun; Zhang, Ning

    2013-01-01

    The deep rock masses show a different mechanical behavior compared with the shallow rock masses. They are classified into alternating fractured and intact zones during the excavation, which is known as zonal disintegration. Such phenomenon is a great disaster and will induce the different excavation and anchoring methodology. In this study, a 3D geomechanics model test was conducted to research the anchoring effect of zonal disintegration. The model was constructed with anchoring in a half and nonanchoring in the other half, to compare with each other. The optical extensometer and optical sensor were adopted to measure the displacement and strain changing law in the model test. The displacement laws of the deep surrounding rocks were obtained and found to be nonmonotonic versus the distance to the periphery. Zonal disintegration occurs in the area without anchoring and did not occur in the model under anchoring condition. By contrasting the phenomenon, the anchor effect of restraining zonal disintegration was revealed. And the formation condition of zonal disintegration was decided. In the procedure of tunnel excavation, the anchor strain was found to be alternation in tension and compression. It indicates that anchor will show the nonmonotonic law during suppressing the zonal disintegration.

  20. Model Test of Anchoring Effect on Zonal Disintegration in Deep Surrounding Rock Masses

    Directory of Open Access Journals (Sweden)

    Xu-Guang Chen

    2013-01-01

    Full Text Available The deep rock masses show a different mechanical behavior compared with the shallow rock masses. They are classified into alternating fractured and intact zones during the excavation, which is known as zonal disintegration. Such phenomenon is a great disaster and will induce the different excavation and anchoring methodology. In this study, a 3D geomechanics model test was conducted to research the anchoring effect of zonal disintegration. The model was constructed with anchoring in a half and nonanchoring in the other half, to compare with each other. The optical extensometer and optical sensor were adopted to measure the displacement and strain changing law in the model test. The displacement laws of the deep surrounding rocks were obtained and found to be nonmonotonic versus the distance to the periphery. Zonal disintegration occurs in the area without anchoring and did not occur in the model under anchoring condition. By contrasting the phenomenon, the anchor effect of restraining zonal disintegration was revealed. And the formation condition of zonal disintegration was decided. In the procedure of tunnel excavation, the anchor strain was found to be alternation in tension and compression. It indicates that anchor will show the nonmonotonic law during suppressing the zonal disintegration.

  1. Biogeochemical processes in a clay formation in situ experiment: Part B - Results from overcoring and evidence of strong buffering by the rock formation

    Energy Technology Data Exchange (ETDEWEB)

    Koroleva, M. [Institute of Geological Sciences, University of Bern, Baltzerstrasse 3, CH-3012 Bern (Switzerland); Lerouge, C. [BRGM, French Geological Survey, 3 Avenue Claude Guillemin, B.P. 36009, 45060 Orleans Cedex 2 (France); Maeder, U., E-mail: urs.maeder@geo.unibe.ch [Institute of Geological Sciences, University of Bern, Baltzerstrasse 3, CH-3012 Bern (Switzerland); Claret, F.; Gaucher, E. [BRGM, French Geological Survey, 3 Avenue Claude Guillemin, B.P. 36009, 45060 Orleans Cedex 2 (France)

    2011-06-15

    Highlights: > A 5-year in situ porewater chemistry experiment in Opalinus Clay was overcored and examined. > A microbial perturbation induced sulfate reduction, pH decrease and alkalinity / P{sub CO2} increase. > Changes to mineralogy, isotopic composition and bulk properties could not be detected. > Precipitation of Fe-sulfides and carbonate occurred at the interface of the test interval. > The chemical perturbation was effectively buffered by the claystone's large capacity. - Abstract: An in situ Porewater Chemistry (PC) experiment in the Opalinus Clay formation was carried out at the Mont Terri underground rock laboratory (Jura Mountains, Switzerland) for a period of 5 a. A traced water with a composition close to that expected in the formation was continuously circulated and monitored in a packed-off borehole to achieve diffusive equilibration. An unwanted microbial perturbation changed the water composition, characterized by reduction of SO{sub 4} combined with increasing sulfide, increasing alkalinity, decreasing pH and increasing P(CO{sub 2}). In contrast, the main cations (Na, Ca, Mg) remained remarkably constant during the experiment, thus indicating the strong buffering of the formation via cation and proton exchange as well as carbonate dissolution/precipitation reactions. After 5 a, the 4.5 m long vertical test interval was overcored and Opalinus Clay samples were analyzed along ca. 15 cm long radial profiles. The analytical investigations included mineralogy (XRD, SEM-EDX), bulk parameters (water content, density, C, S), cation exchange capacity and occupancy, aqueous leachates for Cl{sup -}, Br{sup -}, SO{sub 4}{sup 2-} and water and carbonate stable isotopes. Emphasis was put on best sample preparation and conservation techniques. Results show that the distribution of non-reactive tracers (Br{sup -} and {sup 2}H) follows the expected out/in-diffusion profiles compatible with the time-dependent boundary conditions in the test interval of the

  2. Recent advances in analysis and prediction of Rock Falls, Rock Slides, and Rock Avalanches using 3D point clouds

    Science.gov (United States)

    Abellan, A.; Carrea, D.; Jaboyedoff, M.; Riquelme, A.; Tomas, R.; Royan, M. J.; Vilaplana, J. M.; Gauvin, N.

    2014-12-01

    The acquisition of dense terrain information using well-established 3D techniques (e.g. LiDAR, photogrammetry) and the use of new mobile platforms (e.g. Unmanned Aerial Vehicles) together with the increasingly efficient post-processing workflows for image treatment (e.g. Structure From Motion) are opening up new possibilities for analysing, modeling and predicting rock slope failures. Examples of applications at different scales ranging from the monitoring of small changes at unprecedented level of detail (e.g. sub millimeter-scale deformation under lab-scale conditions) to the detection of slope deformation at regional scale. In this communication we will show the main accomplishments of the Swiss National Foundation project "Characterizing and analysing 3D temporal slope evolution" carried out at Risk Analysis group (Univ. of Lausanne) in close collaboration with the RISKNAT and INTERES groups (Univ. of Barcelona and Univ. of Alicante, respectively). We have recently developed a series of innovative approaches for rock slope analysis using 3D point clouds, some examples include: the development of semi-automatic methodologies for the identification and extraction of rock-slope features such as discontinuities, type of material, rockfalls occurrence and deformation. Moreover, we have been improving our knowledge in progressive rupture characterization thanks to several algorithms, some examples include the computing of 3D deformation, the use of filtering techniques on permanently based TLS, the use of rock slope failure analogies at different scales (laboratory simulations, monitoring at glacier's front, etc.), the modelling of the influence of external forces such as precipitation on the acceleration of the deformation rate, etc. We have also been interested on the analysis of rock slope deformation prior to the occurrence of fragmental rockfalls and the interaction of this deformation with the spatial location of future events. In spite of these recent advances

  3. Preliminary study of uranium favorability of upper cretaceous, paleocene, and lower eocene rocks of the Bighorn Basin, Wyoming and Montana

    International Nuclear Information System (INIS)

    Hesse, S.L.; Dunagan, J.F. Jr.

    1978-02-01

    This report presents an evaluation of the uranium favorability of continental sediments of the Upper Cretaceous Lance, Paleocene Polecat Bench, and lower Eocene Willwood Formations in the Bighorn Basin of Wyoming and Montana, an intermontane structural basin of Laramide age. Previous work dealing with the Bighorn Basin was reviewed, and field investigations were carried out in the spring and summer of 1976. Subsurface data were collected and results of surface and subsurface investigations were evaluated with respect to uranium favorability. Precambrian plutonic and metamorphic rocks and Tertiary tuffaceous rocks in the Bighorn Basin and bordering uplifts are considered insignificant as source rocks, although the Wiggins Formation (White River equivalent) cannot be evaluated as a possible source because of a lack of data. Potential host rocks locally show only limited favorability. Lithology of strata exposed along the western and southern basin margins is more favorable than that of rocks in the central and eastern parts of the basin, but there is little organic material, pyrite, or other reducing agents in these rocks. Strata of the Lance, Polecat Bench, and Willwood Formations in the Bighorn Basin are considered generally unfavorable for sandstone uranium deposits

  4. Petrophysics and hydrocarbon potential of Paleozoic rocks in Kuwait

    Science.gov (United States)

    Abdullah, Fowzia; Shaaban, Fouad; Khalaf, Fikry; Bahaman, Fatma; Akbar, Bibi; Al-Khamiss, Awatif

    2017-10-01

    Well logs from nine deep exploratory and development wells in Kuwaiti oil fields have been used to study petrophysical characteristics and their effect on the reservoir quality of the subsurface Paleozoic Khuff and Unayzah formations. Petrophysical log data have been calibrated with core analysis available at some intervals. The study indicates a complex lithological facies of the Khuff Formation that is composed mainly of dolomite and anhydrite interbeds with dispersed argillaceous materials and few limestone intercalations. This facies greatly lowered the formation matrix porosity and permeability index. The porosity is fully saturated with water, which is reflected by the low resistivity logs responses, except at some intervals where few hydrocarbon shows are recorded. The impermeable anhydrites, massive (low-permeability) carbonate rock and shale at the lower part of the formation combine to form intraformational seals for the clastic reservoirs of the underlying Unayzah Formation. By contrast, the log interpretation revealed clastic lithological nature of the Unayzah Formation with cycles of conglomerate, sandstone, siltstone, mudstone and shales. The recorded argillaceous materials are mainly of disseminated habit, which control, for some extent, the matrix porosity, that ranges from 2% to 15% with water saturation ranges from 65% to 100%. Cementation, dissolution, compaction and clay mineral authigenesis are the most significant diagenetic processes affecting the reservoir quality. Calibration with the available core analysis at some intervals of the formation indicates that the siliciclastic sequence is a fluvial with more than one climatic cycle changes from humid, semi-arid to arid condition and displays the impact of both physical and chemical diagenesis. In general, the study revealed that the Unyazah Formation has a better reservoir quality than the Khuff Formation and possible gas bearing zones.

  5. Rocking response of tanks containing two liquids

    International Nuclear Information System (INIS)

    Tang Yu

    1994-01-01

    A study of the dynamic response of upright circular cylindrical liquid storage tanks containing two different liquids under a rocking base motion with an arbitrary temporal variation is presented. Only rigid tanks were studied. The response quantities examined include the hydrodynamic pressure, the sloshing wave height and associated frequencies, and the base shear and moments. Each of these response quantities is expressed as the sum of the so-called impulsive component and convective component. Unlike the case of tanks containing one liquid, in which the response is controlled by one parameter, the height-to-radius ratio, the response of tanks containing two different liquids is controlled by three parameters: the height-to-radius ratio and the mass density ratio and height ratio of the two liquids. The interrelationship of the responses of the tank-liquid system to rocking and lateral base excitations is established by examining numerical results extensively. It is found that some of the response quantities for a tank-liquid system under a rocking base motion can be determined from the corresponding response quantities for an identical tank under a horizontal base motion. ((orig.))

  6. Simulation of rock deformation behavior

    Directory of Open Access Journals (Sweden)

    Я. И. Рудаев

    2016-12-01

    Full Text Available A task of simulating the deformation behavior of geomaterials under compression with account of over-extreme branch has been addressed. The physical nature of rock properties variability as initially inhomogeneous material is explained by superposition of deformation and structural transformations of evolutionary type within open nonequilibrium systems. Due to this the description of deformation and failure of rock is related to hierarchy of instabilities within the system being far from thermodynamic equilibrium. It is generally recognized, that the energy function of the current stress-strain state is a superposition of potential component and disturbance, which includes the imperfection parameter accounting for defects not only existing in the initial state, but also appearing under load. The equation of state has been obtained by minimizing the energy function by the order parameter. The imperfection parameter is expressed through the strength deterioration, which is viewed as the internal parameter of state. The evolution of strength deterioration has been studied with the help of Fokker – Planck equation, which steady form corresponds to rock statical stressing. Here the diffusion coefficient is assumed to be constant, while the function reflecting internal sliding and loosening of the geomaterials is assumed as an antigradient of elementary integration catastrophe. Thus the equation of state is supplemented with a correlation establishing relationship between parameters of imperfection and strength deterioration. While deformation process is identified with the change of dissipative media, coupled with irreversible structural fluctuations. Theoretical studies are proven with experimental data obtained by subjecting certain rock specimens to compression.

  7. Carbonate rocks of Cambrian and Ordovician age in the Lancaster quadrangle, Pennsylvania

    Science.gov (United States)

    Meisler, Harold; Becher, Albert E.

    1968-01-01

    Detailed mapping has shown that the carbonate rocks of Cambrian and Ordovician age in the Lancaster quadrangle, Pennsylvania, can be divided into 14 rock-stratigraphic units. These units are defined primarily by their relative proportions of limestone and dolomite. The oldest units, the Vintage, Kinzers, and Ledger Formations of Cambrian age, and the Conestoga Limestone of Ordovician age are retained in this report. The Zooks Corner Formation, of Cambrian age, a dolomite unit overlying the Ledger Dolomite, is named here for exposures along Conestoga Creek near the village of Zooks Corner. The Conococheague (Cambrian) and Beekmantown (Ordovician) Limestones, as mapped by earlier workers, have been elevated to group rank and subdivided into formations that are correlated with and named for geologic units in Lebanon and Berks Counties, Pa. These formations, from oldest to youngest, are the Buffalo Springs, Snitz Creek, Millbach, and Richland Formations of the Conococheague Group, and the Stonehenge, Bpler, and Ontelaunee Formations of the Beekmantown Group. The Annville and Myerstown Limestones, which are named for lithologically similar units in Dauphin and Lebanon Counties, Pa., overlie the Beekmantown Group in one small area in the quadrangle.

  8. Rebel Rock : Lynyrd Skynyrd, Normaal, and Regional Identity

    NARCIS (Netherlands)

    Zwiers, Maarten

    2015-01-01

    This essay examines the construction of regional identity in the music of two rock bands that became popular during the 1970s: Lynyrd Skynyrd and the Dutch formation Normaal. I discuss the similarities and differences between both bands and analyze the most important sites and characters that appear

  9. Case histories of roller cone core bit application in crystalline rock

    International Nuclear Information System (INIS)

    Dahlem, J.S.

    1988-01-01

    The increased interest in deep crystalline rock drilling projects has resulted in a requirement for premium coring bits which are effective in such a harsh and abrasive environment. Hard formation roller cone insert bits have traditionally and constantly performed well in crystalline rock. As a result, the application of state of the art roller cone rock bit technology to the design and development of core bits has made crystalline coring projects more viable than ever before. This paper follows the development of roller cone core bits by examining their use on project such as HDR (Hot Dry Rock, Los Alamos); NAGRA (Nuclear Waste Disposal Wells in Switzerland); Camborne School of Mines Geothermal Project in Cornwall, UK; Deep Gas Project in Sweden; and the KTB Deep Drilling Project in West Germany

  10. Rock mechanics studies for SMES

    International Nuclear Information System (INIS)

    Haimson, B.C.

    1981-01-01

    Superconducting magnetic energy storage (SMES) systems capable of storing thousands of MWh develop tremendous magnetically induced forces when charged. To prevent rutpure of the magnets these forces must be confined. Bedrock offers a practical and relatively inexpensive magnet containment structure. This paper examines the need for rock mechanics research in connection with the construction and use of SMES rock caverns; the unique problems related to housing superconducting magnets in bedrock; site investigations of granite, quartzite and dolomite deposits in Wisconsin; and cavern design requirements to assure cavern stability and limited deformation under the expected mechanical leads. Recommendations are made for siting SMES caverns

  11. Soot Formation Modeling of n-dodecane and Diesel Sprays under Engine-Like Conditions

    DEFF Research Database (Denmark)

    Pang, Kar Mun; Poon, Hiew Mun; Ng, Hoon Kiat

    2015-01-01

    This work concerns the modelling of soot formation process in diesel spray combustion under engine-like conditions. The key aim is to investigate the soot formation characteristics at different ambient temperatures. Prior to simulating the diesel combustion, numerical models including a revised...

  12. Stratigraphy and environments of deposition of the Cretaceous Hell Creek Formation (reconnaissance) and the Paleocene Ludlow Formation (detailed), southwestern North Dakota. Report of investigations No. 56

    International Nuclear Information System (INIS)

    Moore, W.L.

    1976-01-01

    The Cretaceous Hell Creek and Paleocene Ludlow Formations of southwestern North Dakota, with the exception of the included lignite beds and minor amounts of concretions and nodules, are almost exclusively clastic sediments and sedimentary rocks. Massive clays, clays alternating with silts and sands, sandstones filling channels and other depressions, sheet sandstones, and lignites are the dominant sediment and rock types present. These sediments and sedimentary rocks were mostly deposited in a continental environment and were largely alluvial, lacustrine or paludal in origin; though marginal marine deposition, in part, is indicated by the occurrence of brackish water faunas in portions of the upper Ludlow Formation. With the possible exception of a persistent lignite near the base, persistent lignites are not present in the Hell Creek Formation. The Ludlow can be subdivided into several informal units, typically coal-bounded, which can be traced laterally over large areas. This informal subdivision permits isolation of stratigraphic units for the study of local environments of deposition. Channel and depression fill sandstones of the Ludlow Formation have a relatively low permeability and a high organic content at the surface and, for this reason, are considered poor prospective uranium host rocks. The lighter colored yellow winnowed sheet sandstones of the Ludlow are more permeable and relatively free of organic matter. They are considered as possible host rocks for uranium occurring in association with an oxidation/reduction interface at shallow depths. The uranium potential is enhanced where the latter sandstones occur along paleodivides which have been overlain by the Oligocene White River Formation, or in local areas where the latter formation is still preserved. Light yellow winnowed sheet sandstones are rare in the Hell Creek Formation, and the chances for uranium prospects in this interval seem correspondingly reduced

  13. Sorption of radionuclides from spent fuel in crystalline rocks

    International Nuclear Information System (INIS)

    Nikula, A.

    1982-10-01

    The safe disposal of spent nuclear fuel or reprocessed waste is an essential element in the expansion of the nuclear power industry. Stable rock formations e.g. granite are considered to be potential sites for disposal. A major factor in evaluating the degree of safety of the disposal is the sorption of radionuclides in rock, which affects their retardation. The report considers the chemical forms of the hazardous radionuclides of spent nuclear fuel in groundwater and the effects of the water's properties on them. In the groundwater near the Olkiluoto power plant site cesium, strontium and radium are in cationic form, iodine as I - . Technetium would occur as TcO +2 , but the pertechnetate form is also possible. Uranium most probably would be as U(VI) plutonium and neptunium as Np(IV) or Np(V). The valences for thorium, americium and curium are not changed in this groundwater and would be +4, +3 and +3, respectively. The actinides in groundwater are all in hydrated or complex form. An increase on the ionic stregth of the groundwater in most instances causes a decrease in the sorption of nuclides since the ion exchange capacity of the rock is limited. Anionic ligands also decrease sorption of cations by complex formation. In some case, on the other hand, high salt concentrations may cause formation of radiocolloids of lanthanides and neptunium and thus increase sorption. In all cases the degree of sorption described by the distribution ratio Ksub(d) was influenced by the pH of the groundwater. Sorption of cesium and strontium increased with growing pH. The sorption behaviour of actinides was in positive correlation with formation of hydroxide complexes at different pH values. The Ksub(d) values of Cs, Sr, Co, Ni and Am for Olkiluoto granites were found to agree with Swedish values, also determined at ambient atmospheric conditions

  14. Formation of chemical gardens on granitic rock. A new type of alteration for alkaline systems

    Energy Technology Data Exchange (ETDEWEB)

    Satoh, Hisao [Mitsubishi Materials Corporation, Naka (Japan). Energy Project and Technology Center; Tsukamoto, Katsuo [Tohoku Univ. Aramaki, Sendai (Japan). Dept. of Earth and Planetary Materials Science; Garcia-Ruiz, Juan Manuel [Granada Univ., Armilla (Spain). Lab. de Estudios Cristalograficos

    2014-06-15

    In order to understand the groundwater flow at near-underground facilities such as waste repositories, we have studied the effects of flowing an alkaline solution leached from cementitious building materials through the fractures of low-porosity granitic rocks under laboratory conditions. The results show that silica released from the dissolution of sodium-rich plagioclase and quartz reacts with the calcium leached from cementitious buildings to form calcium silicate hydrates (C-S-H) phases in the form of hollow tubular structures. These tubular structures form selectively on the surface of plagioclase in a similar way to reverse silica gardens structures. It was found that the rate of precipitation of C-S-H phases is faster than the rate of dissolution of plagioclase. This selftriggered dissolution/precipitation phenomenon may be an important factor controlling groundwater permeation in natural alkaline underground systems.

  15. Formation of chemical gardens on granitic rock. A new type of alteration for alkaline systems

    International Nuclear Information System (INIS)

    Satoh, Hisao; Tsukamoto, Katsuo; Garcia-Ruiz, Juan Manuel

    2014-01-01

    In order to understand the groundwater flow at near-underground facilities such as waste repositories, we have studied the effects of flowing an alkaline solution leached from cementitious building materials through the fractures of low-porosity granitic rocks under laboratory conditions. The results show that silica released from the dissolution of sodium-rich plagioclase and quartz reacts with the calcium leached from cementitious buildings to form calcium silicate hydrates (C-S-H) phases in the form of hollow tubular structures. These tubular structures form selectively on the surface of plagioclase in a similar way to reverse silica gardens structures. It was found that the rate of precipitation of C-S-H phases is faster than the rate of dissolution of plagioclase. This selftriggered dissolution/precipitation phenomenon may be an important factor controlling groundwater permeation in natural alkaline underground systems.

  16. What Happens Where the Water and the Rock Touch in Small Space Bodies

    Science.gov (United States)

    Byrne, P. K.; Regensburger, P. V.; Klimczak, C.; Bohnenstiehl, D. R.; Dombard, A. J.; Hauck, S. A., II

    2017-12-01

    There are several small space bodies that go around bigger worlds that might have a layer of water under a layer of ice. Lots of study has been done to understand the outside ice layer of these small space bodies, because the ice can tells us important things about the big water layer under it. Some of these small space bodies are very interesting because the right things for life—water, hot rock, and food—might be at the bottom of the water layer, where it touches the top of the next layer down, which is made of rock. But it is very hard to understand what this rock at the bottom of the water is like, because we can't see it. So, we are imagining what this rock is like by thinking about what the rock is like under the water layer on our own world. If hot rock comes out of the rock layer through cracks under the water, the cold of the water makes the hot rock go very cold very fast, and it makes funny rolls as it does so. This might happen on some small space bodies that are hot enough on the inside to make hot rock. We know that on our own world the rock layer under the water is wet to as far down as cracks can go, so it makes sense that this is true for small space bodies, too. We did some thinking about numbers and found out that the cracks can go a few ten hundred steps into the rock layer on small space bodies, but for bigger (well, not quite so small) space bodies, the cracks can go at least tens of ten hundred steps into the rock layer. This means that water goes into the rock layer this much, too. But get this: some small bodies are not really that small—one of them is bigger than the first world from the Sun! And on a few of these big (small) bodies, the layer of water is so heavy that the bottom of that water is pushed together from all sides and turns into a type of hot ice. This means that, for these big (small) worlds, the water can't get into the rock layer through cracks (since there is a layer of hot ice in the way), and so these bodies are

  17. Rock mechanics in the disposal of radioactive wastes by hydraulic fracturing

    Energy Technology Data Exchange (ETDEWEB)

    McClain, W C

    1968-01-01

    The ultimate capacity of a hydraulic-fracturing waste disposal facility is governed primarily by the integrity of the rocks overlying the injected wastes. The objective of this study is to analyze theoretically the stresses and strains generated by the injected wastes in an effort to understand the behavior of the system sufficiently well that the failure mechanism can be predicted and the capacity of the injection well estimated. The surface uplifts at Oak Ridge National Laboratory's fracturing site were compared with theoretical curves obtained by assuming the uplifts to be inversely analogous to the subsidence which occurs over mining excavations. This analysis, based on assumptions of homogeneity, isotropy, and linear elasticity, provided considerable insight into the mechanics of the process. The most probable mechanism of failure of the rock appears to be by the formation of a vertical instead of a horizontal fracture. Fracture orientation is controlled primarily by the orientation of the principal stress field in the rock. Each successive waste injection slightly modifies this stress field toward a condition more favorable to the formation of a vertical fracture. (16 refs.)

  18. Rho-associated kinase (ROCK) function is essential for cell cycle progression, senescence and tumorigenesis.

    Science.gov (United States)

    Kümper, Sandra; Mardakheh, Faraz K; McCarthy, Afshan; Yeo, Maggie; Stamp, Gordon W; Paul, Angela; Worboys, Jonathan; Sadok, Amine; Jørgensen, Claus; Guichard, Sabrina; Marshall, Christopher J

    2016-01-14

    Rho-associated kinases 1 and 2 (ROCK1/2) are Rho-GTPase effectors that control key aspects of the actin cytoskeleton, but their role in proliferation and cancer initiation or progression is not known. Here, we provide evidence that ROCK1 and ROCK2 act redundantly to maintain actomyosin contractility and cell proliferation and that their loss leads to cell-cycle arrest and cellular senescence. This phenotype arises from down-regulation of the essential cell-cycle proteins CyclinA, CKS1 and CDK1. Accordingly, while the loss of either Rock1 or Rock2 had no negative impact on tumorigenesis in mouse models of non-small cell lung cancer and melanoma, loss of both blocked tumor formation, as no tumors arise in which both Rock1 and Rock2 have been genetically deleted. Our results reveal an indispensable role for ROCK, yet redundant role for isoforms 1 and 2, in cell cycle progression and tumorigenesis, possibly through the maintenance of cellular contractility.

  19. Deformability and strength of granite under the influence of stress, temperature, rate of loading and water environment

    International Nuclear Information System (INIS)

    Shivkumar, K.; Nagaraja Rao, G.M.

    1995-01-01

    The design of nuclear waste repository in geological formation is a unique rock mechanics problem for at least two reasons. These are the usually long service life and the relatively high service temperature. These play a major role in rock deformation. Laboratory simulation studies under the anticipated environmental conditions for waste disposal vaults, and the data generated through these investigations will be helpful in designing a theoretical/experimental model for the repository. Towards this end, some efforts were made to understand the mechanical behaviour of granites. (author)

  20. Loading History Effect on Creep Deformation of Rock

    Directory of Open Access Journals (Sweden)

    Wendong Yang

    2018-06-01

    Full Text Available The creep characteristics of rocks are very important for assessing the long-term stability of rock engineering structures. Two loading methods are commonly used in creep tests: single-step loading and multi-step loading. The multi-step loading method avoids the discrete influence of rock specimens on creep deformation and is relatively time-efficient. It has been widely accepted by researchers in the area of creep testing. However, in the process of multi-step loading, later deformation is affected by earlier loading. This is a key problem in considering the effects of loading history. Therefore, we intend to analyze the deformation laws of rock under multi-step loading and propose a method to correct the disturbance of the preceding load. Based on multi-step loading creep tests, the memory effect of creep deformation caused by loading history is discussed in this paper. A time-affected correction method for the creep strains under multi-step loading is proposed. From this correction method, the creep deformation under single-step loading can be estimated by the super-position of creeps obtained by the dissolution of a multistep creep. We compare the time-affected correction method to the coordinate translation method without considering loading history. The results show that the former results are more consistent with the experimental results. The coordinate translation method produces a large error which should be avoided.