Journal articles on the topic 'Clay-Shale'
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1
Idrus M, Alatas, Simatupang Pintor T, Kuswaya Wawan, and Panji. "Re-weathering of stabilized clay shale with Portland cement behavior." MATEC Web of Conferences 276 (2019): 05009. http://dx.doi.org/10.1051/matecconf/201927605009.
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Clay shale is a claystone which in fresh condition has a very high shear strength. When it reacts with the atmosphere or hydrosphere it will weather so that the shear strength of clay shale will drop drastically. The weathering potential of clay shale is generally done by the slake durability test and the weathering process is measured by disintegration ratio test (DR). The strength of clay shale that has fully weathered will increase again when it is stabilized with a minimum of 6% PC (Portland Cement). It was found from the wetting drying cycle process testing that durability of re-weathering of stabilized clay shale with PC is increased compared to natural clay shale. Disintegration ratio of natural clay shale DR was smaller than stabilized clay shale with 6% PC. Additionally, more than 6% PC increased the durability of re-weathering of clay shale.
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Nusyura Al Islami, Auliya, Wiwik Rahayu, and Budi Susilo Soepandji. "Effect of Propylene Glycol and Laterite on California Bearing Ratio of Clay Shale." International Journal of Engineering & Technology 7, no. 4.36 (December 9, 2018): 383. http://dx.doi.org/10.14419/ijet.v7i4.36.23807.
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Clay shale in natural condition has a very high strength. But due to weathering caused by exposure with air and water, its strength decreased significantly. Propylene glycol is established as an effective shale inhibitor in water-based muds. The effect mixing propylene glycol with clay shale to its strength is needs to be discussed. Sample of Citereup clay shale has been mixed with propylene glycol with ratio 0.3, 0.5, and 0.7 of its optimum water content. California Bearing Ratio test have been performed to determine clay shale bearing strength. Result from study indicate that clay shale stabilization using 30% propylene glycol can increase strength in unsoaked condition. Laterite soil mix were also give additional bearing strength to clay shale specimen.
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Zhang, Yao, Lingzhi Xie, Peng Zhao, and Bo He. "Study of the quantitative effect of the depositional layering tendency of inclusions on the elastic anisotropy of shale based on two-step homogenization." Geophysical Journal International 220, no. 1 (October 3, 2019): 174–89. http://dx.doi.org/10.1093/gji/ggz431.
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SUMMARY Shale anisotropy is related to numerous small-scale factors, including the transverse isotropy of clay particles, clay shape aspect ratio, shape preference orientation, pore/crack alignment, infilling materials and the depositional distribution and shape aspect ratio of inclusion minerals. Although a depositional layering tendency of inclusions due to sedimentation has been observed, few studies of its effect on shale anisotropy have been carried out. In this work, the effect of the depositional layering tendency of inclusions on the elastic anisotropy of shale is quantitatively analysed along with three other factors (i.e. the inclusion fraction, the orientation dependence of clay elastic properties, where ‘oriented’ refers to transverse isotropic clay and ‘non-oriented’ refers to isotropic clay, and the clay elastic moduli) based on analysis of variance and the two-step homogenization of shale by assuming that shale is a composite of clay and inclusions. The results show that the depositional layering tendency of inclusions of this type of shale has a relatively limited effect on the elastic anisotropy of intact shale, while the orientation dependence of the elastic properties of the clay has a predominant influence.
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Dewanto, Ordas, Istifani Ferucha, Darsono Darsono, and Sri Rizky. "Conversion of Oil Shale To Liquid Hydrocarbons as A New Energy Resources Using Iron (Fe)-Pillared Clay (Kaolinite) Catalyst." INDONESIAN JOURNAL OF APPLIED PHYSICS 12, no. 2 (November 1, 2022): 197. http://dx.doi.org/10.13057/ijap.v12i2.58414.
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In the context of new energy exploration, oil shale is currently a source of energy that is being developed so that it can be used as an alternative energy in the future. Based on this background, it is important to research the conversion method of oil shale to liquid hydrocarbons. The method used is using clay (kaolinite) catalyst and iron (Fe)-pillared clay (kaolinite) catalyst. Clay catalyst products are capable of making organic mature faster and even requiring a lower temperature for the changes (through thermal cracking of non-volatile organic material). The addition of Fe metal in the clay catalyst product to oil shale, causing the surface area of the natural clays were significantly increased, then the volume of micro pore were also increased, it causes the organic material to mature faster and the temperature required for the change is less than the shale material without Fe. The catalyst method by the pillarization technique able to increase the surface area and pore volume, thus accelerating the reaction and changing the reaction rate to be greater. It is observed that clay catalyst products can serve as catalysts for accelerating organic maturation reactions. if compared between the clay material of OD1-Ast1 (50% clay-50% organic), OD1-Ast2 (33% clay-67% organic), and the OD1-Ast3 shale material (67% clay - 33% organic),then OD1-Ast3 has a faster reaction rate. Comparison of clay material is smaller than organic, then the properties of the catalyst product to accelerate the reaction are reduced, such as the OD1-Ast2 shale material has a slow reaction rate compared to the OD1-Ast3 shale material. The addition of Fe metal in the clay catalyst product to the OD1-Ast2 shale material, resulting in OD1-Ast2-Fe shale material (75% OD1-Ast2 and 25% Fe) having a faster reaction rate than before the addition of Fe metal.The design of heavy (%) clay (kaolinite) and Fe pilaration on oil shale were greatly influence the change of TOC values when heated,then affecting maturation and Tmax. The temperature of maturation and Tmax as the main parameters of conversion of oil shale to liquid hydrocarbon. This method supports the development of science and technology in the field of exploitation and processing of natural resources.
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Abdideh, Mohammad. "STUDY OF DEPENDENCE BETWEEN CLAY MINERAL DISTRIBUTION AND SHALE VOLUME IN RESERVOIR ROCKS USING GEOSTATISTICAL AND PETROPHYSICAL METHODS." Geodesy and Cartography 41, no. 2 (October 25, 2015): 92–100. http://dx.doi.org/10.3846/20296991.2015.1051333.
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Identify and obtain a detailed understanding of shale and its clay minerals in three segments; exploration, drilling and reservoir in the oil industry are very important. The study of the formation clay minerals in terms of depth and layers of earth is done through X-ray tests on samples taken from the reservoir which in comparison with logging requires a lot more time and cost and also can't provide continuous results because continuous sampling from the whole well is not possible. NGS (Gamma-ray Spectrometry) log is used to identify formation clay minerals that is an indicator of three radioactive elements thorium, uranium and potassium and the amount of each of these elements and according to amount of each of these elements and their ratio gives a description of clay minerals of each zone. CGR log represents the sum of two elements Thorium and potassium that are present in the shale and uranium has no effect on it. The CGR log is usually used as a shale indicator and it is an essential tool for determining the Shale volume in well logging operation. In this study the relationship between shale volume shown by the CGR log and the type of formation clay mineral was investigated. A very clear relationship between the shale volume and formation clay minerals was observed. In intervals with low shale volume the amount of active clay minerals, especially montmorillonite was higher and in intervals with high shale volume, inactive clay minerals were more. In order to investigate the spatial relation between the logging data, frequency distribution and correlation between logging data was studied. By using logging data and identifying the type of clay minerals in each zone and also the spatial correlation between logging data a suitable program for drilling and exploitation of oil fields in different areas can be proposed.
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Liu, Kerui, Dangliang Wang, James J. Sheng, and Jianfeng Li. "Review of the Generation of Fractures and Change of Permeability due to Water-Shale Interaction in Shales." Geofluids 2022 (June 13, 2022): 1–20. http://dx.doi.org/10.1155/2022/1748605.
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In shale development, water-based liquids are injected into the formations. In this process, water can interact with shales, especially with clay content. The interaction can lead to some phenomena, including clay swelling, reduction of mechanical properties of shales and fractures, generation and propagation of fractures, particle detachment, and permeability change. All the phenomena can impact productivity during the development, thereby impacting our investment and return on investment (ROI). So far, many researchers have put their time and efforts into this topic, and many articles have been published. However, some discrepancies still exist in shale reservoirs regarding the role of the interaction between water and shale, especially the impact of clay swelling. Some believe that clay swelling causes formation damage, mainly impairing shale permeability. Others state that fractures can be induced because of clay swelling, leading to the enhancement of shale permeability. So far, few articles have reviewed the various views on this interaction. Additionally, the relationship between each phenomenon is not discussed. In this paper, we try to draw a clear picture of water-shale interaction by reviewing the published studies, mainly focusing on experimental methodology and experimental results. Based on the review, we summarized the influencing factors as well as the mechanisms about the formation of fractures and change of permeability due to water-shale interaction. In water-shale interaction, the induced fractures are generated by the combined effects from clay swelling, reduction of mechanical properties of shales and fractures, and stress anisotropy. Shale permeability can be enhanced if the generated fractures can form an effective flow channel. However, if the generated fractures cannot serve as an effective flow channel, shale permeability will be impaired by clay swelling, water blocking, stress-sensitive, etc.
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Shen, Junjun, Decheng Chen, Kongquan Chen, Yubing Ji, Pengwan Wang, Junjun Li, Quansheng Cai, and Jianghui Meng. "Shale types and sedimentary environments of the Upper Ordovician Wufeng Formation-Member 1 of the Lower Silurian Longmaxi Formation in western Hubei Province, China." Open Geosciences 13, no. 1 (January 1, 2021): 1595–615. http://dx.doi.org/10.1515/geo-2020-0320.
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Abstract By performing scanning electron microscopy, microscopic observations, whole-rock X-ray diffraction analysis, organic geochemistry analysis, and elemental analysis on drill core specimens and thin sections, in this study, we classified the shale types of the Wufeng Formation-Member 1 of the Longmaxi Formation in western Hubei, southern China, and explored the development characteristics and formation environments of the different shale types. The results show that (1) the shales of the Wufeng Formation-Member 1 of the Longmaxi Formation are composed of three types of shale: siliceous shale, mixed clay-siliceous shale, and clay shale. The siliceous shale is a type of shale unique to deep-water environments; clay shale is the main type of shale formed in shallow-water environments; and mixed clay-siliceous shale falls between the two. (2) The changes in shale type are characterized by multiple depositional cycles in the vertical direction with strong heterogeneity and an obvious tripartite character, and the siliceous shales gradually thicken as they laterally extend northwestward, with their last depositional cycle gradually ending at a later time. (3) The Late Ordovician-Early Silurian paleoenvironment can be divided into six evolutionary stages (A, B, C, D, E, and F) from early to late. In particular, the sea level was relatively lower in stages A and F when the bottom water was mainly oxygen rich with higher terrigenous inputs and a lower paleoproductivity, which led to the formation of clay shales poor in organic matter but rich in terrigenous quartz clasts. The sea level was higher in stages B, C, and D when the bottom water was anoxic with lower terrigenous inputs and a higher paleoproductivity, which led to the formation of siliceous shales rich in organic matter and biogenic silica. The total organic carbon (TOC) contents of siliceous shales decrease in the order of stage C > stage D > stage B, which is mainly attributed to the different degrees of water restriction in the three stages and the consequently different paleoproductivities. Stage E corresponds to the mixed clay-siliceous shales, the depositional environment of which is between those of the siliceous shales and the clay shales, thereby resulting in the mineral composition and TOC content of the mixed clay-siliceous shales being between those of the other two shale types.
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Sagitaningrum, Fathiyah Hakim, Samira Albati Kamaruddin, Ramli Nazir, Budi Susilo Soepandji, and Idrus Muhammad Alatas. "Evaluation of Slope Stability at Interface using Thin Soil Material Model in Finite Element Software." IOP Conference Series: Earth and Environmental Science 1111, no. 1 (December 1, 2022): 012053. http://dx.doi.org/10.1088/1755-1315/1111/1/012053.
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Abstract Cases of landslides on clay shale slopes have been an intriguing study in Indonesia. Most of the slopes failed due to the weathering of the clay shale rock. As studies focused on the properties of clay shale, several FEM analyses indicated a unique translational type of failure between the interface of clay shale and its overburden. However, the modeling of the interface in a case study was still limited. This study aims to evaluate a landslide using a thin-soil interface model using FEM software. The model used two conditions, extreme groundwater level conditions. There were several iterations of the shear strength parameters of the interface layer conducted. Results indicated that the thin-soil interface could portray the interface condition at the landslide. Compared to laboratory interface results, the interface would fail at a high degree of saturation due to water infiltration at the surface. Also, granular overburden with high permeability had a higher chance of failure than cohesive overburden. From the results, this study opened the path to incorporating the interface layer in clay shale slope analysis. However, further studies are needed using the thin-soil interface model in other clay shale landslide cases to synthesize its repeatability.
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Brilyant Arief, Rifqi, Masyhur Irsyam, Idrus M Alatas, Sugeng Krisnanto, Endra Susila, Hasbullah Nawir, and Ramli Nazir. "EFFECT OF CLAY SHALE SHEAR STRENGTH DEGRADATION ON BORED PILE FRICTION IN CLAY SHALE." Jurnal Teknologi 84, no. 5 (July 26, 2022): 177–83. http://dx.doi.org/10.11113/jurnalteknologi.v84.18220.
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This research aims at investigating and modeling the axial bearing capacity degradation of a bored pile on clay shale due to the bored pile installation processes. Clay shale sample models were prepared to simulate the wetting and drying cycles through weathering process between 0 to 6 hours. All samples were tested in which every 1 hour of the weathering process representing 1 cycle of wetting and drying. The direct shear laboratory tests were performed to obtain the peak and residual shear strength parameters of the interface between the bored pile and clay shale. The peak and residual shear strength parameters were obtained after 6 hours of the weathering process. The residual shear strength parameters were measured by applying with and without stress release. This investigation showed that the shear strength degradation at peak, residual without stress release, and residual with stress release respectively reached 87-62%, 28-20%, and 25-14% after 1 to 6 hours of weathering process. This result is very useful for predicting the bored pile skin friction in clay shale soils.
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Bian, Congsheng, Wenzhi Zhao, Tao Yang, Wei Liu, Chaocheng Dai, Xu Zeng, Kun Wang, Yongxin Li, and Di Xiao. "The Impact of Lamina Characteristics and Types on Organic Matter Enrichment of Chang 73 Submember in Ordos Basin, NW China." Geofluids 2022 (June 18, 2022): 1–19. http://dx.doi.org/10.1155/2022/6558883.
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The Chang 7 member in Ordos Basin is an important shale oil exploration layer, with new shale-oil discoveries in recent years. The Chang 73 submember is rich in organic shale, which is the main source rock of shale oil in the Yanchang Formation. In order to clarify the lamina structure, composition, types, and distribution characteristics in Chang 73 submember and its influence on organic matter enrichment, a full coring well in Chang 73 submember located in deep-lacustrine facies is selected to obtain intensive systematic core samples. Core observation, thin section identification, X-ray fluorescence element analysis, X-diffraction analysis, scanning electron microscope, electron probe, rock pyrolysis, and other techniques are performed to systematically analyze the morphology, structure, thickness, mineral compositions, and organic matter content of the shale lamina in the Chang 73 submember. Five types of lamina are identified: silty felsic lamina (SF), tuffaceous lamina (TF), organic-rich clay lamina (ORC), organic-bearing clay lamina (OBC), and homogeneous clay lamina (HC), which are further subdivided into eight subtypes. The lamina types change greatly vertically in the Chang 73 submember, in which the lower part is mainly silty felsic lamina, organic-rich clay, and tuffaceous lamina, the middle part is mainly organic rich and organic clay lamina and organic-bearing clay lamina, and the upper part is mainly homogeneous clay lamina and a small amount of silty felsic organic-bearing clay lamina and organic-bearing clay lamina. Different laminae show various organic matter types, organic matter content (TOC), and organic matter occurrence states which can be divided into four occurrence types. The TOC in organic-rich clay lamina and part of homogeneous clay lamina is high, while that of silty felsic lamina is lower. The relationship between shale lamina and organic matter enrichment is established according to the correlation analysis of laminar characteristics, mineral content, and organic matter content. Among them, the organic-rich lamina is richest of TOC and is a favorable “sweet point” for shale oil exploration.
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Al Ismail, Maytham I., and Mark D. Zoback. "Effects of rock mineralogy and pore structure on stress-dependent permeability of shale samples." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 374, no. 2078 (October 13, 2016): 20150428. http://dx.doi.org/10.1098/rsta.2015.0428.
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We conducted pulse-decay permeability experiments on Utica and Permian shale samples to investigate the effect of rock mineralogy and pore structure on the transport mechanisms using a non-adsorbing gas (argon). The mineralogy of the shale samples varied from clay rich to calcite rich (i.e. clay poor). Our permeability measurements and scanning electron microscopy images revealed that the permeability of the shale samples whose pores resided in the kerogen positively correlated with organic content. Our results showed that the absolute value of permeability was not affected by the mineral composition of the shale samples. Additionally, our results indicated that clay content played a significant role in the stress-dependent permeability. For clay-rich samples, we observed higher pore throat compressibility, which led to higher permeability reduction at increasing effective stress than with calcite-rich samples. Our findings highlight the importance of considering permeability to be stress dependent to achieve more accurate reservoir simulations especially for clay-rich shale reservoirs. This article is part of the themed issue ‘Energy and the subsurface’.
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Liang, Hai An, Qing Rui Lu, Shi Jun Chen, and Hai Yang Hu. "Experimental Investigation on the Physical and Mechanical Features of Clay Shale in Bayingobi Basin of Inner Mongolia." Applied Mechanics and Materials 580-583 (July 2014): 879–82. http://dx.doi.org/10.4028/www.scientific.net/amm.580-583.879.
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The basic physical and mechanical characteristics of Clay shale in Bayingobi Basin of Inner Mongolia have been investigated by using supersonic testing system, rock mechanical testing system, and rock triaxial testing system. The results indicate that the deep clay shale of this region is characterized by high density, high mechanical strength, low deformation and strong brittleness. More specifically, according to the tests, because of their relative small particle size, the carbonate grains of clay rocks in this region are distributed more uniformly, and the average clay mineral content is comparatively low, as a result, the deep clay shale of this region are featured by large internal friction angle and high mechanical strength.
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Wilson, M. J., and L. Wilson. "Clay mineralogy and shale instability: an alternative conceptual analysis." Clay Minerals 49, no. 2 (April 2014): 127–45. http://dx.doi.org/10.1180/claymin.2014.049.2.01.
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AbstractThe instability of shales in drilled formations leads to serious operational problems with major economic consequences for petroleum exploration and production. It is generally agreed that the nature of the clay minerals in shale formations is a primary causative factor leading to their instability, although the exact mechanism involved is more debateable. Currently, the principal cause of shale instability is considered to be volume expansion following the osmotic swelling of Nasmectite. However, illitic and kaolinitic shales may also be unstable, so that interlayer expansion cannot therefore be considered as a universal causative mechanism of shale instability. This review considers alternative scenarios of shale instability where the major clay minerals are smectite, illite, mixed-layer illite-smectite (I/S) and kaolinite respectively. The influence of interacting factors that relate to shale clay mineralogy such as texture, structure and fabric are discussed, as are the pore size distribution and the nature of water in clays and shales and how these change with increasing depth of burial. It is found from the literature that the thickness of the diffuse double layer (DDL) of the aqueous solutions associated with the charged external surfaces of clay minerals is probably of the same order or even thicker than the sizes of a significant proportion of the pores found in shales. In these circumstances, overlap of the DDLs associated with exposed outer surfaces of clay minerals on opposing sides of micropores (<2 nm in diameter) and mesopores (2–50 nm in diameter) in a lithostatically compressed shale would bring about electrostatic repulsion and lead to increased pore/ hydration pressure in smectitic, illitic and even kaolinitic shales. This pressure would be inhibited by the use of more concentrated K-based fluids which effectively shrink the thickness of the DDL towards the clay mineral surfaces in the pore walls. The use of soluble polymers would also encapsulate these clay mineral surfaces and so inhibit their hydration. In this scenario, the locus of action with respect to shale instability and its inhibition is moved from the interlamellar space of the smectitic clays to the charged external surfaces of the various clay minerals bounding the walls of the shale pores.
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Wang, Shengxiu, Jia Wang, Yuelei Zhang, Dahua Li, Weiwei Jiao, Jinxi Wang, Zhian Lei, Zhongqiang Yu, Xiaojun Zha, and Xianfeng Tan. "Relationship between Organic Geochemistry and Reservoir Characteristics of the Wufeng-Longmaxi Formation Shale in Southeastern Chongqing, SW China." Energies 14, no. 20 (October 15, 2021): 6716. http://dx.doi.org/10.3390/en14206716.
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Shale gas accumulates in reservoirs that have favorable characteristics and associated organic geochemistry. The Wufeng-Longmaxi formation of Well Yucan-6 in Southeast Chongqing, SW China was used as a representative example to analyze the organic geochemical and reservoir characteristics of various shale intervals. Total organic carbon (TOC), vitrinite reflectance (Ro), rock pyrolysis, scanning electron microscopy (SEM), and nitrogen adsorption analyses were conducted, and a vertical coupling variation law was established. Results showed the following: the Wufeng-Longmaxi formation shale contains kerogen types I and II2; the average TOC value at the bottom of the formation is 3.04% (and the average value overall is 0.78%); the average Ro value is 1.94%; the organic matter is in a post mature thermal evolutionary stage; the shale minerals are mainly quartz and clay; and the pores are mainly intergranular, intragranular dissolved pores, organic matter pores and micro fractures. In addition, the average specific surface area (BET) of the shale is 5.171 m2/g; micropores account for 4.46% of the total volume; the specific surface area reaches 14.6%; and mesopores and macropores are the main pore spaces. There is a positive correlation between TOC and the quartz content of Wufeng-Longmaxi shale, and porosity is positively correlated with the clay mineral content. It is known that organic pores and the specific area develop more favorably when the clay mineral content is higher because the adsorption capacity is enhanced. In addition, as shale with a high clay mineral content and high TOC content promotes the formation of a large number of nanopores, it has a strong adsorption capacity. Therefore, the most favorable interval for shale gas exploration and development in this well is the shale that has a high TOC content, high clay mineral content, and a suitable quartz content. The findings of this study can help to better identify shale reservoirs and predict the sweet point in shale gas exploration and development.
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Joseph Henri Nainggolan, Maxwel, Wiwik Rahayu, and Puspita Lisdiyanti. "Effect of Urease Enzyme on Shear Strength of Clay Shale." International Journal of Engineering & Technology 7, no. 4.36 (December 9, 2018): 424. http://dx.doi.org/10.14419/ijet.v7i4.36.23909.
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In recent years, utilization of biotechnology in geotechnical field has rapidly grown. One of the biotechnologies being utilized is urease enzyme, a stabilization material by bio-cementation method studied in this research. Urease enzyme is manually mixed with additional 10% of clay soil to clay shale. The objective of mixing it is to increase the bearing capacity of the clay shale. Consolidated undrained triaxial test was performed for testing the soil strength performance for samples that had undergone curing for 2, 4, and 6 weeks. The results indicated that the sample stiffens, proved by the increase of shear strength from consolidated undrained triaxial test. The shear strength value produced by the variation of the urease enzyme mixture + 10% the clay is higher than that of without the original clay shale.
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Nichols Jr., Thomas C., Donley S. Collins, and Richard R. Davidson. "In situ and laboratory geotechnical tests of the Pierre Shale near Hayes, South Dakota—A characterization of engineering behavior." Canadian Geotechnical Journal 23, no. 2 (May 1, 1986): 181–94. http://dx.doi.org/10.1139/t86-028.
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A geotechnical investigation of the Pierre Shale near Hayes, South Dakota, was conducted by the U.S. Geological Survey as a basis for evaluating problems in deep excavations into that formation. The physical and mechanical properties of the shale were determined through use of core holes drilled to a maximum depth of 184 m. In situ borehole determinations included a gravimeter survey, pressuremeter testing, thermal profile measurements, and borehole velocity measurements. Onsite and offsite laboratory measurements included rebound measurements, sonic velocity measurements of shear and primary waves, X-ray mineralogy and major element determinations, size analyses, fracture analyses, fabric analyses, and determination of thermal properties.Below 15–22 m, the shale is an unweathered, saturated, overconsolidated, underpressured clay shale with a clay-mineral content ranging between 50 and 100%, dominantly composed of mixed-layer illitic smectites. The physical and mechanical properties vary widely. The variation is related to the clay mineral content (especially in bentonite zones), a large transverse mechanical anisotropy, and zones of fractures and microfractures, which may result from rebound caused by erosion. These may contribute to slope instability over large areas. The thermal and mechanical properties change markedly if the shale is permitted to dry out. The state of stress and overconsolidation appear to be functions of the depositional and erosional history of the deposit. Both are markedly affected by the large fracture zones. The properties of the clay shale indicate problems that may be encountered in excavation and use of deep underground facilities. Key words: anisotropy, characterization, clay shale, consolidation state, physical properties, rebound, relaxation, stress state, thermal properties.
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Sørensen, Morten Kanne, and Ida Lykke Fabricius. "Clay squirt: Local flow dispersion in shale-bearing sandstones." GEOPHYSICS 82, no. 1 (January 1, 2017): MR51—MR63. http://dx.doi.org/10.1190/geo2015-0036.1.
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Dispersion of elastic-wave velocity is common in sandstone and larger in shaly sandstone than in clean sandstone. Dispersion in fluid-saturated shaly sandstone often exceeds the level expected from the stress-dependent elastic moduli of dry sandstone. The large dispersion has been coined clay squirt and is proposed to originate from a pressure gradient between the clay microporosity and the effective porosity. We have formulated a simple model that quantifies the clay-squirt effect on bulk moduli of sandstone with homogeneously distributed shale laminae or dispersed shale. The model predictions were compared with the literature data. For sandstones with dispersed shale, agreement was found, whereas other sandstones have larger fluid-saturated bulk modulus, possibly due to partially load-bearing shales or heterogeneous shale distribution. The data that agree with the clay-squirt model indicated nonuniform pore pressure in the high-frequency regime and uniform pore pressure in the low-frequency regime. Therefore, our model showed that clay-squirt dispersion can attain a sufficient magnitude to explain much of the large dispersion observed in shaly sandstone.
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Iqbal, Muhammad Atif, Reza Rezaee, Gregory Smith, and Partha Pratim Mandal. "Implications of thin laminations on pore structure of marine shale reservoir: Goldwyer Formation case study from Western Australia." APPEA Journal 61, no. 1 (2021): 205. http://dx.doi.org/10.1071/aj20025.
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The pore structure of a shale reservoir is a major control on hydrocarbon potential, yet shale pore systems are complex and affected by various factors. This paper focuses on the differences in pore structure between thinly laminated and massive black shale (MBSh) beds in the Ordovician Goldwyer-III shale, Canning Basin, Western Australia. A multiscale approach included image logs, core descriptions, thin sections, scanning electron microscope and X-ray diffraction analysis with low-pressure nitrogen and carbon dioxide gas adsorption tests. The results indicate that the Goldwyer shale comprises laminated beds of quartz silt and shale with thin beds of organic-rich clay, plus minor interbedded carbonate bands or concretions. The pore types are subjected to rock type, and the thinly laminated shale (LSh) is enriched in intergranular and intragranular pores. In contrast, the MBSh mainly comprises organic matter pores. The LSh is slightly enriched in mesopores but has negligible micropores. The mesopores are wedge-shaped and associated with an inorganic matrix of clay and pyrite. In comparison, the MBSh contains both mesopores and micropores. These pores are slit-like and related to organic matter and clay. The clay content and total organic carbon fluctuations control the development of mesopores and micropores in both the laminated and MBSh beds in the Goldwyer-III shale. The MBSh layers are suggested as the most important rock types for fluid flow via pore systems due to higher total pore volume, specific surface area and gas adsorption capacity.
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Yang, Rongyan, Furong Wang, Nianhan Yun, Hongbin Zeng, Yuanjia Han, Xing Hu, and Ninglin Diao. "Pore Structure Characteristics and Permeability Stress Sensitivity of Jurassic Continental Shale of Dongyuemiao Member of Ziliujing Formation, Fuxing Area, Eastern Sichuan Basin." Minerals 12, no. 12 (November 23, 2022): 1492. http://dx.doi.org/10.3390/min12121492.
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A shale condensate gas reservoir with a high clay content and a high formation pressure was found in the Jurassic shale of the Dongyuemiao Member in the Fuxing area of the eastern Sichuan Basin. Reservoir characteristics and formation pressure have a significant influence on optimal development. The present study investigated the continental shale of the Dongyuemiao Member in Well F. The petrological properties, physical properties, and pore structure of the Dongyuemiao Member were studied using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), N2 adsorption, and mercury intrusion porosimetry (MIP). The permeability stress sensitivity characteristics of the shale reservoirs are discussed based on the change in shale porosity and permeability under overburden pressure. The tested shale samples yielded total organic carbon (TOC) and S1 + S2 values ranging mainly from 1.0 wt.% to 1.5 wt.% and from 0.39 to 2.28 mg/g, respectively, which was in the high maturity stage of the thermal evolution of organic matter (OM). The shales of the Dongyuemiao Member were found to contain high average clay mineral contents (more than 50%) of calcite and quartz, as well as albite, pyrite, dolomite, and halite. The main developments were identified as silica-rich argillaceous shale lithofacies, argillaceous shale lithofacies, and mixed argillaceous shale lithofacies. The pores were found to mainly be plate-like and flake-like interlayer pores of clay minerals and OM pores with various shapes. The pore size was mainly concentrated below 110 nm, and the pore volume increment increased in flakes with pore diameter. The average porosity and permeability of shale were found to be 4.827% and 0.243 mD, respectively. Clay minerals and quartz are beneficial for improving the porosity and permeability of reservoirs, while carbonate minerals have the opposite effect. The permeability of the shale showed a negative exponential change with increasing effective stress under overburden pressure. When the effective confining pressure was greater than 20 MPa, the decline rate of the shale permeability decreased with increases in the effective stress. The higher the clay mineral and TOC content, the stronger the stress sensitivity of shale permeability. The higher the carbonate mineral content, the weaker the stress sensitivity of shale permeability. The porosity sensitivity exponent indicates that matrix pores and micro-fractures are both developed in the Dongyuemiao Member, and the development of internal fractures is the main factor in the strong stress sensitivity of the shale permeability in the study area.
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Baharizan, Fatimah Zahrah, and Mohd Suhaili Ismail. "The brittleness and ductility of shale from Setap shale, Miri, Sarawak." IOP Conference Series: Earth and Environmental Science 1003, no. 1 (April 1, 2022): 012012. http://dx.doi.org/10.1088/1755-1315/1003/1/012012.
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Abstract The brittleness and ductility of Setap Shale from Bekenu, Beluru and Long Lama area can be shown by analyzing the relationship between Poisson’s Ratio and Young’s Modulus. Both Young’s Modulus and Poisson’s Ratio can be calculated using P-wave and Swave value from ultrasonic velocity test. Ultrasonic velocity analysis on core samples from Bekenu, Beluru and Long Lama shows typical values of Poisson’s ratio and static Young’s Modulus of shale. The mineral composition of samples was analyzed using X-ray diffraction (XRD). Beluru 3 was described as marl samples shows significant number of quartz and dolomite which increase the density of the rock higher than Bekenu and Long Lama area. In the other hand, the Long Lama-5 sample shows high ductility compares to other location due to high clay constituents. High clay constituents can be defined by clay constituents greater than 40% composition. The shale with more than 40% are “true shale” where it may affect the conductivity of hydraulic fracturing phase due to high ductility. High ductile shale has the ability to re-seal the fracture due to high elastic material content. The brittleness of shale shows strong relationship between the mineralogical composition of the shale at different locality of Setap Shale and its elastic properties as different samples show different mineral composition.
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Atabo, Nathaniel Odoma, and Ojochogwu Idakwo Sunday. "Geochemical evaluation of Campanian-Maastritchian clay-shale sediments of Patti formation, Southern Bida and Mamu Formation, northern Anambra basins." Global Journal of Geological Sciences 18 (November 3, 2020): 97–118. http://dx.doi.org/10.4314/gjgs.v18i1.9.
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Two basins (Southern Bida and Northern Anambra Basins) were investigated to deduce weathering, paleooxygenation, provenance, depositional environment and tectonic setting, as well as to establish a relationship between the two basins. The obtained high values of calculated weathering indices such as Chemical index of alteration (CIA > 90), Chemical Index of Weathering (CIW > 90), Plagioclase Index of Alteration (PIA > 90) and the Al2O3-(CaO + Na2O)-K2O ternary relationship for the clay – shale sediments from both basins indicate intense weathering in the source area. Important geochemical ratios such as V/Cr, Cu/Zn, Ni/Co, (Cu+Mo)/Zn, revealed predominantly oxic conditions for the clay – shale sediments from both basins, although, a more reducing or an anoxic condition cannot be ruled out for the clay – shale sediments from the Southern Bida basin due to high ratios of U/Th (1.93-5.67) and Cu/Zn (0.19-5.00). In addition, the Sr/Ba ratios (0.16–3.50) for the clay-shales from the Southern Bida basin indicated an alternated marine and continental paleo-depositional settings and only continental setting (Sr/Ba ratios = 0.22 – 0.50) for the Northern Anambra basin. The Th/Sc, La/Sc, Th/Co and the LREE/HREE ratios showed a derivation of the shale and clay deposits from similar felsic-rich source rock while the log of (K2O/Na2O) vs SiO2, revealed a Passive Margin tectonic setting for the two Basins. There is insignificant differences between the geochemical classifications, weathering, source rock/provenance and tectonic settings of clay-shale sediments of both sedimentary basins, however, there exist slight disparity in their salinity conditions and redox settings.
Keywords: Geochemistry, Clay-shale, Provenance, Tectonic Setting, Northern Anambra and Southern Bida Basins
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Han, Yifu, and Siddharth Misra. "Joint petrophysical inversion of multifrequency conductivity and permittivity logs derived from subsurface galvanic, induction, propagation, and dielectric dispersion measurements." GEOPHYSICS 83, no. 3 (May 1, 2018): D97—D112. http://dx.doi.org/10.1190/geo2017-0285.1.
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Borehole-based subsurface electromagnetic (EM) measurements, namely, galvanic resistivity (laterolog), induction, propagation, and dielectric dispersion logs, are commonly used for water-saturation estimation in hydrocarbon-bearing formations. EM logs exhibit frequency dependence due to the interfacial polarization (IP) effects arising from clay-grain surfaces, conductive minerals, and charge blockage in pore throats. IP effects in shale formations adversely affect the log-derived water-saturation estimates, especially when there is low porosity, high salinity, the presence of pyrite disseminations, and high clay concentration. Conventional EM log-interpretation methods estimate water saturation in shale formations by separately interpreting the galvanic, induction, propagation, and dielectric dispersion logs using various empirical models or mixing laws. This approach leads to significant variations and uncertainties in petrophysical estimations. We have developed an inversion-based joint petrophysical interpretation of multifrequency effective electrical conductivity and dielectric permittivity logs derived from various combinations of the four aforementioned downhole EM logs acquired in clay- and pyrite-rich shale formations. The proposed joint-interpretation method uses a single mechanistic model that accounts for the IP effect arising from clay and conductive mineral grains, thereby generating physically consistent water-saturation estimates in shales. The proposed inversion-based interpretation also generates estimates of formation brine conductivity, surface conductance of clay, and average radius of clay and conductive mineral grains. The proposed method is applied to one field case and three synthetic geologic formations, with varying clay type, conductive mineral properties, and water saturation. Further, the sensitivity of inversion-derived estimates to the presence of various types of noise in the EM logs is investigated. The joint petrophysical inversion algorithm is applied to field broadband dispersion EM data acquired in an organic-rich shale formation. Water saturation, brine conductivity, surface conductance of clay, and radius of clay were consistently estimated in the shale formation using various combinations of available EM logs.
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Wang, Ziyi, Liuping Zhang, Yuan Gao, Wenxiu Yang, Yongshi Wang, Huimin Liu, Zhaoyang Li, and Shanshan Zhou. "Pore Properties of the Lacustrine Shale in the Upper Part of the Sha-4 Member of the Paleogene Shahejie Formation in the Dongying Depression in East China." Geofluids 2021 (March 15, 2021): 1–20. http://dx.doi.org/10.1155/2021/6616843.
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Lacustrine shales hold a huge potential oil resource in China. Pore properties (pore volume, diameter, specific surface area, and fractal dimensions) and their relationships with geological factors (mineralogy, insoluble organic carbon, burial depth, and vitrinite reflectance) are critical for evaluating shale oil resource. However, the factors controlling pores for lacustrine shale oil remain unclear, as the relationships between pore properties of Soxhlet-extracted samples and geological factors have not been studied using multivariate analytical methods. In this paper, the samples from the lacustrine shale in the upper part of the Sha-4 Member of the Paleogene Shahejie Formation in the Dongying Depression were tested with a set of experiments including Soxhlet (solvent) extraction, X-ray diffraction mineral analysis, insoluble organic carbon, vitrinite reflectance, and low-pressure CO2 and N2 adsorption experiments. The micromesopore volume varies from 0.003 cm3/g to 0.045 cm3/g. The relationships of pore properties with geological factors were studied with partial least square regression analysis (PLSR analysis, a powerful multivariate regression analysis). The results of the PLSR analyses indicate that clay minerals and carbonates are two key factors affecting the pore properties of the lacustrine shale. Compared with marine shales, more clay minerals in the lacustrine shale make them become more important for controlling pores than organic matter. The PLSR results also illustrate that the shale with higher pore volume contains more clay minerals and fewer carbonates and thus is unfavorable for hydraulic fracturing. Therefore, the shale with high micromesopore volume may be unfavorable for shale oil production. The shale with the modest micromesopore volume (~0.036 cm3/g), relatively high content of brittle minerals (~71 wt%), and low clay mineral content (~29 wt%) is conducive to both oil storage and hydraulic fracturing for the development of the Es4U shale oil in the Dongying Depression in East China.
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Deng, Qiang, Deng Feng Wei, Zheng Qin Ye, and Jin Fang Xu. "Preparation and Swelling Inhibition of Polyammonium." Advanced Materials Research 482-484 (February 2012): 1317–20. http://dx.doi.org/10.4028/www.scientific.net/amr.482-484.1317.
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A new anti-swelling agent was synthesized by polymerizing epichlorohydrin and dimethyl amine polymer. The swelling inhibition properties were investigated over clay and shale. It was found that the clay inhibition of swelling properties was greatly enhanced compared with common inorganic salts. However, to shale, the swelling properties did not inhibited efficiently by using prepared polymers. Furthermore, the influence of cross linking of polyammonium to the swelling ability of prepared polymer has been also carried out by using triethylenetetramine cross linking agent. In the case of shale, the swelling inhibit properties was improved after cross link, while opposite swelling effect was observed over clay.
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Yuan, Yujie, and Reza Rezaee. "Comparative Porosity and Pore Structure Assessment in Shales: Measurement Techniques, Influencing Factors and Implications for Reservoir Characterization." Energies 12, no. 11 (May 31, 2019): 2094. http://dx.doi.org/10.3390/en12112094.
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Porosity and pore size distribution (PSD) are essential petrophysical parameters controlling permeability and storage capacity in shale gas reservoirs. Various techniques to assess pore structure have been introduced; nevertheless, discrepancies and inconsistencies exist between each of them. This study compares the porosity and PSD in two different shale formations, i.e., the clay-rich Permian Carynginia Formation in the Perth Basin, Western Australia, and the clay-poor Monterey Formation in San Joaquin Basin, USA. Porosity and PSD have been interpreted based on nuclear magnetic resonance (NMR), low-pressure N2 gas adsorption (LP-N2-GA), mercury intrusion capillary pressure (MICP) and helium expansion porosimetry. The results highlight NMR with the advantage of detecting the full-scaled size of pores that are not accessible by MICP, and the ineffective/closed pores occupied by clay bound water (CBW) that are not approachable by other penetration techniques (e.g., helium expansion, low-pressure gas adsorption and MICP). The NMR porosity is largely discrepant with the helium porosity and the MICP porosity in clay-rich Carynginia shales, but a high consistency is displayed in clay-poor Monterey shales, implying the impact of clay contents on the distinction of shale pore structure interpretations between different measurements. Further, the CBW, which is calculated by subtracting the measured effective porosity from total porosity, presents a good linear correlation with the clay content (R2 = 0.76), implying that our correlated equation is adaptable to estimate the CBW in shale formations with the dominant clay type of illite.
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Xue, Haitao, Guozhi Ding, Zhentao Dong, Rixin Zhao, Ce An, Boheng Li, Yuan Zhou, et al. "Study on the Wettability and Spontaneous Imbibition Characteristics of Lacustrine Shale." Geofluids 2022 (February 10, 2022): 1–14. http://dx.doi.org/10.1155/2022/4023435.
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Wettability plays a significant role in the exploration and development of shale oil. The wettability affects the oil enrichment and restricts the selection of fracturing fluids. Shale is composed of complex minerals and organic matter. The pores composed of inorganic minerals have water wettability, while the pores composed of organic matter show the characteristics of oil wetting. The contact angle experiment and the spontaneous imbibition experiment are the most commonly used methods for characterizing wettability. The Qingshankou Formation in the Songliao Basin has thick source rocks, which is a favorable interval for shale oil exploration and development. Strengthening the wettability research in this area is of great significance for the exploration of shale oil. The wettability of different lithofacies shale in the northern Songliao Basin is seldom characterized, and there is a lack of comparative studies on contact angle and imbibition characteristics. In view of this situation, the shale of the Qingshankou Formation in the northern Songliao Basin has been classified. This article used the method of spontaneous imbibition combined with nuclear magnetic resonance to characterize the wettability of shale and analyze the influencing factors of the wettability of different shale lithofacies. Six samples with different lithological characteristics were used for this experiment. The study found that the imbibition results of samples with different lithofacies are different. The imbibition of sandy interlayer is less affected by the direction, while the imbibition of shale is more affected by the direction. The water imbibition volume of the sample is related to the content of clay minerals. The relationship of water imbibition volume in different lithofacies samples is as follows: low organic matter laminated siliceous shale > high organic matter massive clay shale > sandy interlayer > high organic matter laminated siliceous shale > high organic matter massive siliceous shale. Excessive content of clay minerals will cause shale to absorb water and expand and block pores, which is not conducive to further water imbibition by shale. The volume of oil imbibed is related to the organic carbon content. The relationship of oil imbibition volume in different lithofacies samples is as follows: high organic matter massive clay shale > high organic matter laminated siliceous shale > sandy interlayer > low organic matter laminated siliceous shale > high organic matter massive siliceous shale. The higher the total organic carbon content, the more developed the lipophilic pore network, and the more the volume of oil imbibed by the sample.
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Wu, Zhonghu, Yujun Zuo, Shanyong Wang, Jibin Sunwen, and Leilei Liu. "Experimental Study on the Stress Sensitivity and Influence Factors of Shale under Varying Stress." Shock and Vibration 2018 (July 11, 2018): 1–9. http://dx.doi.org/10.1155/2018/3616942.
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Shale reservoirs are characterized by extremely low permeability and high clay content. To further study the stress sensitivity of a shale reservoir, the Lower Cambrian shale in north Guizhou was utilized. Through laboratory testing, the relationships between the shale porosity and permeability and the effective stress were established, and the stress sensitivity of shale was analysed. The mechanical properties and mineral composition of this shale were studied by rock mechanics testing and X-ray diffraction. The main factors affecting the stress sensitivity were analysed. The results show that the porosity and permeability of this shale decrease with increasing effective stress; the shale reservoir permeability damage rate is 61.44 ~ 73.93%, with an average of 69.92%; the permeability stress sensitivity coefficient is 0.04867 ~ 0.05485 MPa−1, with an average of 0.05312 MPa−1; and the shale reservoir stress sensitivity is strong. Shale stress sensitivity is related to the rock mineral composition and rock mechanical properties. The higher the clay content in the mineral composition, the lower the elastic modulus of shale, the higher the compressibility, and the greater the stress sensitivity coefficient.
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Meng, Guangming, Tengfei Li, Haifeng Gai, and Xianming Xiao. "Pore Characteristics and Gas Preservation of the Lower Cambrian Shale in a Strongly Deformed Zone, Northern Chongqing, China." Energies 15, no. 8 (April 18, 2022): 2956. http://dx.doi.org/10.3390/en15082956.
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The Lower Paleozoic marine shale in southern China has undergone several strong tectonic transformations in an extensive region outside the Sichuan Basin. Although some shale strata underwent strong deformation, they still contain a significant amount of shale gas. The gas preservation mechanism in the strongly deformed shale has become the focus of attention. In this paper, the Lower Cambrian gas-bearing shale samples with a strong deformation taken from an exploration well in northern Chongqing, China, were investigated on their pore types and structure, with the aim to reveal the reason for the gas preservation. The pore types of the Lower Cambrian shale are dominated by microfractures and interparticle (interP) pores occurring mainly between clay minerals and between organic matter (OM) and clay minerals, while pores within OM that can be observed by FE-SEM (field emission-scanning electron microscopy) are rare. The shale has a low porosity, with an average of 1.56%, which is mainly controlled by the clay mineral content. The adsorption experiments of low pressure N2 (LPNA) and CO2 (LPCA) indicate that the shale is rich in micropores and small mesopores (<2–3 nm) provided mainly by OM, but mesopores with a size range of 3–50 nm are underdeveloped. The shale, as revealed by LPNA data, has dominant slit-like or plate-like pores and an obvious low-pressure hysteresis (LPH), indicating a low gas diffusion. The deformed shale samples with a removal of OM by oxidation and their isolated kerogen further indicate that the LPH is completely related to OM, without any relationship with minerals, while an undeformed shale sample, taken from another well for a comparison, has no obvious LPH for both of its OM-removed sample and kerogen. Based on a comprehensive analysis of the relative data, it is suggested that the nanopores related to OM and clay minerals in the shale were significantly altered owing to the deformation, with a result of the pores being squeezed into the slit-like shape and converted into micropores. This extraordinary pore structure of the shale formed during the deformation process should be the main preservation mechanism of shale gas.
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Abdou, Saleh Mahmoud, Nabila Amin Ali, and Mohamed Rajaa Balboul. "Characterization of shale formation of abandoned petroleum wells and treatment using acid simulation technique." Technology audit and production reserves 2, no. 3(58) (April 30, 2021): 20–24. http://dx.doi.org/10.15587/2706-5448.2021.227619.
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The object of research is shale, which is a combination of carbonate (calcite or dolomite), and non clay minerals such as silica (quartz) and clay minerals such as kaolinite. Characterization of various minerals in shale formed in six abandoned petroleum wells was done using Energy Dispersive X-ray (EDX), X-ray diffraction (XRD) and Fourier Transformation Infra-Red (FTIR). Shale may contain a wide variety of minerals. The shale formation within the abandoned wells in the current study is at a deep of about (2600±300) meters. Three shale formation samples were collected from each of the abandoned wells. Characterizing the constituents of the clay minerals of the shale is important in the drilling and the treatment process. The analyses declared that, some shale formation samples are similar. The study was continued on three abandoned petroleum wells (I, II and III). The XRD and FTIR obtained results of shale analysis show the existence of calcite (CaCO3) and quartz (SiO2) in the shale samples. Dolomite CaMg(CO3)2 is present in well (II) and well (III), and muscovite H2KAl3Si3O12 is present in well (I). Also, Kaolinite Al2Si2O5(OH)4, and barite (BaSO4) components are detected in the FTIR results. Mg, K, Al and Ba trace elements are detected by EDX analyses and may contribute chemically. Shale technology and research development is concern with three steps: Characterization, simulation, and permeability stimulation. The present study focusing on the characterization and simulation of the shale formed in six abandoned (non-producing) petroleum wells for enhancing the productivity of carbonate reservoirs.
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Xiaojin, Zhou, Duan Yonggang, He XiaoPing, Zeng Bo, and Song Yi. "Study on Postfrac Softening Mechanism of Deep Marine Shale Reservoir in South Sichuan Basin." Geofluids 2023 (January 27, 2023): 1–10. http://dx.doi.org/10.1155/2023/4433439.
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Shale softening is an important factor affecting fracturing effect. Through the Brinell hardness measurement of deep marine shale reservoir in South Sichuan Basin, the softening mechanism of shale after fracturing is explored. Through laboratory test, the key parameters of shale Brinell hardness measurement are proposed as follows: indenter size 5 mm, loading force 613 N, 1226 N, and 2452 N, and holding time > 10 s . It is determined that the content of quartz and clay is the main factor controlling the Brinell hardness of dry shale samples, and the mineral composition, microstructure, and fluid system jointly affect the shale softening process. The results show that (1) the marine shale in the South Sichuan Basin softens obviously, with the Brinell hardness decrease by more than 50%, (2) microfracture propagation and clay hydration expansion accelerate the shale softening process, leading to the decreased porosity and the increased number of micro-pores, and (3) the softening process is different between middeep shale and deep shale, with the latter characterized by high initial hardness and low softening rate.
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Suryajaya, Julio, and Aniek Prihatiningsih. "STUDI PENGGUNAAN BAHAN MORTAR SIKADUR-52 SEBAGAI PELINDUNG TANAH CLAY SHLAE TERHADAP PELAPUKAN." JMTS: Jurnal Mitra Teknik Sipil 2, no. 3 (October 30, 2019): 35. http://dx.doi.org/10.24912/jmts.v2i3.5779.
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Penelitian ini dilatarbelakangi oleh rawannya tanah clay shale atau clay stone, mengalami pelapukan secara cepat jika terekpose udara dan air. Untuk mencegah terjadinya pelapukan, diperlukan usaha perlindungan tanah dengan cara melapisi tanah dengan bahan tambahan seperti mortar yang mudah diaplikasikan di lapangan agar tanah terlindung dari udara dan air. Penelitian dilakukan pada sampel tanah yang telah dilapisi mortar, dalam kondisi terendam air dan kondisi kering udara selama kurun waktu 1,3,5, dan 7 minggu. Setelah dilakukan pengkondisian tersebut akan dilakukan uji unconfined untuk mengetahui nilai tekan tanah dalam kondisi terlindungi. Hasil dari uji unconfined diharapkan, tidak ada perubahan pada nilai kuat tekan bebas dari masing-masing benda uji selama kurun waktu 1,3,5, dan 7 minggu. Pemilihan bahan mortar diharapkan menjadi bahan yang mudah di aplikasikan dan ekonomis, yang dapat melindungi tanah clay shale atau clay stone dari pelapukan yang disebabkan oleh udara dan air. Pada penelitian ini menunjukan bahan Sikadur-52 dapat melindungi tanah clay shale dengan cara pelapisan yang sempurna tanpa ada celah pada saat bahan dilapisi.
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Cai, Yi, Rukai Zhu, Zhong Luo, Songtao Wu, Tianshu Zhang, Chang Liu, Jingya Zhang, et al. "Lithofacies and Source Rock Quality of Organic-Rich Shales in the Cretaceous Qingshankou Formation, Songliao Basin, NE China." Minerals 12, no. 4 (April 11, 2022): 465. http://dx.doi.org/10.3390/min12040465.
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The organic-rich shale of the Qingshankou Formation (K2qn) is the most important target in the Songliao Basin. The relationship between lithofacies and source rock quality, however, is still controversial. Core observation, thin section identification, X-ray diffraction, organic geochemistry, and other analytical methods were adopted to investigate the petrology and its effects on hydrocarbon potential of the Qingshankou shale. Based on the differences in minerals, bioclastic, and fabric of laminae, four main lithofacies were defined as: (i) felsic shale (FS), (ii) clay shale (CS), (iii) bio-bearing shale (BS), and (iv) mixed shale (MS). The clay minerals content in the CS (average: 46.72 wt%) and MS (average: 41.11 wt%) was higher than that in FS (average: 39.97 wt%) and BS (average: 35.48 wt%). This classification allows the following comparative quantification of total organic carbon (TOC) content to be differentiated: CS > BS > MS > FS. Geochemical analysis indicated that the oil generation potential of the CS was the best, and the hydrocarbons generated from CS might migrate and accumulate in other lithofacies. All this knowledge could shed light on the lithofacies classification in shale systems with high clay mineral content, and may provide references for sweet spotting of the Qingshankou Formation in the Songliao Basin.
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Han, Qiang, Zhan Qu, and Zhengyin Ye. "Research on the mechanical behaviour of shale based on multiscale analysis." Royal Society Open Science 5, no. 10 (October 2018): 181039. http://dx.doi.org/10.1098/rsos.181039.
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In view of the difficulty in obtaining the mechanical properties of shale, the multiscale analysis of shale was performed on a shale outcrop from the Silurian Longmaxi Formation in the Changning area, Sichuan Basin, China. The nano-/micro-indentation test is an effective method for multiscale mechanical analysis. In this paper, effective criteria for the shale indentation test were evaluated. The elastic modulus was evaluated at a multiscale and the engineering validation of drilling cuttings was performed. The porosity tests showed that the pore distribution of shale from the nanoscale to macro-pore could be better displayed by the nuclear magnetic resonance test. The micro-scale elastic modulus and hardness increased nonlinearly with the increase in the clay packing density. It was observed that the size effect of the micro-hardness was based on porosity and composition. The partial spalling of shale at the micro-scale could lead to irregular bulges or steps in a load–displacement curve. The elastic modulus of pure clay minerals was 24.2 GPa on the parallel bedding plane and 15.8 GPa on the vertical bedding plane. The contact hardness (pure clay minerals) was 0.51 GPa. The indentation results showed that the micro-elastic modulus of shale obeyed the normal distribution, and the statistical average could predict the macro-mechanical properties effectively. The present work can provide a new way to recognize the mechanical behaviour of shale.
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Wang, Jianfeng, Yuke Liu, Chao Yang, Wenmin Jiang, Yun Li, and Yongqiang Xiong. "Modeling the Viscoelastic Behavior of Quartz and Clay Minerals in Shale by Nanoindentation Creep Tests." Geofluids 2022 (January 13, 2022): 1–16. http://dx.doi.org/10.1155/2022/2860077.
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The viscoelastic behavior of minerals in shales is important in predicting the macroscale creep behavior of heterogeneous bulk shale. In this study, in situ indentation measurements of two major constitutive minerals (i.e., quartz and clay) in Longmaxi Formation shale from the Sichuan Basin, South China, were conducted using a nanoindentation technique and high-resolution optical microscope. Firstly, quartz and clay minerals were identified under an optical microscope based on their morphology, surface features, reflection characteristics, particle shapes, and indentation responses. Three viscoelastic models (i.e., three-element Voigt, Burger’s, and two-dashpot Kelvin models) were then used to fit the creep data for both minerals. Finally, the effects of peak load on the viscoelastic behavior of quartz and clay minerals were investigated. Our results show that the sizes of the residual imprints on clay minerals were larger than that of quartz for a specific peak load. Moreover, the initial creep rates and depths in clay minerals were higher than those in quartz. However, the creep rates of quartz and clay minerals displayed similar trends, which were independent of peak load. In addition, all three viscoelastic models produced good fits to the experimental data. However, due to the poor fit in the initial holding stage of the three-element Voigt model and instability of the two-dashpot Kelvin model, Burger’s model is best in obtaining the regression parameters. The regression results indicate that the viscoelastic parameters obtained by these models are associated with peak load, and that a relatively small peak load is more reliable for the determination of viscoelastic parameters. Furthermore, the regression values for the viscoelastic parameters of clay minerals were lower than those of quartz and the bulk shale, suggesting the former facilitates the viscoelastic deformation of shale. Our study provides a better understanding of the nanoscale viscoelastic properties of shale, which can be used to predict the time-dependent deformation of shale.
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Mo, Peng, Junhui Luo, Decai Mi, Zhenchao Chang, Haifeng Huang, Tao Zhang, Guanhua Sun, Yan Li, Ling Zeng, and Shihai Wang. "Classification and Disintegration Characteristics of the Carboniferous Rocks in Guangxi, China." Advances in Civil Engineering 2021 (November 19, 2021): 1–9. http://dx.doi.org/10.1155/2021/8929808.
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To investigate the disintegration characteristics of the carbonaceous rocks in Guangxi Province, the typical carbonaceous rocks in the section exposed by the Hechi-Baise Expressway were investigated in this study. First, based on their mineral compositions and contents, the carbonaceous rocks were divided into four types: carbonate chert, carbonaceous argillaceous limestone, carbonaceous illite clay mudstone, and carbonaceous illite clay shale. Then, through indoor wet-dry cyclic disintegration test, the disintegration characteristics of the four types of rocks were studied. The test results showed the following: (1) the disintegration residues of the carbonate chert and the carbonaceous argillaceous limestone decrease linearly as the number of wetting-drying cycles increases. (2) The disintegration index of the carbonaceous illite clay mudstone and the carbonaceous illite clay shale decreases exponentially as the number of wetting-drying cycles increases. (3) As the number of wetting-drying cycles increases, the disintegration index curves of the carbonaceous illite clay mudstone and the carbonaceous illite clay shale samples gradually become stable until the disintegration of the samples is completed. (4) The disintegration of carbonaceous rocks is mainly affected by the clay content, followed by the structural form, but it cannot be ignored.
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Yang, Xiao-Guang, and Shao-Bin Guo. "Porosity model and pore evolution of transitional shales: an example from the Southern North China Basin." Petroleum Science 17, no. 6 (July 23, 2020): 1512–26. http://dx.doi.org/10.1007/s12182-020-00481-7.
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AbstractThe evolution of shale reservoirs is mainly related to two functions: mechanical compaction controlled by ground stress and chemical compaction controlled by thermal effect. Thermal simulation experiments were conducted to simulate the chemical compaction of marine-continental transitional shale, and X-ray diffraction (XRD), CO2 adsorption, N2 adsorption and high-pressure mercury injection (MIP) were then used to characterize shale diagenesis and porosity. Moreover, simulations of mechanical compaction adhering to mathematical models were performed, and a shale compaction model was proposed considering clay content and kaolinite proportions. The advantage of this model is that the change in shale compressibility, which is caused by the transformation of clay minerals during thermal evolution, may be considered. The combination of the thermal simulation and compaction model may depict the interactions between chemical and mechanical compaction. Such interactions may then express the pore evolution of shale in actual conditions of formation. Accordingly, the obtained results demonstrated that shales having low kaolinite possess higher porosity at the same burial depth and clay mineral content, proving that other clay minerals such as illite–smectite mixed layers (I/S) and illite are conducive to the development of pores. Shales possessing a high clay mineral content have a higher porosity in shallow layers (< 3500 m) and a lower porosity in deep layers (> 3500 m). Both the amount and location of the increase in porosity differ at different geothermal gradients. High geothermal gradients favor the preservation of high porosity in shale at an appropriate Ro. The pore evolution of the marine-continental transitional shale is divided into five stages. Stage 2 possesses an Ro of 1.0%–1.6% and has high porosity along with a high specific surface area. Stage 3 has an Ro of 1.6%–2.0% and contains a higher porosity with a low specific surface area. Finally, Stage 4 has an Ro of 2.0%–2.9% with a low porosity and high specific surface area.
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Zhang, Yayun, and Cong Xiao. "Molecular Dynamics Simulation of Clay Hydration Inhibition of Deep Shale." Processes 9, no. 6 (June 19, 2021): 1069. http://dx.doi.org/10.3390/pr9061069.
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In the process of the exploitation of deep oil and gas resources, shale wellbore stability control faces great challenges under complex temperature and pressure conditions. It is difficult to reflect the micro mechanism and process of the action of inorganic salt on shale hydration with the traditional experimental evaluation technology on the macro effect of restraining shale hydration. Aiming at the characteristics of clay minerals of deep shale, the molecular dynamics models of four typical cations (K+, NH4+, Cs+ and Ca2+) inhibiting the hydration of clay minerals have been established by the use of the molecular dynamics simulation method. Moreover, the micro dynamics mechanism of typical inorganic cations inhibiting the hydration of clay minerals has been systematically evaluated, as has the law of cation hydration inhibition performance in response to temperature, pressure and ion type. The research indicates that the cations can promote the contraction of interlayer spacing, compress fluid intrusion channels, reduce the intrusion ability of water molecules, increase the negative charge balance ability and reduce the interlayer electrostatic repulsion force. With the increase in temperature, the inhibition of the cations on montmorillonite hydration is weakened, while the effect of pressure is opposite. Through the molecular dynamics simulation under different temperatures and pressures, we can systematically understand the microcosmic dynamics mechanism of restraining the hydration of clay in deep shale and provide theoretical guidance for the microcosmic control of clay hydration.
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Ortega, J. Alberto, Franz-Josef Ulm, and Younane Abousleiman. "The nanogranular acoustic signature of shale." GEOPHYSICS 74, no. 3 (May 2009): D65—D84. http://dx.doi.org/10.1190/1.3097887.
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A multiscale, micromechanics model has been developed for the prediction of anisotropic acoustic properties of shale. The model is based on the recently identified nanogranular mechanical response of shale through indentation experiments. It recognizes the dominant role of the anisotropic elastic properties of compacted clay in the anisotropic elasticity of shale at different length scales compared to contributions of shape and orientation of particles. Following a thorough validation at multiple length scales using mineral elasticity data, nanoindentation experiment results, and ultrasonic pulse velocity tests, the model predictions compare adequately with measurements on kerogen-free and kerogen-rich shales and shaley sandstones. The acoustic signature of shale thus is found to be controlled by two volumetric parameters that synthesize the porosity and mineralogy information: the clay-packing density and the silt inclusion volume fraction. Through a series of dimensionless isoparametric plots, the micromechanics model predicts trends of increasing elastic anisotropy with increasing clay-packing density (or decreasing porosity), which correspond to the intrinsic mechanical response of unfractured shale, and quantifies the stiffness reduction induced by the presence of kerogen.
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Shang, Fuhua, Yanming Zhu, Haitao Gao, Yang Wang, and Ruiyin Liu. "Relationship between Tectonism and Composition and Pore Characteristics of Shale Reservoirs." Geofluids 2020 (February 20, 2020): 1–14. http://dx.doi.org/10.1155/2020/9426586.
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Tectonism is one of the major controlling factors of shale gas accumulation and enrichment in China. To explore the relationship between tectonism and composition and pore characteristics of shale reservoirs, this research carried out mineralogy tests, organic geochemistry tests, field emission scanning electron microscopy (FE-SEM) experiments, and low-pressure gas adsorption (LPGA, N2 and CO2) experiments on the shale samples of various deformation intensities from Southwestern China. Based on the FE-SEM image analyses, it can be found that there are large differences in pore characteristics in shale samples with different deformation intensities. The samples with strong deformation have more organic pores, mainly related to the clay-organic aggregates and rigid grains. Tectonism can cause organic matter (OM) and clay minerals to be mixed or OM to fill in the clay layers, resulting in the retention of some organic pores. It is the presence of pressure shadows around the rigid grains that can resist tectonic extrusion and protect some organic pores. LPGA experiment results also show that micropore-specific surface areas and pore volumes of the samples with strong deformation are larger than those with weak deformation. The shale samples with strong deformation also have more microchannels and microfractures. Tectonism can also cause some micropores to become macropores; for example, tectonism can cause the rigid grains to slide and rotate, enlarging the dissolution pores at the edges of rigid grains. Shale samples with strong deformation have a smaller mesopore volume; but due to the presence of organic-clay aggregates, a larger mesopore-specific surface area embarks on these samples. According to fractal dimension calculations, it is found that in strong deformed shale, more multiple dimensions of the pore system tend to represent rougher pore surfaces and more irregular shapes. Besides, rougher pore surfaces are eager to provide more adsorption sites and enhance the adsorption capacity of the deformed shale. This study investigates the relationship between tectonism and composition and pore characteristics of shale reservoirs and may promote understanding of the accumulation of shale gas in highly deformed areas.
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Pamungkas, Goji, Thomas Triadi Putranto, Suharyanto, Muhrozi, and Yanuar Niko Priambodo. "Residual Strength Parameter Method for Slope stability on a Toll Road with Expansive Clay." Journal of Geoscience, Engineering, Environment, and Technology 7, no. 2 (June 30, 2022): 49–58. http://dx.doi.org/10.25299/jgeet.2022.7.2.9251.
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The decreasing stability phenomenon needs to be considered during the design of cut slopes on problematic soil. Excavation slope of toll road construction tends to fail when it lies above clay-shale strata. Certain common correlations and ordinary analytical methods are not recommended for safety calculation. This study is intended to find out the characteristic of clay-shale and proper slope inclination design on Semarang Batang Toll Road. The behaviour of a clay-shale area on the cut slope of Batang-Semarang toll road segment STA 438+000–STA 439+000 was identified. The degradable and expansive properties caused slope failure of the initial design with an inclination of 1 H: 1 V. Laboratory tests found that the soil had a clay faction > 40% and can be categorized as high plasticity (LL > 50%). An empirical approach determined that the residual shear strength decreased to phi < 6 degrees. To describe the swelling after the excavation stage, the flow deformation was determined by a finite element simulation. During the swelling phase, the pore water pressure was maintained at a certain value, and a gentler slope fulfilled the minimum safety factor with an inclination of 1 V: 3 H. Furthermore, the shear strength of the clay-shale was reduced to that for a fully softened material, and all the slope factors for safety moved to a critical state. According to the simulation, the minimum suggested slope inclination is 5 H: 1 V. This approach is important for the maintenance of pore water pressure and the prevention of an additional reduction in the shear strength so as to avoid slope failure on clay-shale regions in the yielding stage.
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Hou, Dali, Fengming Gong, Hongming Tang, Jianchun Guo, Xianyu Qiang, and Lei Sun. "Molecule Simulation of CH4/CO2 Competitive Adsorption and CO2 Storage in Shale Montmorillonite." Atmosphere 13, no. 10 (September 25, 2022): 1565. http://dx.doi.org/10.3390/atmos13101565.
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The main source of production in the middle and late stages of shale gas extraction is the adsorbed gas in shale, and the adsorbed gas in shale mainly comes from organic matter casein and clay minerals in shale; therefore, this paper uses sodium-based montmorillonite to characterize the clay minerals in shale and study the CH4 adsorption law in clay minerals, and this study has certain guiding significance for shale gas extraction. In addition, this paper also conducts a study on the competitive adsorption law of CH4 and CO2, and at the same time, predicts the theoretical sequestration of CO2 in shale clay minerals, which is a reference value for the study of CO2 burial in shale and is beneficial to the early realization of carbon neutral. In this paper, the slit model of sodium-based montmorillonite and the fluid model of CH4 and CO2 were constructed using Materials Studio software, and the following two aspects were studied based on the Monte Carlo method: Firstly, the microscopic adsorption behavior of CH4 in sodium-based montmorillonite was studied, and the simulations showed that the adsorption capacity of montmorillonite decreases with increasing temperature, increases and then decreases with increasing pressure, and decreases with increasing pore size. CH4 has two states of adsorption and free state in the slit. The adsorption type of CH4 in montmorillonite is physical adsorption. Secondly, the competitive adsorption of CH4 and CO2 in sodium-based montmorillonite was studied, and the simulations showed that the CO2 repulsion efficiency increased with increasing CO2 injection pressure, and the CO2/CH4 competitive adsorption ratio decreased with increasing pressure. The amount of CO2 storage decreased with increasing temperature and increased with increasing CO2 injection pressure.
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Wang, Yong, Fen Wang, and Min Ji. "Research on Drying Sludge in Brick Making." Advanced Materials Research 777 (September 2013): 19–25. http://dx.doi.org/10.4028/www.scientific.net/amr.777.19.
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Dried sludge could be used for brick production by firing with shale or clay, which would reduce clay resource exploitation and realize sludge resource utilization. Physical and mechanics parameters of fired shale-sludge brick and clay-sludge brick are tested to examine technical feasibility, and heavy metal leaching concentrations are tested to examine brick safety. The results show that after municipal sludge in Changsha Wastewater Treatment Plant is dried with water content no more than 30%, it can be used for shale-sludge brick and clay-sludge brick firing and qualified produces can be produced. Compressive strength of brick is 10-20 MPa, there is no scum and lime crack on brick body. Under high firing temperature, heavy metal in sludge can be solidified, and leaching concentrations can meet the requirements. By doing so, calorific power of sludge can be utilized and energy saving can be realized.
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Han, Changcheng, Geng Liu, Cunfei Ma, Ming Qi, Yi Yang, and Guan Li. "Influencing Factors of Shale Permeability in the Longmaxi Formation, Southern Sichuan Basin and Northern Yunnan-Guizhou Depression." Geofluids 2022 (July 22, 2022): 1–20. http://dx.doi.org/10.1155/2022/6832272.
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The current paper studies the influencing factors of permeability in shales of the Longmaxi Formation, located in the southern Sichuan Basin, China. The methodologies used in the present study include overburden pore permeability experiments, whole rock analysis and geochemical tests, NMR measurements of fluid saturation, pore size distribution and specific surface area distribution, SEM and extraction of pore structure parameters, and core analysis. The results show the following: (1) high TOC and high maturity generate a large number of organic pores, which may improve the permeability of shale. (2) Mineral composition and rock relative permeability also have influence on permeability to a certain degree, since different minerals have different effects on shale permeability. Clay in the study area has an adverse effect on permeability. The results show that the organic-rich siliceous clay mixed shale facies in this area has the best permeability. (3) A large specific surface area and total pore volume are associated with good shale permeability, while average pore size does not correlate with permeability. A small fractal dimension of pore morphology and simple pore structure result in good permeability, and bedding is the key controlling factor for the anisotropy of shale permeability. (4) Water in shales can influence the permeability of microfractures by binding to clay minerals. Low permeability in shales with high bound water saturation suggests that water and clay mineral absorption may block flow channels, resulting in poor permeability. The purpose of this study is to clarify the influencing factors on shale permeability of the Longmaxi Formation in the study area and to provide a reference for the exploration and development of shale gas in this area of the Sichuan Basin.
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Wedage, AMP, N. R. Morgenstern, and D. H. Chan. "Simulation of time-dependent movements in Syncrude tailings dyke foundation." Canadian Geotechnical Journal 35, no. 2 (April 1, 1998): 284–98. http://dx.doi.org/10.1139/t97-086.
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Foundation movements at the Syncrude tailings dyke continued over several years in response to the construction of the dyke. Major movements have been observed in a relatively narrow layer of previously sheared clay-shale material of the Clearwater Formation. The residual strength of this highly plastic clay increases with the rate of shear. By reviewing the existing literature on the rate effects on residual strength and using data from new experiments on Clearwater Clay Shale, a general correlation between soil plasticity and rate effects is found. This rate dependence of the residual strength of Clearwater clay shale has been incorporated into a deformation analysis, which made it possible to compute time-dependent movements of the foundation soil to a satisfactory level. By using a rate-dependent plasticity model, a prediction of anticipated foundation velocities and how they decrease with time may be achieved.Key words: finite element, rate effects, residual strength, Syncrude tailings dyke, time-dependent movements.
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Li, Minghui, Mingliang Li, Haiping Huang, Lei Gong, and Debao Zheng. "Differences of Pore Features in Marine Shales between Lower Cambrian and Lower Silurian Formations of Upper Yangtze Area, South China." Energies 15, no. 3 (January 24, 2022): 820. http://dx.doi.org/10.3390/en15030820.
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Lower Cambrian shale and lower Silurian shale are both typical of oil-prone kerogen and siliceous composition, but different in thermal maturities. Porosity differences were determined in marine shales between the two shales. Measurements were utilized including organic geochemistry, XRD, scanning electron microscopy (SEM) and N2 gas adsorption. Pore volume (PV) of lower Silurian shale was approximately 1.5 times higher than that of lower Cambrian shale, and pore surface area (PSA) of lower Silurian shale was almost 2.5 times higher than that of lower Cambrian shale. Lower Cambrian shale and lower Silurian shale possess similar materials, but distinctive thermal degrees. Evolution mechanisms of different types of pores, especially organic matter (OM)-hosted pores, may trigger this different pore features. Pores of rigid framework are the residue of primary interparticle pores during the burial history. Pores associated with clay flakes can be preserved well adjacent to rigid grains or secondary minerals acting as rigid frameworks or grain supporters. Dissolved pores in both lower Cambrian shale and lower Silurian shale barely contribute to the total porosity and mean little to the permeability. Both excessive OM content and over thermal maturity are detrimental to development of OM-hosted pores. Rigid particles, clay flakes, and OM commonly co-exist within shale matrix. Rigid grains act as supporters, clay flakes confine ample space, and OM first migrates into and provides secondary OM-hosted pores. In this condition, pores can be preserved owing to associating matrix with good mechanic and chemical stability. The significant differences of structural settings result into various hydrocarbon explosion efficiency and different pressure circumstance, which consequently leads to the different pore features between the two shales. For lower Cambrian shale, overpressure circumstance diminish if hydrocarbon expels outside of the shale system, and OM-hosted pores destroy through compaction. Sustaining overpressure and abundant residue hydrocarbon (migrated OM) make positive contributions to the pore properties, in terms of numbers, diameters and connectivity of the lower Silurian shale samples.
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Xiao, Zhenghui, Jisong Liu, Jingqiang Tan, Rongfeng Yang, Jason Hilton, Ping Zhou, Zhaohui Wang, and Yunjiang Cao. "Geologic characterization of a lower Cambrian marine shale: Implications for shale gas potential in northwestern Hunan, South China." Interpretation 6, no. 3 (August 1, 2018): T635—T647. http://dx.doi.org/10.1190/int-2017-0117.1.
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We have investigated the geologic features of the lower Cambrian-aged Niutitang Shale in the northwestern Hunan province of South China. Our results indicate that the Niutitang Shale has abundant and highly mature algal kerogen with total organic carbon (TOC) content ranging from 0.6% to 18.2%. The equivalent vitrinite reflectance (equal-Ro) value is between 2.5% and 4.3%. Mineral constituents are dominated by quartz and clay. The average quartz content (62.8%) is much higher than that of clay minerals (26.1%), and this suggests a high brittleness index. Organic-matter pores, interparticle pores, intraparticle pores, interlaminated fractures, and structural fractures are all well developed. The porosity ranges from 0.6% to 8.8%, with an average of 4.8%, whereas the permeability varies from 0.0018 to [Formula: see text] (microdarcy) (averaging [Formula: see text]). The porosity of TOC- and clay-rich shale samples is generally higher than that of quartz-rich shale samples. The gas adsorption capacity of the Niutitang Shale varies from 2.26 to [Formula: see text], with a mean value of [Formula: see text]. The TOC content appears to significantly influence gas adsorption capacity. In general, TOC-rich samples exhibit a much higher adsorption capacity than TOC-poor samples.
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Xu, Gui Xi, Shu Zhong Wang, Xiang Rong Luo, and Ze Feng Jing. "Investigation on Jurassic Shale Gas Reservoir Characteristics from Northern Qaidam Basin." Key Engineering Materials 748 (August 2017): 441–45. http://dx.doi.org/10.4028/www.scientific.net/kem.748.441.
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The Jurassic continental shale from northern Qaidam basin was selected as the research object, through the analysis of X-ray diffraction (XRD), field emission scanning electron microscopy (SEM) and nitrogen adsorption experiment, the mineral composition and pore structure characteristics of Jurassic continental shale from the northern Qaidam basin have been investigated in detail. All shale samples studied are quite rich in clay minerals. The clay mineral content ranges from 59.8% to 83.3% with an average of 74.6%, and the brittle mineral content accounts for 16.5% to 39.3%. Nitrogen adsorption test results indicate that for mesopores and macropores of shale samples the average pore width is 2~200 nm, mainly centering on 10~50 nm, and the micropores of the shale samples have a centralized distribution of 0.5~1 nm. The shale samples show high specific surface areas of 4.6~15.2 m2/g. According to SEM results, interparticle mineral matrix pores are main pore type and slit-type pore are well developed.
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Qu, Yuanzhi, Ren Wang, Shifeng Gao, Hongjun Huang, Zhilei Zhang, Han Ren, Yuehui Yuan, Qibing Wang, Xiangyun Wang, and Weichao Du. "Study on the Shale Hydration Inhibition Performance of Triethylammonium Acetate." Minerals 12, no. 5 (May 13, 2022): 620. http://dx.doi.org/10.3390/min12050620.
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Shale inhibitor is an additive for drilling fluids that can be used to inhibit shale hydration expansion and dispersion, and prevent wellbore collapse. Small molecular quaternary ammonium salt can enter the interlayer of clay crystal, and enables an excellent shale inhibition performance. In this paper, a novel ionic shale inhibitor, triethylammonium acetate (TEYA), was obtained by solvent-free synthesis by using acetic acid and triethylamine as raw materials. The final product was identified as the target product by Fourier transform infrared spectroscopy (FT-IR). The inhibition performance of TEYA was studied by the mud ball immersion test, linear expansion test, rolling recovery test and particle size distribution test. The results demonstrated that the shale inhibitor shows a good shale hydration inhibition performance. The inhibition mechanism was studied by FT-IR and X-ray diffraction (XRD), respectively; the results showed that triethylammonium acetate TEYA could enter the crystal layer of clay and inhibit it through physical adsorption.
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Oktaviani, Revia, Paulus P. Rahardjo, and Imam A. Sadisun. "Landslides induced by slaking of geomaterial." MATEC Web of Conferences 229 (2018): 03011. http://dx.doi.org/10.1051/matecconf/201822903011.
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The geological event that happens because of an unbalance between shear strength and shear stress on rock mass is known as a landslide. This usually occurs due to improper handling of the exposed material. The landslide occurs because of the reaction to reduce the burden it bears so that the mass of the rock will move rock mass from the higher elevation to lower elevation. Many landslides, in west java, Indonesia occurred on exposed clay shale that is protected by soldier pile with 3m in distance between pile. On top of the clay shale, there is a building which gives an additional load on the clay shale. To determine the effect of water and temperature on clay shale, static slaking index test was conducted. With a submerge variation, it was found that the slaking index value ranged from 2.17% to 12.0% with the slaking classification from very low to medium. The size distribution was produced from 1/4 and 1/2 sample submerge show bigger rock breakage than rock with 3/4 sample submerge and sample fully submerge. Observations of the sample in room temperature without contact of water and no additional mass were also done. The sample was still intact until the end of research work.
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Han, Yong, Yanming Zhu, Yu Liu, Yang Wang, Han Zhang, and Wenlong Yu. "Nanostructure Effect on Methane Adsorption Capacity of Shale with Type III Kerogen." Energies 13, no. 7 (April 3, 2020): 1690. http://dx.doi.org/10.3390/en13071690.
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This study focuses on the nanostructure of shale samples with type III kerogen and its effect on methane adsorption capacity. The composition, pore size distribution, and methane adsorption capacities of 12 shale samples were analyzed by using the high-pressure mercury injection experiment, low-temperature N2/CO2 adsorption experiments, and the isothermal methane adsorption experiment. The results show that the total organic carbon (TOC) content of the 12 shale samples ranges from 0.70% to ~35.84%. In shales with type III kerogen, clay minerals and organic matter tend to be deposited simultaneously. When the TOC content is higher than 10%, the clay minerals in these shale samples contribute more than 70% of the total inorganic matter. The CO2 adsorption experimental results show that micropores in shales with type III kerogen are mainly formed in organic matter. However, mesopores and macropores are significantly affected by the contents of clay minerals and quartz. The methane isothermal capacity experimental results show that the Langmuir volume, indicating the maximum methane adsorption capacity, of all the shale samples is between 0.78 cm3/g and 9.26 cm3/g. Moreover, methane is mainly adsorbed in micropores and developed in organic matter, whereas the influence of mesopores and macropores on the methane adsorption capacity of shale with type III kerogen is small. At different stages, the influencing factors of methane adsorption capacity are different. When the TOC content is <1.4% or >4.5%, the methane adsorption capacity is positively correlated with the TOC content. When the TOC content is in the range of 1.4–4.5%, clay minerals have obviously positive effects on the methane adsorption capacity.