المؤلفون: Jiang Shengming, Zhang Jiarui, Tang Shuai, Xu Jianting

المصدر: Petroleum Research, Vol 6, Iss 4, Pp 423-430 (2021)

مصطلحات موضوعية: Oils, fats, and waxes, Sedimentary environment, QEMSCAN, Energy Engineering and Power Technology, Mineralogy, 02 engineering and technology, Electron microscope, 010502 geochemistry & geophysics, 01 natural sciences, Longmaxi formation, Sedimentary depositional environment, 020401 chemical engineering, Geochemistry and Petrology, TP670-699, 0204 chemical engineering, Petroleum refining. Petroleum products, Quartz, Weiyuan area, 0105 earth and related environmental sciences, QemScan scanning, Geology, Authigenic, Grain size, Diagenesis, Quartz grain size, Clastic rock, Sedimentary rock, TP690-692.5

الوصف: As a key factor restricting the fracturing effect of shale reservoir, the origin and content of quartz components have always been the focus of academic and industrial circles. Due to the great influence of diagenesis process, the accuracy of trace element determination to identify the origin of quartz is not good, which can not meet the increasingly accurate research requirements. In this paper, mineral quantitative analysis technology (QemScan) is used to identify quartz components by two-dimensional quantitative scanning, and the content data of quartz components with different grain sizes are extracted. The results show that the size of quartz particles is obviously controlled by the difference of sedimentary water and sedimentary environment, that is, quartz particles less than 30 μm are mainly concentrated in Long112 and Long114 layers, which is the normal oxygen environment under the background of medium retention in deep water environment; quartz particles larger than 20 μm are mainly concentrated in Long111 and Long113 layers, which is the poor oxygen environment under the background of strong retention in deep water environment. In shallow water environment, the stronger hydrodynamic conditions make the strata rich in terrigenous clastic quartz particles with larger grain size, and oxygen poor environment is conducive to the enrichment of authigenic quartz with smaller grain size.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::bc7d320d6393070707c124b8e3a1ad65Test
http://www.sciencedirect.com/science/article/pii/S2096249521000260Test

المؤلفون: Yiqing Zhu, Jun Xie, Rui Yong, Xinhua Ma

المصدر: Petroleum Exploration and Development, Vol 47, Iss 5, Pp 901-915 (2020)

مصطلحات موضوعية: 0211 other engineering and technologies, Geochemistry, Energy Engineering and Power Technology, chemistry.chemical_element, southern Sichuan Basin, 02 engineering and technology, 010502 geochemistry & geophysics, 01 natural sciences, Pressure coefficient, Sedimentary depositional environment, Lower Silurian Longmaxi Formation, Geochemistry and Petrology, 021108 energy, deeply buried shale gas, lcsh:Petroleum refining. Petroleum products, 0105 earth and related environmental sciences, shale gas reservoir, Thorium, Geology, Uranium, Geotechnical Engineering and Engineering Geology, Anoxic waters, Waves and shallow water, Volume (thermodynamics), chemistry, lcsh:TP690-692.5, deep water and deep burial, Economic Geology, Oil shale, high production control factors

الوصف: Marine shale gas resources have great potential in the south of the Sichuan Basin in China. At present, the high-quality shale gas resources at depth of 2000–3500 m are under effective development, and strategic breakthroughs have been made in deeper shale gas resources at depth of 3500–4500 m. To promote the effective production of shale gas in this area, this study examines key factors controlling high shale gas production and presents the next exploration direction in the southern Sichuan Basin based on summarizing the geological understandings from the Lower Silurian Longmaxi Formation shale gas exploration combined with the latest results of geological evaluation. The results show that: (1) The relative sea depth in marine shelf sedimentary environment controls the development and distribution of reservoirs. In the relatively deep water area in deep-water shelf, grade-I reservoirs with a larger continuous thickness develop. The relative depth of sea in marine shelf sedimentary environment can be determined by redox conditions. The research shows that the uranium to thorium mass ratio greater than 1.25 indicates relatively deep water in anoxic reduction environment, and the uranium to thorium mass ratio of 0.75–1.25 indicates semi-deep water in weak reduction and weak oxidation environment, and the uranium to thorium mass ratio less than 0.75 indicates relatively shallow water in strong oxidation environment. (2) The propped fractures in shale reservoirs subject to fracturing treatment are generally 10–12 m high, if grade-I reservoirs are more than 10 m in continuous thickness, then all the propped section would be high-quality reserves; in this case, the longer the continuous thickness of penetrated grade-I reservoirs, the higher the production will be. (3) The shale gas reservoirs at 3500–4500 m depth in southern Sichuan are characterized by high formation pressure, high pressure coefficient, well preserved pores, good pore structure and high proportion of free gas, making them the most favorable new field for shale gas exploration; and the pressure coefficient greater than 1.2 is a necessary condition for shale gas wells to obtain high production. (4) High production wells in the deep shale gas reservoirs are those in areas where Long11– Long13 sub-beds are more than 10 m thick, with 1500 m long horizontal section, grade-I reservoirs penetration rate of over 90%, and fractured by dense cutting + high intensity sand injection + large displacement + large liquid volume. (5) The relatively deep-water area in the deep-water shelf and the area at depth of 3500–4500 m well overlap in the southern Sichuan, and the overlapping area is the most favorable shale gas exploration and development zones in the southern Sichuan in the future. With advancement in theory and technology, annual shale gas production in the southern Sichuan is expected to reach 450×108 m3.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::b4e45c5d1777a20b1d56aa6c21df3df5Test
http://www.sciencedirect.com/science/article/pii/S1876380420601057Test

المؤلفون: Jin Wu, Zhensheng Shi, Hongyan Wang, Dazhong Dong, Shasha Sun

المصدر: Petroleum Exploration and Development, Vol 47, Iss 4, Pp 888-900 (2020)

مصطلحات موضوعية: Lamina, Bedding, 0211 other engineering and technologies, Energy Engineering and Power Technology, Mineralogy, 02 engineering and technology, Silt, 010502 geochemistry & geophysics, 01 natural sciences, reservoir characteristics, chemistry.chemical_compound, Geochemistry and Petrology, genetic mechanism, parasitic diseases, Organic matter, 021108 energy, Porosity, Quartz, lcsh:Petroleum refining. Petroleum products, 0105 earth and related environmental sciences, gas-bearing shale, chemistry.chemical_classification, Lower Silurian, lamina, Geology, Geotechnical Engineering and Engineering Geology, chemistry, Longmaxi Formation, lcsh:TP690-692.5, Carbonate, Economic Geology, Oil shale

الوصف: Based on thin-section, argon-ion polished large-area imaging and nano-CT scanning data, the reservoir characteristics and genetic mechanisms of the Lower Silurian Longmaxi shale layers with different laminae and laminae combinations in the Sichuan Basin were examined. It is found that the shale has two kinds of laminae, clayey lamina and silty lamina, which are different in single lamina thickness, composition, pore type and structure, plane porosity and pore size distribution. The clayey laminae are about 100 μm thick each, over 15% in organic matter content, over 70% in quartz content, and higher in organic pore ratio and plane porosity. They have abundant bedding fractures and organic matter and organic pores connecting with each other to form a network. In contrast, the silty laminae are about 50 μm thick each, 5% to 15% in organic matter content, over 50% in carbonate content, higher in inorganic pore ratio, undeveloped in bedding fracture, and have organic matter and organic pores disconnected from each other. The formation of mud lamina and silt lamina may be related to the flourish of silicon-rich organisms. The mud lamina is formed during the intermittent period, and silt lamina is formed during the bloom period of silicon-rich organisms. The mud laminae and silt laminae can combine into three types of assemblages: strip-shaped silt, gradating sand-mud and sand-mud thin interlayers. The strip-shaped silt assemblage has the highest porosity and horizontal/vertical permeability ratio, followed by the gradating sand-mud assemblage and sand-mud thin interlayer assemblage. The difference in the content ratio of the mud laminae to silt laminae results in the difference in the horizontal/vertical permeability ratio.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::c893aca790acc2ff874eab2c9aa822e0Test
http://www.sciencedirect.com/science/article/pii/S1876380420601045Test

المؤلفون: Dianshi Xiao, Jianhua Zhao, Shu Jiang, Yuchao Li, Yuying Zhang, Zhiliang He, Guohui Chen

المصدر: Energies; Volume 14; Issue 9; Pages: 2679
Energies, Vol 14, Iss 2679, p 2679 (2021)

مصطلحات موضوعية: reservoir, Technology, Control and Optimization, 010504 meteorology & atmospheric sciences, Geochemistry, Energy Engineering and Power Technology, 010502 geochemistry & geophysics, 01 natural sciences, Methane, Bottom water, chemistry.chemical_compound, source rock, Wufeng-Longmaxi Formation, Sichuan Basin, shale gas, Electrical and Electronic Engineering, Sedimentology, Engineering (miscellaneous), 0105 earth and related environmental sciences, Total organic carbon, Renewable Energy, Sustainability and the Environment, Sapropel, Source rock, chemistry, Sedimentary rock, Oil shale, Geology, Energy (miscellaneous)

الوصف: In order to analyze the main factors controlling shale gas accumulation and to predict the potential zone for shale gas exploration, the heterogeneous characteristics of the source rock and reservoir of the Wufeng-Longmaxi Formation in Sichuan Basin were discussed in detail, based on the data of petrology, sedimentology, reservoir physical properties and gas content. On this basis, the effect of coupling between source rock and reservoir on shale gas generation and reservation has been analyzed. The Wufeng-Longmaxi Formation black shale in the Sichuan Basin has been divided into 5 types of lithofacies, i.e., carbonaceous siliceous shale, carbonaceous argillaceous shale, composite shale, silty shale, and argillaceous shale, and 4 types of sedimentary microfacies, i.e., carbonaceous siliceous deep shelf, carbonaceous argillaceous deep shelf, silty argillaceous shallow shelf, and argillaceous shallow shelf. The total organic carbon (TOC) content ranged from 0.5% to 6.0% (mean 2.54%), which gradually decreased vertically from the bottom to the top and was controlled by the oxygen content of the bottom water. Most of the organic matter was sapropel in a high-over thermal maturity. The shale reservoir of Wufeng-Longmaxi Formation was characterized by low porosity and low permeability. Pore types were mainly 3/t and 3.719 m3/t, and the total gas contents were between 0.44 m3/t and 5.19 m3/t, both of which gradually decreased from the bottom upwards. Shale with a high TOC content in the carbonaceous siliceous/argillaceous deep shelf is considered to have significant potential for hydrocarbon generation and storage capacity for gas preservation, providing favorable conditions of the source rock and reservoir for shale gas.

وصف الملف: application/pdf

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::84244c35577bd0922d786db48c15e200Test

المؤلفون: Weiwei Xue, Xuanbo Gao, Jia Wang, Chao Luo, Jingchun Tian, Chunlin Zeng, Lei Zhang, Long Luo, Xianfeng Tan

المصدر: Frontiers in Earth Science, Vol 9 (2021)

مصطلحات موضوعية: Outcrop, Science, 0211 other engineering and technologies, Geochemistry, Compaction, 02 engineering and technology, Structural basin, 010502 geochemistry & geophysics, Feldspar, 01 natural sciences, shale, diagenetic evolution, 021108 energy, 0105 earth and related environmental sciences, organic matter, Drilling, Sediment, Diagenesis, structural evolution, Longmaxi Formation, visual_art, visual_art.visual_art_medium, General Earth and Planetary Sciences, Sichuan Basin, Oil shale, Geology

الوصف: The diagenetic evolution is an important controlling factor of shale gas reservoir. In this study, based on field outcrop and drilling core data, analytical techniques including X-ray diffraction (XRD), field emission scanning electron microscope combined with a focused ion beam (FIB-FESEM), and energy dispersive spectroscopy (EDS) analysis were performed to determine diagenetic evolution of the Longmaxi Formation shale , and reveal effect of diagenetic evolution on the shale gas exploration and development in the Sichuan Basin, Southwest China. The diagenetic evolution can be divided into eodiagenesis, mesodiagenesis, and teleodiagenesis. The eodiagenesis and mesodiagenesis were subdivided into two and three evolution stages respectively both in Basin margin and center. Absorbed capacity and artificial fracturing effect of the Longmaxi Formation shale gas was related to mineral composition, which was influenced by the sediment characteristics and diagenetic evolution. Diagenetic system in the Basin margin was more open than that in Basin center due to different structural burial history. The more open diagenetic system consisting of more micro-fractures and soluble constitute (e.g. feldspar) was in favour for formation and preservation of secondary dissolved pores and organic pores in the Basin margin. The relatively closed diagenetic system with stronger compaction resulted in deformation of pore space in the central Basin due to different burial history and diagenetic evolution.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::c2ccbea45b7d8abf333839bf78eaba4bTest
https://www.frontiersin.org/articles/10.3389/feart.2021.661581/fullTest

المؤلفون: Majia Zheng, Hu Li, Hongming Tang

المصدر: Minerals
Volume 9
Issue 9
Minerals, Vol 9, Iss 9, p 548 (2019)

مصطلحات موضوعية: fractal dimension, Materials science, lcsh:QE351-399.2, Thin section, pore structure, 0211 other engineering and technologies, Mineralogy, 02 engineering and technology, 010502 geochemistry & geophysics, 01 natural sciences, Fractal dimension, mineral composition, Sedimentary depositional environment, 021108 energy, 0105 earth and related environmental sciences, pore type, lcsh:Mineralogy, Macropore, Geology, Microporous material, Geotechnical Engineering and Engineering Geology, Diagenesis, Longmaxi Formation, heterogeneity, Mesoporous material, Oil shale

الوصف: In recent years, the shale gas in the southern Sichuan Basin has achieved great commercial development, and the Silurian Longmaxi Formation is the main development stratum. In order to solve the problems of great difference production and inaccurate gas content of the Longmaxi Formation shale gas field in the southern Sichuan Basin, based on thin section identification, argon ion polishing-field emission scanning electron microscopy, high pressure mercury injection, low temperature nitrogen adsorption and the fractal method, the micropore structural heterogeneity of the siliceous shale reservoir of the Longmaxi Formation has been studied. The results show the following: The pores of siliceous shale are mainly intergranular pores and organic pores. Image analysis shows that there are obvious differences in size and distribution of shale pores among different types. The micropore structural heterogeneity is as follows: intragranular pore >
intergranular pore >
organic pore. In the paper, the combination of low temperature nitrogen adsorption method and high-pressure mercury injection method is proposed to characterize the micropore size distribution and fractal dimension, which ensures the credibility of pore heterogeneity. The shale pores are mainly composed of mesopores (2&ndash
20 nm), followed by macropores (100&ndash
300 nm). For different pore sizes, the fractal dimension from large to small is mesopore, micropore and macropore. Shale pore structure and fractal dimension are correlated with mineral composition and total organic carbon (TOC) content, but the correlation is significantly different in different areas, being mainly controlled by the sedimentary environment and diagenesis.

وصف الملف: application/pdf

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::bb84e8d53f733f250afb1df32d3dd03dTest

المؤلفون: Yang Wang, Yanming Zhu, Fuhua Shang, Xiaorong Qu

المصدر: Minerals, Vol 9, Iss 8, p 494 (2019)
Minerals
Volume 9
Issue 8

مصطلحات موضوعية: Provenance, graptolite, lcsh:QE351-399.2, 0211 other engineering and technologies, Geochemistry, 02 engineering and technology, Structural basin, 010502 geochemistry & geophysics, 01 natural sciences, Sedimentary depositional environment, 021108 energy, Porosity, Tight gas, 0105 earth and related environmental sciences, Total organic carbon, lcsh:Mineralogy, biozonation, Geology, Lomgmaxi Formation, Geotechnical Engineering and Engineering Geology, lithological characteristics, Longmaxi Formation, Middle-Upper Yangtze, Sedimentary rock, Oil shale

الوصف: The organic-enriched thick shale at the bottom of Longmaxi Formation is laterally continuous distributed and has been proven to be of good production capability in Fuling of Upper Yangtze. Uplifts that developed during the sedimentation influenced the reservoir characteristics by taking control of the sedimentary environment and provenance. The sedimentary environments are mainly deep-water shelf, shallow-water shelf, and tidal flat. By analyzing reservoir characteristic of these three environments, the deep-water shelf, which dominated the early stage of sedimentation, formed a high-quality reservoir with high TOC (Total Organic Carbon) content, porosity, and brittleness, while the environment was maintained around the basin centre until the Early Silurian. The shales deposited under the shallow-water environment were of low porosity because of the increasing calcareous and argillaceous contents. Sediments which formed on the tidal flat were arenaceous and of the lowest TOC content as the organic preservation conditions deteriorated. The good correlation of graptolite abundance and TOC content, and high porosity within graptolite fossils emphasize the importance of palaeontological development. The argillaceous cap over the Longmaxi shale is of good sealing capability, and the continuous sedimentation zone along southern Sichuan&ndash
eastern Chongqing is the best optimized hydrocarbon-bearing system. However, a weak interface on the discontinuity is the potential lateral pathway for gas diffusion at Northern Guizhou and Western Hunan, but on the southeast margin where the dark shale and the tidal sandstone contact, it promises to form a tight gas reservoir.

وصف الملف: application/pdf

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::3718dd5a5e8c83adaaa0a2adeaf8c0bdTest
https://www.mdpi.com/2075-163X/9/8/494Test

المؤلفون: Ying Hu, Yanbo Guo, Li Du, Shi Xuewen, Jia Liu, Jun Xie, Chunhai Ji, Shengxian Zhao, Wei Wu

المصدر: Journal of Natural Gas Geoscience, Vol 2, Iss 4, Pp 263-271 (2017)

مصطلحات موضوعية: lcsh:Gas industry, Shale gas, 020209 energy, Metamorphic rock, Carbon isotope, lcsh:TP751-762, Sichuan basin, Geochemistry, 02 engineering and technology, 010502 geochemistry & geophysics, 01 natural sciences, Graptolites, chemistry.chemical_compound, Tectonics, chemistry, Longmaxi Formation, Preservation condition, 0202 electrical engineering, electronic engineering, information engineering, Kerogen, Cleavage (geology), Resource evaluation, Oil shale, Geology, 0105 earth and related environmental sciences

الوصف: Wufeng-Longmaxi Formations shale gas is a new exploration field in Wuxi area, Sichuan Basin, China. Some geological parameters related to shale gas evaluation of the new exploration wells in Wuxi area have been studied, including shale reservoir, gas-bearing, geochemical and paleontological characteristics. The study suggests that the original shale gas generation conditions of the area were good, but later this area went through serious and multi-phase tectonic damage. The major evidences include that: the δ 13 C 2 value of shale gas is obviously higher than that in areas with the same maturity, indicating the shale gas is mainly late kerogen cracking gas and high hydrocarbon expulsion efficiency; the porosity of shale in Wuxi area is very low because of strong tectonic movements and lack of retained oil in the shale; some shale cores near faults even show very weak metamorphic characteristics with intense cleavage, and the epidermis of graptolite fossils was pyrolyzed. The comprehensive study shows shale gas in Wuxi area has prospective resources, but the possibility to get scale commercial production in recent time is very low.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::869a181313c3325b389123a2722cb849Test
http://www.sciencedirect.com/science/article/pii/S2468256X17300652Test

المؤلفون: Ruobing Liu, Xiangfeng Wei, Tonglou Guo

المصدر: Journal of Natural Gas Geoscience, Vol 1, Iss 5, Pp 361-371 (2016)

مصطلحات موضوعية: 020209 energy, Mineralogy, chemistry.chemical_element, Genesis and sources, 02 engineering and technology, 010502 geochemistry & geophysics, 01 natural sciences, Methane, Wufeng–Longmaxi Formation, chemistry.chemical_compound, Shale gas, Shell in situ conversion process, Natural gas, Propane, Gas components, Jiaoshiba area, 0202 electrical engineering, electronic engineering, information engineering, 0105 earth and related environmental sciences, chemistry.chemical_classification, lcsh:Gas industry, business.industry, Carbon isotope, lcsh:TP751-762, Oil shale gas, Hydrocarbon, Source rock, chemistry, business, Carbon, Geology, Fuling Shale Gas Field

الوصف: Taking natural gas from marine strata of the Wufeng–Longmaxi Formation in the Jiaoshiba Block of the Fuling Shale Gas Field as a research subject, the analyses of the gradients of shale gas and carbon isotope shows that the natural gas from the Jiaoshiba area belongs to a high-quality hydrocarbon gas. The contents of methane range 97.22%–98.41%, with a little amount of ethane and propane, an average wetness of 0.74%, and little amount of non-hydrocarbons such as CO 2 , N 2, H 2, however, there's no H 2 S. The carbon isotopes of methane, ethane, and propane are characterized by their complete isotopic reversal (δ 13 C 1 > δ 13 C 2 > δ 13 C 3) . The natural gas from the Wufeng–Longmaxi Formation comes from the source rocks of the same formation, it classifies as a typical shale gas. According to the statistical determination criterion, natural gas in the Jiaoshiba area is derived from the sapropelic source rocks, which is a result of high-temperature pyrolysis. It is the product of mixing primary kerogen pyrolysis and secondary pyrolysis of crude oil, with apparent features of secondary pyrolysis of oil. The reason for the complete carbon isotopic reversal is the mixing of the two aforementioned gasses. Moreover, it has some sort of relationship with the loss function of shale gas after the Late Yanshan.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::ee4ba1bf5f955813738e444bf317d10dTest
http://www.sciencedirect.com/science/article/pii/S2468256X1630075XTest

المؤلفون: Yu Qi, Ying Sun, Liting Ju, Cheng Huang, Kun Yu, Yiwen Ju, Hongjian Zhu

المصدر: Minerals, Vol 9, Iss 6, p 356 (2019)
Minerals
Volume 9
Issue 6

مصطلحات موضوعية: fractal dimension, lcsh:QE351-399.2, pore structure, 0211 other engineering and technologies, Mineralogy, 02 engineering and technology, 010502 geochemistry & geophysics, 01 natural sciences, Fractal dimension, Adsorption, 021108 energy, helium ion microscope, Porosity, 0105 earth and related environmental sciences, Total organic carbon, chemistry.chemical_classification, lcsh:Mineralogy, Geology, Geotechnical Engineering and Engineering Geology, N2 adsorption, Hydrocarbon, chemistry, Volume (thermodynamics), Longmaxi Formation shale, Oil shale, Field ion microscope

الوصف: This paper tries to determine the key evaluation parameters of shale reservoirs in the complex tectonic provinces outside the Sichuan Basin in South China, and also to target the sweet spots of shale reservoirs accurately. The pore-structure characteristics of the Lower Silurian Longmaxi shale gas reservoirs in Well LD1 of the Laifeng&ndash
Xianfeng Block, Upper Yangtze region, were evaluated. N2 adsorption and helium ion microscope (HIM) were used to investigate the pore features including pore volume, pore surface area, and pore size distribution. The calculated results show good hydrocarbon storage capacity and development potential of the shale samples. Meanwhile, the reservoir space and migration pathways may be affected by the small pore size. As the main carrier of pores in shale, organic matter contributes significantly to the pore volume and surface area. Samples with higher total organic carbon (TOC) content generally have higher porosity. Based on the Frenkel&ndash
Halsey&ndash
Hill equation (FHH model), two different fractal dimensions, D1 and D2, were observed through the N2 adsorption experiment. By analyzing the data, we found that large pores usually have large values of fractal dimension, owing to their complex pore structure and rough surface. In addition, there exists a good positive correlation between fractal dimension and pore volume as well as pore surface area. The fractal dimension can be taken as a visual indicator that represents the degree of development of the pore structure in shale.

وصف الملف: application/pdf

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::b05ee570fa2b8986f8d76ff47778a910Test
https://www.mdpi.com/2075-163X/9/6/356Test