المؤلفون: Surong Zhang, Dazhong Dong, Hualing Zhang, Shasha Sun, Quanzhong Guan, Wen Guo

المصدر: Petroleum Exploration and Development, Vol 48, Iss 4, Pp 813-823 (2021)

مصطلحات موضوعية: chemistry.chemical_classification, reservoir-forming mechanism, Geochemistry, Energy Engineering and Power Technology, biogenic quartz, Geology, Biogenic silica, organic-rich shale, Geotechnical Engineering and Engineering Geology, Hydrothermal circulation, Grain size, Wufeng–Longmaxi Formation, Hydrocarbon, chemistry, Geochemistry and Petrology, Ordovician, Economic Geology, Organic matter, Sichuan Basin, Petroleum refining. Petroleum products, Oil shale, Quartz, TP690-692.5

الوصف: Biogenic quartz in the Upper Ordovician Wufeng Formation to Lower Silurian Longmaxi Formation (Wufeng– Longmaxi) shale layers in the Sichuan Basin and its periphery is qualitatively analyzed and quantitatively characterized by organic petrologic, mineralogic, and geochemical methods to find out the coupling effect between organic matter and quartz. (1) There are two types of biogenic quartz in the shale layers: Type I quartz is submicron quartz appearing in clusters around the organic matter. Type II quartz is in nano-scale grain size and floats in spherical shape on organic matter, with grains in point-to-point or surface-to-surface contact; this type of quartz is mainly biologic origin and slightly affected by hydrothermal activity in local parts. (2) The reservoirs in the Wufeng–Longmaxi formations is consistent in distribution with biogenic silica content in them, and mainly concentrated at the bottom of the Wufeng–Longmaxi formations, and is thinner in the Changning and Weiyuan regions, while thicker in the Fuling region. (3) The biogenic quartz in the Wufeng–Longmaxi shale worked through the entire evolution process of hydrocarbon generation. The presence of biogenic quartz can enhance the development of organic matter pores and microcracks, and can effectively preserve the organic matter pores and residual intergranular pores, forming “biological silicon intergranular pores, organic pores and micro-fractures”. This would benefit later hydraulic fracturing and result in high production/stable production of well. The coupling effect between biogenic quartz development and organic matter evolution and hydrocarbon generation is a critical factor for high-quality shale reservoir development.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f222d916ea3ee650e48e7bf65f5a7a06Test
http://www.sciencedirect.com/science/article/pii/S187638042160068XTest

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: Jinxi Wang, Xianfeng Tan, Jia Wang, Hualian Zhang, Ye Zhang, Dongxin Guo, Xiaofeng Wang, Zhian Lei, Chunlin Zeng, Guanghua Yao

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

مصطلحات موضوعية: Total organic carbon, chemistry.chemical_classification, the Wufeng formation, southeastern Chongqing, 020209 energy, shale reservoir, Science, Geochemistry, 02 engineering and technology, Sedimentary depositional environment, Permeability (earth sciences), 020401 chemical engineering, chemistry, 0202 electrical engineering, electronic engineering, information engineering, Fracture (geology), physical characteristics, General Earth and Planetary Sciences, Organic matter, the Longmaxi formation, 0204 chemical engineering, Porosity, Clay minerals, Oil shale, Geology

الوصف: Compared with the overpressure conditions of shale reservoirs in the Jiaoshiba area, exploring the controlling factors of changes in shale reservoir physical properties under normal-pressure accumulation is of great significance to shale gas exploration. To achieve this, X-ray powder diffraction, nitrogen adsorption, and scanning electron microscopy were carried out to determine mineral content, permeability, porosity, and pore structure for well core and outcrop samples of the Wufeng–Longmaxi Formation in southeastern Chongqing, China. Field observations and drilling cores revealed abundant structural fractures in southeastern Chongqing, offering potential main storage space for shale gas. Findings also determined that high-quality source rocks are located in the lower part of the Wufeng–Longmaxi Formation, which features low porosity and low permeability, yet existing structural fractures could potentially improve permeability to a certain extent. The main factors controlling the shale reservoir with the above characteristics include the depositional environment, mineral components, total organic carbon content, and tectonic movement. The deep-water anoxic depositional environment was conducive to the complete preservation of organic matter and sedimentation of the biogenic siliceous minerals, which had a strong effect on improving the porosity of organic matter and brittleness of the rocks. The high content of quartz was found to improve rock compression resistance and brittleness, and increasing clay proportion was found to enhance the interlayer pores of clay minerals. Total organic carbon content, specific surface area, pore volume, and fracture development were all found to have direct contributions to shale gas entrapment. Overall, the most important factor resulting in normal-pressure accumulation in southeastern Chongqing was the intense tectonic movements since the Late Jurassic period which destroyed the original overpressure accumulation conditions.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::4a05af57c2b80e0458204afe042767abTest
https://www.frontiersin.org/articles/10.3389/feart.2021.661706/fullTest

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

المؤلفون: Chao Wang, Zhiyong Meng, Hanyong Bao, Boqiao Zhang, Xiaowei Zheng, Hamed Sanei, Kai Li

المصدر: Zheng, X, Zhang, B, Sanei, H, Bao, H, Meng, Z, Wang, C & Li, K 2019, ' Pore structure characteristics and its effect on shale gas adsorption and desorption behavior ', Marine and Petroleum Geology, vol. 100, pp. 165-178 . https://doi.org/10.1016/j.marpetgeo.2018.10.045Test

مصطلحات موضوعية: 010504 meteorology & atmospheric sciences, Stratigraphy, Compaction, Mineralogy, engineering.material, 010502 geochemistry & geophysics, Oceanography, 01 natural sciences, Adsorption, Jiaoshiba area, Organic matter, Porosity, Pore sorption capacity, 0105 earth and related environmental sciences, chemistry.chemical_classification, Geology, Sorption, Shale reservoir, Wufeng-Longmaxi formation, Geophysics, chemistry, engineering, Economic Geology, Pyrite, Clay minerals, Pore structure, Oil shale

الوصف: As the largest producing shale gas field in China and had just announced its great annual production of 10 billion cubic meters capacity, the Wufeng-Longmaxi (O3w-S1l) formation in Fuling shale gasfield, Sichuan Basin had obtained great attention both in China and globally. Twelve samples from three different wells were collected to explore the pore types and the corresponding pore developing status, pore structure characteristics, sorption capacity and their relationship, for fundamental shale gas reservoir evaluation. The TOC (total organic carbon) content ranges from 0.21% to 6.79%, while quartz and clay mineral content made up 46.92% and 34.12% of the mineral composition. Intergranular pore, intragranular pore, fracture and different OM pore types (in biotic debris organic matter, within porous solid bitumen and in organo-mineral compound) were identified. Porosity obtained by different methods showed great difference because of detecting limitation, therefore it is necessary to combine multiple porosity detecting methods to explore the reservoir porosity more accurately. He porosity is not effective in detecting unaccessible discrete micropore in organic matter while NMR could reflect the nanopore although it is influenced by pore surface wettability. The preserved inorganic pores are affected by diagenesis, with intergranular pore volume and OM pores, without sufficient mineral framework, reduced by compaction and dissolved pores developed in unstable mineral, like carbonate. Clay mineral and other accessory mineral also influence OM pore development, as energy dispersive X-ray spectroscopy (EDS) result illustrated that solid bitumen mixing with mineral during hydrocarbon charging tend to be more porous. Surface area obtained from MIP, N2-GA and CO2 experiment all showed positive correlation with the content of TOC, quartz and pyrite, which also are the main contributors of reservoir sorption capacity, total gas content and desorption rate.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::62435792877bd6209f7ab21f776279b6Test
https://pure.au.dk/portal/da/publications/pore-structure-characteristics-and-its-effect-on-shale-gas-adsorption-and-desorption-behaviorTest(755f6ad7-da31-40ee-a602-a84354030363).html

المؤلفون: Xue Ding, Fangwen Chen, Shuangfang Lu, Zhao Hongqin, Yiwen Ju

المصدر: Minerals
Volume 9
Issue 1
Minerals, Vol 9, Iss 1, p 5 (2018)

مصطلحات موضوعية: lcsh:QE351-399.2, 020209 energy, Mineralogy, 02 engineering and technology, 010502 geochemistry & geophysics, Feldspar, 01 natural sciences, 0202 electrical engineering, electronic engineering, information engineering, Organic matter, Porosity, Quartz, 0105 earth and related environmental sciences, chemistry.chemical_classification, shale gas reservoir, lcsh:Mineralogy, Geology, Porosimetry, Geotechnical Engineering and Engineering Geology, Permeability (earth sciences), chemistry, Longmaxi Formation, visual_art, visual_art.visual_art_medium, Clay minerals, Oil shale, Southeast Chongqing, total porosity

الوصف: Measuring total porosity in shale gas reservoir samples remains a challenge because of the fine-grained texture, low porosity, ultra-low permeability, and high content of organic matter (OM) and clay mineral. The composition content porosimetry method, which is a new method for the evaluation of the porosity of shale samples, was used in this study to measure the total porosity of shale gas reservoir samples from the Lower Silurian Longmaxi Formation in Southeast Chongqing, China, based on the bulk and grain density values. The results from the composition content porosimetry method were compared with those of the Gas Research Institute method. The results showed that the composition content porosimetry porosity values of shale gas reservoir samples range between 2.05% and 5.87% with an average value of 4.04%. The composition content porosimetry porosity generally increases with increasing OM and clay content, and decreases with increasing quartz and feldspar content. The composition content porosimetry results are similar to the gas research institute results, and the differences between the two methods range from 0.05% to 1.52% with an average value of 0.85%.

وصف الملف: application/pdf

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f17ea569a4e57b7e196f82f65d274189Test

المؤلفون: Di Zhao, Delu Li, Rongxi Li, Feng Xu

المصدر: Minerals
Volume 8
Issue 10
Minerals, Vol 8, Iss 10, p 439 (2018)

مصطلحات موضوعية: lcsh:QE351-399.2, 020209 energy, education, Geochemistry, organic geochemistry, 02 engineering and technology, 010502 geochemistry & geophysics, 01 natural sciences, petrography, Dabashan foreland belt, chemistry.chemical_compound, Organic geochemistry, 0202 electrical engineering, electronic engineering, information engineering, Kerogen, Organic matter, 0105 earth and related environmental sciences, chemistry.chemical_classification, Total organic carbon, lcsh:Mineralogy, Maceral, Geology, organic-rich shale, Geotechnical Engineering and Engineering Geology, Niutitang Formation, chemistry, Source rock, Longmaxi Formation, Sedimentary rock, Oil shale

الوصف: Measurements of total organic carbon, Rock-Eval pyrolysis, X-ray diffraction, scanning electron microscope, maceral examination, gas chromatography, and gas chromatography-mass spectrometry were conducted on the organic-rich shale of Lower Paleozoic Niutitang Formation and Longmaxi Formation in Dabashan foreland belt to discuss the organic matter characteristic, organic matter origin, redox condition, and salinity. The results indicate that the Niutiang Formation and Longmaxi Formation organic-rich shale are good and very good source rocks with Type I kerogen. Both of the shales have reached mature stage for generating gas. Biomarker analyses indicate that the organic matter origin of Niutitang Formation and Longmaxi Formation organic-rich shale are all derived from the lower bacteria and algae, and the organic matter are all suffered different biodegradation degrees. During Niutitang Formation and Longmaxi Formation period, the redox conditions are both anoxic with no stratification and the sedimentary water is normal marine water.

وصف الملف: application/pdf

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::1b567430041b3eb4be0a6ccbf38b3ef4Test