Article
Engineering, Marine
Sile Wei, Mingyi Hu, Sheng He, Yanbo Shu, Tian Dong, Qing He, Wei Yang, Quansheng Cai
Summary: Investigation on the Lower Cambrian Shuijingtuo Formation shale in South China revealed the types and sources of authigenic quartz and its relation to organic matter pores. Four types of quartz were identified in the shale: detrital quartz, replacement of biosiliceous debris, euhedral quartz in interparticle pores, and microquartz dispersed in a clay matrix. The dominant forms of authigenic quartz were found to be euhedral quartz and matrix-dispersed microquartz. The silica sources were identified as biogenic silica and clay-derived silica, with biogenic silica being the major source for authigenic quartz in organic-rich samples. Petrographic observations suggested that the precipitation of euhedral quartz in interparticle pores during early diagenesis enhanced rock stiffness and protected organic matter pores, while the precipitation of microquartz in the clay matrix during late diagenesis reduced the capacity for retained petroleum and limited the development of organic matter pores.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2023)
Article
Geosciences, Multidisciplinary
Ping Gao, Xianming Xiao, Guangming Meng, Gary G. Lash, Shuangjian Li, Yueqing Han
Summary: Quartz is essential for the reservoir properties of organic mudstones and plays a crucial role in shale gas production. However, the types and origins of quartz in deeply-buried mudstones in South China are poorly understood. A study of mudstone samples from the Upper Permian Dalong Formation in the Sichuan Basin revealed the presence of six major forms of quartz, of which five are authigenic. Authigenic quartz affects pore development and preservation in shale reservoirs, and moderate abundance of authigenic quartz is most favorable for pore development in deep mudstones. The DL mudstone deposits, enriched in organic matter and containing moderate contents of authigenic quartz, are especially promising targets for shale gas exploration.
MARINE AND PETROLEUM GEOLOGY
(2023)
Article
Geosciences, Multidisciplinary
Xianglin Chen, Wanzhong Shi, Qinhong Hu, Yuguang Hou, Gangyi Zhai, Tian Dong, Zhi Zhou, Xuebin Du
Summary: Quartz plays a pivotal role in shale gas development, but its types, origins, and effects on pore network remain unclear. This study used various analytical techniques to assess the Niutitang Formation in south China, a key target formation for shale gas exploration. The results showed that the shale in the Niutitang Formation had a siliceous lithofacies type and quartz existed in various forms. Geochemical analyses revealed that biogenic silica was the main source, with higher detrital silica content in some wells. Microcrystalline quartz and aggregates of euhedral quartz improved pore network connectivity and protected organic matter pores as a rigid framework.
MARINE AND PETROLEUM GEOLOGY
(2022)
Article
Geosciences, Multidisciplinary
Ping Gao, Xianming Xiao, Dongfeng Hu, Ruobing Liu, Fei Li, Qin Zhou, Yidong Cai, Tao Yuan, Guangming Meng
Summary: Deeply-buried shale has attracted attention for shale gas exploration in China. This study investigates the gas-in-place content and controlling factors of deep shale in the Dingshan area of the Sichuan Basin. The results show high gas-in-place content and porosity, suggesting great potential for deep shale gas in the basin. Organic matter and rock mechanical properties are the main controlling factors for deep shale gas.
FRONTIERS OF EARTH SCIENCE
(2023)
Article
Geosciences, Multidisciplinary
Zixin Xue, Zhenxue Jiang, Xin Wang, Zhiye Gao, Jiaqi Chang, Zhou Nie, Hui Li, Wei Wu, Hengyuan Qiu, Qianyou Wang, Mianzhu Hao, Ruihua Chen, Zhikai Liang
Summary: Low-resistance shale reservoirs, which have higher yields in high-mature shale gas plays, are influenced by the degree of graphitization and pore structure of organic matter. High graphitization significantly reduces rock resistivity and changes the mechanical properties of organic matter. The change in organic pore size and shape leads to a decrease in resistivity, while graphitization exceeding 15% results in poor pore development and increased exploration risk.
MARINE AND PETROLEUM GEOLOGY
(2022)
Article
Geosciences, Multidisciplinary
Yapei Ye, Shuheng Tang, Zhaodong Xi, Renqi Lu, Zhongyao Zhang, Jintao Li
Summary: Studying the microscopic characteristics of shale can provide a theoretical basis for evaluating its macroscopic mechanical properties and fracturability. Different types of quartz in shale have different effects on the quality of shale oil/gas reservoirs. This study used finite element numerical simulation to set up different models based on the microscopic occurrence states of quartz, and found that the size and occurrence mode of quartz have a significant impact on shale compressive strength, while quartz content has the most significant influence on shale brittleness. The presence of quartz particles can enhance the compressive strength of shale and form complex fracture networks.
NATURAL RESOURCES RESEARCH
(2023)
Article
Chemistry, Physical
Jiaqi Chang, Xiaodong Fan, Zhenxue Jiang, Xingmeng Wang, Lei Chen, Jitong Li, Lin Zhu, Chengxiang Wan, Zhixiang Chen
Summary: This study investigated the effects of organic matter, clay minerals and organo-clay composites on the pore structure and pore complexity of shale reservoirs. The results showed that the type and maturity of macerals, illite, kaolinite, and organo-clay composites are the main factors influencing shale pore development. The study also found that different clay mineral types have different effects on shale pore structure and pore complexity.
APPLIED CLAY SCIENCE
(2022)
Article
Energy & Fuels
Ruolong Chi, Ping Gao, Yidong Cai, Ruobing Liu, Jinghan Du, Qin Zhou
Summary: This study investigated the types and development characteristics of pores in the ultra-deep organic-rich shale reservoirs of the Eastern Sichuan Basin. The results showed that the dominant pore types were organic pores, mineral matrix pores, and micro-fractures. The development of organic pores was influenced by the content of organic matter and brittle minerals, with higher contents contributing to their development and preservation.
Article
Geosciences, Multidisciplinary
Zhouhai Xiong, Yingchang Cao, Chao Liang, Keyu Liu, Guanmin Wang, Rui Zhu, Ping Lei, Yanli Wang
Summary: This study found that authigenic microcrystalline quartz and albite develop together in lacustrine carbonate-rich fine-grained sedimentary rocks. The paragrowth and intergrowth of these minerals depend on the degree of supersaturation of ion concentration. Furthermore, the migration and enrichment of shale oil in calcareous fine-grained sedimentary rocks can be explained through the genetic mechanism of these authigenic minerals.
MARINE AND PETROLEUM GEOLOGY
(2022)
Article
Geosciences, Multidisciplinary
Wei Du, Ruiqin Lin, Fulun Shi, Nina Luo, Yisong Wang, Qingqing Fan, Junying Cai, Ziya Zhang, Li Liu, Wei Yin, Fuping Zhao, Zhao Sun, Yi Chen
Summary: Investigation of pore structure is crucial for evaluating shale reservoirs and predicting sweet spots. The study comprehensively characterized the pore structure of lower Longmaxi shale reservoirs in northern Guizhou using various methods. The results showed the presence of numerous organic matter-hosted pores, clay interlayer pores, interparticle pores, and intraparticle pores within the shale reservoirs. The specific surface area and pore volume were found to be correlated with organic matter and carbonate contents.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Thermodynamics
Hongjian Zhu, Yiwen Ju, Manping Yang, Cheng Huang, Hongye Feng, Peng Qiao, Chao Ma, Xin Su, Yanjun Lu, Erxiu Shi, Jinxuan Han
Summary: The study focuses on analyzing the quartz forms, origins, and textures, and evaluating their impacts on reservoir property and mechanical behavior's response to hydraulic fracturing. Quartz microstructures play a significant role in controlling reservoir properties, and authigenic quartz grains have a significant impact on mechanical fracture properties.
Article
Green & Sustainable Science & Technology
Jing Wang, Fawang Ye, Gary G. Lash, Zhaodong Xi
Summary: This study used scanning electron microscopy to investigate the types of organic matter and pore development in shale deposits in southern China, and found that the sedimentary environment is the main factor influencing these features.
Article
Geochemistry & Geophysics
Xing Niu, Detian Yan, Mingyi Hu, Zixuan Liu, Xiaosong Wei, Mingtao Zuo
Summary: This study investigated the impacts of rock composition on pore structure in shale samples from Lower Cambrian in south China. Two distinct lithofacies, siliceous shale and argillaceous shale, were identified based on mineral composition, showing different pore structure characteristics. Siliceous shales with authigenic quartz have more interparticle pores and organic matter-associated pores, while argillaceous shales lack authigenic quartz and have mainly intraparticle pores controlled by illite content.
Article
Energy & Fuels
Jianglin He, Lixia Zhu, Ankun Zhao, Dong Wang, Zhen Qiu, Ping Yang
Summary: This study investigates the reservoir conditions of lacustrine shale in the Sichuan Basin through experiments on samples from wells and outcrops. The results show that lacustrine shale has different pore characteristics compared to marine shale. The arrangement of pores in marine shale is affected by compaction, while lacustrine shale is characterized by under-compaction. The findings suggest that high-quality areas for lacustrine shale gas may be located in under-compacted regions influenced by upward fluid pressure.
Article
Geosciences, Multidisciplinary
Jia Jianliang, Liu Zhaojun, Zhou Renjie, Liu Rong, Gao Yuan
Summary: In this study, the variation in pore space and structure of low mature lacustrine shales in the Songliao Basin was investigated. It was found that the variation of organic matter (OM) and minerals is a key control on the pore space and structure of these shales.
ACTA GEOLOGICA SINICA-ENGLISH EDITION
(2022)
Article
Energy & Fuels
Zhaodong Xi, Shuheng Tang, Jing Wang
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2018)
Article
Energy & Fuels
Zhaodong Xi, Shuheng Tang, Songhang Zhang, Yongxiang Yi, Feng Dang, Yapei Ye
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2019)
Article
Energy & Fuels
Yapei Ye, Shuheng Tang, Zhaodong Xi
Article
Environmental Sciences
Yang Li, Shuheng Tang, Songhang Zhang, Zhaodong Xi, Pengfei Wang
Article
Energy & Fuels
Zhaodong Xi, Shuheng Tang, Songhang Zhang, Yapei Ye
Article
Energy & Fuels
Zhaodong Xi, Shuheng Tang, Songhang Zhang
ENERGY SOURCES PART A-RECOVERY UTILIZATION AND ENVIRONMENTAL EFFECTS
(2020)
Article
Geography, Physical
Zhaodong Xi, Shuheng Tang, Gary G. Lash, Bing Zhang, Donglin Lin
Summary: This study on the O-S transition sedimentary environments of China's Upper Yangtze Platform reveals the evolution process driven by global climate change and tectonism, impacting organic carbon content and thickness of shale gas targets. The findings indicate the significant role of these factors in shale gas exploration risks in the region.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2021)
Article
Geosciences, Multidisciplinary
Zhaodong Xi, Shuheng Tang, Gary G. Lash, Yapei Ye, Donglin Lin, Bing Zhang
Summary: The study focuses on the impact of depositional environment on pore structure evolution, demonstrating that variations in sedimentary environments lead to differences in porosity and dominant pore types in shale formations.
MARINE AND PETROLEUM GEOLOGY
(2021)
Article
Geochemistry & Geophysics
Donglin Lin, Shuheng Tang, Zhaodong Xi, Bing Zhang, Yapei Ye
Summary: This study investigated the redox environment changes in Late Ordovician seawater, revealing higher paleoproductivity in the P. pacificus zone compared to the M. extraordinarius zone. The results suggest that continental weathering and uplift of the Xiang'e Submarine High played a role in the redox environment change in the inner Yangtze Sea during this time period.
Article
Energy & Fuels
Zhaodong Xi, Shuheng Tang
Summary: The Ordovician shale (Wufeng Formation) in the Upper Yangtze Platform is a successful development interval. The accumulation mechanisms of organic matter within the Wufeng shale are influenced by variations in redox conditions and paleoproductivity. OM accumulation in the Wufeng Formation is controlled by sea level, which is affected by global climate and tectonics.
Article
Geosciences, Multidisciplinary
Yapei Ye, Shuheng Tang, Zhaodong Xi, Dexin Jiang, Yang Duan
Summary: Quartz, as an important component of shale, has different effects on the porosity evolution and brittleness of shale. Biogenic quartz is dominant in siliceous shale, while extrabasinal detrital quartz is dominant in argillaceous and mixed shale. Most of the Wufeng-Longmaxi shale samples experience a reduction in porosity mainly due to compaction. Biogenic quartz acts as a pore protector, while S-I quartz derived from the conversion of smectite to illite acts as a pore destroyer. Siliceous shale samples have the highest brittleness index.
MARINE AND PETROLEUM GEOLOGY
(2022)
Article
Engineering, Chemical
Jing Wang, Fawang Ye, Chuan Zhang, Zhaodong Xi, Carlos Sierra Fernandez
Summary: This study comprehensively examines the sedimentary environment, distribution of sand bodies, and physical characteristics of tight sandstone reservoirs in the Carboniferous-Permian coal-bearing sedimentary succession in the eastern edge of the Ordos Basin. The results indicate that the reservoir quality is relatively poor, primarily due to compaction and cementation reducing porosity. Dissolution has a limited effect on porosity but contributes to the tight nature of the reservoirs.
Article
Microbiology
Yang Li, Jian Chen, Shuheng Tang, Zhaodong Xi
Summary: The rise of coalbed methane bioengineering allows for the conversion and utilization of carbon dioxide through microbial action and the carbon cycle. Hydraulic fracturing improves the natural permeability of tight reservoirs, enhances the living conditions of microbial communities, and strengthens the carbon circulation process in coal reservoirs.
Article
Green & Sustainable Science & Technology
Jing Wang, Fawang Ye, Gary G. Lash, Zhaodong Xi
Summary: This study used scanning electron microscopy to investigate the types of organic matter and pore development in shale deposits in southern China, and found that the sedimentary environment is the main factor influencing these features.