Article
Engineering, Chemical
Qin Zhang, Feng Liang, Jingbo Zeng, Zhen Qiu, Shangwen Zhou, Wen Liu, Weiliang Kong
Summary: A comparative study of the depositional environments of the Qiongzhusi and Longmaxi formations was conducted using well cores. The study found that the Qiongzhusi formation had lower detrital flow and higher anoxic conditions compared to the Longmaxi formation.
Article
Geosciences, Multidisciplinary
Hao Xu, Wen Zhou, Qinhong Hu, Ting Yi, Jiang Ke, Ankun Zhao, Zihui Lei, Yu Yu
Summary: This study investigates the impact of various forms and sources of quartz on the porosity evolution and rock mechanics of shale samples from the Longmaxi Formation in the Sichuan Basin. Different types of quartz were identified, along with their associated pores, with biogenic silica playing a substantial role in total silica content. The origin of quartz was found to be significant in understanding porosity evolution and rock mechanics, with biogenic silica being a major contributor to brittleness in the lower Longmaxi Formation.
MARINE AND PETROLEUM GEOLOGY
(2021)
Article
Chemistry, Multidisciplinary
Guozhen Wang, Zhenxue Jiang, Houjian Gong, Yuguang Shi, Shijie He, Huan Miao
Summary: In this study, a mathematical model of shale gas diffusion was established and the evolution history of temperature, pressure, and stratigraphic physical properties was calculated. The study found that there is a significant amount of gas diffusion loss in the Longmaxi Formation shale in the Sichuan Basin, which has important implications for the migration and accumulation of natural gas.
APPLIED SCIENCES-BASEL
(2023)
Article
Geosciences, Multidisciplinary
Yang Wang, Hongfei Cheng, Qinhong Hu, Luofu Liu, Lewei Hao
Summary: The study investigated the impact of diagenesis on pore systems in different lithofacies of Wufeng-Longmaxi shale from Sichuan Basin, China. Different lithofacies showed varying diagenetic pathways and evolution of pore systems under the same burial history. Diagenesis played a crucial role in determining the final status of the initial pore space and controlling the distribution of migrated OM, influencing the development of dominant OM pores in the entire pore spectrum.
MARINE AND PETROLEUM GEOLOGY
(2021)
Article
Energy & Fuels
Jian Xiong, Yukang Li, Shangwen Zhou, Xiangjun Liu, Hui Han, Lixi Liang, Jun Zhao
Summary: In this study, the pore structure characteristics of shales and the factors controlling them were analyzed using various methods. The results showed that the main minerals in the shales are quartz and clay minerals, and the organic matter and quartz have a positive influence on the pore structure parameters, while clay minerals have a negative impact. The pore volume and specific surface area of the shales vary within a certain range, with mesopores and macropores contributing the most to the total pore volume and mesopores contributing the main specific surface area.
JOURNAL OF PETROLEUM EXPLORATION AND PRODUCTION TECHNOLOGY
(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
Energy & Fuels
Guan Quanzhong, Dong Dazhong, Zhang Hualing, Sun Shasha, Zhang Surong, Guo Wen
Summary: The coupling effect between organic matter and quartz plays a critical role in the analysis and characterization of biogenic silica in the shale layers of the Sichuan Basin. The presence of two types of biogenic quartz influences the development of organic matter pores and micro-cracks in the shale, affecting later hydraulic fracturing and well production. This coupling effect is a key factor for the high-quality development of shale reservoirs.
PETROLEUM EXPLORATION AND DEVELOPMENT
(2021)
Article
Energy & Fuels
Junfeng Lin, Haiyan Hu, Lihong Zhang, Xiaodong Zhang, Zhigang Liu
Summary: Accurate assessment of the thermal maturity of Longmaxi shale was carried out using various methods including solid bitumen reflectance, basin modeling, and laser Raman spectroscopy. The findings suggest that Raman spectra can effectively evaluate the maturation of marine shale without vitrinites.
JOURNAL OF PETROLEUM EXPLORATION AND PRODUCTION TECHNOLOGY
(2022)
Article
Geosciences, Multidisciplinary
Ping Gao, Xianming Xiao, Dongfeng Hu, Gary G. Lash, Ruobing Liu, Yidong Cai, Zihan Wang, Baoyue Zhang, Tao Yuan, Siyi Liu
Summary: Silica diagenesis plays a critical role in the reservoir properties of shale, but its influence on the porosity evolution of deeply-buried shale remains uncertain. This study investigates the silica diagenesis in deep gas shale samples from the Sichuan Basin and finds that siliceous skeletal fragments are the main source of silica involved in diagenetic alteration. Authigenic quartz has a dual effect on porosity preservation and evolution. Optimal development and preservation of porosity, especially organic porosity, is observed when the content of authigenic quartz is moderate (10-30% Sixs). The study underscores the great potential of WF-LMX deep shale for shale gas exploration.
MARINE AND PETROLEUM GEOLOGY
(2022)
Article
Geochemistry & Geophysics
Wei Fu, Wangshui Hu, Quansheng Cai, Sile Wei, Jiachao She, Xiaochen Wang, Xiaodong Liu
Summary: The sedimentary environment and organic matter enrichment relationship of the Upper Ordovician Wufeng Formation black shale, Guanyinqiao mudstone, and Lower Silurian Longmaxi Formation black shale in the Sichuan Basin of Weiyuan are analyzed using geochemical methods. The results show that both the Wufeng and Longmaxi Formations are organic matter enrichment layers, and different depositional conditions are indicated by various indicators.
Article
Geosciences, Multidisciplinary
Shun He, Qirong Qin, Hu Li, Shengxian Zhao
Summary: This study investigates the geological characteristics and exploration potential of shale gas in the southern Sichuan Basin. The research focuses on the coupling relationship between hydrocarbon generation and storage conditions of the Longmaxi Formation, as well as the preservation conditions from the lateral and vertical migration mechanisms of shale gas. The results show that the organic-rich shale at the bottom was formed in a strongly euxinic and anoxic reducing environment. The organic matter type in the shale is dominantly type I kerogen and a small amount of type II1 kerogen. The enrichment of siliceous organisms increases the organic matter and enhances the brittleness of shale, resulting in superior hydrocarbons and a favorable reservoir. The high vertical formation pressure guarantees the sealing of shale and restrains the lateral and vertical escape of shale gas. The analysis of three-dimensional preservation conditions suggests that areas with a short tectonic uplift time, small amplitudes, large-scale underdeveloped fractures, and a high formation pressure coefficient are favorable for shale gas exploration.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Geosciences, Multidisciplinary
Qian Pang, Guang Hu, Chaowei Hu, Cong Zhang
Summary: A study successfully identified three maceral types in the Longmaxi Shale of the Sichuan Basin using a combination of reflected light microscopy, focused ion beam SEM, and Raman spectrum, revealing the connection between pore structure and maceral types.
FRONTIERS IN EARTH SCIENCE
(2021)
Article
Energy & Fuels
Lei Chen, Xin Chen, Xiucheng Tan, Jian Zheng, Yang Yang, Cui Jing, Hao Zhou, Gaoxiang Wang
Summary: This study examined organic matter accumulation and controlling factors of the Longmaxi Formation shale in the Changning area, southern Sichuan Basin, based on TOC tests and major-trace element test data. The results showed that redox conditions, paleoproductivity, and terrigenous input were the main factors controlling organic matter accumulation in this area. These findings are expected to contribute to shale gas exploration and development.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2023)
Article
Energy & Fuels
Juan Teng, Bei Liu, Maria Mastalerz, Juergen Schieber
Summary: Organic matter-hosted pores play a crucial role in controlling the porosity and gas content of gas shales. However, the development and preservation mechanisms of organic pores are poorly understood due to the inability to distinguish organic matter types under the scanning electron microscope (SEM). This study reveals important insights into the thermal evolution of organic matter and the development of organic pores in source-rock reservoirs through organic petrography and SEM analysis.
INTERNATIONAL JOURNAL OF COAL GEOLOGY
(2022)
Article
Geochemistry & Geophysics
Guangzhao Zhou, Zhiming Hu, Xiangui Liu, Xianggang Duan, Jin Chang
Summary: Recent research has focused on the breakthroughs in the Weiyuan marine shale gas play in the Sichuan Basin. By utilizing various data analysis methods and conventional well logging, the spatial distribution of organic-rich shale in the area has been successfully mapped. The results reveal a high content of total organic carbon in the shale units, indicating the potential for shale gas accumulation.
INTERPRETATION-A JOURNAL OF SUBSURFACE CHARACTERIZATION
(2023)
