Article
Geosciences, Multidisciplinary
Haikuan Nie, Zhijun Jin, Pei Li, Barry Jay Katz, Wei Dang, Quanyou Liu, Jianghui Ding, Shu Jiang, Donghui Li
Summary: Deep shale gas at a burial depth greater than 3500 m in China is an important potential target for exploration and development. This study systematically investigates the spatial distribution, reservoir types and properties, preservation conditions, and gas content of deep shale gas in the Sichuan Basin. It is recommended to establish a volume fracturing plan and optimize production systems with excellent pressure management procedures to maximize deep shale gas production and achieve commercial development.
JOURNAL OF ASIAN EARTH SCIENCES
(2023)
Article
Geosciences, Multidisciplinary
Zhen Qiu, Bei Liu, Bin Lu, Zhensheng Shi, Zhiyang Li
Summary: This study focused on the depositional and diagenetic processes controlling the fabric and petrophysical properties of black shales through the analysis of the Wufeng-Longmaxi Shale. It was found that the studied shale is mainly composed of over-mature black shales with organic matter dominated by pyrobitumen and graptolite, while minerals consist of quartz, carbonates, and clay minerals. Vertical variations in lithofacies and mineral content exhibited three cycles, likely corresponding to three transgressive-regressive cycles.
MARINE AND PETROLEUM GEOLOGY
(2022)
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
Energy & Fuels
Ping Gao, Xianming Xiao, Dongfeng Hu, Ruobing Liu, Yidong Cai, Tao Yuan, Guangming Meng
Summary: This study investigated the water content and its distribution in the different nanopores of deep and ultra-deep shales in China. The results showed that irreducible water is the dominant form of water in ultra-deep shales, primarily occurring in clay-hosted pores and parts of organic pores. It is mainly distributed in non-micropores, especially in micropores with a diameter of 0.4-0.6 nm and mesopores with a diameter of 2-10 nm. The presence of irreducible water significantly affects the specific surface area of non-micropores, which is more pronounced in organic-rich shale samples.
Article
Energy & Fuels
Wang Hongyan, Shi Zhensheng, Sun Shasha
Summary: By identifying graptolites and analyzing the characteristics of shale samples from the Ordovician Wufeng Formation-Silurian Longmaxi Formation in the Sichuan Basin, the different graptolite zones with varied mineral composition, TOC content, and lamina types have been sorted out. The deposition environments and conditions during the formation of these graptolite zones play a significant role in determining the mineral composition, TOC, and lamina types of the shale layers within each zone.
PETROLEUM EXPLORATION AND DEVELOPMENT
(2021)
Article
Geosciences, Multidisciplinary
Jing Wu, Chao Liang, Ren-Chao Yang, Zongquan Hu, Wenjin Li, Jun Xie
Summary: The Late Ordovician-Early Silurian sedimentary succession in the Sichuan Basin, China, provides valuable information about the changes in sedimentary environments. The mineral composition and lithofacies of the shales in this region reflect these changes. The study analyzes the main minerals present (quartz, clay minerals, and carbonate) and identifies five major lithofacies. By examining various proxies, such as provenance indicators, chemical index of alteration, paleoproductivity proxies, redox condition indicators, proxies of detrital influx, and sedimentation rate, the paleoenvironment is analyzed. The study reveals the relationship between environmental changes and shale mineral composition and lithofacies.
JOURNAL OF ASIAN EARTH SCIENCES
(2022)
Article
Energy & Fuels
Wang Yuman, Wang Hongyan, Qiu Zhen, Shen Junjun, Zhang Qin, Zhang Leifu, Wang Canhui, Li Xinjing
Summary: This study systematically examines the basic characteristics of key interfaces, mainly bentonite layers, in the Upper Ordovician Wufeng Formation-Lower Silurian Longmaxi Formation in the Sichuan Basin and its surrounding areas. The study also investigates the relationship between these key interfaces and the deposition of organic-rich shale. There are four types of marker beds with interface attributes in the Wufeng Formation-Longmaxi Formation, which can be used for stratigraphic division and correlation of the graptolite shale. The shell layer in Guanyinqiao Member is the most standard key interface, and can also be used as an important indicator for judging the depositional scale of organic-rich shale in key areas.
PETROLEUM EXPLORATION AND DEVELOPMENT
(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
Engineering, Marine
Zhibo Zhang, Yinghai Guo, Hengye Wei, Chunlin Zeng, Jiaming Zhang, Difei Zhao
Summary: The Late Ordovician-Early Silurian period in the Sichuan Basin was a significant transitional phase in geological history. This study focused on the black shale series of the Wufeng Formation-Longmaxi Formation during this period. Analysis of samples from the Yucan-1 Well revealed three third-order sequences and identified two subfacies and three microfacies. The climate during this period experienced shifts from warm and humid to cold and dry, with corresponding pulse-type biological extinction events and changes in organic carbon burial.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2023)
Article
Geosciences, Multidisciplinary
Yongbo Wei, Shuangfang Lu, Junqian Li, Rongze Yu, Wenbiao Li, Feng Cheng, Chunbo Fu, Tianlong Zhao, Wenjun Feng, Zhaojing Song
Summary: The study investigates methane carbon isotope fractionation during shale gas desorption, revealing the impact of various factors on the process and providing insights into evaluating gas content and production status in shale gas wells.
MARINE AND PETROLEUM GEOLOGY
(2021)
Article
Geosciences, Multidisciplinary
Tonglou Guo, Xianghao Meng, Wei Lei, Mingming Liu, Liang Huang
Summary: This study conducted systematic experimental characterization to understand the pore structures and methane sorption in deep-marine shales. The results showed that factors such as organic matter content and clay minerals affect the pore structures and sorption behaviors in deep shales. The findings also indicate that deep shales have higher micropore content from organic matter and lower macropore content from clay minerals compared to shallow shales. The total organic carbon (TOC) content is the primary controlling factor on pore structure and sorption capacity in deep shales, while the influence of clay minerals on gas sorption is less pronounced.
NATURAL RESOURCES RESEARCH
(2023)
Article
Engineering, Environmental
Wenbin Jiang, Gaohui Cao, Chao Luo, Mian Lin, Lili Ji, Ji Zhou
Summary: The study investigated the relationship between the composition of Wufeng-Longmaxi Formation shale samples in Sichuan Basin and methane adsorption characteristics, establishing a composition-based methane adsorption model. Differences in clay contribution to methane adsorption for different sublayers were revealed, aiding in improving the accuracy of shale reservoir evaluation.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Geosciences, Multidisciplinary
Leifu Zhang, Hongyan Wang, Dazhong Dong, Qun Zhao, Chenjun Wu
Summary: The black shales in the Wufeng-Longmaxi Formation within the Sichuan Basin have been found to contain sedimentary gravity-flow deposits, which challenge the prevailing view of deep-water shelf dominance and sole development of shales. The presence of turbidite, slump, and slide deposits supports the change in paleogeography from shelf to slope to bathyal plain. This discovery may have implications for hydrocarbon exploration and development in the basin and its periphery.
Article
Geosciences, Multidisciplinary
Wenping Liu, Juan Wu, Hua Jiang, Zheng Zhou, Chao Luo, Wei Wu, Xiaojia Li, Shugen Liu, Bin Deng
Summary: This study examines the relationship and multi-stage evolution between the upper Ordovician Wufeng and lower Silurian Longmaxi formations at the Changning shale gas field in southern Sichuan basin. The research utilizes low-temperature thermochronological data and structural evolution to analyze the rapid exhumation and history of the field. The results suggest a four-stage thermal evolution and significant impact of pressure index changes on shale gas enrichment.
MARINE AND PETROLEUM GEOLOGY
(2021)
Article
Geochemistry & Geophysics
Jianlin Guo, Chengye Jia, Dongbo He, Fankun Meng
Summary: The study proposed classification criteria for net pay of shale gas reservoirs in the Shunan area of the Sichuan Basin, based on the analysis of porosity, gas saturation, density of rock, brittleness index, and gas content. The application of gas content and brittleness index parameters reflects reservoir resource basis and fracability respectively. The net pay can be classified into three types based on the ranges of these two parameters, with implications for testing production and economic benefits.
Article
Geochemistry & Geophysics
Fuqiang Lai, Yuejiao Liu, Xiaopan Kou, Zhaohui Huang, Zhen Chen, Yuanqi Liu, Guoqiang Jiang, Yongqian Zang, Min Wang, Ruyue Wang, Martina Zucchi
Summary: In this study, the pore characteristics of tight sandstone reservoirs were determined using NMR and high-pressure mercury injection experiments. A method for fluid identification was developed and showed better performance in identifying high-resistivity water layers compared to conventional methods.
Article
Geochemistry & Geophysics
Shuang Wang, Zhonghu Wu, Jun Chen, Hao Liu, Ruyue Wang, Jingshou Liu
Summary: This study analyzed the mineralogical composition of shale cores from a well in northern Guizhou and investigated the impact of mineral components on the permeability impairment rate and stress sensitivity coefficient of shale reservoirs. The results showed that clay mineral content and effective stress were negatively correlated with permeability and porosity, while detrital mineral content was positively correlated. Quartz content and modulus of elasticity were negatively correlated with permeability impairment rate and stress sensitivity factor, while clay mineral content was positively correlated. Shale with higher brittle mineral content was more likely to undergo brittle damage and exhibited lower stress sensitivity factor.
Article
Energy & Fuels
Gang Zhao, Wenlong Ding, Jing Tian, Jingshou Liu, Yang Gu, Siyu Shi, Ruyue Wang, Ning Sun
Summary: The study investigated the correlations between elemental, mineral contents, and mechanical parameters of shale in the Lower Cambrian Niutitang Formation in the Fenggang block of northeastern Guizhou. It was found that within certain ranges of silicon content, there were significant positive/negative correlations between static Young's modulus, shear modulus, bulk modulus, and brittleness index with silicon content, clay, and quartz, feldspar, and mica contents. There is uncertainty in determining rock mechanical parameters within certain elemental content ranges, indicating the need for more mathematical models and factors to adequately characterize those parameters.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Energy & Fuels
Gang Zhao, Zhijun Jin, Wenlong Ding, Guangxiang Liu, Jinbiao Yun, Ruyue Wang, Guanping Wang
Summary: The study on fractures in the Wufeng-Longmaxi Formation in Hunan Province reveals that these fractures can be divided into different types based on their combination characteristics and roughness. The fractures mainly occurred in the late Yanshanian-Himalayan period and experienced repeated processes of splitting, healing, and re-splitting. The gas migration and enrichment in these fractures play a key role in the distribution and preservation of shale gas.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Review
Geosciences, Multidisciplinary
Quanyou Liu, Peng Li, Zhijun Jin, Yuewu Sun, Guang Hu, Dongya Zhu, Zhenkai Huang, Xinping Liang, Rui Zhang, Jiayi Liu
Summary: The study focused on the impact of volcanic activity on paleoproductivity and preservation conditions in lacustrine shale formation. The results indicated that volcanic activity enhanced ancient productivity and promoted organic matter preservation.
SCIENCE CHINA-EARTH SCIENCES
(2022)
Article
Geosciences, Multidisciplinary
Ming Guan, Xiaoping Liu, Zhijun Jin, Jin Lai, Jie Liu, Biao Sun, Tian Liu, Zuxian Hua, Wen Xu, Honglin Shu, Gaocheng Wang, Mengcai Liu, Yufeng Luo
Summary: The heterogeneity and lack of proper parameters in lacustrine shale oil occurrences hinder the assessment of shale oil reserves. This study characterized shale oil content using petroleum compositional characteristics and determined its spatial occurrence. The controlling factors of shale oil content were also discussed. This work has implications for optimizing exploration targets and evaluating resource potential.
MARINE AND PETROLEUM GEOLOGY
(2022)
Article
Geosciences, Multidisciplinary
Tao Jiang, Zhijun Jin, Guangxiang Liu, Zongquan Hu, Xuanhua Chen, Zhongbao Liu, Guanping Wang
Summary: This study focuses on the pore structure and reservoir capacity evaluation of the Lower Jurassic shale in the northeastern Sichuan Basin. The results show that the shale contains mainly mineral matrix and organic matter pores, with locally developed microcracks. The main pore size distribution falls within the mesoporous range. The TOC content is not significantly correlated with pore volumes and specific surface areas, as pore development is hindered by organic vitrinite and fusinite, and soluble organic matter occupies pore volume and adsorption sites. Clay minerals mainly contribute to the formation of larger pores. The reservoir capacity of the shale was evaluated using a two-factor method, indicating mainly free reservoirs with a gas storage capability level of II-IV.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Energy & Fuels
Guanping Wang, Qian Zhang, Rukai Zhu, Xuan Tang, Kouqi Liu, Zhijun Jin
Summary: The main pore space in the lacustrine Chang 7 Shale is dominated by macro- and meso-pores, while the pores within organic matter are rarely observed. Quartz promotes the development of macro- and meso-pores, while clay minerals show negative effects on their heterogeneity. A critical maturity point of 0.8% Ro is observed for the change of the pore system, and both fractal dimensions and pore structure proxies show inverse trends before and after this point. These findings contribute to a better understanding of pore system evolution and identification of high-quality reservoirs in lacustrine shales.
GEOENERGY SCIENCE AND ENGINEERING
(2023)
Article
Geosciences, Multidisciplinary
Guanping Wang, Zhijun Jin, Qian Zhang, Rukai Zhu, Xuan Tang, Kouqi Liu, Lin Dong
Summary: This study investigates the controls of organic matter and clay minerals on the pore structure evolution of the lacustrine organic-rich Chang 7 Shale. The results show that micropores and mesopores contribute to the main storage space in the shale. Organic matter content influences the development of micropores, while total clay content is correlated with mesopores volume. Different clay minerals control pores of different sizes. Thermal maturity has a positive effect on pore volume and porosity. Clay mineral conversions have positive effects on pore volume, except for the smectite-illite conversion which negatively affects pore connectivity. Chlorite also plays a role in controlling macropore volume, porosity, and pore throat radius.
JOURNAL OF ASIAN EARTH SCIENCES
(2023)
Article
Geochemistry & Geophysics
Xuan Wang, Ruyue Wang, Jianping Bai, Na Zhang, Haoting Xing, Michael Kamoto, Weiling He
Summary: This study characterizes the sedimentary fabric and formation environment of dendrolites in the Cambrian Zhangxia Formation in Zibo, Shandong Province, and analyzes its genetic mechanism. It has great significance for studying microbial carbonate in geological history and its implications for oil exploration.
Article
Energy & Fuels
Guanping Wang, Zhijun Jin, Guangxiang Liu, Ruyue Wang, Gang Zhao, Xuan Tang, Kouqi Liu, Qian Zhang
Summary: This study systematically analyzed the overall pore system of the Triassic Chang 7 lacustrine shale formation in the Ordos Basin, China, and identified the different effects of rock components and diagenetic processes on the development of multi-lithologic pore systems. The results showed the negative impact of organic matter on pore volume and the positive influence on pore throat, while clay minerals generally played a negative role except for in organic-rich laminated shale. Quartz and feldspar were found to contribute to pore development, while calcite and dolomite had negative effects. Pyrite and siderite facilitated pore throat preservation but inhibited pore space development. This study contributes to a better understanding of sweet spot prediction in lacustrine shale formations.
INTERNATIONAL JOURNAL OF COAL GEOLOGY
(2023)
Article
Geochemistry & Geophysics
Yuejiao Liu, Fuqiang Lai, Ruyue Wang, Zhonghu Wu, Xiaoshu Zhang, Hao Xu, Jiao Li
Summary: This paper discusses the brittleness characteristics and controlling factors of continental shale in the Da'anzhai Member of the Ziliujing Formation in the northeast Sichuan Basin. Carbonate minerals play a significant role in controlling the brittleness of continental shale, and the presence of shell limestone interlayers and laminates greatly improves the reservoir's brittleness.
Article
Geochemistry & Geophysics
Yuejiao Liu, Haitao Wang, Fuqiang Lai, Ruyue Wang, Haijie Zhang, Xiaoshu Zhang, Fahui Ou
Summary: A 3D digital core model was constructed to simulate the influences of gas saturation, mineral composition, stratification, and fractures on Poisson's ratio in a shale gas reservoir. The results showed that stratification dip angle and fracture dip angle had the greatest impact on Poisson's ratio, reaching its minimum value when the angles were close to 45 degrees. Poisson's ratio was most sensitive to the content of calcite and least influenced by gas saturation. The average error between the measured and simulated Poisson's ratio was 4.920%.
Article
Agricultural Engineering
Linrong Shi, Wuyun Zhao, Wei Sun, Xiaoping Yang, Guanping Wang, Shanglong Xin
Summary: This study uses the discrete element method to investigate the impact of irregular maize on the performance of a high-filling-rate seed metering device. The results reveal that the disturbances caused by the three wheels in the seed box lead to the formation of large and small cycles of seed transport. Increasing the angular speed of the three wheels reduces the rate of seed filling in the seed filling regions due to gravity and disturbances. Additionally, the analysis shows that the angular speed of the taking seed wheel has an effect on the coefficient of variation of the seed drop location.
INTERNATIONAL JOURNAL OF AGRICULTURAL AND BIOLOGICAL ENGINEERING
(2023)