Types of fine-grained sedimentary rocks assemblage and its significance for shale oil exploration: A case study of the fifth member of Xujiahe Formation in western Sichuan Depression, Sichuan Basin
Due to the complex lithology of fine-grained sedimentary rocks and the difficulty to determine the “sweet spot” of the fifth member of Xujiahe Formation（short for Xu-5 Member） of western Sichuan Depression, Sichuan Basin, a comprehensive geological analysis was conducted. This analysis encompassed v...
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Editorial Department of Petroleum Reservoir Evaluation and Development
2023-10-01
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| Series: | Youqicang pingjia yu kaifa |
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| Online Access: | https://red.magtech.org.cn/fileup/2095-1426/PDF/1698828878785-2140759049.pdf |
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| author | XIONG Liang, CAO Qinming, ZHANG Ling, WANG Linghui |
| author_facet | XIONG Liang, CAO Qinming, ZHANG Ling, WANG Linghui |
| author_sort | XIONG Liang, CAO Qinming, ZHANG Ling, WANG Linghui |
| collection | DOAJ |
| description | Due to the complex lithology of fine-grained sedimentary rocks and the difficulty to determine the “sweet spot” of the fifth member of Xujiahe Formation（short for Xu-5 Member） of western Sichuan Depression, Sichuan Basin, a comprehensive geological analysis was conducted. This analysis encompassed various geological data sources, including X-ray diffraction, thin sections, scanning electron microscopy, physical properties, organic carbon content, and elemental analysis. Additionally, core observations were incorporated into the study. Upon scrutinizing this array of data, a classification of 14 distinct lithofacies types was established. This categorization was formulated based on the analysis of lithofacies and the evolution of sedimentary paleoenvironments. Furthermore, through a comparative examination of shale gas evaluation parameters, the primary lithofacies types constituting the “sweet spots” were identified. This not only sheds light on the composition of Xu-5 Member but also provides valuable guidance for the exploration of continental shale gas within this formation. The results indicate that: ①The main lithofacies of Xu-5 Member in western Sichuan Depression are massive clayey siltstone and massive mixed sedimentary rock, followed by laminated mixed sedimentary rock, laminated clayey siltstone and massive silty clay rock; ②The sedimentary paleoenvironment of Xu-5 Member undergoes the process from dry heat sedimentary with shallow brackish water to wet sedimentary with deep fresh water, then back to dry heat sedimentary with shallow brackish water. The land source input decreases first and then increases. The middle part of Xu-5 Member is the “sweet spot” for the enrichment of organic matter. ③Laminated clayey siltstone and laminated mixed sedimentary rock are favorable lithofacies types for “sweet spot” development due to the high organic matter content, debris particle dissolution pore, high content of brittle minerals and good fracturing performance. |
| format | Article |
| id | doaj-art-4f4f0f85fce941f5aa3cdc90d59f5d38 |
| institution | OA Journals |
| issn | 2095-1426 |
| language | zho |
| publishDate | 2023-10-01 |
| publisher | Editorial Department of Petroleum Reservoir Evaluation and Development |
| record_format | Article |
| series | Youqicang pingjia yu kaifa |
| spelling | doaj-art-4f4f0f85fce941f5aa3cdc90d59f5d382025-08-20T02:03:08ZzhoEditorial Department of Petroleum Reservoir Evaluation and DevelopmentYouqicang pingjia yu kaifa2095-14262023-10-0113554855810.13809/j.cnki.cn32-1825/te.2023.05.002Types of fine-grained sedimentary rocks assemblage and its significance for shale oil exploration: A case study of the fifth member of Xujiahe Formation in western Sichuan Depression, Sichuan BasinXIONG Liang, CAO Qinming, ZHANG Ling, WANG Linghui01. Sinopec Southwest China Oil & Gas Company, Chengdu, Sichuan 610041, China;2. Research Institute of Exploration and Development, Sinopec Southwest China Oil & Gas Company, Chengdu, Sichuan 610041, ChinaDue to the complex lithology of fine-grained sedimentary rocks and the difficulty to determine the “sweet spot” of the fifth member of Xujiahe Formation（short for Xu-5 Member） of western Sichuan Depression, Sichuan Basin, a comprehensive geological analysis was conducted. This analysis encompassed various geological data sources, including X-ray diffraction, thin sections, scanning electron microscopy, physical properties, organic carbon content, and elemental analysis. Additionally, core observations were incorporated into the study. Upon scrutinizing this array of data, a classification of 14 distinct lithofacies types was established. This categorization was formulated based on the analysis of lithofacies and the evolution of sedimentary paleoenvironments. Furthermore, through a comparative examination of shale gas evaluation parameters, the primary lithofacies types constituting the “sweet spots” were identified. This not only sheds light on the composition of Xu-5 Member but also provides valuable guidance for the exploration of continental shale gas within this formation. The results indicate that: ①The main lithofacies of Xu-5 Member in western Sichuan Depression are massive clayey siltstone and massive mixed sedimentary rock, followed by laminated mixed sedimentary rock, laminated clayey siltstone and massive silty clay rock; ②The sedimentary paleoenvironment of Xu-5 Member undergoes the process from dry heat sedimentary with shallow brackish water to wet sedimentary with deep fresh water, then back to dry heat sedimentary with shallow brackish water. The land source input decreases first and then increases. The middle part of Xu-5 Member is the “sweet spot” for the enrichment of organic matter. ③Laminated clayey siltstone and laminated mixed sedimentary rock are favorable lithofacies types for “sweet spot” development due to the high organic matter content, debris particle dissolution pore, high content of brittle minerals and good fracturing performance.https://red.magtech.org.cn/fileup/2095-1426/PDF/1698828878785-2140759049.pdf|western sichuan depression|xu-5 member|fine-grained sedimentary|types of lithofacies assemblages |
| spellingShingle | XIONG Liang, CAO Qinming, ZHANG Ling, WANG Linghui Types of fine-grained sedimentary rocks assemblage and its significance for shale oil exploration: A case study of the fifth member of Xujiahe Formation in western Sichuan Depression, Sichuan Basin Youqicang pingjia yu kaifa |western sichuan depression|xu-5 member|fine-grained sedimentary|types of lithofacies assemblages |
| title | Types of fine-grained sedimentary rocks assemblage and its significance for shale oil exploration: A case study of the fifth member of Xujiahe Formation in western Sichuan Depression, Sichuan Basin |
| title_full | Types of fine-grained sedimentary rocks assemblage and its significance for shale oil exploration: A case study of the fifth member of Xujiahe Formation in western Sichuan Depression, Sichuan Basin |
| title_fullStr | Types of fine-grained sedimentary rocks assemblage and its significance for shale oil exploration: A case study of the fifth member of Xujiahe Formation in western Sichuan Depression, Sichuan Basin |
| title_full_unstemmed | Types of fine-grained sedimentary rocks assemblage and its significance for shale oil exploration: A case study of the fifth member of Xujiahe Formation in western Sichuan Depression, Sichuan Basin |
| title_short | Types of fine-grained sedimentary rocks assemblage and its significance for shale oil exploration: A case study of the fifth member of Xujiahe Formation in western Sichuan Depression, Sichuan Basin |
| title_sort | types of fine grained sedimentary rocks assemblage and its significance for shale oil exploration a case study of the fifth member of xujiahe formation in western sichuan depression sichuan basin |
| topic | |western sichuan depression|xu-5 member|fine-grained sedimentary|types of lithofacies assemblages |
| url | https://red.magtech.org.cn/fileup/2095-1426/PDF/1698828878785-2140759049.pdf |
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