Sedimentary environment and shale gas exploration potential of Qiongzhusi Formation in the upslope area: A case study on Well W-207, Weiyuan area, Sichuan Basin
To deeply analyze the thalassochemical conditions and organic matter enrichment mechanism during the Early Cambrian (541-509 Ma)and actively evaluate the potential of shale gas resources of the Lower Cambrian Qiongzhusi Formation(Fm) in the southwestern Sichuan Basin, based on the analysis of the pe...
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| Format: | Article |
| Language: | zho |
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Editorial Department of Bulletin of Geological Science and Technology
2022-09-01
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| Series: | 地质科技通报 |
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| Online Access: | https://dzkjqb.cug.edu.cn/en/article/doi/10.19509/j.cnki.dzkq.2022.0159 |
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| author | Xiao Liang Shaoguang Ma Guoqin Li Guoyong Xia Ruolin Liu Gensheng Ni Menglin Zhang Yilong Kou Cuiping Yuan Jia Chen |
| author_facet | Xiao Liang Shaoguang Ma Guoqin Li Guoyong Xia Ruolin Liu Gensheng Ni Menglin Zhang Yilong Kou Cuiping Yuan Jia Chen |
| author_sort | Xiao Liang |
| collection | DOAJ |
| description | To deeply analyze the thalassochemical conditions and organic matter enrichment mechanism during the Early Cambrian (541-509 Ma)and actively evaluate the potential of shale gas resources of the Lower Cambrian Qiongzhusi Formation(Fm) in the southwestern Sichuan Basin, based on the analysis of the petrology, organic geochemistry, element characteristics, pore structure and adsorption capacity of Qiongzhusi Formation, Well W-207, Weiyuan area, this study has discussed the Early Cambrian paleo-ocean environment, organic matter enrichment control factors and gas-bearing properties of shale gas in the upslope area of the Upper Yangtze Platform. Sedimentary cycle shows that multiple interactive conversioncycles of deep-water continental shelf and shallow-water continental shelf are developed during the fine-grained deposition period of Qiongzhusi Formation under the control of eustasy. In particular, the slope turbidite (fan) and gravity flow sediments indicate that shallow-water continental shelf facies are dominant, and the wells in the upslope of the Weiyuan area are not in deep-water for a long time, with the sedimentary thickness of organic-rich black shale limited. Organic geochemistry evidence indicates that the organic matter of Qiongzhusi Formation in Well W-207 is mainly Type-Ⅰ kerogen, with a high degree of thermal evolution, fewer residual hydrocarbons and a low hydrocarbon generation capacity. The redox parameters indicate that the marine environment on the upslope has a medium restrictive degree, and there is a certain degree of upwelling. The seawater has experienced the transformation process of "anoxic-oxidation-anoxic-secondary oxidation- oxidation". Therefore, the paleo-ocean productivity level in the upslope area is generally low, with an obvious downward trend from bottom to top. The pore structure and nitrogen adsorption curve show that the reservoirs of the Qiongzhusi Formation are mainly complex and irregular slit pores. The methane adsorption capacity is positively correlated with TOC but negatively correlated with temperature, indicating that the high-pressure and high-temperature conditions generally faced by the Qiongzhusi Fm are not suitable for methane adsorption. As a result, the geological conditions of shale gas for Qiongzhusi Fm in the upslope area are complex. With high exploration risk, this study suggests that the resource evaluation direction should change to the intracratonic sag (downslope area), which is characterized by deep-water continental shelf facies. |
| first_indexed | 2024-03-07T15:50:14Z |
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| id | doaj.art-476f339f64af4131b232f86a275ce92e |
| institution | Directory Open Access Journal |
| issn | 2096-8523 |
| language | zho |
| last_indexed | 2024-03-07T15:50:14Z |
| publishDate | 2022-09-01 |
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| series | 地质科技通报 |
| spelling | doaj.art-476f339f64af4131b232f86a275ce92e2024-03-05T02:58:19ZzhoEditorial Department of Bulletin of Geological Science and Technology地质科技通报2096-85232022-09-01415688210.19509/j.cnki.dzkq.2022.0159dzkjtb-41-5-68Sedimentary environment and shale gas exploration potential of Qiongzhusi Formation in the upslope area: A case study on Well W-207, Weiyuan area, Sichuan BasinXiao Liang0Shaoguang Ma1Guoqin Li2Guoyong Xia3Ruolin Liu4Gensheng Ni5Menglin Zhang6Yilong Kou7Cuiping Yuan8Jia Chen9CCDC Geological Exploration and Development Research Institute, Chengdu 610051, ChinaPetroChina Southwest Oil & Gas Field Company, Chengdu 610051, ChinaCCDC Geological Exploration and Development Research Institute, Chengdu 610051, ChinaPetroChina Southwest Oil & Gas Field Company, Chengdu 610051, ChinaCCDC Geological Exploration and Development Research Institute, Chengdu 610051, ChinaPetroChina Southwest Oil & Gas Field Company, Chengdu 610051, ChinaCCDC Geological Exploration and Development Research Institute, Chengdu 610051, ChinaCCDC Geological Exploration and Development Research Institute, Chengdu 610051, ChinaCCDC Geological Exploration and Development Research Institute, Chengdu 610051, ChinaCCDC Geological Exploration and Development Research Institute, Chengdu 610051, ChinaTo deeply analyze the thalassochemical conditions and organic matter enrichment mechanism during the Early Cambrian (541-509 Ma)and actively evaluate the potential of shale gas resources of the Lower Cambrian Qiongzhusi Formation(Fm) in the southwestern Sichuan Basin, based on the analysis of the petrology, organic geochemistry, element characteristics, pore structure and adsorption capacity of Qiongzhusi Formation, Well W-207, Weiyuan area, this study has discussed the Early Cambrian paleo-ocean environment, organic matter enrichment control factors and gas-bearing properties of shale gas in the upslope area of the Upper Yangtze Platform. Sedimentary cycle shows that multiple interactive conversioncycles of deep-water continental shelf and shallow-water continental shelf are developed during the fine-grained deposition period of Qiongzhusi Formation under the control of eustasy. In particular, the slope turbidite (fan) and gravity flow sediments indicate that shallow-water continental shelf facies are dominant, and the wells in the upslope of the Weiyuan area are not in deep-water for a long time, with the sedimentary thickness of organic-rich black shale limited. Organic geochemistry evidence indicates that the organic matter of Qiongzhusi Formation in Well W-207 is mainly Type-Ⅰ kerogen, with a high degree of thermal evolution, fewer residual hydrocarbons and a low hydrocarbon generation capacity. The redox parameters indicate that the marine environment on the upslope has a medium restrictive degree, and there is a certain degree of upwelling. The seawater has experienced the transformation process of "anoxic-oxidation-anoxic-secondary oxidation- oxidation". Therefore, the paleo-ocean productivity level in the upslope area is generally low, with an obvious downward trend from bottom to top. The pore structure and nitrogen adsorption curve show that the reservoirs of the Qiongzhusi Formation are mainly complex and irregular slit pores. The methane adsorption capacity is positively correlated with TOC but negatively correlated with temperature, indicating that the high-pressure and high-temperature conditions generally faced by the Qiongzhusi Fm are not suitable for methane adsorption. As a result, the geological conditions of shale gas for Qiongzhusi Fm in the upslope area are complex. With high exploration risk, this study suggests that the resource evaluation direction should change to the intracratonic sag (downslope area), which is characterized by deep-water continental shelf facies.https://dzkjqb.cug.edu.cn/en/article/doi/10.19509/j.cnki.dzkq.2022.0159early cambrianqiongzhusi formationshale gaspaleo-ocean environmentpaleo-productivityadsorption capacityupslope areaweiyuan area |
| spellingShingle | Xiao Liang Shaoguang Ma Guoqin Li Guoyong Xia Ruolin Liu Gensheng Ni Menglin Zhang Yilong Kou Cuiping Yuan Jia Chen Sedimentary environment and shale gas exploration potential of Qiongzhusi Formation in the upslope area: A case study on Well W-207, Weiyuan area, Sichuan Basin 地质科技通报 early cambrian qiongzhusi formation shale gas paleo-ocean environment paleo-productivity adsorption capacity upslope area weiyuan area |
| title | Sedimentary environment and shale gas exploration potential of Qiongzhusi Formation in the upslope area: A case study on Well W-207, Weiyuan area, Sichuan Basin |
| title_full | Sedimentary environment and shale gas exploration potential of Qiongzhusi Formation in the upslope area: A case study on Well W-207, Weiyuan area, Sichuan Basin |
| title_fullStr | Sedimentary environment and shale gas exploration potential of Qiongzhusi Formation in the upslope area: A case study on Well W-207, Weiyuan area, Sichuan Basin |
| title_full_unstemmed | Sedimentary environment and shale gas exploration potential of Qiongzhusi Formation in the upslope area: A case study on Well W-207, Weiyuan area, Sichuan Basin |
| title_short | Sedimentary environment and shale gas exploration potential of Qiongzhusi Formation in the upslope area: A case study on Well W-207, Weiyuan area, Sichuan Basin |
| title_sort | sedimentary environment and shale gas exploration potential of qiongzhusi formation in the upslope area a case study on well w 207 weiyuan area sichuan basin |
| topic | early cambrian qiongzhusi formation shale gas paleo-ocean environment paleo-productivity adsorption capacity upslope area weiyuan area |
| url | https://dzkjqb.cug.edu.cn/en/article/doi/10.19509/j.cnki.dzkq.2022.0159 |
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