Sedimentary environment, hydrocarbon potential and development of black rocks in upper Maokou Formation, northwestern Sichuan
A set of organic-rich black rocks (23.8 m), mainly consisting of siliceous rocks, shale and limestones, outcrops between carbonate rocks of the Maokou and Wujiaping formations in the Xibeixiang section, northwestern Sichuan Basin, at the margin of the Upper Yangtze Platform. Detailed conodont strati...
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| Format: | Article |
| Language: | zho |
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Editorial Office of Petroleum Geology and Experiment
2020-03-01
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| Series: | Shiyou shiyan dizhi |
| Subjects: | |
| Online Access: | https://www.sysydz.net/cn/article/doi/10.11781/sysydz202002202 |
| _version_ | 1797277201178034176 |
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| author | Chaowei HU Guang HU Xihua ZHANG Cong CHEN Hanlin PENG Zhaolong Gao Zhiwei LIAO Qian PANG Jie YOU |
| author_facet | Chaowei HU Guang HU Xihua ZHANG Cong CHEN Hanlin PENG Zhaolong Gao Zhiwei LIAO Qian PANG Jie YOU |
| author_sort | Chaowei HU |
| collection | DOAJ |
| description | A set of organic-rich black rocks (23.8 m), mainly consisting of siliceous rocks, shale and limestones, outcrops between carbonate rocks of the Maokou and Wujiaping formations in the Xibeixiang section, northwestern Sichuan Basin, at the margin of the Upper Yangtze Platform. Detailed conodont stratigraphy, organic petrology and organic geochemistry studies were performed on samples from the Xibeixiang section. The conodonts found in the study area were Jinogondolella prexuanhanensis, J. xuanhanensis and Clarkina posbitteri hongshuiensis. All of them lived at the end of Guadalupian, confirming that the black rocks in the section were deposited during the late period of the Maokou Formation indicating that the Guangyuan-Wangchang Marine Trough began to develop in the late Guadalupian stage on the Upper Yangtze Platform. The detailed study of organic petrology reveals that benthic algae is the main contributor for hydrocarbon in the black rock series, with a small amount of macroplanktonic algae, and the organic matter is type Ⅱ. The organic geochemical analyses of the black rocks show that the TOC content ranges 1.04% to 32.58% and the chloroform bitumen "A" content ranges 0.03% to 1.05%, indicating favorable source rocks. Thermal parameters, such as the vitrinite reflectance (Ro) value ranges 1.0% to 1.4%, the Tmax value ranges 440 to 460℃, the conodont color index (CAI) ranges 1.5 to 2.5, the Ts/Tm ratio ranges 0.35 to 1.43, the moretane/hopane ratio ranges 0.05 to 0.39, the C2920S/(20S+20R) ranges 0.39 to 0.65, and the C29αββ/(αββ+ααα) ranges 0.26 to 0.58, which indicate that these black rocks are mature to highly mature. The integrated study of lithology, hydrocarbon-forming organisms, conodonts and biomarkers indicate that these black rocks were deposited in a relatively reductive deep-water environment with a high salinity. |
| first_indexed | 2024-03-07T15:44:15Z |
| format | Article |
| id | doaj.art-21213a5b38774bbc896d389909384ae9 |
| institution | Directory Open Access Journal |
| issn | 1001-6112 |
| language | zho |
| last_indexed | 2024-03-07T15:44:15Z |
| publishDate | 2020-03-01 |
| publisher | Editorial Office of Petroleum Geology and Experiment |
| record_format | Article |
| series | Shiyou shiyan dizhi |
| spelling | doaj.art-21213a5b38774bbc896d389909384ae92024-03-05T04:44:34ZzhoEditorial Office of Petroleum Geology and ExperimentShiyou shiyan dizhi1001-61122020-03-0142220221410.11781/sysydz202002202sysydz-42-2-202Sedimentary environment, hydrocarbon potential and development of black rocks in upper Maokou Formation, northwestern SichuanChaowei HU0Guang HU1Xihua ZHANG2Cong CHEN3Hanlin PENG4Zhaolong Gao5Zhiwei LIAO6Qian PANG7Jie YOU8State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, ChinaState Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, ChinaExploration and Development Research Institute, PetroChina Southwest Oil & Gasfield Company, Chengdu, Sichuan 610041, ChinaExploration and Development Research Institute, PetroChina Southwest Oil & Gasfield Company, Chengdu, Sichuan 610041, ChinaExploration and Development Research Institute, PetroChina Southwest Oil & Gasfield Company, Chengdu, Sichuan 610041, ChinaExploration and Development Research Institute, PetroChina Southwest Oil & Gasfield Company, Chengdu, Sichuan 610041, ChinaState Key Laboratory of Coal Mine Disaster Dynamics and Control, School of Resources and Safety Engineering, Chongqing University, Chongqing 400044, ChinaState Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, ChinaState Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, ChinaA set of organic-rich black rocks (23.8 m), mainly consisting of siliceous rocks, shale and limestones, outcrops between carbonate rocks of the Maokou and Wujiaping formations in the Xibeixiang section, northwestern Sichuan Basin, at the margin of the Upper Yangtze Platform. Detailed conodont stratigraphy, organic petrology and organic geochemistry studies were performed on samples from the Xibeixiang section. The conodonts found in the study area were Jinogondolella prexuanhanensis, J. xuanhanensis and Clarkina posbitteri hongshuiensis. All of them lived at the end of Guadalupian, confirming that the black rocks in the section were deposited during the late period of the Maokou Formation indicating that the Guangyuan-Wangchang Marine Trough began to develop in the late Guadalupian stage on the Upper Yangtze Platform. The detailed study of organic petrology reveals that benthic algae is the main contributor for hydrocarbon in the black rock series, with a small amount of macroplanktonic algae, and the organic matter is type Ⅱ. The organic geochemical analyses of the black rocks show that the TOC content ranges 1.04% to 32.58% and the chloroform bitumen "A" content ranges 0.03% to 1.05%, indicating favorable source rocks. Thermal parameters, such as the vitrinite reflectance (Ro) value ranges 1.0% to 1.4%, the Tmax value ranges 440 to 460℃, the conodont color index (CAI) ranges 1.5 to 2.5, the Ts/Tm ratio ranges 0.35 to 1.43, the moretane/hopane ratio ranges 0.05 to 0.39, the C2920S/(20S+20R) ranges 0.39 to 0.65, and the C29αββ/(αββ+ααα) ranges 0.26 to 0.58, which indicate that these black rocks are mature to highly mature. The integrated study of lithology, hydrocarbon-forming organisms, conodonts and biomarkers indicate that these black rocks were deposited in a relatively reductive deep-water environment with a high salinity.https://www.sysydz.net/cn/article/doi/10.11781/sysydz202002202organic geochemistry characteristicshydrocarbon potentialblack rocksmaokou formationnorthwestern sichuan basin |
| spellingShingle | Chaowei HU Guang HU Xihua ZHANG Cong CHEN Hanlin PENG Zhaolong Gao Zhiwei LIAO Qian PANG Jie YOU Sedimentary environment, hydrocarbon potential and development of black rocks in upper Maokou Formation, northwestern Sichuan Shiyou shiyan dizhi organic geochemistry characteristics hydrocarbon potential black rocks maokou formation northwestern sichuan basin |
| title | Sedimentary environment, hydrocarbon potential and development of black rocks in upper Maokou Formation, northwestern Sichuan |
| title_full | Sedimentary environment, hydrocarbon potential and development of black rocks in upper Maokou Formation, northwestern Sichuan |
| title_fullStr | Sedimentary environment, hydrocarbon potential and development of black rocks in upper Maokou Formation, northwestern Sichuan |
| title_full_unstemmed | Sedimentary environment, hydrocarbon potential and development of black rocks in upper Maokou Formation, northwestern Sichuan |
| title_short | Sedimentary environment, hydrocarbon potential and development of black rocks in upper Maokou Formation, northwestern Sichuan |
| title_sort | sedimentary environment hydrocarbon potential and development of black rocks in upper maokou formation northwestern sichuan |
| topic | organic geochemistry characteristics hydrocarbon potential black rocks maokou formation northwestern sichuan basin |
| url | https://www.sysydz.net/cn/article/doi/10.11781/sysydz202002202 |
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