Organic geochemical characteristics of Jurassic Yan ’an Formation source rock in Pengyang area of southwestern Ordos basin
The Jurassic Yan ’an Formation in the southwestern margin of Ordos Basin has developed many sets of coal-associated and non-associated mudstone as well as oil shale. Different analytical methods including total organic carbon (TOC), Rock-Eval pyrolysis, and conventional biomarker analyses were appli...
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Frontiers Media S.A.
2025-02-01
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| Series: | Frontiers in Earth Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/feart.2025.1536268/full |
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| author | Yaling Zhu Yaling Zhu Wenmei Tan Lianfu Hai Lianfu Hai Caixia Mu Caixia Mu Kun Wang Mengyuan Li |
| author_facet | Yaling Zhu Yaling Zhu Wenmei Tan Lianfu Hai Lianfu Hai Caixia Mu Caixia Mu Kun Wang Mengyuan Li |
| author_sort | Yaling Zhu |
| collection | DOAJ |
| description | The Jurassic Yan ’an Formation in the southwestern margin of Ordos Basin has developed many sets of coal-associated and non-associated mudstone as well as oil shale. Different analytical methods including total organic carbon (TOC), Rock-Eval pyrolysis, and conventional biomarker analyses were applied on the mudstone, the coal and the oil shale extracts to unravel their organic geochemical characteristics and the paleo depositional environment. Results reveal that all the source rock samples are immature to mature with good petroleum generation potentials. The redox environment is generally reducing. The organic matter input is mainly terrestrial higher plants. The low Ga/C30 hopane ratio of all the samples indicate the low salinity of the paleo-water column. The oil shale samples show much higher thermal maturity than the coals and mudstones as indicated by the higher C31 homohopane isomerization indexes, C32 homohopane isomerization indexes and the C29 sterane ααα20S/(S + R) ratios. The depositional environment of the oil shale is more reduced compared to the coals and mudstones as can be reflected by the low oxygen index and the higher C35 hopane/(C31-C35 homohopanes) ratios. Thus, the oil shale layers should be the target of the next exploration and development. And the Oil shale and coal can be exploited simultaneously in Pengyang area. |
| format | Article |
| id | doaj-art-d1b46f0d3a0a44d69ab319a9a3cdcf0f |
| institution | Kabale University |
| issn | 2296-6463 |
| language | English |
| publishDate | 2025-02-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Earth Science |
| spelling | doaj-art-d1b46f0d3a0a44d69ab319a9a3cdcf0f2025-02-04T06:31:47ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632025-02-011310.3389/feart.2025.15362681536268Organic geochemical characteristics of Jurassic Yan ’an Formation source rock in Pengyang area of southwestern Ordos basinYaling Zhu0Yaling Zhu1Wenmei Tan2Lianfu Hai3Lianfu Hai4Caixia Mu5Caixia Mu6Kun Wang7Mengyuan Li8School of Geosciences, Yangtze University, Wuhan, ChinaHubei Key Laboratory of Complex Shale Oil and Gas Geology and Development in Southern China, Wuhan, ChinaSchool of Geosciences, Yangtze University, Wuhan, ChinaMineral Geological Survey Institute of Ningxia Hui Autonomous Region, Yinchuan, ChinaInstitute of Mineral Geology of Ningxia Hui Autonomous Region, Yinchuan, ChinaMineral Geological Survey Institute of Ningxia Hui Autonomous Region, Yinchuan, ChinaInstitute of Mineral Geology of Ningxia Hui Autonomous Region, Yinchuan, ChinaSchool of Geosciences, Yangtze University, Wuhan, ChinaSchool of Geosciences, Yangtze University, Wuhan, ChinaThe Jurassic Yan ’an Formation in the southwestern margin of Ordos Basin has developed many sets of coal-associated and non-associated mudstone as well as oil shale. Different analytical methods including total organic carbon (TOC), Rock-Eval pyrolysis, and conventional biomarker analyses were applied on the mudstone, the coal and the oil shale extracts to unravel their organic geochemical characteristics and the paleo depositional environment. Results reveal that all the source rock samples are immature to mature with good petroleum generation potentials. The redox environment is generally reducing. The organic matter input is mainly terrestrial higher plants. The low Ga/C30 hopane ratio of all the samples indicate the low salinity of the paleo-water column. The oil shale samples show much higher thermal maturity than the coals and mudstones as indicated by the higher C31 homohopane isomerization indexes, C32 homohopane isomerization indexes and the C29 sterane ααα20S/(S + R) ratios. The depositional environment of the oil shale is more reduced compared to the coals and mudstones as can be reflected by the low oxygen index and the higher C35 hopane/(C31-C35 homohopanes) ratios. Thus, the oil shale layers should be the target of the next exploration and development. And the Oil shale and coal can be exploited simultaneously in Pengyang area.https://www.frontiersin.org/articles/10.3389/feart.2025.1536268/fullOrdos basinYan ’an Formationsource rocksbiomarkeroil shale |
| spellingShingle | Yaling Zhu Yaling Zhu Wenmei Tan Lianfu Hai Lianfu Hai Caixia Mu Caixia Mu Kun Wang Mengyuan Li Organic geochemical characteristics of Jurassic Yan ’an Formation source rock in Pengyang area of southwestern Ordos basin Frontiers in Earth Science Ordos basin Yan ’an Formation source rocks biomarker oil shale |
| title | Organic geochemical characteristics of Jurassic Yan ’an Formation source rock in Pengyang area of southwestern Ordos basin |
| title_full | Organic geochemical characteristics of Jurassic Yan ’an Formation source rock in Pengyang area of southwestern Ordos basin |
| title_fullStr | Organic geochemical characteristics of Jurassic Yan ’an Formation source rock in Pengyang area of southwestern Ordos basin |
| title_full_unstemmed | Organic geochemical characteristics of Jurassic Yan ’an Formation source rock in Pengyang area of southwestern Ordos basin |
| title_short | Organic geochemical characteristics of Jurassic Yan ’an Formation source rock in Pengyang area of southwestern Ordos basin |
| title_sort | organic geochemical characteristics of jurassic yan an formation source rock in pengyang area of southwestern ordos basin |
| topic | Ordos basin Yan ’an Formation source rocks biomarker oil shale |
| url | https://www.frontiersin.org/articles/10.3389/feart.2025.1536268/full |
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