Geochemistry and shale gas potential of the lower Permian marine-continental transitional shales in the Eastern Ordos Basin
Marine–continental transitional strata were widely developed in the Ordos Basin in Upper Carboniferous - Lower Permian. The Taiyuan - Shanxi Formation possesses promising shale gas exploration layers. Shale samples from two drilling wells of Shanxi-Taiyuan Formation in Shilou and Xixian, Ordos Basin...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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SAGE Publishing
2021-05-01
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| Series: | Energy Exploration & Exploitation |
| Online Access: | https://doi.org/10.1177/0144598720979242 |
| _version_ | 1797278752178176000 |
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| author | Jingyi Wei Yongli Wang Gen Wang Zhifu Wei Wei He |
| author_facet | Jingyi Wei Yongli Wang Gen Wang Zhifu Wei Wei He |
| author_sort | Jingyi Wei |
| collection | DOAJ |
| description | Marine–continental transitional strata were widely developed in the Ordos Basin in Upper Carboniferous - Lower Permian. The Taiyuan - Shanxi Formation possesses promising shale gas exploration layers. Shale samples from two drilling wells of Shanxi-Taiyuan Formation in Shilou and Xixian, Ordos Basin, were investigated to study their carbon–sulfur contents and distribution characteristics of organic components using carbon/sulfur analyzer and gas chromatography–mass spectroscopy. Using results of total organic carbon analyses, Rock-Eval pyrolysis, X-ray diffraction analysis, shale gas desorption experiments, and other relevant experimental data, the shale samples were comprehensively analyzed. The exploitability of the shale in the study area was evaluated. The Shanxi-Taiyuan Shale in the Shilou and Xixian areas was characterized by high total organic carbon contents of 7.1% and 2.1% and high T max values of 499 and 505 °C, respectively. The organic matter of the shale is types II 2 and III. Moreover, biomarker parameters including n-alkanes, P aq , P wax , average carbon chain length, and the ternary diagram of C 27 -C 28 -C 29 steranes show the organic matter constituted terrestrial higher plants and aquatic low biological algae. Multiple n-alkane parameters show the organic matter input in the Shilou area is mainly derived from terrestrial higher plants. The Pr/Ph value and trace element indicators show the deposition environment is dominated by weak oxidation–reduction conditions. A shale gas desorption experiment shows the average desorbed gas contents of the shale samples in the Shilou and Xixian areas were 1.79 and 0.37 m 3 /t, respectively. The organic matter content determined the differences in shale gas properties between the two areas in Ordos Basin. The composition and content of inorganic minerals affect the reservoir physical properties. According to the analyses, the shale in the Shilou area has good shale gas reservoir characteristics in terms of desorbed gas content and the above-mentioned geochemical parameters. Furthermore, the Shanxi shale has good potential for shale gas industrial exploitation. |
| first_indexed | 2024-03-07T16:12:45Z |
| format | Article |
| id | doaj.art-315099ad6d914225bc4b1f0e92b73b5d |
| institution | Directory Open Access Journal |
| issn | 0144-5987 2048-4054 |
| language | English |
| last_indexed | 2024-03-07T16:12:45Z |
| publishDate | 2021-05-01 |
| publisher | SAGE Publishing |
| record_format | Article |
| series | Energy Exploration & Exploitation |
| spelling | doaj.art-315099ad6d914225bc4b1f0e92b73b5d2024-03-04T16:03:57ZengSAGE PublishingEnergy Exploration & Exploitation0144-59872048-40542021-05-013910.1177/0144598720979242Geochemistry and shale gas potential of the lower Permian marine-continental transitional shales in the Eastern Ordos BasinJingyi WeiYongli WangGen WangZhifu WeiWei HeMarine–continental transitional strata were widely developed in the Ordos Basin in Upper Carboniferous - Lower Permian. The Taiyuan - Shanxi Formation possesses promising shale gas exploration layers. Shale samples from two drilling wells of Shanxi-Taiyuan Formation in Shilou and Xixian, Ordos Basin, were investigated to study their carbon–sulfur contents and distribution characteristics of organic components using carbon/sulfur analyzer and gas chromatography–mass spectroscopy. Using results of total organic carbon analyses, Rock-Eval pyrolysis, X-ray diffraction analysis, shale gas desorption experiments, and other relevant experimental data, the shale samples were comprehensively analyzed. The exploitability of the shale in the study area was evaluated. The Shanxi-Taiyuan Shale in the Shilou and Xixian areas was characterized by high total organic carbon contents of 7.1% and 2.1% and high T max values of 499 and 505 °C, respectively. The organic matter of the shale is types II 2 and III. Moreover, biomarker parameters including n-alkanes, P aq , P wax , average carbon chain length, and the ternary diagram of C 27 -C 28 -C 29 steranes show the organic matter constituted terrestrial higher plants and aquatic low biological algae. Multiple n-alkane parameters show the organic matter input in the Shilou area is mainly derived from terrestrial higher plants. The Pr/Ph value and trace element indicators show the deposition environment is dominated by weak oxidation–reduction conditions. A shale gas desorption experiment shows the average desorbed gas contents of the shale samples in the Shilou and Xixian areas were 1.79 and 0.37 m 3 /t, respectively. The organic matter content determined the differences in shale gas properties between the two areas in Ordos Basin. The composition and content of inorganic minerals affect the reservoir physical properties. According to the analyses, the shale in the Shilou area has good shale gas reservoir characteristics in terms of desorbed gas content and the above-mentioned geochemical parameters. Furthermore, the Shanxi shale has good potential for shale gas industrial exploitation.https://doi.org/10.1177/0144598720979242 |
| spellingShingle | Jingyi Wei Yongli Wang Gen Wang Zhifu Wei Wei He Geochemistry and shale gas potential of the lower Permian marine-continental transitional shales in the Eastern Ordos Basin Energy Exploration & Exploitation |
| title | Geochemistry and shale gas potential of the lower Permian marine-continental transitional shales in the Eastern Ordos Basin |
| title_full | Geochemistry and shale gas potential of the lower Permian marine-continental transitional shales in the Eastern Ordos Basin |
| title_fullStr | Geochemistry and shale gas potential of the lower Permian marine-continental transitional shales in the Eastern Ordos Basin |
| title_full_unstemmed | Geochemistry and shale gas potential of the lower Permian marine-continental transitional shales in the Eastern Ordos Basin |
| title_short | Geochemistry and shale gas potential of the lower Permian marine-continental transitional shales in the Eastern Ordos Basin |
| title_sort | geochemistry and shale gas potential of the lower permian marine continental transitional shales in the eastern ordos basin |
| url | https://doi.org/10.1177/0144598720979242 |
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