Geochemistry and shale gas potential of the lower Permian marine-continental transitional shales in the Eastern Ordos Basin

作者：Jingyi Wei, Yongli Wang, Gen Wang, Zhifu Wei, Wei He · 发表于：Energy Exploration & Exploitation · 年份：2020 · DOI：10.1177/0144598720979242 · 被引用次数：13 · 研究领域：Hydrocarbon exploration and reservoir analysis、Atmospheric and Environmental Gas Dynamics、Petroleum Processing and Analysis

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 con...