Chemical, carbon and sulfur isotopic compositions constrain the origin of Upper Carboniferous-Lower Triassic gases in eastern Sichuan Basin, SW China  

作　　者：Chunfang CAI Ilya KUTUZOV Wenhua MEI Daowei WANG Bing LUO Shipeng HUANG Bing HE Alon AMRANI 

机构地区：[1]China University of Petroleum,National Key Lab Petroleum Resource&Engineering,Beijing 102249,China [2]State Key Laboratory of Lithospheric and Environmental Coevolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China [3]Institute of Earth Sciences,The Hebrew University,Jerusalem 91904,Israel [4]College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China [5]Yulin University,Yulin 719000,China [6]Research Institute of Exploration and Development,Southwest Oil&Gas Field Company,PetroChina,Chengdu 610051,China [7]PetroChina,Research Institute of Petroleum Exploration and Development,Beijing 100083,China

出　　处：《Science China Earth Sciences》2024年第10期3169-3185,共17页中国科学（地球科学英文版）

基　　金：financially supported by the National Natural Science Foundation of China (Grant No.41961144023);the Israeli Science Foundation (Grant No.3195/19)。

摘　　要：Methane dominated gas is one of the cleanest energy resources;however, there is no direct method to determine its source rock. Natural gases produced from the eastern Sichuan Basin together with seismic data were studied for their sources and secondary alteration by thermochemical sulfate reduction(TSR). Our results demonstrate that Upper Permian to Lower Triassic(P_(3)ch-T_(1)f) gases in the surrounding of the Kaijiang-Liangping area show volatile organic sulfur compounds(VOSCs) δ^(34)S values close to those of the associated H_(2)S, and may have been altered by methane-dominated TSR, resulting in positive shift in methane δ^(13)C_(1)values with increasing TSR extents. Other(or group 2) gases produced from the P_(3)ch-T_(1)f reservoirs from the southern area and the Upper Carboniferous to Middle Permian(C_(2)h-P_(2)q) from the eastern Sichuan Basin are not significantly changed by TSR, show similar δ^(34)S values between the kerogens and some VOSCs, and may have been derived from the Lower Silurian and Middle Permian source rocks. This study demonstrates a case for the first time showing the δ^(34)S values of VOSCs can be used as a tool for direct correlation between non-TSR altered gas and source rocks. Methane-dominated gas pools can be found using gas and source rock geochemistry combined with seismic data.

关 键 词：Sulfur isotopes Volatile organic sulfur compounds Thermochemical sulfate reduction Sichuan Basin Gas-source rock correlation 

分 类 号：P618.13[天文地球—矿床学]