Accumulation model and geochemistry characteristics of oil occurring from Jurassic coal measures in the Huangling mining area of the Ordos Basin, China

作     者：Yuan BAO Yiliang HU Wenbo WANG Chen GUO Guochang WANG Yuan BAO;Yiliang HU;Wenbo WANG;Chen GUO;Guochang WANG

作者机构：College of Geology and EnvironmentXi’an University of Science and TechnologyXi’an 710054China Key Laboratory of Coal Resources Exploration and Comprehensive UtilizationXi’an 710021China Engineering DepartmentSaint Francis UniversityLorettoPA 15940USA 

出 版 物：《Frontiers of Earth Science》 (地球科学前沿（英文版）)

年 卷 期：2023年第17卷第1期

页      面：158-169页

核心收录：

学科分类：081803[工学-地质工程] 08[工学] 0818[工学-地质资源与地质工程] 0708[理学-地球物理学] 

基　　金：This work was supported by the National Natural Science Foundation of China(Grant Nos.42172200 and 41972183) the“Chunhui Plan”Cooperative Research for Ministry of Education. 

主　　题：coal measures oil source biomarker compounds carbon isotope Ordos Basin 

摘      要：The Ordos Basin is an important intracontinental sedimentary basin in China,containing a significant amount of coal,oil,and natural gas.This study analyzed the sedimentary environment,sedimentary facies,parent material type,maturity,and carbon isotopic composition of the coal-bearing organic matter using gas chromatography–mass spectrometry(GC–MS)and stable isotope ratio mass spectrometry.The source of oil occurring in the No.2 coal seam of the Jurassic Yan’an Formation(An-1 oil)and its accumulation model were also investigated.The results show that the relative abundances of C_(27),C_(28),and C_(29) steranes in the An-1 oil are 43.8%,33.0%,and 23.2%,respectively.The tricyclic terpanes,C_(29)20S/(20S+20R),and C_(29)ββ/(ββ+αα)contents of the An-1 oil are 31.4%−34.8%,0.85 and 0.81,respectively.Pr/n-C17,Ph/n-C18,and Pr/Ph values are 0.34,0.42,and 0.87,respectively.Biomarker parameters indicate that the An-1 oil mainly comes from the plankton source rock deposited in the freshwater lake facies and a reducing environment,which has evolved to maturity.The correlation of oil-oil indicates that the An-1 oil is homologous to the Chang-7 oil(Chang-7 member of the Triassic Yanchang Formation).The correlation of oil-source rock presents that the An-1 oil is generated from the Yanchang Formation(Chang-6 and Chang-7 source rocks)and occurred in the coal seam during the stage of stratum uplift since the Early of Late Cretaceous.The distribution characteristics of δ13C group components in the An-1 oil and Chang-7 oil also reveal the fractionation phenomenon during the migration of crude oil.