Hydrocarbon generation mechanism of lamalginite- and telalginite-dominated source rocks in a saline lake basin: A case study of the Permian Lucaogou formation in the Jimusaer Sag, Junggar Basin  

作　　者：Lichang Chen Jingqiang Tan Haisu Cui Xiao Ma Xueqi Song Qiang Yuan Jin Liu 

机构地区：[1]Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring(Central South University),Ministry of Education,Changsha,410083,China [2]School of Civil Engineering(Central South University),Changsha,410083,China [3]Research Institute of Experiment and Testing,PetroChina Xinjiang Oilfield Company,Karamay,834000,China

出　　处：《Energy Geoscience》2023年第3期220-232,共13页能源地球科学（英文）

基　　金：funded by Fundamental Research Funds for the Central Universities of Central South University(Grant No.2022ZZTS0531);China Hunan Provincial Science&Technology Department(Grant No.2022WK2004);the Department of Natural Resources of Hunan Province,China(No.2022-5).

摘　　要：The hydrocarbon generation of source rocks is significantly influenced by organic matter type, chemical element composition, and structural characteristics of kerogen. We classified the organic matter types in the shale of the Lucaogou Formation, Jimusar Sag, Junggar Basin, using organic petrology and rock pyrolysis as well as kerogen element and Fourier transform infrared (FT-IR) spectroscopy analyses, and compared the hydrocarbon generation mechanisms of source rocks with different types of organic matter. The organic matter of the Lucaogou Formation contains mostly two types of hydrocarbon generating macerals, the lamalginite and the telalginite based on physical and optical properties (texture, fluorescence, and optical reflectance). The lamalginite is a continuous sheet of less than 5 μm thick and greater than 50 μm in length. It has strong yellow fluorescence. The telalginite occurs as discontinuous short strips or pear-shaped objects with length of 10–30 μm and relatively weak fluorescence. The lamalginite-dominated shale has higher atomic H/C and lower atomic O/C ratios, indicating better hydrocarbon generation potential, whereas the telalginite-dominated shale has higher N and S heteroatom contents. The results of FT-IR spectroscopy of the kerogen indicate that the lamalginite-dominated shale is rich in aliphatic groups with long linear methylene sequences. The aromatic groups content is relatively low, but the carboxyl/carbon group (Cdouble bondO) content is high. The aliphatic group content of the telalginite-dominated shale is relatively low, with short-branched chains. The aromatic group content is relatively high. The methyl vibration signal directly connected to the benzene ring is strong, and the sulfoxide (Sdouble bondO) group has a high-intensity peak. Our results provide new insights into distinguishing organic matter types in the Lucaogou Formation and understanding the hydrocarbon generation mechanisms of source rocks in saline lake basins.

关 键 词：Luca ogou formnation Larnalginite Telalginite KEROGEN Fourier transformn infared spectroscopy 

分 类 号：P618.13[天文地球—矿床学]