长直链烷基苯及其异构体母质来源研究及地球化学意义

发布时间：2019-02-27 08:43

【摘要】：烷基苯系列化合物广泛分布在岩石圈中,但其母质来源和指示意义仍存在一定争议。对四川盆地晚三叠世须家河组和鄂尔多斯盆地晚三叠世延长组烃源岩样品进行了岩石热解及GC-MS(GC-MS-MS)分析,检测出一系列的长直链烷基苯及其异构体。烃源岩基本地球化学参数表明四川盆地和鄂尔多斯盆地样品均遭受过较强程度的微生物降解作用,有机质类型以腐殖腐泥型为主,埋藏期间经历过一定程度的黏土矿物催化作用,以弱氧化的淡水沉积为主。此外,两个研究区样品中长直链烷基苯及其异构体的相对含量呈现出相反的分布模式,在前人研究基础上并结合研究区烃源岩沉积环境和热演化背景,认为烷基苯系列化合物可能来自于类脂化合物(如脂肪酸和脂肪醇)或简单芳烃化合物与类脂化合物的反应,且热作用会导致长直链烷基苯向其异构体转化。综合以上研究表明长直链烷基苯及其异构体可以作为一种指示有机质热演化程度和母质来源的有效参数。
[Abstract]:Alkyl benzene compounds are widely distributed in the lithosphere, but their parent material sources and indicating significance are still controversial. Rock pyrolysis and GC-MS (GC-MS-MS) analysis were carried out on the source rock samples of the late Triassic Sujiahe formation and Yanchang formation in the Ordos Basin, Sichuan Basin. A series of long straight chain alkylbenzene and its isomers were detected. The basic geochemical parameters of source rocks indicate that the samples of Sichuan basin and Ordos basin have been subjected to strong microbial degradation, and the organic matter type is mainly humus humic type. During burial period, clay minerals underwent catalytic action to a certain extent, mainly weakly oxidized fresh water deposits. In addition, the relative contents of long straight chain alkylbenzene and its isomers in the two study areas present opposite distribution patterns. Based on previous studies and combined with the sedimentary environment and thermal evolution background of the source rocks in the study area, It is suggested that the alkylbenzene series of compounds may result from the reaction of aliphatic compounds (such as fatty acids and fatty alcohols) or simple aromatic compounds with lipoid compounds, and the thermal interaction may result in the conversion of long linear alkylbenzene to its isomers. All the above studies indicate that long straight chain alkylbenzene and its isomers can be used as an effective parameter to indicate the thermal evolution of organic matter and the source of parent matter.
【作者单位】：甘肃省油气资源研究重点实验室/中国科学院油气资源研究重点实验室;中国科学院大学;
【基金】：国家自然科学基金项目(No.41072106) 兰州油气资源研究中心“十三五”创新基金(No.135CCJJ20160523) 甘肃省重点实验室专项(No.1309RTSA041)~~
【分类号】：P618.13

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