柴达木盆地欧南凹陷上石炭统克鲁克组海陆过渡型烃源岩有机质组成及生烃特征  

The organic matter composition and hydrocarbon generation characteristics of the source rocks in the Upper Carboniferous Keluke Formation,Ounan depression,Qaidam basin

作　　者：施辉 李宗星[1] 彭博[1] 孙玉琦 张浩 杨元元[1] 胡俊杰[1] 方欣欣[1] 魏小洁 SHI Hui;LI Zongxing;PENG Bo;SUN Yuqi;ZHANG Hao;YANG Yuanyuan;HU Junjie;FANG Xinxin;WEI Xiaojie(Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing100081,China;Key Laboratory of Paleomagnetism and Tectonic Reconstruction,Ministry of Natural Resources,Beijing 100081,China;Key Laboratory of Petroleum Geomechanics,China Geological Survey,Beijing 100081,China;Qinghai Bureau of Coal Geology,Xining,Qinghai 810001,China)

机构地区：[1]中国地质科学院地质力学研究所,北京100081 [2]自然资源部古地磁与古构造重建重点实验室,北京100081 [3]中国地质调查局油气地质力学重点实验室,北京100081 [4]青海煤炭地质局,青海西宁810001

出　　处：《地质学报》2023年第1期179-196,共18页Acta Geologica Sinica

基　　金：中国地质调查局地质调查项目(编号DD20190107,DD20190094);中国地质科学院基本科研业务费项目(编号DZLXJK202006)联合资助的成果。

摘　　要：柴达木盆地北缘东段欧南凹陷上石炭统克鲁克组海陆交互混积型储层中获得良好油气发现,但该层段内烃源岩海陆混合型生物有机质组分及类型、生烃差异性等基础性问题的认识尚不清楚。选择尕海南山南坡柏树沟剖面克鲁克组烃源岩开展有机地球化学、XRD、岩石薄片、SEM等分析测试,研究了岩性及组分、丰度质量及类型、可溶有机质族组分及生烃母质等,结果表明:克鲁克组烃源岩残余有机质丰度总体较高,原始生烃能力强,处于高成熟演化阶段,残留腐殖型(Ⅲ型)为主的干酪根,可溶有机质主要来源于海洋低等水生生物有机质母质(Ⅱ型),反映出海陆两相混源生物有机质的特征,海相有机质在前次生烃过程中对生烃量的贡献相对高于陆源生物。大量放射虫等浮游硅质生物是克鲁克组烃源岩海相有机质的主要组分,是海相干酪根的主力生烃物质;晚石炭世,欧南凹陷南部古陆和北部海槽分别向凹陷提供陆相高等植物和海洋低等水生生物或富硅上升流,海相有机质的富集与硅质生物活动直接相关。该研究认识为探索石炭系有机质富集机制和优质烃源岩分布规律提供了参考依据,也对区域性油气勘探部署具有指导意义。Although some hydrocarbon has been discovered in the C2k transitional reservoirs in the east of northern Qaidam basin,there remain fundamental unanswered questions about the C2k source rocks with mixed terrestrial and marine organic matter,i.e.,component and type of organic matter and discrepant hydrocarbon generation.Successive C2k source rock samples were collected from the Baishugou outcrop located in the southern slope of Gahainan Mountain for organic geochemistry,XRD,thin section,SEM analyses.The results indicate that the abundance of organic matter in source rocks is high,suggesting an excellent original productivity.Organic matter was already in the high-maturity thermal evolution stage and has primarily remained with humic kerogens,but the dissolved organic matter from the samples are hydrocarbon generation products of lower marine aquatic organisms,which represent mixed characteristics of marine and terrestrial organic matter.The contribution of marine OMs to hydrocarbon generation was higher than that of terrestrial organisms during the latest generation.Biogenic silica consists of remains of siliceous radiolarian organisms that were the main hydrocarbon generation material of marine kerogens.The archicontinent to the south,and the ocean trough to the north of the Ounan depression respectively provided terrestrial and marine OMs or silicon-rich upwelling,and the enrichment of marine OMs is related to the siliceous biological activity in the late Carboniferous.This study is of guiding significance for exploring the mechanism of organic matter enrichment in the Carboniferous and regional oil and gas exploration.

关 键 词：海陆过渡相 有机质类型 生烃母质 柴达木盆地 克鲁克组 

分 类 号：P618.13[天文地球—矿床学]