塔里木盆地库车坳陷克拉苏构造带轻质油/凝析油地球化学特征与成藏过程  

Geochemical characteristics of light crude oils/condensates from the Kelasu structural belt of the Kuqa Depression in the Tarim Basin,Northwest China

作　　者：邓晗宇 张海祖[4] 莫涛[4] 程斌[1,3] 陈乃东[4] 王云鹏 廖泽文[1,3] DENG Hanyu;ZHANG Haizu;MO Tao;CHENG Bin;CHEN Naidong;WANG Yunpeng;LIAO Zewen(State Key Laboratory of Organic Geochemistry,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,Guangdong,China;University of Chinese Academy of Sciences,Beijing 100049,China;CAS Center for Excellence in Deep Earth Science,Guangzhou 510640,Guangdong,China;Research Institute of Petroleum Exploration and Development,PetroChina,Tarim Oilfield Company,Korla 841000,Xinjiang,China)

机构地区：[1]中国科学院广州地球化学研究所,有机地球化学国家重点实验室,广东广州510640 [2]中国科学院大学,北京100049 [3]中国科学院深地科学卓越创新中心,广东广州510640 [4]中国石油塔里木油田分公司勘探开发研究院,新疆库尔勒841000

出　　处：《地球化学》2024年第5期668-680,共13页Geochimica

基　　金：中国科学院先导A专项(XDA14010103);中国科学院广州地球化学研究所有机地球化学国家重点实验室“十四五”自主课题项目(SKLOG2020-1)联合资助。

摘　　要：塔里木盆地库车坳陷克拉苏构造带浅层–深层储层中广泛产出轻质油/凝析油气藏,其油气相态变化大,母质来源多样,油气充注与成藏过程复杂。本研究对克拉苏构造带上58个轻质油开展有机地球化学分析,探讨其母质来源、热成熟度及油气成藏过程。结果显示,克拉苏构造带轻质油中正构烷烃以中、低碳数为主,烷基苯相对含量较高,全油稳定C同位素值主要分布在-29‰~-26‰之间。姥植比(Pr/Ph)、甲基环己烷指数(I_(MCH))、甲基菲比值等地球化学参数显示,克拉苏构造带轻质油主要来自湖相腐殖型、沉积于偏氧化环境烃源岩的贡献,经历了多期次油气充注成藏。其中,克深1-2段轻质油热成熟度普遍高于大北段,主要来自三叠系黄山街组烃源岩的贡献,经历了“早油晚气”2期烃类充注;大北段轻质油热成熟度偏低,主要来自侏罗系恰克马克组和三叠系黄山街组烃源岩的贡献,主要经历了3期油气充注与成藏。Light crude oils/condensates are widely found in the shallow-deep reservoirs in the Kelasu structural belt of the Kuqa Depression in the Tarim Basin,Northwest China.They featured various oil and gas phases,various source material origins,and complex hydrocarbon charges and accumulation processes.In this work,58 light oils and condensates from the Kelasu structural belt were analyzed,and their material sources,maturity,and hydrocarbon accumulation processes were discussed.The results showed that n-alkanes in the light oils were mainly intermediate and low carbon numbers,and the relative content of alkylbenzene was high.The stable carbon isotopes of the oils were mainly in the range of−29‰to−26‰.Geochemical parameters such as Pr/Ph,I_(MCH),and the methyl phenanthrene ratio indicated that the light oils mainly originated from lacustrine humic source rocks,experienced multi-stage oil and gas charges,and their parental materials were deposited in a partially oxidizing environment.The light oils in the Keshen segment were of high maturity and experienced two periods of hydrocarbon charges.These were characterized by“early oil and late gas”,mainly from the source rocks of the Triassic Huangshanjie Formation.The light oils from the Dabei segment were of low maturity and experienced three stages of oil and gas charges and accumulation,mainly from the source rocks of the Jurassic Qiakemake Formation and the Triassic Huangshanjie Formation.

关 键 词：轻质油/凝析油 成藏过程 克拉苏构造带 塔里木盆地 

分 类 号：P618.13[天文地球—矿床学]