库车南斜坡中—新生界油气运移地球化学示踪  

Geochemical tracer of hydrocarbon migration path of Middle-Cenozoic in the south slope of the Kuqa foreland basin

作　　者：刘春 陈世加[1] 赵继龙[2] 苏洲[3] 陈戈 刘学彦 高乔 LIU Chun;CHEN Shijia;ZHAO Jilong;SU Zhou;CHEN Ge;LIU Xueyan;GAO Qiao(School of Geosciences&Technology,Southwest Petroleum University,Chengdu,610500;PetroChina Research Institute of Petroleum Exploration&Development,Beijing,100083;PetroChina Tarim Oilfield Company,Korla,Xinjiang,841000;School of Geosciences,Yangtze University,Wuhan,430100)

机构地区：[1]西南石油大学地球科学与技术学院,成都610500 [2]中国石油勘探开发研究院,北京100083 [3]中国石油塔里木油田公司勘探开发研究院,新疆库尔勒841000 [4]长江大学地球科学学院,武汉430100

出　　处：《地质学报》2020年第11期3488-3502,共15页Acta Geologica Sinica

基　　金：国家科技重大专项(编号2017ZX05001-002)资助的成果。

摘　　要：库车南部斜坡中—新生界属于库车陆相油气系统,油气主要来源于库车坳陷的三叠系和侏罗系烃源岩。本文利用色谱、色谱-质谱及碳同位素分析手段,对库车南部斜坡带已发现的白垩系和古近系油气地球化学组成特征进行了详细研究,在明确油气来源基础上,根据典型油气藏解剖,分析油气运移输导路径,优选油气地球化学运移参数示踪油气运移充注路径。研究表明:库车南斜坡中—新生界原油呈现低密度、低黏度、低凝固点、低含硫及高含蜡的陆相原油特征。原油总体以藻类和水生浮游生物母源为主,反映生烃母质弱还原-弱氧化的沉积环境,体现混合型干酪根母源特征,其中白垩系原油母源以湖相水生生物为主,主要来自三叠系湖相烃源岩;古近系原油除了三叠系湖相烃源岩的贡献外,伴随有以陆生高等植物输入为主的侏罗系煤系烃源岩。天然气具有中等甲烷含量、重烃含量高、氮气含量高和无硫化氢的特点,白垩系天然气主要是三叠系湖相原油伴生油型气;古近系天然气主体属于煤成气,主要来源于中下侏罗统煤系烃源岩,部分混有早期三叠系湖相烃源岩的原油伴生油型气。区内中—新生界发育由砂体、不整合、断裂构成的复杂油气输导体系,三叠系烃源岩生成的大量原油主要是沿白垩系底部不整合或下伏连接砂体运移到白垩系下部的圈闭中,侏罗系烃源岩生成天然气主要是沿古近系底部不整合面及下伏巨厚砂体运移到古近系底砂岩段圈闭中。综合油气藿烷参数Tm/(Ts+Tm)、重排藿烷参数C(30)DH/C(30)H、甲基二苯并噻吩(MDBT)参数4-/1-甲基二苯并噻吩、C1/C2值、iC4/nC4值、天然气烷烃碳同位素组成,认为库车南部斜坡带存在却勒到玉东构造带由北向南和英买力、红旗构造带由北东向南西方向的2个主运移充注路径和却勒到羊塔克构造带由西向东的1个次级充注运The Mesozoic-Cenozoic in the southern slope of Kuqa belong to the Kuqa continental petroleum system.Oil and gas mainly come from transverse migration of hydrocarbons generated by Triassic and Jurassic source rocks in the Kuqa Depression.In this paper,the characteristics of petroleum geochemical composition of Cretaceous and Paleogene discovered in the southern slope zone of Kuqa have been studied in detail by means of chromatography,chromatography-mass spectrometry and carbon isotope analysis.By identifying the source of oil and gas,the migration and transportation path of oil and gas were analyzed according to the typical oil and gas reservoirs,and the geochemical migration parameters were optimized to trace the migration and filling path of oil and gas.The following results are presented:the Mesozoic-Cenozoic crude oil in the southern slope of Kuqa presents the characteristics of continental crude oil,such as low density,low viscosity,low solidification point,low sulfur content and high wax content.Crude oil was primarily derived from algae and aquatic planktons,reflecting the sedimentary environment of weak reduction-weak oxidation of maternal materials and the characteristics of mixed kerogen source.The Cretaceous crude oil is mainly derived from lake-facies aquatic organisms,mainly from Triassic lake-facies source rocks.Paleogene crude oil is contributed by Triassic lake-facies source rocks in addition to Jurassic lake-facies source rocks;these are accompanied by Jurassic coal measures hydrocarbon source rocks,which are dominated by terrestrial higher plant inputs.Natural gas is characterized by medium methane content,high heavy hydrocarbon content,high nitrogen content and no hydrogen sulfide.Paleogene natural gas mainly belongs to coal-generated gas,which mainly comes from coal-measured source rocks of the middle and lower Jurassic,and some of the oil-associated types of crude oil mixed with early Triassic lacustrine source rocks.The Mesozoic-Cenozoic complex oil and gas transport systems consisting of san

关 键 词：库车南斜坡 中—新生界 分子地球化学 油气运移 路径示踪 

分 类 号：P618.13[天文地球—矿床学]