西昆仑山前柯东-柯克亚构造带油气来源及成藏模式

摘要

In the foreland of Western Kunlun Mountain, 3 sets of hydrocarbon source rock developed, including the Heshilafu Formation in the Lower Carboniferous, the Pusige Formation in the Lower Permian and the Yangye Formation in the Middle Jurassic. Analysis of source rock distribution, hydrocarbon property, oil-source and gas-source correlation in the Kedong-Kekeya tectonic belt in the foreland of Western Kunlun Mountain led to the fo-llowing 2 conclusions:a) Oil in the Kedong-Kekeya tectonic belt mainly originated from relatively highly-mature organic matter of typeⅡin Permian. b) Natural gas mainly came from Permian, and partially from Jurassic and Carboniferous. Based on the study of tectonic evolution, fluid inclusions and hydrocarbon accumulation evolution history of the well Kedong 1 and the Kedong-Kekeya tectonic belt, the author analyzed the accumulation process of hydrocarbon and summarized the accumulation model of hydrocarbon in the Kedong-Kekeya tectonic belt. Accumulation process of hydrocarbon in the Kedong-Kekeya tectonic belt can be divided into 4 periods which include initial charging period of oil, oil-charging window, gas-charging window and hydrocarbon-adjusting period. To figure out the source and accumulation process of hydrocarbon in the Kedong-Kekeya tectonic belt can provide important reference to expand exploration scope and find more petroleum resource in the study area.%　　西昆仑山前主要发育下石炭统和什拉甫组、下二叠统普司格组和中侏罗统杨叶组3套烃源岩。通过西昆仑山前柯东—柯克亚构造带烃源岩特征、油气特征和油—源对比与气—源对比分析，指出柯东—柯克亚构造带原油主要来自二叠系类型较好的Ⅱ型有机质，热演化程度较高；天然气主要来源于二叠系源岩，有部分侏罗系和石炭系天然气混入。从柯东1井和柯克亚含油气构造的构造演化、流体包裹体、油气成藏演化史出发，分析了成藏演化过程，总结出柯东—柯克亚构造带油气成藏演化模式，得出其成藏可分为4个阶段：原油初始充注时期、主充油时期、主充气时期和油气调整时期。搞清柯东—柯克亚构造带油气来源及油气成藏过程具有极其重要的意义，可为该区甩开勘探、进一步扩大勘探成果提供重要依据。