准噶尔盆地木垒凹陷油气来源及成藏特征

Hydrocarbon source and reservoir-forming analysis in Mulei sag,Junggar basin

为解决准噶尔盆地木垒凹陷油气来源认识不清、成藏特征不明确问题,应用油源对比技术分析油气源;利用地震、测井和分析化验资料,综合评价生储盖条件、输导体系及圈闭条件。结果表明:木垒凹陷油气来源于二叠系平地泉组烃源岩,二叠系平地泉组深湖—半深湖相暗色泥岩为主力烃源岩,纵向上发育砂砾岩、云质岩和火山岩三类优质储层;受多期构造运动的影响,发育多层系、多类型(构造、岩性和不整合等)圈闭,为油气聚集提供良好的储集空间;断裂和骨架砂体构成立体复合式输导体系。木垒凹陷存在自生自储型和古生新储型两类成藏模式,其中以二叠系平地泉组烃源岩为主要油源的自生自储型岩性油藏和古生新储型构造—岩性油藏,是最有利的勘探方向。

In view of the fact that the source of hydrocarbon and the reservoir-forming characteristic are not clear in Mulei sag,the hydrocarbon source correlation analysis technology has been applied to analyze the hydrocarbon source.The seismic,well logging and lab test data have been deployed to comprehensively evaluate the source-reservoir-cap rock system,transportation and trap as well.The result shows that the deep and semi-deep lacustrine dark mudstone in Permian Pingdiquan formation is the main source rock.There are three types of high quality reservoir,including glutinite,dolomitic rock and volcanic rock.Due to the effect of multiphase tectonic movements,it develops various traps(structural,lithological and stratigraphic trap)in multiple zones,which provides favorable reservoir space for hydrocarbon accumulation.The fault and main sand build up the three dimensional compound transporting system.According to the study of reservoir forming conditions,it is believed that there are two types of reservoir forming mechanism,including self-generating-storing and elder-source with younger reservoir storing.The lithological reservoir and structural-lithological reservoir is the favorable exploration direction,in which the hydrocarbon is mainly from the Permian source rock.