准噶尔盆地春光油田油藏特征及成藏模式

Reservoir Characteristics and Hydrocarbon Accumulation Model in Chunguang Oilfield,Junggar Basin

春光油田是一个多层系含油、多油藏类型、稀油稠油共存的复式油气聚集区。为明确春光油田的油藏特征和成藏模式,系统开展了成藏要素和典型油藏分析。双凹陷供烃、多套储盖组合、多类型储集砂体、复式输导体系是春光油田多层系含油、立体成藏的必要条件,地层超覆线、剥蚀线和砂体尖灭线附近是油气有利聚集区。含膏盐区域性盖层、高孔渗储集物性是春光油田沙湾组稀油高产的关键因素,生物降解作用是白垩系原油稠化的主要原因,稀油和稠油分布主要受保存条件控制。进一步明确春光油田的油气成藏模式为:双凹供烃、两期充注、复式输导、立体成藏、降解稠化,并指出了春光油田的增储领域,对准噶尔盆地西部隆起及周缘油气勘探具有一定的启示和借鉴意义。

Chunguang oilfield is a multi-layer oil-bearing,multi-reservoir type,light oil and heavy oil co-existing complex oil-gas accumulation area.In order to determine the reservoir characteristics and hydrocarbon accumulation model in Chunguang oilfield,the paper analyzes the reservoir-forming factors and typical reservoirs.Double sag hydrocarbon supply,multiple reservoir-cap combinations,multiple reservoir sand bodies and compound transportation system are the necessary conditions for the multi-layer oil-bearing and three-dimensional reservoir-forming of Chunguang oilfield,and the peripheral areas of stratigraphic overlap line,denudation line and sandbody pinchout line are favorable areas for oil and gas accumulation.Gypsum-salt-bearing regional caprock and high-porosity and high-permeability reservoirs are the key factors for high oil production of Shawan formation in Chunguang oilfield,biodegradation is the main reason for the thickening of Cretaceous crude oil and the distributions of light oil and heavy oil are mainly controlled by preservation conditions.The hydrocarbon accumulation model can be summarized as follows:double sag hydrocarbon supply,two-stage charging,compound transportation,three-dimensional reservoir forming and crude oil biodegradation and thickening,and the favorable areas are presented,which can provide references for the oil and gas exploration of the western uplift and its surrounding areas in Junggar basin.