柴达木盆地西部地区隐蔽油气藏形成与分布

Formation and distribution of the Subtle Pools in the western Qaidam Basin

柴达木盆地西部地区沉积以近物源、多物源的冲积扇—河流—三角洲—湖泊沉积体系为特征,岩性横向变化大,各种砂体岩性圈闭十分发育;构造活动强烈且具多期性,形成多种地层、裂缝、复合型隐蔽圈闭以及隐伏的构造圈闭.充足的油源为该区隐蔽油气藏的形成提供了丰厚的物质基础;晚期生烃保证了后期形成的裂缝型隐蔽圈闭也可成藏.分析柴西地区隐蔽油气藏的形成条件,认为柴西地区隐蔽油气藏类型多,分布广,蕴藏储量大,具有相当大的勘探潜力.

Sedimentary system in the western Qaidam Basin is characterized as alluvial fan-fluvial--dalta system.The lateral variation of lithology is great,and the lithologic traps of various sandbodies are very developed.And there are multi-stage strong tectonic movements,which form many types of subtle pools,such as lithologic hydrocarbon reservoir,stratigraphic hydrocarbon reservoir,fractured hydrocarbon reservoir,composite pool and buried structural trap.Plenty of oil source provides material foundation for the formation of the subtle pools.Moreover late hydrocarbon generation makes it possible that the fractured traps formed late catches the hydrocarbon.According to the analyses of geological elements of forming the subtle pools and the types and the distribution of the subtle pools in the western Qaidam Basin,it is held that there are plenty of subtle pools in the studied area,and they distribute widely.Therefore,the exploration potential in the area is very great.