柴达木盆地北缘冷湖-南八仙构造带油气成藏条件及成藏模式

冷湖-南八仙构造带是柴达木盆地油气勘探的重点地区之一。综合地质、地震和分析化验等资料,应用现代油气成藏、地球物理学、地球化学等理论和方法,对该地区油气成藏的地质条件及成藏模式进行了分析。结果表明,该区带油源丰富,储集条件好,发育多套有效的储盖组合,多种类型圈闭（尤其是构造圈闭）发育且成排成带分布,各成藏要素配置良好,具有形成大中型油气田的有利条件。在此基础上,提出了该区带油气有近源断层输导纵向成藏、远源不整合输导侧向成藏、近源不整合输导纵向成藏和近源混合输导成藏4种模式。其中,近源断层输导纵向成藏模式和近源混合输导成藏模式是本区主要的油气成藏模式,而近源不整合输导纵向成藏模式的油藏可作为本地区下一步勘探的方向。

Oil-gas reservoir-forming conditions and patterns in Lenghu-Nanbaxian structural belt in the northern margin of Qaidam Basin

Lenghu-Nanbaxian structural belt,an important region for oil-gas exploration,is located in the northern margin of Qaidam Basin.The geologic conditions and patterns of hydrocarbon accumulation were researched by using theories and methods of modern reservoir formation,geophysics,geochemistry,and the data of geology,seismics and analysis assay.The results show that this area is likely to be large or medium-sized oil-gas field with abundant oil-sources,good reservoirs,developed several sets of effective reservoir-caprock assemblage,multiple types of trap(especially structural trap) distributing in lines and belts,and good allocation of various reservoir-forming factors.Based on these researches,the reservoir-forming patterns of the Lenghu-Nanbaxian structural belt can be classified as four kinds: near-source fault translocation vertical reservoir-forming pattern,far-source unconformity translocation lateral reservoir-forming pattern,near-source mixed translocation reservoir-forming pattern and near-source unconformity translocation vertical reservoir-forming pattern.The near-source fault translocation vertical reservoir-forming pattern and near-source mixed translocation reservoir-forming pattern are main reservoir-forming patterns of the area.Near-source unconformity translocation vertical reservoir-forming pattern can be looked on as exploration direction in future.