柴达木盆地北缘山前带平台地区天然气成藏条件及勘探方向

Accumulation Conditions of Natural Gas and Exploration Domains in Pingtai Area, Piedmont Zone of the North Qaidam

柴达木盆地北缘山前带平台地区为长期继承性古隆起,位于祁连山前,紧邻赛什腾凹陷。从烃源岩、储盖组合、圈闭及油气运移等方面,分析了平台地区的成藏条件。研究表明:平台凸起为源外成藏模式,赛什腾凹陷的侏罗系烃源岩所生油气,经断层及不整合面运移到具有古隆起背景的古近系砂岩储集层聚集成藏。平1井的突破,证实了柴北缘山前带源外成藏模式和古隆起具备较好的勘探潜力,也是下一步柴达木盆地主要的勘探方向。

Pingtai area,which is located in the Qilian Mountains,is an ancient uplift for long-term and next to the Saishiteng Depression.In this paper,we discuss the accumulation conditions of oil and gas in the Pingtai area in combination with source rocks,reservoir-cap rock assemblages,trap,and migration pathway.Results show that the oil and gas accumulation in the Pingtai salient was happened outside of source rocks,oil and gas generated from the Jurassic source rocks in the Saishiteng Depression was migrated and gathered into the Tertiary sandstone reservoirs though faults and unconformity,those reservoirs always have background of ancient uplift.The exploration breakout of Ping 1well confirmed that the ancient uplift and accumulation outside sources have good exploration potential in the piedmont zone of the Northern Margin and is main exploration direction in the Qaidam Basin.