准噶尔盆地侏罗系地层和岩性油气藏形成条件及勘探前景

侏罗系是准噶尔盆地最主要的勘探目的层系，随着勘探程度的不断提高，地层、岩性等非构造油气葳已成为该盆地侏罗系勘探的必然选择。独特的构造背景和油源条件为准噶尔盆地侏罗系地层、岩性油气葳的形成提供了重要的地质基础和物质基础。侏罗系头屯河一齐古组介于两个不整合面之间，地层、岩性、岩相、厚度变化大，非常有利于地层、岩性圈闭的发育。SB3层序界面之下形成了大型的三角洲和沉积坡折带，层序界面上深切河谷很多，也有利于地层圈闭发育。侏罗系以河湖三角洲沉积体系为主，曲流河和曲流河三角洲的沉积能量相对较弱，砂泥比相对较低，有利于岩性圈闭的发育。准噶尔盆地腹部侏罗系中存在规模巨大的异常压力流体封存箱，极有可能形成巨大的成岩圈闭。因此，准噶尔盆地地层、岩性油气葳有着广阔的勘探前景。

The formation conditions and exploration prospect of stratigraphic and lithologic oil - gas reservoirs of Jurassic in Junggar Basin

Jurassic system is the most major exploration target se-ries of strata in Junggar Basin.With the increase of ex-ploration degree the stratigraphic,lithologic and some other non-structural oil-gas reservoirs have become the inevitable selection for the exploration of the Juras-sic in Jungaar Basin.The unique tectonic background and plenty of oil sources provided the geologic and ma-terial bases for the formation of stratigraphic and lithol-ogic oil-gas reservoirs.Toutunhe-Qigu formation of Jurassic lay between two unconformable surfaces and was very favorable to develop stratigraphic and litholog-ic traps for great variance of strata,lithology,rock facies and thickness.There existed large deltas and sedimen- tary slope break belt under the boundary of sequence SB3 and there were deep-cutting stream valleys on the boundary,which was favorable to develop the strati-graphic traps.The Jurassic of the Junggar Basin was dominated by fluvial-lake-deltaic depositional sys-tem and had lower sedimentary energy in meandering stream and meandering stream delta.The sand-shale ratio in the meandering stream and meandering stream delta was relatively low so it was favorable for the de-velopment of lithologic traps.There was huge abnormal -pressure fluid sealing compartment of Jurassic in the center of the basin,which would form a great diagenetic trap under given conditions.The exploration of the stra-tigraphic and lithologic oil-gas reservoirs of Jurassic in Juneear Basin has a bright future.