中国北方中小型侏罗─白垩纪含油气盆地勘探靶区展望

侏罗─白垩纪盆地,在北方板内是以同裂谷期(后裂谷期)伸展断陷或坳陷盆地和同造山期(后造山期)走滑前陆或走滑拉分盆地形式,在中生代构造运动控制产生的。盆内发育与暖湿古气候相适应的湖沼相沉积,为油气盆地提供物质基础。相对晚期的板内造山作用,导致烃类的排运聚并被捕获形成诸如现今被发现的油气构造带,这类中小盆地油气勘探靶区应为由侏罗─白垩系地层构成的油气成藏组合以及毗邻生油坳陷区相对隆起或低幅度凸起部位上的构造圈闭(如背冲背斜,断块挠曲或块断滚动背斜等)。 

PROSPECT FOR EXPLORATION TARGETS IN SMALL—MEDIUM JURA—CRETACEOUS BASINS,NORTH CHINA

In the north China intraplate,Jura-Cretaceous basins could occur in a form of either an extensionalfaulted or depressed basin in synrifting(or post-rifting)or strike-slip foreland,or a strike-slip pull apartbasin during synorogeny(or post orogeny),whose formation was controlled by Mesozoic tectonic movements.Corresponding to a warm and humic paleo-climate,limnetic sediments were developed in the basin,which became basins' material basis.The relative late intraplate orogeny caused the expulsion,migration,and accumulation of hydrocarbons,which were entrapped to form into the petroleum structural belts discovered up to now.In such a basin,the reservoir assemblages consist of Jura-Cretaceous strata and thestructural traps(pop-up anticline,fault block flexure or block fault-rolling anticline)on relative upliftedor lowly embossed parts close to the down-warping source region should be regarded as petroleum exploration targets.