泌阳凹陷北部斜坡带油气富集条件及油藏类型

HYDROCARBON ACCUMULATION FACTORS AND POOL TYPES IN NORTH SLOPE OF BIYANG DEPRESSION

近年在泌阳凹陷北部斜坡带先后发现五个油田,形成一个面积较大的油气富集区。该区油气富集条件主要有:①继承性的沉积-构造复合斜坡是油气运移的主要指向;②多个砂体发育提供了良好的储集条件;③一系列鼻状构造对油气富集起着控制作用;④两组断层为油藏的形成提供了遮挡条件;⑤区域不整合面上的盖层使浅层油藏得以保存。该斜坡存在多种类型油藏,而以断鼻、断块、地层不整合油藏为主。

Biyang Depression covers an area of 1000 km^2.Within it,530 km^2 belongs to itsnorth slope.The 4 oilfields discovered before 1985 are distributed in the south slope andthe central deep subsided area.In recent years,5 oilfields have been discovered in thenorth slope,the prospected and controlled hydrocarbon reserves occupies above 40% ofthe total reserves of the depression,and this percentage may even rise as the explorationcarrying on.Favourable conditions for hydrocarbon accumulation in the north slope are:1.Thesuccessional sedimentation-structure complex slopes are the target area for hydrocarbonmigration;2.Multiple sandbodies provide good reservoirs;3.A series of nose-structuresare in control of hydrocarbon accumulation;4.Two sets of faults provide the conditionof shelter for hydrocarbon accumulation;5.Cap rocks on regional unconformity makeswell preservation for shallow pools in slope.There are various kinds of oil pools,withinwhich fault-nose,fault-block and unconformity ones are the main types.