岩性油藏聚油排水机理探讨

Oil accumulation and water discharge mechanism of lithologic reservoir

被烃源岩包裹的砂岩透镜体注入油气后,原有地层水与新注入流体构成的混合流体排出有两种模式:①压力封存箱泄压排水模式,当压力封存箱泄压后,砂体的流体压力高于围岩,混合流体向压力相对低的围岩排出。②断层泄压排水模式,切割砂岩透镜体的断层活动开启时,混合流体沿断层排出。由于断陷盆地构造活动的多期性,压力封存箱和断层均多次开启、封闭,在油气多次充注和混合流体多次排出的过程中,岩性圈闭的油气充满度不断增加。

After oil and gas filling into the sandstone lens that is around by source rocks, the original mixture liquid composite by formation water and latterly filled water will have two types model: ①seal-bounded fluid compartment evolvement, in which after the seal-bounded fluid compartment close down, the pressure of the liquid within the sandstone lens will higher than that of wall rocks, so the mixture liquid will be discharged to the wall rocks where the pressure is relatively lower; ②fault drainage are put forward, when the fault actives the mixture liquid will be discharged along the fault. Owing to multiphase structure of rifted basin, fluid compartment and fault time after time close down or close down, oil and gas will follow the actions and the full degree of oil and gas in the lithologic trap is increased.