辽西低凸起及辽中凹陷压力场特征与油气分布关系

Characteristics of pressure field and its relationship with hydrocarbon distribution in Liaoxi Low Uplift and Liaozhong Sag

周东红 李建平 郭永华

中海石油（中国）有限公司天津分公司，天津 300452

Tianjin Branch of CNOOC, Tianjin 300452, China

辽西低凸起及辽中凹陷古近系广泛发育超压，异常高压主要分布在东营组二段下部至沙河街组一段和沙河街组三段。主力烃源岩生成的油气，在超压的强动力驱动下，沿断层、砂体、不整合面等输导体系侧向传递到辽西低凸起及凹陷两侧斜坡带等有利圈闭中聚集成藏。天然气藏主要分布于异常高压带的内部，油藏主要分布于异常高压带内部或异常高压带边缘（常压带或过渡压力带），少数岩性油气藏或封闭条件优越的凝析气藏位于超压区内，若油气藏上覆有压力和泥岩的双重封堵，则油气聚集量明显加大。

The phenomenon of overpressure extensively exists in Liaoxi Low Uplift and Liaozhong Sag. The abnormal overpressure mainly distributes from lower Ed2 to Es1 and Es3 members. The hydrocarbons generated from the main hydrocarbon source rocks in Liaozhong Sag which is driven by the strong power of overpressure are delivered to the favorable traps in Liaoxi Low Uplift and the slope belt of Liaozhong Sag, then, gather together as reservoirs along the transferring systems (fault, sand body and unconformity, etc). Gas is mainly accumulated in abnormal overpressure belt and oil is mainly accumulated in abnormal overpressure belt or the edge of it (normal pressure belt or transitional pressure belt). A few lithologic reservoirs and condensate gas reservoirs with the superior sealing conditions are located in overpressure zone. If there is double sealing of overlying mudstone and pressure in the reservoir, the accumulation quantity of oil and gas is obviously increased.

10.6056/dkyqt201201015