西湖凹陷保俶斜坡断裂特征及与油气成藏的关系

西湖凹陷受区域构造应力场作用,经历了断陷、坳陷和区域沉降三个演化阶段。保俶斜坡是西湖凹陷的一个二级构造单元,在区域构造作用背景下,不同的演化阶段发育了不同规模、不同性质以NE~NEE向和NW向为主的两组断裂。这些断裂平面上具有明显的方向性、南北分段性;垂向上具有分层性。断层成为油气运移的通道,使油气沿断层作垂向运移或横穿断层作侧向运移,也成为阻止油气运移的屏障。保俶斜坡内局部构造类型主要与断裂有关,断裂构造的性质决定了圈闭类型;断裂作用的阶段性控制着油气藏的垂向叠置关系,断裂作用的构造迁移控制着油气藏的平面分布。斜坡内已发现了平湖、宝云亭、武云亭油气田和孔雀亭含油气构造。

The effect of rupture on oil accumulation in Baochu slope of Xihu Sag

Effected by regional tectonic stress field,Xihu Sag has undergone rifting,sinking and regional subsidence phases.Baochu slope is a sub-structure union, it developed two group of faults different size and different kind according to the different evolvement time,giving priority to the NE～NEE and NW direction.Being observed from the top,all the faults had clear orientation and subsection of SN,and had clear beds in the vertical.The faults were the channels of oil & gas in the vertical and lateral direction,but also may be the barrier of movement of oil & gas.The faults also had effected the local structures in Baochu slope,including the types of traps and their forming phases controlled the vertical superposed mode of oil & gas.The tectonic transport controlled the lateral distribution of oil & gas. Now there were four petroliferous structures such as Pinghu,Baoyunting,Wuyunting and Kunqueting.