东海西湖凹陷平湖组油气运移特征模拟分析

平湖组是东海西湖凹陷的主力生烃层位,花港组沉积时就已经进入生烃门限,具有良好的生排烃条件.多次构造运动改变了构造面貌,促使油气运移.计算机模拟研究表明,西湖凹陷的油气运移方向主要是西部斜坡带和中央背斜带.西部斜坡带以侧向运移为主,断裂隔挡和岩性封隔成藏,重点地区是平湖地区.中央背斜带以垂向运移为主,局部背斜构造成藏,成藏圈闭与断坳叠加关系密切.西湖凹陷平湖组的油气除了在西湖凹陷聚集成藏之外,有可能向周边地区运移.

SIMULATION ANALYSIS OF THE MIGRATION CHARACTERISTICS OF HYDROCARBON IN THE PINGHU FORMATION OF THE XIHU DEPRESSION, THE EAST CHINA SEA

The Pinghu Formation, which is the major hydrocarbon-generating horizon in the Xihu Depression of the East China Sea, was in the threshold of hydrocarbon generation during the sedimentation period of the Huagang Formation and has good conditions for hydrocarbon generation and expulsion. Multiple tectonic movements changed tectonic morphology and impelled hydrocarbon migration. The study of computer simulation showed that the migration directions of hydrocarbon in the Xihu Depression were mainly the west slope zone and the central anticline zone. The west slope zone was dominated by lateral migration, and pools were formed by fault barriers and lithologic seals, especially in the Pinghu area. The central anticline zone was dominated by vertical migration, pools were formed in regional anticlinal structures, and pool-forming traps were closely related to fault-depression superimpositon. Besides accumulating and forming pools in the Xihu Depression, the hydrocarbon in the Pinghu Formation of the Xihu Depression probably migrated to the circumferential areas.