大港油田埕北断阶带油气运移、成藏期次及成藏模式

Models of Hydrocarbon Migration and Accumulation in Chengbei Fault-step Belt in Dagang Oil Field

通过原油中类异戊二烯烃地球化学变化特征的对比分析,指出大港油田埕北断阶带的油气主运移方向是由北边的生油凹陷(歧口凹陷)向南(埕北断阶带)运聚和由西边的生油凹陷(歧南凹陷)向(北)东(张东地区、关家堡地区和埕海地区)运聚。利用流体包裹体、生排烃法、饱和压力法等方法技术,认为存在两个充注期:古近纪东营末期和新近纪明化镇末期—第四纪。结合输导体系研究成果,提出了4种油气成藏模式:沿连通砂体—不整合面侧向运聚成藏模式、沿断层垂向运聚成藏模式、沿连通砂体(不整合面)—断层阶梯状运聚成藏模式、源内砂岩透镜体运聚成藏模式。

Correlation analysis of geochemical characteristics of isoprenoid in crude oil from Chengbei Fault-step Belt in Dagang Oil Field shows two directions of hydrocarbon migration,one is from the hydrocarbon-generating depression （Qikou Depression） in the north to the Chengbei Fault-step Felt in the south, and the other is from the hydrocarbon-generating depression （Qinan Depression） in the west to the Zhangdong,Guanjiaobao and Chenghai areas in the northeast/east. With methods of the fluid inclusion, the generation and discharge of hydrocarbon and the saturation pressure,two periods of hydrocarbon emplacement are obtained. The first was at the end of Lower Tertiary Dongying Formation and the second is at the end of Upper Tertiary Minghuazhen Formation to Quater- nary. Four models of hydrocarbon accumulation are proposed： the model of lateral migration and accumulation through connecting sand bodies-unconformities,the model of vertical migration and accumulation through faults,the model of stepping migration and accumulation through connecting sand bodies-unconformities-faults, and the model of migration and accumulation in sandstone lens within source rocks.