渤海海域断裂对油气优势运移通道的影响及其控藏类型

Influences of Faults on the Petroleum Dominant Migration Pathway and Its Controlling Reservoir Types in the Bohai Area

渤海海域为新生代陆内断陷盆地,断裂作用贯穿油气运移过程始终,且不同类型的断裂控藏作用差异明显,但均表现为优势运移通道控制着油气富集带形成。根据钻井资料和三维地震精细解释成果,结合渤海海域成盆机制及勘探实践,提出了断面形态主导油气宏观运聚趋势,断裂结构影响油气输导效率,断裂组合控制油气分流走向,势—效—流三大因素耦合是断裂优势输导油气的内在原因。结合典型油田实例,将不同断裂组合对油气运移过程中的作用分为垂向输导和侧向分流2种;根据断裂的差异输导作用将油气成藏模式分为侧向分流型、垂向输导型和逐级截流型3种类型,提出了"断面定势、结构控效,组合分流"是渤海海域寻找油气富集断块区的有效方法。

Faulting works through hydrocarbon migration process and has differential control on accumula- tion in Bohai Rift Basin, but dominant migration pathway controls the formation of hydrocarbon enrich- ment zone. This study, based on the drilling and 3D seismic interpretation in combination with the basin- formation mechanism and exploration practice, analyzes comprehensively the primary reason for the forma- tion of the fault dominant migration pathway according to the fault texture and origin mechanism. The re- sults show that the fault surface shape determines the macro trends of hydrocarbon migration and accumu- lation, while the fault texture affects the efficiency of hydrocarbon migration and the fault assemblages control the direction of hydrocarbon partial flow. These three coupling factors of potential field and effi- ciency and partial flow are the inner reasons of fault dominant migrating hydrocarbons. With a typical oil- field as an example, this paper introduces the vertical migration and lateral partial flow under the different fault assemblages. The hydrocarbon accumulation patterns affected by different migration include vertical migration and lateral partial flow and step closure. The analysis results that the fault surface determines the macro trends, the fault texture affects migration efficiency and the fault assemblages control migration direction are the effective approach for searching hydrocarbon enrichment fault block in Bohai Sea.