渤海油田富砂性湖底扇沉积模式及有利勘探目标

Depositional models of sand-rich sublacustrine fan and favorable exploration targets in Bohai oilfield

通过对渤海油田湖底扇发育特征系统分析,认为渤海油田发育的湖底扇从成因机制上可分为两种沉积模式,一种与早期继承性发育坡折带相关,另一种与同沉积坡折带相关;并对两种模式的湖底扇规模与富砂特征进行了对比。以BZ21区为例,在对古地貌背景和三角洲推进形成同沉积坡折带特征分析的基础上,通过精细地震追踪、复合微相刻画等手段,建立了BZ21区大型湖底扇群沉积模式,精细刻画了各个湖底扇富砂区和富砂边界,并指明BZ21区、BZ19区是隐蔽油气藏勘探的有利目标。

Through systematic analysis on development characteristics of sublacustrine fans in Bohai oilfield,the sublacustrine fans of Bohai oilfield could be divided into two depositional models:one type was related to early inherited slope break belt and the other was related to synsedimentary slopebreak belt built by large delta construction.The sand-rich characteristics and the scale of these two types was compared and analyzed.By taking BZ21 area as an example,based on the analysis of palaeomorphologic patterns and synsedimentary slope break belt,by means of fine seismic tracing and composite microfacies features description,the depositional models of large-scale sublacustrine fan group in BZ21 area were established,which found sand-rich areas,described sadrich boundaries and pointed out favorable subtle reservoir exploration targets of sublacustrine fan types in BZ21 and BZ19 areas.