Abstract:

Gravity flow depositswere widely developed in deep and sem ideep lakes during the deposition of the m iddle Es 3 in the Dongxin area，the Bohai Bay Basin.An integrated analysis on core，logging and seism ic data reveals that the gravity flow deposits can be classified into four types of sandbody，namely they are slope cumulate complex associated with delta front slump，slump turbidite fan，distal turbidite，and subaquaceous debris flow deposits of flood origin.A gravity flow sedimentarymodelwas also built up for the area.Oil potentials of various types of sandbodies are analyzed based on comparative studies of oil source，physical properties and trap conditions in the area.It is pointed out that oil potentials of slump turbidite fans and parts of the distal turbidite are higher than that of slope cumulate complex and subaquaceous debris flow.

Key words: gravity flow deposit, sandstone type, sedimentarymodel, oil potential, Dongxin oilfield, BohaiBay Basin