An analysis of geological and geophysical data and hydrocarbon-pooling factors shows that the buriedhills of the Bohai Bay Basin are characterized by diversities in lithology

structure and genesis.The lithology includes metamorphic

sedimentary(carbonates and/or clastics)and volcanic rocks;the structure can be divided into single structure and composite structure;and the genesis includes thrusting

extension and strike-slip.The metamorphic and volcanic buried-hills occur mainly in the Liaohe

Bozhong and Jiyang depressions;the tilting fault-block carbonate buried-hills occur in the Jizhong depression;while the inner carbonate buried-hills occur in the Huanghua and Jiyang depressions.Reservoir space is the main controlling factor for hydrocarbon-pooling in buried-hills.The reservoir spaces in the metamorphic and volcanic buried hills are dominated by fractures; while that of carbonate buried hills have both fractures and disollution pore-vug-fractures.The development of fractures in the metamorphic buried hills is affected by lithology

geomorphology and structural stress;while the development of the pore-vug-fractures in carbonate buried hills are related to lithology

horizon and other factors.