Origin background and reservoir forming condition of lithologic oil pools in Songliao Basin

Heterogeneity of lithologic oil pools is high in Songliao Basin,which reservoir is dominated by thin interbed and changes quickly,its forming condition is more complex,concealment is strong and is hard to discover.Therefore,using new theory,new method of plate tectonics,sequence stratigraphy and reservoir-forming system,etc.to implement tectonics,sedimentation and hydrocarbon-forming condition study and achieving a new understanding to origin condition and distribution rule of the lithologic oil pools.The study shows that long time and stable tectonic subsidence is the basis of forming a large-scale lithologic oil pool. Level of lake waves frequently and alternately changes the lake shoreline,resulted in sand-shale interactive deposits in vertical,forming multi sets of oil-bearing assemblages and all kinds of type of lithologic traps formed in sand-shale interactive sedimentation zone of delta front.The reservoir forming condition and controlling factor of the upper,middle and the lower three reservoirs forming system is defferent.Under this guideness a favourable prediction is made.It points out exploration direction and it has an important guiding sence for hydrocarbon exploration in Songliao Basin and in like basins.