Expressway of Hydrocarbon Migration and the Thought to Find the Reservoirs beyond the Region of Source Rock

According to source control theory,most reservoirs lie in ambient region of source rock.The kernel content of "Source Control Theory" is that oil gas migration distance is short.Most of them distribute between 20 km and 30 km.The west slope in the Songliao basin is outside of source rock distribution.However,several oilfield have been found in the west slope,such as Fulaerji,Pingyang ,Taobao,Tumuji and so on.A large channel is found in the west slope and this research shows that this channel control distribution of Baicheng Honggang river system.The channel and its river system is the most effective migration way for the reservoirs in the west slope.The wells in this channel all have good signs oil migration.The regional cap formed by the lacustrine shale in Nen Ⅰ and Ⅱ members,sandstone of high porosity and high permeability in the channel,and single slanted slope provide the geologic conditions for the hydrocarbon generated in Changelin Sag to migrate towards the west slope the channel and its river is a kind of expressway of hydrocarbon migration.Therefore,it is possible that explorer may seek reservoirs alone expressway beyond the region of source rock.