Oil-Gas Vertical Migration and Its Controlment to Formation and Distribution of Oil-Gas Reservoirs in the North of Songliao Basin

Based on the study of the migration and accumulation characteristics of oil or gas in the north of Songliao Basin, this paper studies the vertical migration characteristics of oil or gas. It points out faults to be the sole passages of oil or gas vertical migration.Oil or gas can only migrate through faults both upwards and downwards.Oil or gas vertical migration upwards or downwards is determined by the power of oil or gas vertical migration. If there is abnormal pore fluid pressure in hydrocarbon source rock, oil or gas can migrate upwards and downwards. If there is no abnormal pore fluid pressure in hydrocarbon source rock, oil or gas can only migrate upwards. The power and passages of oil or gas vertical migration are the main factors controlling the formation and distribution of oil or gas reservoirs in the vertical direction. They show in following three aspects in the north of Songliao Basin: The long-term development faults control accumulation and distribution of gas from K₁sh+yc source rock in shallow strata; abnormal pore fluid pressure and T₂ faults control accumulation and distribution of oil or gas in F,Y oil layers; the faults from T₂ or T₁ to T₀₆ control accumulation and distribution of oil or gas in H oil layer.