The fault depressions

isolated with one another but genetically related

are developed in deep of southern Songliao basin and most of them are considered to be capable of generating hydrocarbon.An analysis carried out on the reservoiring pattern of natural gas in Shiwu and Changlin fault depressions suggests that the gas reservoiring be controlled by the distribution and evolution of source rocks and the configuration between large-scale structure belt and the sedimentary facies and their preservation conditions.The deep gas reservoirs were formed in two phases

namely Denlouku and Nenjiang

in which the later is more important.Large-scale structure belt in area with medium to high hydrocarbon-generating intensity is critical for the accumulation and reservoiring because the favorable reservoirs and faults inside the belt control the local enrichment of oil and gas.However

the preservation condition is not ideal due to an absence of regional cap adjacent to hydrocarbon source rock.It is concluded that different combinations of source rock

structure

deposition

and preservation

can form various complex hydrocarbon accumulation zones.The central structure

the eastern Qinjiatun strike slip structure and the northern complex hydrocarbon accumulation zone of overlap pinchout type in Shiwu fault depression

and Dongling complex accumulation zone on the eastern slope and the entral low uplift complex accumulation in Changlin fault depression

are the main exploration targets in the future

and the large submarine alluvial fan western steep slope in Changlin fault depression is also regarded as a potential hydrocarbon accumulation zone.