The geological characteristics and master control factors of hydrocarbon accumulation in Jiangqiao area

Jiangqiao area is in the middle of the west slope in north Songliao Basin.The oil pool is mainly consisted of little amplitude structures,lithological and stratigraphic-lithological reservoirs.The target stratum distributes at the top of Gaotaizi oil bed and S2+3 oil layer.The oil layer is thicker with better physical property and high porosity and permeability.The formation is in normal thermobaric system.The formation fluids include heavy crude and humid gas.The main controlling factors for hydrocarbon accumulation are traps and migration pathways.The oil and gas are mainly accumulated in three types of traps: lithological updip pinchout,river channel lenticular sand body and structure-lithological trap.In this area,long range fluid migration takes the main role,and the main migration pathways are regional unconformity at the top of Gaotaizi oil layer and sand body in reservoirs.