Research on hydrocarbon accumulation process is the basis for studying hydrocarbon enrichment patterns and identifying favorable areas for petroleum exploration.Based on the microscopic description of fluid inclusion and analysis of homogenization temperature

hydrocarbon inclusions mainly occur in the secondary quartz overgrowth

microfractures crossing these overgrowth and calcite cement.The dominant frequency of homogeneous temperature was 130-150 ℃.The diagenetic history and burial history show that high maturity natural gas migrated upward with maturing of hydrocarbon source rock and displaced the oil accumulated in the lower traps into the higher traps

resulting in the formation of Well SN189 and Well SN183 accumulations.Residual asphalt in the Yingcheng Formation in Well SN115

which is near the hydrocarbon generation center

was the product of crude oil pyrolysis in this period.Natural gas generated during later period migrated upward along the fault and formed Well SN182 natural gas pool where the inclusions are mainly of natural gas.As a result

along the fault up-dip direction

the number of liquid hydrocarbon inclusions gradually decreases

while the number of natural gas inclusions gradually increases.Oil accumulated in the higher position

and gas accumulated in the lower parts.The oil and gas share the same hydrocarbon source.Up-dip pinchout sandstone and sandstone lens in the depression and slope area of Changling rift are the main targets for natural gas exploration.