The Gas Dominant Migration Path Of East Slope Of Shaximiao Group In The Western Depression Of The Sichuan Basin

The western depression of the Sichuan basin is a foreland basin formed by the thrusting and pushing motion of the Longmenshan tectonic belt.The eastern slope of the western depression of the Sichuan basin is a secondary structure of the western depression of the Sichuan basin.The study area includes four secondary structure of Hexing-Fenggu structure,Xinchang-Shiquan structure,Zhongjiang-Huilong structure and Huangde oblique structure.The east slope of the western depression of the Sichuan basin is affected by multiple structure movements with developing a large number of faults.The Shaximiao Formation on the east slope of the western depression of the Sichuan basin is a set of continental clastic rocks that can not produce oil and gas.But Xujiahe Formation which is the underlying strata is good hydrocarbon source rock.During f the study,using the 2DMove software restores the structural evolution of the east slope of the western depression of the Sichuan basin.The structural evolution of the eastern slope of the western depression of the Sichuan basin is mainly characterized by the structural tectonic stress of the Yanshanian structural movement.The initial formation of the western depression of the Sichuan basin structural zone to north-south direction.The strata develops a large number of faults with forming faulted structural traps.The thickness of the formation is thick in the south,thin in the nouth,thick in the west and thin in the east.The western depression was pressed by the Himalayan large-scale structural to east-west direction.The strata was uplift and setting.Resuming of degradation thickness is with the method of mud stone AC acoustic during the Himalayan.The western depression's degradation thickness is from high to low to west-east and south-north.Research work of hydrocarbon dominant migration pathway is on the basis of the comprehensive advantages of hydrocarbon dominant migration pathway technology and based on ArcGIS platform.The research used the fluid inclusions temperature measurement,hydrocarbon generation history analysis,burial history,thermal history analysis and other test analysis data.It comprehensively determined the accumulation period and critical moment with the existing results.Based on the analysis of fault-transport system and sand body transport system,the fault-sand-source space matching relationship is determined with the analysis results of oil and gas distribution,drilling-logging displaying,reservoir pore evolution history and fault activity history.Transport grid space combination style was studied in the eastern slope of the western depression of the Sichuan basin during the critical time of reservoir formation.The geological conceptual model was established,and the spatial numerical model was constructed.To establish initial geological model the research studied power,channel and hydrocarbon expulsion model of hydrocarbon dominant migration at the critical time of reservoir formation.The application was based on the probability model of oil and gas migration numerical simulation technology.The application of oil and water distribution,distribution of oil and gas displaying,geological analysis results and other data was to test the results of distribution path of the dominant migration path of the reservoir period.The purpose are to found the distribution law,main controlling factors and the characteristics of Yanshanian gas reservoirs.