Characteristics of deep gas transportation in Changling Fault Depression, Songliao Basin

There are four deep transportation types in the Changling Fault Depression: fault,sandstone,fracture and unconformity surface.Faults are the main pathways for gas vertical migration.Sandstones which interbed with source rocks are the main pathways for gas lateral migration.Fractures in volcanic rocks provide favorable pathways for gas migration,which is the controlling factor for the effectiveness of volcanic reservoirs.The effectiveness of deep transportation system in the Changling Fault Depression is affected by the matching of hydrocarbon kitchen location and hydrocarbon generation and expulsion stages as well as the matching of gas migration pathway and transportation system.The transportation system which exists during hydrocarbon generation and expulsion stages and is connected along favorable migration pathways is critical for gas accumulation.Closely related to the time and space distributions of transportation system,natural gas is widespread laterally and is found in multiple layers vertically.Fault transportation close to source rocks is the most common transportation way for volcanic reservoirs in the Changling Fault Depression,which controlls the regular migration pattern of deep gas.Gas migrates along faults and accumulates nearby.