Relationship between characteristics of volcanic migration system and distribution of hydrocarbon in Huoshiling Formation, Longfengshan area

Key words:  volcanic rocks  distribution of hydrocarbon  faults  unconformity structure  effective transporting layer  migration system

Abstract:

Influenced by the tectonics and weathering leaching, the complex pathway networks developed in Huoshiling Formation in Longfengshan area, contists of fault, unconformity and effective transport bed, which affects the migration, accumulation and distribution of oil and gas. In Huoshiling Formation, two sets of upper and lower oil-bearing reservoirs are developed, and oil and gas are found in the plane from the northern depression belt to the western tectonic belt. By analyzing the distribution characteristics and evolution rules of different transport systems, the relationship between the transport system and oil and gas distribution is discussed. The results show that the horizontal and vertical distribution of oil and gas in the study area are closely related to the combination type and evolution process of the transport system. The early active faults and effective transport layers are important channels for oil to migrate to the western tectonic belt and form the lower oil-bearing strata, while the late faults, unconformity structures and effective transport layers are important transport systems for gas to migrate to the eastern slope belt and form the upper gas-bearing strata. The combination and evolution of the transport systems result in significant differences in the plane distribution of oil and gas, which is characterized by "early far source oil bearing, late near source rich gas".