Keywords: 
• hydrocarbon /
• migration /
• minimum /
• saturation /
• essentia /
• l

Abstract: Based on the microscopic features of pore structure,this article quantita tively discusses several essential problems about hydrocarbon migration principl e in petroleum geology.It mainly investigates the primary pore structure charact eristics,fluid properties and direction of hydrocarbon migration as well as the hydrocarbon migration behaviors in the reservoir of the homogeneous pore structu re and in the reservoir which has the various combinations of heterogeneous pore structure.The conclusion could enrich and supplement the theories of petroleum geology (1) Only under certain condition can the hydrocarbon migrate.It includes pore s tructure and fluid condition.The former is the coordination number is bigger tha n or equal to 2 and the pore throat which the hydrocarbon immigrant by.The latte r is fluid number reaching saturation of hydrocarbon migration. (2) The diversification of microscopic pore structure in reservoir cause that th e hydrocarbon migrates in multi-direetion.The trend of the hydrocarbon migratio n is upward,but when the coordination number is bigger than 2,it may migrate upw ard as well as updip. (3) The hydrocarbon migration show heterogeneity of the hydrocarbon migration d irection,saturation and height of oil column in heterogenous reservoir which por e structure is complex.