Abstract: In the migration process of oil and gas,the liquid's features may change because of oxidation-deterioration and thermal-deterioration and the change of the hydrodynamic force.So the information about the migration and preservation of oil and gas can be learned from the features of the liquids in formation.The results indicate that the fault can act as a passage for the liquid flowing,including oil and gas's migration and water's permeating.The flowing includes horizontal way along the formation.The permeating water obstructs the oil and gas migrating and disappearing.The Cainan North Fault and Cainan Fault in Jurassic Xishanyao Formation are not belong to one hydrodynamic force system,and the hydrodynamic force is weaker in the west of the Cainan North Fault than in other areas.The weaker hydrodynamic force is good for the hydrocarbon preservation.The Jurassic Badaowan Formation is one hydrodynamic force system in the west of the Cainan North Fault and the Cainan Fault,and the higher water salinity is good for the preservation of oil and gas.