Hydrocarbon migration and accumulation are closed related with hydrodynamic field.In this paper

the hydrocarbon migration and accumulation mechanism of southern Dongpu Sag was analyzed in respect of the paleo-hydrodynamic evolution.Forming time of hydrocarbon reservoir was determined by analyzing the homogenization temperature of fluid inclusions

and then hydrocarbon charging process was restored.The results show that there are three hydrodynamic units in southern Dongpu Sag:centrifugal flow of mudstone compaction-released water developed in the east and west sub-sags

centripetal flow of meteoric water occurred in the Lanliao fault belt

and cross-formational flow and discharge area in the central uplifted belt.The later is the most favorable place for hydrocarbon accumulation.The sedimentary period of Dongying Formation(Ed)was the primary stage for hydrocarbon migrating to and accumulating in the bottom of down-thrown blocks of faults.The stage of Dongying tectonic uplifting was the main period of hydrocarbon adjustment.Hydrocarbons from the deep reservoirs formed in early stage remigrated to and accumulated in the shallow layers on structural high

forming the secondary oil reservoirs.The Guantao and Minghuazhen were the main periods for gas accumulation.Natural gas mainly accumulated in the deep strata of structural limbs

owing to the increasing sealing ability of faults

resulting in the "upper oil lower gas

top oil marginal gas" hydrocarbon distribution pattern.