INVESTIGATION ON PREDICTION METHODS OF FAVORABLE AREA FOR PETROLEUM MIGRATION AND ACCUMULATION——TAKING THE DONGYING SAG OF BOHAI BAY BASIN AS AN EXAMPLE

Integrated researches of formation pore fluid pressure field on main geological evolution stages occurred in the Dongying Sag of the Bohai Bay Basin,its exploration status and sedimentary characteristics,sandstone rebounding amount caused by the erosion unloading during the Dongying phase of the Oligocene and the Minghuazhen phase of the Pliocene and their interaction analysis of formation pore fluid paleo-pressure field,the paper proposes 2 more effective methods of predicting hydrocarbon migration and accumulation for petroliferous basins which are mainly composed of sandstone and mudstone.Two methods are follows as:1)Predicting favorable direction of petroleum migration based on dynamics research of pressure field differentiated of hydrocarbon rocks reservoir area at stages of basin uplift denudation after forming hydrocarbon by sustainable subsidence;2)Predicting favorable zones of hydrocarbon accumulation based on dynamics research of sandstone rebounding amount at stages of basin uplift denudation after forming hydrocarbon by sustainable subsidence,and meanwhile,combining with the distribution of reservoir cap rocks at the same stage in geological time.