STUDY OF FACIES AND POTENTIAL COUPLING EFFECT IN OIL AND GAS POOL FORMATION——A CASE STUDY IN THE JIYANG DEPRESSION, THE BOHAI BAY BASIN

Exploration practices in the Jiyang Depression of the Bohai Bay Basin have indicated that,under the same dynamic condition of oil and gas pool forming,resistivity(breakthrough pressure) of entrance and exit interface is different,so fluid enters reservoir and pore respectively.It is caused by reservoir property(facies),fluid dynamics(potential) and their coupling effect.Mechanism of the effect is discussed and pool-controlling model is set up.Critical terms for reservoir to hold oil and gas are pointed out.As reservoir getting shallow and far away from source bed,buoyancy and residual entry pressures of source rock reduce,oil-water interface tension increases,and critical permeability and porosity for reservoir to hold hydrocarbon gradually increase.Thereby,critical qualification forecast model of pool forming is set up to enrich exploration theory and method in continental fault basins.