特低渗透油藏CO2非混相驱油机理研究

针对大庆油田树101井区特低渗透油层，结合油藏条件，通过一系列室内实验，确定了CO2驱油机理。研究表明：随着CO2注入量增加，溶解油气比、体积系数和膨胀系数增大，粘度降低，束缚水体积膨胀。在27MPa下注入CO2，地层油体积膨胀1.4847倍，残余油饱和度降低11.43%，地层油粘度降低到原粘度的48.51%，束缚水体积膨胀1.1324倍。同时当地层压力从27Mpa降低到原始地层压力后，依靠溶解CO2膨胀能，可采出原油15.49%。此外，注入CO2后，CO2-地层油的界面张力降低，CO2可使地层油中的轻质烃抽提和汽化，从而提高采收率。

The Study on CO2 Immiscible Mechanism in Low Permeability Reservoir

Because shu101 well area of Daqing Oilfield is low permeability reservoir, I combined with reservoir conditions, through a series of laboratory experiments to determine the CO2 flooding mechanism. Research shows that with the increased CO2 injection, dissolved gas oil ratio, volume expansion coefficient and coefficient increases, viscosity decreases, bound water volume expansion.When injection CO2 with 27MPa, 1.4847 times the volume expansion of oil formation, the residual oil saturation decreased 11.43%, formation of oil viscosity decreases the viscosity of 48.51% to the original, bound water volume expansion 1.1324 times. At the same time reducing the formation pressure from 27Mpa to the original formation pressure, the expansion will depend on dissolved CO2 can be taken out of crude oil 15.49%. In addition, after the injection of CO2, CO2-formation reduces the interfacial tension of oil, CO2 can lead light hydrocarbons in the formation of oil extraction and vaporization, thereby improving oil recovery.