The invention relates to a method for reducing the minimum miscible phase pressure between CO2 and
crude oil of miscible
phase displacement of CO2-containing oil deposits, overcoming the defect that the minimum miscible phase pressure between the CO2 and the
crude oil is high, so CO2-containing miscible
phase displacement cannot be achieved. In the technical scheme, surfactant
slug is injected into an
oil well at first, and when surfactants are dissolved in the in-place oil, the
viscosity of the in-place oil is reduced to the
viscosity range of the CO2-containing miscible
phase displacement; and CO2
slug is injected under the pressure of 18.00-23.00 MPa, and since the surfactants injected at first can be dissolved in the supercritical CO2, the interface tension between a
gas phase and an
oil phase can be reduced rapidly due to the surfactants after injection of the CO2, the minimum miscible phase pressure between the CO2 and the
crude oil can be reduced, the miscible phase can be achieved rapidly, and the miscible phase displacement can be realized. The invention has dual characteristics of reducing the
viscosity and decreasing the minimum miscible phase pressure; the consumption of the surfactants and the cost are low; and the
recovery rate of the crude oil is 5-14 percent higher than the
recovery rate in the pure CO2 displacement under the same pressure.