Multiphase belt discrimination method based on spatial and temporal change characteristics of CO2-drive reservoir fluid

The embodiment of the invention provides a multiphase belt discrimination method based on spatial and temporal change characteristics of CO2 drive reservoir fluid. Comprising the following steps: acquiring phase state data of formation fluid at a to-be-observed position and oil saturation of an oil reservoir; inputting the phase state data into a numerical simulation component model to output fluid characteristic parameters of the formation fluid; the oil saturation of the oil reservoir and the fluid characteristic parameters are input into the reservoir geologic model, and the production pressure of the production well module is set to be preset pressure; the CO2 injection amount of the injection well module is sequentially changed, so that a first CO2 oil displacement parameter corresponding to the CO2 injection amount each time is output through the reservoir geologic model; and different phase belt distribution characteristics between the injection well and the production well are determined according to