In order to clarify the effect of extraction on miscible pressure during CO

2

flooding and make clear the characteristics of minimum miscible pressure of gas front or after gas sweep

the CO

2

extraction rate under different pressure and the distribution characteristics of oil components in the extraction process are studied by the extraction experiments under high temperature and chromatographic analysis. The changes of minimum miscible pressure of extracted oil and residual oil are quantitatively analyzed by the interfacial tensio

n vanishing method. Under the experimental condition of 95 ℃ and 10 ~ 45 MPa

the supercritical CO

2

can extract the components of each carbon number of the crude oil

and more than 80 % of the extracted oil is C

5-20

. The extraction rate of supercritical CO

2

and the minimum miscibility pressure of extracted oil and residual oil are positively correlated with the extraction pressure. Under the influence of extraction and pressure

the minimum miscible pressure in the CO

2

displacement and migration process is a dynamic value

which reduces in the following order: residual oil

crude oil and extracted oil. The minimum miscibility pressure of extracted oil and residual oil is related to component distribution. The critical components affecting miscibility in formation oil are C

5-10

and C

26+

components. The study result provides good reference for CO

2

miscible displacement design and miscible phase prediction.