Abstract:carbon dioxide flooding (CO2) is an effective means to further develop old oilfields with high water cuts and improve oil recovery based on tertiary oil recovery. Aiming at the gas channeling problem caused by the large viscosity difference between carbon dioxide and crude oil, a supercritical carbon dioxide thickener agent P-1 that can be applied to oil flooding was prepared. Through orthogonal experimental analysis, it is concluded that the amount of initiator has the greatest influence on the molecular weight distribution of the reaction, the optimal molar ratio of the synthetic monomer is 4:1:1, the molecular weight distribution is 1.12, and the yield is 88%. The synthesized product under optimal conditions was characterized by infrared characterization, and the characteristic absorption peaks matched the product. The evaluation results show that the saturation solubility of P-1 in supercritical carbon dioxide is 2.30%, and the minimum miscible pressure is 7.77Mpa.The thickener with a monomer concentration of 0.2% increased the viscosity of supercritical carbon dioxide by 42 times at 30Mpa, 50℃, the viscosity was 1.1675mPa.s, and the viscosity retention rate was 46.41%, while the temperature was raised to 110℃. Simulating the formation environment (15MPa), adding the thickening agent P-1 with a mass concentration of 0.2% can effectively improve the oil displacement effect of supercritical carbon dioxide flooding, and the lower the permeability, the more significant the extraction effect. In the same core, the total recovery degree of supercritical carbon dioxide flooding is more than 10% higher than that of supercritical carbon dioxide flooding after water flooding.