The re⁃injection block containing the sewage in the Xing 13 area is affected by the residual polymer,which leads to a decrease in the water absorption effect of the block and affects the development effect of the oil field. Therefore,the formulation and supporting process parameters of the depressurization and infusion injection of the sewage⁃containing block were studied.Firstly,the total water quality of injected water was analyzed; Then the petroleum sulfonate was used as the basic agent to screen the compounding agent and additives by measuring the interfacial tension;After the performance evaluation of the system, the indoor core flooding experiment was carried out to optimize the injection parameter.The results show that the optimal formulation of the anti⁃hypertensive surfactant is(mass fraction):0.7% petroleum sulfonate+2.0% HABS+0.5% absolute ethanol+1.0% NaCl,and the interfacial tension between the crude oil and the interfacial tension is 6×10-3 mN/m.In the core flooding experiment,the optimal injection rate is 0.15 mL/min,the optimal injection volume is 1 PV,and the optimal slug combination is 0.5 PV+0.3 PV+0.2 PV. Under different permeability conditions,the pressure rate is more than 24%.