Feasibility Study On EOR Of Carbonated Water Injection For Daqing Punan Oil Field

The physical properties of some blocks in Punan oilfield are poor,and the recovery of depletion and water injection is low.Therefore,it is urgent to explore effective methods to improve the oil recovery.The reservoir permeability ranges from 0.1×10^-3?m² to 10×10^-3?m²,and the porosity ranges from 10%to 15%.Sensitivity analysis experiments were carried out.The experimental results show that the velocity sensitivity was moderately strong,the water sensitivity was moderately strong,the acid sensitivity was moderately weak,the CO₂ sensitivity was weak,and the carbonated water sensitivity was weak.In the field development,the injection fluid velocity and salinity should be controlled,and the sensitivity of the reservoir to acid,CO₂ and carbonated water should not be considered.On the basis of reservoir sensitivity evaluation,the experimental study investigated the EOR of carbonated water.Comparing displacement results of different methods,for the target oil field,the EOR method of carbonated water is feasible.The optimizing methods of carbonated water are carbonated water+surfactant injection and active carbonated water alternating gas injection.Sensitivity analysis investigated factors for EOR performance of carbonated water,including surfactant concentration,carbonated water concentration,and amount of active carbonated water alternating gas injection.Considering the effect of EOR and economic factors,the surfactant concentration is 0.1 wt%,the carbonated water concentration is 0.41 mmol/cm³,and amount of active carbonated water alternative injection is 0.8 PV.This study provides theoretical basis and technical support for the efficient development of Daqing extra-low permeability and tight reservoir.