Experimental Study On Improving Recovery Efficiencecy Of Weak Alkali ASP Flooding With Different Surfactors

At persent,ASP flooding has been the dominant recovery technology in Daqing oilfield.ASP flooding include strong alkali ASP flooding and weak alkali ASP flooding.Weak alkali ASP flooding is gaining increasing attention because of the damage and scaling of formation.Therefore,the research of weak ASP flooding on recovery factor has a guiding significance for further development of oilfield.In this paper,three kinds of surfactants were selected,namely,petroleum sulfonate,controlled variable alkyl benzene and lipopeptide.Among them,petroleum sulfonate and lipopeptide were used to form a complex system.The rheological properties,viscoelasticity,interfacial tension and influencing factors of weak alkali ASP system were studied by studying the performance of weak alkali ASP system.The different surface active agents were analyzed by measuring the resistance coefficient and residual resistance coefficient.Resulting in the weak alkali of the ternary system of liquidity differences;The mechanism of the start-up mechanism of residual oil was studied by visual etching of glass.In the homogeneous core core,the oil displacement experiment was carried out to study the effect of the type of surfactant,the concentration of the component and the size of the main slug on the recovery.The results show that the viscosity of the weak alkali ASP system is inversely proportional to the alkali concentration,and the addition of the alkali will decrease its viscoelasticity.The surfactants decreases and then increases the viscosity of the weak alkali ASP system.The critical micelle concentration of the surfactant is the cutoff point.The viscosity of the ternary system has a negative effect on the viscosity of the weak alkali ASP system.The higher the temperature,the worse the viscosity is.The longer the storage time is,the greater the viscosity loss of the ternary system is,and the viscosity of the lipopeptide complex system is stable The worst sex.The interfacial tension of the weak alkali ASP system of three kinds of surfactants can reach the low interfacial tension level.In the interfacial tension activity diagram,the lipopeptide complex system maintains the most extensive interfacial tension concentration range.The resistance coefficient and the residual resistance coefficient of the weak alkali ASP system will increase after adding the surfactant.Through the microscopic visualization model,it is found that the emulsified oil droplet action is the most important way in the process of recovering residual oil by weak alkali ASP system.Increasing the concentration of petroleum sulfonate and weak alkali,increasing the amount of main slug injection,can effectively improve the recovery rate.