Study On The Effect Of Weak Base ASP System On Residual Oil In Porous Media

At persent,ASP flooding has been the dominant recovery technology in Daqing oilfield.ASP flooding include strong base ASP flooding and weak base ASP flooding.Weak base ASP flooding is gaining increasing attention because of the damage and scaling of formation.At present,compared with the advanced research level of western countries,the basic research of surfactant in China has a very clear drop.The importance of surfactant in the process of oil recovery and oil displacement has been very well understood,and more and more attention has been paid to the preparation of surfactants with superior performance,obvious effect and low cost.Therefore,the study of the influence of the weak base ASP system of different surfactant types on the oil displacement effect is of guiding significance for selecting the appropriate oil displacement system and improving the recovery of the oil field.In this paper,rheology,interfacial tension,interfacial viscosity and influencing factors of weak base ASP system were studied.Secondly,the formation mechanism and start-up mechanism of microscopic residual oil after water flooding are studied by visualization flooding systems.In the third point,the paper analyzed the starting and migration of the residual oil by different ASP systems,studied the oil displacement effect of the three kinds of ASP system in the homogeneous model and the heterogeneous model.The experimental results showed that: The interfacial tension of ASP system decreases with the increase of surfactant concentration,and the interfacial tension of ASP system decreases with the increase of alkali concentration.The interfacial viscosity of ASP system decreases with the increase of alkali concentration.The interfacial viscosity is an important factor affecting the emulsifying ability of the ASP system.Under the same interfacial tension,the lower the interfacial viscosity,the stronger the emulsifying ability,the better the oil displacement effect.In homogeneous models,oil recovery decreases with decreasing permeability.In heterogeneous models,oil recovery decreases when the permeability ratio increases.The stronger the emulsifying ability of ASP system is,the smaller the decline of oil recovery will be.In the ASP systems studied in this paper,the composition of the component controlled alkyl benzene system is the highest,the lipopeptide / petroleum sulfonate compound system is second,and the oil sulfonate system has the worst oil displacement effect.