Study On Alkalescent Alkaline/Surfactant/Polymer(ASP) Flooding To Enhance Oil Recovery And Influential Factors

In recent years, field test and industrialized application of alkaline/surfactant/polymer (ASP) flooding has carried out in oilfields such as Daqing, Shengli, Xinjiang and Liaohe, which has obtained obvious effect of increasing oil and decreasing water and good economic efficiency. But in actual application process, there have been some problems of alkaline alkaline/surfactant/polymer (ASP) flooding, for example, alkali can not only decrease viscosity controlling capacity of polymer solution, but can also cause scaling of well bore and surface production system and emulsification of production fluid, which bring tremendous trouble to oilfield ordinary production and restrict the large-scale extending application of ASP flooding seriously. Recently, in order to lessen adverse effect of alkali on viscosity, emulsification of production fluid and scaling, alkalescent ASP is adopted to replace alkali ASP flooding in oilfields. Study on interfacial tension, viscosity, scaling degree and production behavioral characteristics is not much, and some problem in experiment process also affects the ordinary test. Therefore, carrying out indoor study and effect analysis of field test on property of alkalescent ASP system has important theory significance and application value for perfecting alkalescent ASP technology. On the basis of existing research results, making use of apparatus monitoring, physical simulation and theory analysis method, experiment study on viscosity, variety characteristics of interfacial tension, adsorption, chromatographic resolution characteristic, transmission and migration capability, flooding effect and influence factors and analysis of injector-producer wells behavioral characteristics of alkalescent ASP system were conducted. The results show that temperature, time, shearing action and dilution times can affect viscosity of alkalescent ASP system, concentration of alkali and surfactant and time can effect interfacial tension. The higher the concentration of polymer, alkali and surfactant are, the higher the flowing resistance is, the worse the transmission capability of alkalescent ASP system is, and the stronger the diffluence turning capability is. The higher the viscosity is, the lower the interfacial tension is, the more the hold-up volume of chemical agent is, the better effect of increasing oil of ASP flooding is. For inhomogeneous reservoir, contribution of flooding agent to recovery of enlarging swept volume capability is more important than that of washing oil capability, and the more severe of heterogeneity is, the more obvious the phenomenon is. Moreover, the results show that alkalescent ASP system can form scaling in injection system, around well face, and stratum, which is main reason causing increasing of injection pressure and decreasing liquid absorption. In early stage of injection of alkalescent ASP system, scaling in high permeable layer of injection well can improve fluid entry profile, but it will affect fluid entry profile with injection time increased.