Effect of Injection Water Quality on the Interfacial Tension of ASP/Crude OilEffect of Injection Water Quality on the Interfacial Tension of ASP/Crude Oil

摘要

ASP(alkali/surfactant/polymer)flooding has been successfully applied in several field pilots in Daqing oilfield in China.The oil recovery is improved by about 20%OOIP over recovery by water flooding.The interfacial tension(IFT)of ASP/crude oil is one of the most important factors that control the effectiveness of ASP flooding.The effects of alkali, surfactant,polymer and oil properties on IFT were previously studied.This paper addresses the effect of injection water quality on IFT of ASP/crude oil. This paper analyzes the inorganic ion compositions and organism compositions of injected waste water in different pilots in Daqing.The effect of these compositions and the suspension particles in injection water on IFT of ASP/oil were studied.A carboxylate surfactant was used in the study.All experiments were carried out at 45oC.Results showed that the suspension particles had little influence on IFT,inorganic ion compositions had some influence to some extent but were not the main factor affecting IFT for the low-salinity injection water used in ASP flooding in Daqing.The main factor increasing IFT is certain organisms in the injection water.The paper points out the main types of organisms influencing IFT.Some methods to lower IFT by controlling water quality are proposed.