Low Interfacial Tension Behavior Between Organic Alkali/Surfactant/Polymer System and Crude Oil

摘要

Oil recovery has a great relationship with the interfacial tension (IFT) between displacing fluid and crude oil when using alkali/surfactant/polymer (ASP) aqueous solution to displace oil in reservoir. Alkali such as sodium hydroxide and sodium carbonate are often used to enhance the applied performances of surfactant and polymer. In this paper, two kinds of organic alkalis, triethylamine (TEA) and monoethanolamine (MEA), are applied together with Shengli petroleum sulfonate (SLPS) and partially hydrolyzed polyacrylamide (HPAM) to form two novel organic alkali/surfactant/ polymer (OASP) systems. The dynamic IFT is measured by using the spinning drop IFT meter. The optimum applied concentrations of SLPS, TEA, MEA, and three kinds of HPAM are selected by referring to the dynamic IFT between their aqueous solutions and oil. TEA and MEA both have synergistic effect and can reduce IFT to 10~(-3)mN/m or lower when they are used with SLPS. The formulae of two novel low IFT OASP systems are obtained. These two OASP systems can reduce IFT to the value lower than 10~(-2)mN/m when they are prepared using the produced water. Some influencing factors such as salinity, temperature and shearing are tested by measuring the minimum IFT of OASP aqueous solutions and oil. The results show that two OASP systems both have good tolerance toward these factors. Core displacing experiment is also conducted and the results approve that two OASP systems both can enhance the oil recovery efficiently.