Abstract:
Enhanced oil recovery especially alkaline-polymer flooding is an important technique to improve oil recovery. It involves the injection of alkali to reduce the interfacial tension (IFT) between oil and water, and the injection of polymer to improve mobility ratio to produce more oil. In this study, the interfacial tension of light oil from Fang oilfield with alkaline-polymer solution will be measured and the effects of parameters such as pressure, temperature, salinity, types of solution and solution concentration on the interfacial tension are investigated. The results present that pressure has less effect on the interfacial tension because the experiment is in the liquid phase. For the effect of types of alkaline solution, strong base has higher performance in lowering the interfacial tension compared with weak base because strong base can completely dissociate in the solution so that the amount of ions are higher. This results in the higher amount of the in-situ surfactant and thus lowering more interfacial tension. Concentration of alkali plays a key role in the interfacial tension reduction accounting for 99.49%. Interfacial tension reduces with the increase of temperature for every type of the solution. Increasing polymer concentration tends to increase the interfacial tension. Salinity can increase the interfacial tension at low alkali concentration while decrease the interfacial tension at high alkali concentration. Divalent ions have low impact on the interfacial tension. The results can be used as the fundamental data for future studies such as the core flooding test and simulation for enhanced oil recovery.
