Pore scale experimental and numerical study of surfactant flooding for enhanced oil recovery

Abstract

Surfactant flooding is a traditional method to enhance oil recovery. The surfactant flooding experiment based on glass etching model allows researchers to observe directly how the remaining oil is displaced by surfactant through microscope, so as to explore the mechanism of surfactant enhanced oil recovery. However, microscopic experiments mostly stay at the level of physical experiments, and the operation of physical experiments is too complex and cumbersome. This study is the first to combine surfactant flooding experiment with numerical simulation in glass etching model. Firstly, based on the real pore and throat structure of the real low permeability reservoir core, the glass etching model was developed, and the micro-oil-water displacement experiment was carried out. Through microscopic observation and analysis, combined with testing and image processing technology, the effect of water flooding was quantitatively investigated. Then the surfactant flooding was carried out. Three surfactants were used for displacement. It was found that residual oil in pore network was greatly reduced. The recovery factor has been greatly improved. Finally, numerical simulation of water flooding and surfactant flooding based on micro-physical experiment was carried out. The results of numerical simulation were compared with the experimental results. It is found that the recovery factor and the form of residual oil are basically the same. By analyzing the results of numerical simulation of oil recovery, it is found that the extent of surfactant enhancing oil recovery is different under different interfacial tension. The results showed that the surfactant with interfacial tension of 0.22 mN/m has the highest ability to enhance oil recovery. This work provides a reference for surfactant selection in oilfield development. It can select the best surfactant according to the factors of time, efficiency and cost.