Investigating synergistic effects of surfactants and nanoparticles on emulsion stability

Abstract

A challenge of making oil production viable is emerging with time because most of the oil reserves have been exploited using primary and secondary recovery methods. Chemicals such as surfactants have been used to increase oil production through a method called chemical enhanced oil recovery. However, the application of this method is experiencing difficulties because of excessive use of surfactants that not only has negative effect on the economics of the project, but also poses severe environmental concerns. Another method that is being widely proposed is to apply emulsion flooding to enhance oil production. In order to maximize the impact of this method and as a result achieve higher oil recovery factor, it is vital to maintain the stability of the emulsion used. One of the claimed methods to improve the stability of emulsion is the application of synergistic effect between nanoparticles (NPs) and surfactants. This article aims on investigating the stability of emulsion using bottle test when applying the synergistic effect between NPs and surfactants with varying concentrations of the NPs, and surfactant charge. An anionic surfactant - sodium dodecyl sulphate (SDS) and a cationic surfactant - cetyltrimethylammonium bromide (CTAB) have been utilized in this study. Nano-silica was selected as the NPs used in this study. It was found that synergistic effect is more prominent between SDS and nano-silica with decrease in emulsion phase height percentage (measure of emulsion stability) going down to 22% compared with 43% for combination of CTAB and nano-silica, and 51% in case of using only surfactants. This has proved that the synergistic effect is beneficial in enhancing the emulsion stability, which can be implemented in the application of emulsion flooding where the stability of the emulsion is crucial.