Effect of magnetic field treatment on interfacial tension of CTAB nano-emulsion: Developing a novel agent for enhanced oil recovery

Nanoemulsion is a novel type of emulsified solutions holding great promises for utilizing in industrial applications. Although microemulsions have been the subject of numerous studies in past decades, however, nanoemulsions are quite virgin and merit detailed investigation to scrutinize their characteristics specific to reservoir engineering, in particular, Enhanced Oil Recovery (EOR). To this end, the present study is an attempt to evaluate the effectiveness of a specific nanoemulsion for oil displacement through porous media. In this regard, flooding experiments were designed and Hexa decyl trimethylammonium bromide (CTAB), which is a cationic surfactant, was used as the emulsifying agent. Throughout experiments, surface tension together with incremental oil recovery was measured. Besides flooding experiments, to explore the effect of magnetic field on macroscopic behavior of CTAB solution, all procedures were replicated by exposing CTAB solution under magnetic field with varying intensities. Encouraging observations demonstrated the concealed capability of CTAB nanoemulsion for improving the performance of conventional waterflooding process. Additionally, it was pointed out exposing CTAB solution into magnetic field slightly increased oil/nanoemulsion IFT. However, it resulted in fairly higher oil recovery than the non treated case. Since both cases were of nearly identical IFT and wettability, so we concluded that nanoemulsion is of higher viscosity while exposing to the magnetic field, which in turn gives rise to lower mobility ratio during flooding process. (C) 2018 Elsevier B.V. All rights reserved.