Investigation on the effects of AlOOH nanoparticles on sodium dodecylbenzenesulfonate stabilized o/w emulsion stability for EOR

Abstract

Emulisons stabilized by surfactants have been used in enhanced oil recovery (EOR) for effective profile control and displacement, whereas the lack of long-term stability especially under harsh reservoir conditions limited their wide application. In this study, Pickering emulsions stabilized by sodium dodecylbenzenesulfonate (SDBS) and anisotropic slice-like AlOOH nanoparticles were systematically studied. The adsorption of SDBS on AlOOH nanoparticles was confirmed by the measurements of zeta potential and Fourier Transform Infrared (FTIR) spectra. The three-phase contact angle tests were conducted to explore the reason for the double phase inversion of the AlOOH/SDBS stabilized emulsions from o/w to w/o and back to o/w again. The optical microscopy images verified the adsorption mechanism of SDBS on AlOOH nanoparticles at the oil/water interface. It was found that the three-dimensional network structure formed by the micro-flocculated modified AlOOH nanoparticles could prevent coalescence and phase separation, resulting in the enhanced stability of the emulsion. The AlOOH/SDBS stabilized emulsion showed the super tolerances in a wide range of shear rates, temperature and electrolyte concentrations. The core flooding tests and microscopic visualization flooding experiments demonstrated that the AlOOH/SDBS stabilized emulsions significantly improved the tertiary oil recovery (33 % of IOIP) via the enhanced displacement and sweep efficiencies. The present study provides a typical Pickering emulsion with great stability under harsh reservoir conditions for EOR.