Phase inversion and rheological behavior of emulsions stabilized by silica nanoparticles and nanoclay

Abstract In this work, the phase inversion and stability of O/W emulsions stabilized by solid particles in the presence of salt is investigated for improved oil recovery at high pressure and high temperature conditions. The phase inversion of particle-stabilized emulsions from W/O to O/W can be achieved by adding different concentrations of solid particles. As model system, emulsions are formed with aqueous dispersions of solid particles containing a low concentration of salt (NaCl), paraffin oil and naphthenic acid as surfactant. The stability of the emulsions is analyzed close to inversion conditions, using a high-pressure conductivity sensor. Stability of O/W emulsions is investigated in the range from 40 °C to 80 °C and at pressures up to 80 bar. The results clearly show that the inversion to O/W emulsions leads to a lower viscosity. Thereby, the high potential for Enhanced Oil Recovery (EOR) is demonstrated.