Stability of nanoparticle stabilized oil-in-water Pickering emulsion under high pressure and high temperature conditions: comparison with surfactant stabilized oil-in-water emulsion

Stability of oil-in-water emulsions under high pressure and high temperature (HPHT) conditions has a significant interest in upstream oil and gas industrial applications. Such emulsions are generally stabilized with surfactants, which are thermodynamically unstable under HPHT conditions. Alternate to surfactants, the addition of nanoparticles has emerged as a method for emulsion stabilization, known as Pickering emulsion. In this work, a comparative study of the stability of silica nanoparticle (Ludox CL) stabilized Pickering emulsion against surfactant SDS (sodium dodecyl sulfate) stabilized emulsion under HPHT conditions has been explored. The stability of the emulsions was measured in terms of change in emulsion droplet diameter. Subsequently, emulsion samples are aged under different pressure and temperature conditions in an aging cell for 24 hours. The emulsion mean droplet diameter increases with an increase in temperature. The magnitude of change in the mean droplet diameter of aged SDS stabilized emulsion is higher as compared to Ludox CL stabilized emulsion under varying pressure (0.1–10 MPa) and temperature (303–363 K). It can be concluded that Ludox CL stabilized emulsion shows better stability as compared to SDS stabilized emulsion under HPHT conditions. Hence, emulsion stabilized by Ludox CL nanoparticle may withstand harsh reservoir conditions and can be used for enhanced oil recovery applications.