Investigation of a novel enhanced stabilized foam: Nano-graphite stabilized foam

Abstract

To solve the problem of poor stability of ordinary foam in high-temperature conditions, nano-graphite (NG) was used in this study as a foam stabilizer to enhance stability. First, the foam was statically evaluated by the stirring method, and the influence of surfactants, NG, and temperature on foamability and stability were evaluated. Then, the surface tension, apparent viscosity, micromorphology, and contact angle of the foam were measured using a rheometer, microscope, and contact angle measuring instrument. Finally, the plugging ability of the foam was evaluated through a water flooding experiment. The results showed that the synergistic effects of nano-graphite and surfactant significantly improved foam stability, and the best surfactant and nano-graphite concentrations were determined. Compared with ordinary foam, NG-stabilized foam had better stability with increasing temperature. Using the apparent viscosity, surface tension, micromorphology, and contact angle, the mechanism of nano-graphite stabilization of foam was explained: the mixture of NG and surfactant formed a small number of flocs, which increased the apparent viscosity of the foam. Nanoparticles were adsorbed on the gas–liquid interface, which increased the thickness of the liquid film, improved the mechanical strength of the liquid film, and delayed the drainage of the liquid film and the coalescence of bubbles, thereby improving the stability of the foam. After injecting foam, the pressure difference generated by NG-stabilized foam was approximately twice that of ordinary foam, showing stronger plugging ability.