Visualization experiments on the impact of surfactant and nanoparticle on EOR potential of foam injection

Foam generation is one of the most promising techniques to overcome gas mobility challenges and improve the sweep efficiency of reservoir fluids. The synergistic effect of surfactant and nanoparticle can help produce a stronger and more stable foam in reservoir porous media. In this study, nanoparticle stabilized foam experiments were performed in micromodel, at elevated temperatures and pressures to investigate the flow behavior and displacement mechanisms for enhanced heavy oil recovery. Both surfactant and a mixture of surfactant and nanoparticle were able to enhance oil recovery. The surfactant foam was able to bring the oil recovery to 54% of the original oil in place (OOIP). In contrast, the presence of nanoparticle resulted in higher oil recovery, 59% of the OOIP. The synergistic effect between nanoparticle and surfactant resulted in no significant reduction of the oil-water IFT. As a result, a bank of oil-in-water (O/W) emulsion was formed in the porous medium and moved in front of the surfactant-nanoparticle foam front. The in-situ generated O/W emulsion has a much lower viscosity than the original oil and plays an important role in the observed additional oil recovery.