A novel foam formulation by Al2O3/SiO2 nanoparticles for EOR applications: A mechanistic study

Abstract

Abstract In this study, the influence of Al2O3/SiO2 nanoparticles (NPs) on the Cetyl Trimethyl Ammonium Bromide (CTAB) foam formation and stability is investigated for enhanced oil recovery (EOR). The optimum foaming concentration of CTAB in the presence of heavy crude oil was first determined via visual foam stability inspections for different CTAB concentrations. The results of these sets of experiments were used to find out an appropriate CTAB: Al2O3/SiO2 NPs concentration ratio for foam stabilization through spectroscopy measurements. Different static analyses, including zeta potential, contact angle, and interfacial viscosity measurements were conducted to support the observations in the porous media during flooding. Improved foam stability in the presence of crude oil was observed with Al2O3/SiO2 CTAB foam via electrostatic adsorption of positive CTA+ molecules onto the negatively charged NPs at the appropriate concentration ratio of CTAB: NPs. Contact angle measurements showed a similar glass wettability alteration from an oil-wet (155 ± 3°) to a water-wet condition (19–29°) for all blends of CTAB and Al2O3, SiO2, or Al2O3/SiO2 NPs. Foam/heavy crude oil interfacial viscosity measurements increased with the addition of NPs to the foam solutions, indicating an improved foam bubble deformability, viscoelasticity, and stability, which was consistent with the foam behavior in the porous medium. Oil displacement studies in the glass micromodel showed the highest ultimate and incremental oil recovery of 92% and 73% OOIP, respectively, for Al2O3/SiO2 CTAB foam injection in the dual permeability porous medium. Some new forms of conventional foam mechanisms in the porous medium were also observed during the injection of Al2O3/SiO2 CTAB foam, which are believed to be the possible reason for this high ultimate oil recovery. These results prove the efficient role of Al2O3/SiO2 NPs in enhancing the foam performance via synergistic effects of NPs and CTAB.