Abstract

Foam Assisted Water-Alternating-Gas (FAWAG) flooding is one of the enhanced oil recovery (EOR) technique that had been explored and studied worldwide. The ability of foam to lower the gravity override and create a macroscopic sweeping of oil in the reservoir shows its potential to be a successful technique. However, the rapid degradation of foam at high temperature condition in the presence of light crude oil limits its application. Therefore, introduction of an additive to the surfactant is crucial to maintain foam stability. Nano-scale particle is a well-known material that has attracted a lot of attention due to its unique physiochemical properties. This high surface energy particle has shown to exhibit a catalytic behaviour in various application including EOR chemical flooding. In this study, the effect of four different types of nanoparticles, SiO2 (hydrophilic), SiO2 (hydrophobic), ZnO and TiO2 nanoparticles on foam stability under high temperature condition, and in the presence of light crude oil were investigated. Results from this study has shown that SiO2 nanoparticles of the hydrophilic type at concentration three times lower than the surfactant concentration have significantly improved the foam half-life by 2 times longer than the surfactant alone at temperature of 110°C, in the presence of light crude oil (45° API). No improvement of foam half-life was shown by ZnO nanoparticle used in the surfactant formulation. The presence of SiO2 (hydrophilic) nanoparticles have significantly reduced the detrimental effects of light crude oil and strengthen the foam by increasing the viscosity of surfactant from 4.38 cP to 10.01 cP in the presence of 0.15 wt% SiO2 (philic) nanoparticle. The significant increment in viscosity has maintained the wetness of foam, thus reducing the rate of liquid drainage at the temperature above boiling point of water. The SiO2 (hydrophilic) nanoparticle-surfactant formulation was observed to have produced uniform sized bubbles compared to surfactant formulation alone. This indicates that nanoparticles are able to restrict shrinkage or expansion of bubble by creating a steric layer at the lamella structure which consequently restores the foam stability. The foam stability tests, determined as foam-half-life, were performed using inert nitrogen gas as the gas phase to eliminate other factors that may affect foam stability.

This content is only available via PDF.
You can access this article if you purchase or spend a download.