The effect of nanoparticle types on carbon dioxide foam flooding in enhanced oil recovery

Abstract

Carbon dioxide (CO2) flooding is a well-established and extensively used enhanced oil recovery technique. However, the mobility of the CO2 in the reservoir is higher than the mobility of crude oil which viscous fingering and gravity segregation problems always occur during CO2 injection. To overcome these problems, foams has been used to improve displacement efficiency because foam has high viscosity and low mobility. Although surfactants are good foaming agents, there are several weaknesses on surfactant-stabilized foam which are high surfactant retention in porous media, relatively low foam stability and degradation of surfactant at high reservoir pressure and temperature. However, nanoparticles (NPs) properties such as being solid, able to withstand high temperatures and very small size can be utilized to improve foam stability. The main objective of this project was to investigate CO2 foam performance at various concentrations of different types of nanoparticles ((Silicon Dioxide, Aluminium Oxide, Titanium Dioxide and Copper Oxide in the presence of fixed concentration of surfactant (0.5 wt% of AOS) and salinity (2 wt% of NaCl). In this study, experiments were divided into two parts. The first part was to investigate foam stability at various nanoparticle concentrations (0.1 wt%, 0.3 wt%, 0.5 wt% and 1 wt%), whereas, the second part was the displacement test for determining oil recovery at the optimum concentrations for each nanoparticle. The results revealed that all nanoparticle types used were able to improve the stability of CO2 foam at certain concentrations. However, the optimum concentration was found at 0.1 wt%. It was clearly observed that the introduction of higher nanoparticle concentrations decrease the foam stability for all nanoparticle types. Furthermore, the oil recoveries were 14% by Al2O3 NPs, and 11% by SiO2 NPs. Meanwhile, both TiO2 and CuO NPs recovered about 5%. The recovery results matched with the stability results for all types of nanoparticles used.