Properties of multi-phase foam and its flow behavior in porous media

Abstract

Aqueous foams were produced with partially hydrophobic SiO₂ nanoparticles and sodium dodecyl sulfate (SDS) dispersions. The injection behavior of SiO₂ stabilized foam (SiO₂/SDS foam) was analyzed and compared with SDS stabilized foam (SDS foam). The experimental results showed that the SiO₂ nanoparticles and SDS surfactants had a synergistic effect on foam stability at proper SDS concentration. And the effect was accompanied with a slight decrease in foam volume. The adsorption of nanoparticles on the bubble surface was confirmed by laser-induced confocal fluorescence microscopy. And the effect of absorbed nanoparticles on bubble surface viscoelasticity was also verified by the interfacial dilational rheological measurement. The dilational viscoelasticity increased with increasing SiO₂ concentration, corresponding to foam stability. The plugging flow experiment demonstrated that the maximum differential pressure in SiO₂/SDS foam flooding was 1.9 MPa, much higher than that in SDS foam flooding. The SiO₂/SDS foam had better diversion properties and resistance to water flushing than SDS foam. In the oil displacement experiments, SiO₂/SDS foam could reduce the residual oil saturation noticeably. The enhanced oil recovery and the final oil recovery could reach to 41.2% and 75.7%, respectively. It was deduced that the enhanced foam stability and dilational viscoelasticity were the main reasons for the effective performance in porous media.