Slightly hydrophobic silica nanoparticles for enhanced oil recovery: interfacial and rheological behaviour

Abstract

This paper is aimed at studying AEROSIL® R816 nanoparticle behaviour to see if it has enough feasibility to be used as a chemical agent in enhanced oil recovery (EOR) processes. The main focus is on interfacial and rheological behaviour of this particle in aqueous and polymeric media. Interfacial tension measurements between aqueous nanoparticle suspensions and oil showed that AEROSIL® R816 particles were able to reduce the interfacial tension between water and oil to half of its original value. This property led to development of stabilised oil in water emulsions. Moreover, viscosity measurements showed that AEROSIL® R816 had a great ability in rheology modification of aqueous solutions. The solution viscosity was studied as a function of nanoparticle concentration and shear rate. It was seen that viscosity rose as the nanoparticle concentration was increased. From the standpoint of shear dependency, two regions of shear thinning behaviour were observed for different shear rate regions. Finally, by dissolving a fixed amount of a low molecular weight polyacrylamide into nanoparticle suspensions of different concentrations, the stability of R816 suspensions was significantly improved. This addition also resulted in almost considerable enhancement of nanoparticle thickening property.