Aggregation of Partially Hydrophilic Silica Nanoparticles in Porous Media: Quantitative and Qualitative Analysis

Abstract

In this experimental work, the adsorption of partially hydrophilic silica nanoparticles, SiO2 has been investigated to determine the degree of silica nanoparticle aggregation in the porous media. An integrated quantitative and qualitative method was used by flowing silica nanoparticles into Buff Berea cores and glass micromodel. Water wet Buff Berea cores were flooded with 5 pore volumes of 0.05% silica nanoparticles solution followed by 10 pore volumes of brine post flush subjected to 30 and 60°C. The pressure drops increased rapidly at the initial stage of silica nanoparticles injection indicated the adsorption had taken place. Pressure drops reached the maximum value of ~3.1 psi and between 26.6–82.6 psi at 30 and 60°C respectively. Pressure drops gradually declined and stabilized in between ~0.4 and ~0.7 psi after couple of pore volumes of brine post flush, suggesting complete reversible and irreversible adsorption. Micromodel test provide qualitative information where the straining or log-jamming observed in the form of gelled-like suspension when silica nanoparticles in contact with brine. The adsorption is considered reversible when the suspension decreased after post flooded with brine. Silica nanoparticles used in this experimental work shows minimal aggregation that can be beneficial as improved oil recovery agent.