Rheological properties and swelling behavior of nanocomposite preformed particle gels based on starch-graft-polyacrylamide loaded with nanosilica

Gel treatment using preformed particle gels is a technique applied in mature reservoirs to control excess water production. In this study, a novel nanocomposite gel was proposed and optimized for better performance in high-salinity and high-temperature conditions of oilfields. Gels were prepared by grafting copolymerization of crosslinked polyacrylamide onto starch (starch-g-CPAM) and loaded with silica nanoparticles. Different tests were performed on nanocomposite prepared particle gels (NCPPGs) to investigate the effect of silica content (2-10 wt%), temperature, and brine concentration on network structure, swelling, and mechanical behavior of the gels. The NCPPG with 5 wt% showed a superior swelling ratio. Rheological studies depicted that nanosilica could increase the mechanical strength of the NCPPGS in high temperature and high salinity brines (90 degrees C and 225,000 ppm) up to 900 Pa. Finally, loading nanosilica up to 5 wt. % into the NCPPG resulted in capable mechanical stability and water uptake under harsh conditions.