Investigation of functionalized polyelectrolyte polymer-coated Fe3O4 nanoparticles stabilized in high salinity brine at high temperatures as an EOR agent

The anionic polymer-citrate-coated Fe3O4 nanoparticles suspensions have been studied as a candidate for enhanced oil recovery at harsh conditions in oil reservoir. The efficiency of different nanofluid concentrations was investigated on increasing of oil recovery by sand-pack porous media and carbonated rocks in core flooding setup. In this study, parameters affected the structural disjoining pressure mechanism such as lowering interfacial tension (IFT) and altering wettability were studied. We observed that both IFT and contact angle of aqueous phase were decreased when hydrophilic nanoparticles introduced to brine. From laboratory core flood experiment, the reduction of residual oil saturation due to nanofluid injection was obtained less than 28%. However, we observed an increased differential pressure 0.32 psi across the core plug arising from formation damage due to incompatibility of sea and formation water and/or aggregation of nanoparticles.