Impact of PAM-Grafted Nanoparticles on the Performance of Hydrolyzed Polyacrylamide Solutions for Heavy Oil Recovery at Different Salinities

Nanoparticle (NP) inclusion is proposed to address polyacrylamides performance limitations at reservoir conditions when used for enhanced oil recovery. In this study, the effect of polyacrylamide (PAM)-grafted SiO2, TiO2, and Al2O3 NPs on the performance of hydrolyzed polyacrylamide (HPAM) and sodium dodecyl sulfate (SDS) solutions as a secondary recovery method is analyzed. The attachment of the polymer onto the surface of the NPs was confirmed by scanning electron microscopy (SEM–EDX), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The properties of the nanopolymer sols were evaluated using viscosimetry, interfacial tension (IFT) and contact angle measurements. The oil displacement tests were performed in a linear sand-pack at 25 °C and different salinities (1.0, 2.0, and 3.0 wt % NaCl). According to the results, the surface properties of SiO2, TiO2, and Al2O3 NPs were improved by polymer grafting. The nanopolymer sols exhibited lower IFT and ability to alter the wettability of the glass substrate from oil-wet to intermediate-wet. The thickening behavior of the HPAM solution was improved by the addition of 0.2 and 0.4 wt % TiO2-PAM NPs at all salinities. Moreover, the TiO2-PAM NPs increased the cumulative oil recovery of the polymer solution between 5 and 7%, independent of the salinity.