Experimental insights into synergestic SiO₂ nanoparticle/welan gum: the role of surface interaction in improving oil recovery

This study explored the synergistic interaction of SiO2 NPs and Welan gum for offshore application. Interaction characteristics, rheological behavior, Fluid-rock interaction and oil displacement were evaluated. FTIR, SEM and H-NMR were employed to characterize the SiO2-Welan gum solution. The results showed that SiO2 interacts with Welan gum through chemical bonds and possible hydrogen bonds due to hydroxyl group formation, increasing polymer roughness and causing network disruption. The incorporation of SiO2 NPs into welan gum resulted in a viscosity enhancement of up to 50% at 1.5 wt% salinity, demonstrating significant stability improvement. SiO2 NPs contribute to the thermal resistance of the polymer at elevated temperatures. Their synergistic effect was to mitigate salinity-induced viscosity reduction, maintaining fluid consistency more effectively than in the absence of nanoparticles. With SiO2, the adsorption between polymer and limestone decreased over time, showing an average reduction of 19%. The adsorption was homogeneous and was best described by the Langmuir isotherm model. The oil recovery improved by 15% more efficiently than the welan gum alone. The study suggests that SiO2 interacts with Welan gum in the ionic solution creating a three-dimensional network that resists conformational collapse and controls the polymer diffusion in limestone porous media.