Mitigating fines migration in low salinity water flooding of clay rich sandstones using TiO2 Saponin Zr nanocomposites

Mitigating formation damage due to fines migration is crucial for maintaining reservoir productivity in enhanced oil recovery (EOR) processes. This research introduces a novel composite, Titanium dioxide nanoparticles coated with Saponin and Zirconium (TiO₂@Saponin/Zr(IV)), synthesized via a sol-gel method, to address this challenge, particularly in low salinity water injection scenarios. Characterization through FT-IR confirmed successful functionalization, indicated by the Zr-O band at 480 cm^-1 and saponin bands around 1030-1085 cm^-1 and 2919-2850 cm^-1. Zeta potential measurements showed that in low salinity brine, quartz and kaolinite exhibited highly negative potentials of - 32 mV and - 45 mV, respectively, while TiO₂@Saponin/Zr(IV) displayed a positive potential of + 19 mV. Importantly, mixtures of quartz and kaolinite with TiO₂@Saponin/Zr(IV) in low salinity conditions resulted in moderated zeta potentials of + 3 mV and - 2 mV, indicating surface charge modulation. Core flooding experiments further validated the composite's effectiveness. Injecting high salinity water resulted in a minor permeability reduction from 90 to 78 mD, while low salinity water injection caused a drastic drop from 90 to 8 mD. However, with the introduction of 0.5 wt% TiO₂@Saponin/Zr(IV) in low salinity water, the permeability reduction was significantly controlled, decreasing from 90 to 85 mD. These quantitative results demonstrate that TiO₂@Saponin/Zr(IV) effectively mitigates fines migration by modifying surface charge and preserving permeability, offering a promising solution for formation damage control and enhanced oil recovery.