Residual oil recovery from asphaltene-rich reservoirs via conventional Enhanced oil recovery (EOR) is inefficient, yet nanofluids present a promising solution for simultaneous wettability alteration, Interfacial tension (IFT) reduction, asphaltene stabilization, and enhanced production. Additionally, the synergistic effects of low-salinity water with other additives remain unexplored for asphaltenic crude oils, where asphaltene precipitation severely damages reservoir permeability and reduces production. To bridge this gap, the present study introduces a novel hybrid nanofluid composed of surface-modified TiO2/Fe3O4 nanoparticles and the amphoteric surfactant CAPB (cocamidopropyl betaine) dispersed in low-salinity brine. This formulation is specifically engineered to integrate four pivotal functions into a single sustainable system: (1) extreme wettability alteration from oil-wet to water-wet, (2) ultra-low IFT reduction, (3) effective asphaltene stabilization, and (4) enhanced oil recovery. The combination of CAPB a biodegradable, non-toxic, and cost-effective surfactant with Iron oxide (Fe3O4) and Titanium dioxide (TiO2) nanoparticles presents a green and sustainable alternative to conventional EOR agents. The novelty of this work extends beyond addressing the multifunctionality gap; it also offers new mechanistic insights into the synergistic interactions among low salinity water, modified nanoparticles, and surfactants within asphaltene-rich environments. A comprehensive suite of characterization and performance evaluation techniques including Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), Thermogravimetric analysis (TGA), zeta potential, Dynamic light scattering (DLS), IFT, contact angle measurements, and core flooding experiments was employed to systematically elucidate the underlying oil mobilization mechanisms. The experimental results demonstrated that the synthesized nanofluid reduced IFT to 0.95 mN/m and altered the contact angle to 18°. The coreflood test revealed that nanofluid injection at 150 ppm concentration led to a 38.7% enhancement in oil recovery over that obtained from Low salinity waterflooding alone. These findings offer a practical, scalable, and eco-friendly solution for boosting production from asphaltenic reservoirs. Overall, this work advances next-generation multifunctional EOR agents, promoting sustainable extraction through reduced chemical use, lower environmental impact, and improved efficiency in mature fields.
