Study on Permeability Enhancement and Heat Transfer of Oil Sands Reservoir Based on Hydrophobic Nanofluids

The development of nanofluid-assisted heavy oil extraction can address critical challenges in global energy sustainability, particularly for ultra-heavy oil reserves characterized by high viscosity and low permeability. This study investigates the dual role of hydrophobic nanofluids in enhancing reservoir permeability and heat transfer efficiency. Through advanced triaxial shear seepage experiments and heat transfer experiments, the permeability and thermal conductivity of oil sands cores treated with hydrophobic silica-based nanofluids (0–0.15 wt%) were quantitatively analyzed. The results showed that the permeability increased by up to 536.59% (from 33.18 mD to 211.22 mD) after nanofluid treatment, which was attributed to nanoparticle-induced pore throat modification and reduced interfacial tension. At the same time, the thermal conductivity has increased by up to 132% (from 0.25 W/m·K to 0.58 W/m·K), significantly improving the heat transfer efficiency. There is a linear relationship between the concentration of nanofluids and the thermal conductivity, and the relationship between the thermal conductivity, and the strain of oil sands is established. This work provides a scientifically grounded framework for scaling nanofluid applications in field trials, offering a transformative pathway to reduce energy intensity and improve recovery rates in ultra-heavy oil exploitation.