Advanced Physical Research

A three-dimensional heterogeneous reservoir model was developed to evaluate the physical response of a sandstone oil-water system to magnetized low-salinity water injection. The model contains 50 × 50 × 6 grid blocks and incorporates permeability (250 mD), porosity (26.5%), reservoir pressure (40.3 atm), temperature (25 °C), water saturation (30%) and an injected brine salinity of 1000 ppm. The magnetic treatment was represented through changes in rock-fluid interaction, including wettability alteration, relative permeability behaviour, capillary displacement and water mobility control. Compared with conventional low-salinity water injection, the magnetized case improved oil displacement, increased the peak daily oil rate to 2.25 t/day and reduced produced water by about 80%. Comparison of linear and five-spot injection patterns showed that the five-spot geometry generated a more uniform pressure gradient and displacement front, giving better sweep efficiency and lower residual oil saturation. The results indicate that magnetic treatment can intensify electrokinetic and interfacial effects in porous media and improve reservoir-scale oil recovery when combined with an appropriate well pattern.