<p>With the gradual depletion of conventional recoverable oil reservoirs, enhancing crude oil recovery has emerged as a critical challenge in oilfield development. This study conducts systematic experimental investigations into the performance and enhanced oil recovery mechanisms of oil-in-water emulsions stabilized by SiO₂ nanoparticles, aiming to provide technical support for the efficient exploitation of complex reservoirs. By preparing oil-in-water emulsions stabilized with SiO₂ nanoparticles, key properties including viscosity, wetting contact angle, droplet size, and interfacial tension with crude oil were measured. Core flooding experiments were performed using three cores with varying permeability levels, involving water flooding, emulsion flooding, and secondary water flooding, with analyses of pressure variations, cumulative liquid production, and oil production data. Results demonstrate that the formulated emulsion exhibits superior performance, surface tension of 28.383 mN/m, and interfacial tension with crude oil of 2.853 mN/m, the contact angle with the rock is 17.109°, and the average droplet size is approximately 30.61 μm, and it has good colloidal stability and uniform dispersion. The emulsion flooding significantly enhanced oil recovery, increasing the recovery rate by 37.50% for the medium-permeability Core 2, with a final total recovery rate reaching 81.25%, while also modifying flow paths and enhancing conformance control. The injection pressure during emulsion flooding showed a typical pattern of rapid increase, fluctuation due to pore blocking, followed by stabilization, indicating dynamic plugging and breakthrough behavior. This study provides experimental evidence for the application of SiO₂ nanoparticle-stabilized emulsions in enhanced oil recovery and offers feasible experimental foundations and process recommendations for the demonstration of nanoparticle emulsions in unconventional and complex reservoirs.</p>