Research on the Flow Rules of Nanoemulsions Based on Microfluidic Experiments

To investigate the multiphase transport behavior of nanoemulsions and their mechanisms underlying improving recovery efficiency, the research conducted systematic experiments on nanoemulsions, including TEM characterization, zeta potential analysis, wettability assessment, dilatational rheology test, and microfluidic visualization. The results indicate that increasing nanoemulsion concentration decreased the viscosity coefficient, which facilitated reduction of the mobility of the displacing fluid, optimizes the mobility ratio, suppressed viscous fingering, and enhances oil recovery. The nanoemulsion with a volume fraction of 0.2%(with an oil-water interfacial tension of about 0.092 mN/m and a contact angle of 168°) exhibits excellent crude oil displacement capability. In microfluidic flooding experiments at a displacement rate of 0.5 μL/min, the final recovery rate reached 75.1%. However, introducing high-salinity formation water triggered nanoparticle aggregation through electric double-layer compression, leading to a decline in nanoemulsion displacement efficiency. Synergistic experiments with oxidative nanobubble systems (eg. CO₂, H₂, and air nanobubbles) revealed no significant enhancement effect. Instead, the generation of reactive oxygen species at interfaces increased the risk of nanoemulsion destabilization. These findings offer theoretical and technical insights for field applications of nanoemulsion-based EOR technologies in challenging reservoir conditions.