Silica-based amphiphilic Janus nanofluid with improved interfacial properties for enhanced oil recovery

Silica-based amphiphilic Janus nanoparticles were synthesized for application in the field of enhanced oil recovery. The organic hydrophobic chain was grafted onto the SiO 2 nanoparticles using a Pickering emulsion method. The chemical structure of the synthesized Janus nanoparticles was then characterized by TEM and FT-IR. Their interfacial properties were systematically investigated in terms of interfacial tension, contact angle and interfacial viscosity. The obtained results showed that the oil-water interfacial tension was reduced down to 2.28 mN/m when the concentration of the Janus nanoparticles is 0.05 wt%. Moreover, the Janus nanofluids could effectively alter the wettability of the rock from oil-wet to water-wet. The displacement experiments with low-permeability sandstone cores indicated that up to 15.74% increments of the oil recovery can be obtained by injecting 100 mg/L Janus nanofluids. Attributing to their hydrophilic-lipophilic balance properties, the Janus nanoparticles can quickly transport to the oil-water interface; consequently, a stable interfacial film which is beneficial to enhance oil recovery will form at the oil-water interface. Thus, the synthesized Janus nanoparticles could serve as an ideal candidate for enhanced oil recovery.