Synthesis And Application Of Amphiphilic Janus Nanoparticles Enhanced Oil Recovery For Low-permeability Reservoirs

Low-permeability reservoirs are rich in oil and gas resources,but because of their complex pore structure,it is not conducive to conventional development,leading to low recovery.A novel nanoparticle was synthesized based on silica,and their applications in low-permeability reservoirs to improve oil recovery were studied.In this work,amphiphilic Janus nanoparticles based on nano-SiO₂was synthesized via Pickering emulsion method.The silica nanoparticles were modified with KH550 to graft an amino group.Amphiphilic Janus nanoparticles were prepared by grafting the organic hydrophobic to the nanoparticles by amidation reaction.The morphology and chemical structure of the synthesized Janus nanoparticles was characterized by TEM and FT-IR.Their interfacial properties were systematically investigated in terms of interfacial tension,contact angle,and interfacial viscosity,etc.The results showed that the oil-water interfacial tension was reduced to 2.28 m N/m with a particle concentration of 0.05 wt%.The Janus nanofluids could also effectively transform the rock wettability from oil-wet to water-wet.Janus nanofluid can improve imbibition oil recovery.The experimental results show that the imbibition recovery of Janus nanofluid with a concentration of 0.005 wt%is 17.2%.The displacement experiments indicated that up to 15.74%increments in the oil recovery can be obtained by injecting 0.01 wt%Janus nanofluids.Attributing to their hydrophilic-lipophilic balance properties,the Janus nanoparticles can quickly transport to the oil-water interface and produce a stable interface film at the oil-water interface,helping to enhance oil recovery.