Potential application of novel Janus amphiphilic nanoparticles to improve the viscoelasticity of polymer solution for enhanced oil recovery

Nanomaterials were widely employed to improve the physicochemical properties of various chemicals in enhanced oil recovery (EOR). In the present study, the novel Janus amphiphilic silica nanoparticle (JNS) was successfully prepared, whose structure and property were confirmed via Fourier transform infrared spectroscopy, Zeta potential measurement, transmission electron microscopy, interfacial tension and contact angle measurements. Then the effects of JNS, hydrophilic silica nanoparticles (HLS) and hydrophobic silica nanoparticles (HBS) on the viscosity of the hydrophobic modified HPAM (HOA101) solution were studied. It was found that JNS exhibited a greater ability to enhance the viscosity, temperature resistance and salt resistance of HOA101 solution in comparison to the other two polymer nanofluids. The interaction mechanisms between nanoparticles and HOA101 were proposed, which were verified by the viscoelasticity measurements and control experiments. Core flooding experiments and micromodel flooding tests demonstrated that the JNS/HOA101 dispersion could effectively expand the sweep efficiency to highly increase the oil recovery from 8.4% to 14.3%.