Increased Nonionic Surfactant Efficiency in Oil Recovery by Integrating with Hydrophilic Silica Nanoparticle

Nonionic surfactants are nonvolatile and benign chemicals widely used in the oil and gas industry. However, their huge loss especially under high temperature and high salinity conditions has limited their large-scale applications; thus, various additives were introduced to prepare compounded systems. This paper mainly focuses on nonionic surfactant–silica nanoparticle augmented systems. Herein, an extensive series of adsorption tests related to the adsorption of surfactant on nanoparticles and surfactant adsorption behavior change with the presence of nanoparticles was conducted, together with their combined effects on interfacial properties and their potentials in boosting oil production, trying to systematically evaluate their synergistic interactions and reveal the underlying functional mechanisms. Experimental results showed that surfactant adsorption was generally reduced with the addition of nanoparticles, and the efficiency largely depended on the adsorbents and nanoparticle size. In addition, the properties of nanofluids differ at varying surfactant/nanoparticle concentration ratios because of diverse surfactant adsorption structures, and smaller particles turned out to be better surfactant carriers. In the spontaneous imbibition tests, positive cooperative effects by integrating nanoparticles with surfactant were highlighted, where the nanoparticles efficiently improved the surfactant performance and a considerable amount of additional oil was recovered. Acknowledging the interactions and combined effects of nonionic surfactants and hydrophilic silica nanoparticles may shed light on the development and improvement of potential nanofluids for industrial practices.