Nanoparticle-Assisted Surfactant/Polymer Formulations for Enhanced Oil Recovery in Sandstone Reservoirs: From Molecular Interaction to Field Application

There has been some success with polymer and surfactant injections into depleted sandstone reservoirs for reducing residual oil saturation and improving oil recovery. However, their microemulsion stability is compromised in the harsh conditions of high temperature and salinity. Nanoparticle addition to the polymers and surfactant has resulted in a nanofluid with more stability, improved rheological behaviors, reduced adsorption loss, and much more as a result of the synergistic effects of their components. In this work, the performance of polymeric and surfactant nanofluids and the factors that impair their efficacy were highlighted. Numerous surfactant adsorption mechanisms, such as ion pairing, ion exchange, hydrogen bonds, dipole interactions, and hydrophobic interactions, on the rock surface were illustrated. Synergistic interactions of ternary phases of surfactant, polymer, and nanoparticles to the interfacial tension reduction, wettability alteration, adsorption reduction, rheological enhancement, and nanofluid stability for enhanced oil recovery were also presented. Additionally, the prevailing challenges and their plausible interventions have been highlighted in this review. The summarized results from published papers based on experimental evidence and theoretical deductions presented in this review will uplift the understanding of the screening, designing, and formulation of nanofluids.