Molecular dynamics simulation of microscopic interaction mechanism between oil–water interface by modified graphene oxide oil displacement agent

With the increasing worldwide energy demand, enhanced oil recovery (EOR) is becoming more critical for oil fields. In recent years, the rise of nanotechnology has provided a new direction for developing oil repellents in low-permeability reservoirs, and the new nanomaterial-modified graphene oxide (MGO) has demonstrated good EOR performance in oil and gas field development. In this work, molecular dynamics simulations were carried out to investigate the influence of MGO on the interfacial tension (IFT) of oil water and its microscopic interaction mechanism. The impact of different grafting ratios and lengths of modified NPs on the interfacial properties of oil–water interfaces and their mechanisms were further analyzed. Simulation results indicate that, due to their amphiphilic structure, they are attracted to the oil phase and can spontaneously migrate to the oil–water interface. They form a dense monolayer film structure at the oil–water interface, reducing the IFT from 52.08 mN·m−1 thickness to 28.03 mN·m−1 by increasing the thickness of the oil–water interface. The most significant reduction in IFT was observed when MGO was grafted with sixteen-alkyl-long chains. The molecular-level insights gained from this study can provide valuable guidance for designing modified nanoparticles suitable for EOR applications.