Nanofluid of graphene-based amphiphilic Janus nanosheets for tertiary or enhanced oil recovery: High performance at low concentration

Significance Improving crude oil recovery by 1% worldwide would result in a huge amount of crude oil resources becoming available. However, the economic and environmental concerns are too serious to ignore when chemical methods (surfactants or polymers flooding, etc.) are used for an average 10–20% enhancement for tertiary oil recovery. Simple nanofluid (containing only nanoparticles) flooding at low concentration (0.01 wt % or less) is a promising alternative, but the efficiency is below 5% in a saline environment (2 wt % or higher NaCl content). We report a simple nanofluid of graphene-based Janus amphiphilic nanosheets for enhanced oil recovery with efficiency of about 15.2%, comparable to chemical methods, which is both economically and environmentally beneficial to the petroleum industry.