Oil detachment by modified nanoparticles: A molecular dynamics simulation study

Stripping residual oil adsorbed on reservoir surface is essential for enhanced oil recovery (EOR). Abundant experimental and modelling have investigations identified the superior EOR capability of Janus nanoparticle. However, the tortuous synthesis procedure and expensive cost heavily limit its large-scale application. In this work, adopting molecular dynamics simulation, three kind of modified nanoparticles grafted with hydrophilic chains (NP1), hydrophobic chains (NP2), and mixed hydrophilic and hydrophobic chains (NP3), were designed to detach adsorbed oil droplet on silica surface. These modified nanoparticles could be prepared via conveniently chemical modification. The equilibrium adsorption configuration and dynamic displacing process were investigated. Simulations indicate that the grafted nanoparticles could promote the oil droplet detachment, and the NP3 gives optimal EOR capability. Furthermore, the interaction between oil droplet and silica surface, oil/water interfacial activity, and coherent energy of oil droplet, were analyzed to reveal the underlying EOR mechanism of grafted nanoparticles. This work provides one kind of modified nanoparticle (NP3) for the development of high-performance EOR agent.