Molecular Dynamics Simulation of Nanoparticle-Driven Oil Detachment in Nanochannels

Abstract

Nanoparticles exhibit significant potential in modulating oil-water interfacial tension, altering rock wettability, and optimizing fluid flow for enhanced oil recovery. This study employs MD simulations to investigate the effects of surface-modified nanoparticles (pure-NP, alkyl-NP, carboxylate-NP) on interfacial tension, layer thickness, and displacement energy. Results reveal that alkyl-NP reduces interfacial tension most effectively (32.57 mN·m⁻¹), followed by carboxylate-NP (38.64 mN·m⁻¹) and pure-NP (45.02 mN·m⁻¹). Alkyl-NP also demonstrates the greatest reduction in oil-particle interaction energy (−500 kcal/mol), while Pure-NP and Carboxylate-NP show weaker displacement capacity. Notably, nanoparticle addition significantly increases the interfacial layer thickness (t_oil: 9.5 ∼ 17.4  Å, t_water: 7.9 ∼ 12.5  Å, t_total: 13.4 ∼ 22.5  Å) compared to the pure system (t_oil = 4.8 Å, t_water = 3.8 Å, t_total = 6.5 Å). These findings suggest that nanoparticle systems enhance oil recovery by lowering interfacial tension, thickening interfacial layers, and improving crude oil stripping and migration. Alkyl-NP emerges as the most promising modifier due to its superior interface control and energy reduction.