Elucidating the Multiscale Synergistic Enhancement of Oil Film Mobilization-Stripping by Microbubble Coalescence

This study systematically elucidates the synergistic multiscale mechanisms by which microbubble coalescence enhances the mobilization and stripping of water-flooding residual oil films. A cross-scale analytical framework was established by integrating microscopic visualization displacement experiments, molecular dynamics simulations, and computational fluid dynamics (CFD) numerical simulations, which highlight three core synergistic mechanisms: (1) Marangoni convection-driven energy conversion, (2) dynamic reconstruction of the pressure field, and (3) microscale vortex-induced differential oil-film stripping. Through the coupling of molecular interactions and pore-scale flow dynamics, these mechanisms collectively facilitate multiscale energy transfer and flow field reorganization, effectively overcoming capillary thresholds and establishing preferential flow channels. As a result, both the macroscopic sweep efficiency (+40.4%) and microscopic displacement efficiency (+17.1%) are significantly improved. These findings provide new multiscale mechanistic insight into microbubble-assisted enhanced oil recovery.