Oil-water two-phase dual mobility control for enhancing heavy oil recovery and its underlying mechanism.

Heavy oil constitutes an indispensable part of global energy security, yet its development is severely limited by high crude viscosity and low recovery efficiency. In this study, we apply an oil-water two-phase dual mobility control strategy. We validate its technical feasibility and clarify its intrinsic displacement mechanisms via integrated multiscale experimental characterization. Compared with conventional recovery approaches such as water flooding, polymer flooding, and surfactant-polymer binary flooding, the strategy delivers remarkable improvements in heavy oil recovery efficiency. Notably, natural gas acts as an effective oil-phase mobility modifier and yields prominent enhanced oil recovery performance within this dual mobility control system. Its favorable performance originates from three synergistic mechanisms: viscosity reduction through gas dissolution, improved utilization of tiny pore throats, and altered adsorption characteristics of heavy oil on rock mineral surfaces. In addition, dual mobility control coupled with elevated temperatures may exhibit distinct advantages for certain heavy oil reservoirs, especially formations characterized by ultrahigh crude viscosity and low reservoir permeability.