Interfacial Mobility-Regulated Mass Transfer for Microbubbles and Its Implication for Enhanced Oil Recovery

Microbubbles (MBs) offer transformative potential for mass transfer enhancement in energy-related applications such as carbon storage and enhanced oil recovery. This study investigates the dissolution dynamics of CO2 and N2 MBs under high-temperature and high-pressure conditions, focusing on the time-dependent evolution of interfacial mobility. Experimental results reveal that while N2 MBs exhibit rapid interfacial passivation, governed by interface-limited mass transfer. In contrast, CO2 MBs initially maintain high interfacial mobility due to strong dissolution flux and internal circulation, resulting in markedly enhanced mass transfer, followed by an exponential decay of mobility driven by interfacial adsorption and Marangoni stresses. A unified mass transfer model incorporating time-dependent interfacial mobility is developed to capture the nonsteady behavior across gas systems and temperature–pressure conditions. Elevated pressure (0–8 MPa) leads to high initial enhancement but accelerated interfacial passivation, while increased temperature (20–80 °C) prolongs partial interfacial mobility and enhances overall mass transfer. High-temperature, high-pressure CO2 flooding experiments demonstrate that MBs form more uniform displacement fronts and reduce residual water saturation by up to 24.1%, outperforming conventional macrobubbles. These results highlight the dominant role of interfacial dynamics in MB mass transfer and provide guidance for MB-assisted carbon management and enhanced recovery processes.