STUDY ON THE EFFECT OF DYNAMIC INTERFACIAL PROPERTIES OF LIQUID BRIDGES ON SPONTANEOUS LIQUID-LIQUID IMBIBITION

The phenomenon of multiphase flow in porous media occurs widely in both natural and industrial applications, including groundwater flow, oil and gas development, and unsaturated particulate materials. Liquid bridges play a crucial role in these processes and significantly influence the dynamics of multiphase flows. In this work, we have investigated the effect of liquid bridges on spontaneous liquid-liquid imbibition in capillaries based on a modified spontaneous liquid-liquid imbibition theory model and a two-component Shan-Chen model with an improved fluid-solid interaction force format. The results indicate that the presence of liquid bridges leads to the formation of three interfaces within the capillary, which significantly increases the dynamic contact angles of the entire system and reduces the rate of spontaneous imbibition compared to processes without liquid bridges. Additionally, with the increase of wettability, the presence of liquid bridges enhances the dynamic interface change characteristics more strongly. When the viscosity of the liquid bridge is lower than that of the non-wetting fluids, an increase in the imbibition length will enhance the dynamic contact angles of the entire system; if they both have equal-sized viscosities, then the dynamic contact angles of the entire system remain a constant; and when the viscosity of the liquid bridge is larger than that of the non-wetting fluids, there is a gradual decrease in the dynamic contact angle during imbibition. By incorporating the real-time dynamic contact angle obtained from the simulation into the imbibition theory, the deviation between the theoretical and simulated imbibition lengths due to the dynamic changes of the liquid-bridge interface can be improved, and the results are consistent with the simulation. In this study, we also systematically evaluated the predictive ability of Cox-Voinov models for interface dynamic variation and imbibition length in imbibition processes with and without liquid bridges by using the data from the simulation.