Identification of implicit dynamics of supercritical CO₂ invasion in sub-regions of bench micromodels

The ambiguous dynamics of invading carbon dioxide in subcritical and supercritical states, as well as the response of pore-scale resident fluids, play a key role in understanding CO₂ capture and storage (CCS) and the corresponding phase equilibrium mechanisms. This paper reveals the implicit dynamics of invading supercritical carbon dioxide (sCO₂) in deionized water (DIW)-saturated micromodels using a variant of Lattice-Boltzmann Color Fluid model and descriptive experimental data. The breakthrough time is evaluated by characterizing the displacement velocity, the capillary to pressure-difference ratio, and the transient saturation at a series of micromodels with scaling pore-throats. The recorded sub-regimes are remarkably categorized as oscillatory while the interfacial velocity of sCO₂/DIW is jumping into oscillatory magnitudes. Hence, the transient saturation would be significantly accelerated with decreasing pore-throats, demonstrating increased invasion efficiency. Accordingly, a renovated model is established to account for the transient dynamics of invading sCO₂ towards efficient geological sequestration.