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

Abstract

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.