Characterizing the Dissolution Rate of CO2-Brine in Porous Media under Gaseous and Supercritical Conditions

Abstract

Abstract:The CO 2 -brine dissolution homogenizes the distribution of residual CO 2 and reduces the leakage risk in the saline aquifer. As a key parameter to immobilize the free CO 2 , the dissolution rate of CO 2 -brine could be accelerated through mechanisms like diffusion and dispersion, which are affected by the subsurface condition, pore structure, and background hydrological flow. This study contributed the calculated dissolution rates of both gaseous and supercritical CO 2 during brine imbibition at a pore-scale. The flow development and distribution in porous media during dynamic dissolution were imaged in two-dimensional visualization using X-ray microtomography. The fingerings branching and expansion resulted in greater dissolution rates of supercritical CO 2 with high contact between phases, while the brine bypassed the clusters of gaseous CO 2 with a slower dissolution and longer duration due to the isolated bubbles. The dissolution rate of supercritical CO 2 was about two or three orders of magnitude greater than that of gaseous CO 2 , while the value distributions both spanned about four orders of magnitude. The dissolution rates of gaseous CO 2 increased with porosity, but the relationship was the opposite for supercritical CO 2 . CO 2 saturation and the Reynolds number were analyzed to characterize the different impacts on gaseous and supercritical CO 2 at different dissolution periods.

Pore‐Scale Modeling of Coupled CO2 Flow and Dissolution in 3D Porous Media for Geological Carbon Storage

“…Wu et al. (2018) also conducted gaseous/supercritical CO 2 dissolution in brine and observed the scCO 2 flow and dissolution in 2D images. Based on advanced microfluidic techniques, Chang et al.…”

“…L. Jiang et al (2018) investigated the dynamic displacement and gaseous/supercritical CO 2 dissolution under different temperature/pressure conditions and analyzed the relationship between dissolution rate and flow rate. Wu et al (2018) also conducted gaseous/supercritical CO 2 dissolution in brine and observed the scCO 2 flow and dissolution in 2D images. Based on advanced microfluidic techniques, Chang et al (2016Chang et al ( , 2017 conducted scCO 2 imbibition/drainage and dissolution experiments at pore-scale in 2D heterogeneous sandstone micromodels and found water-flow paths and scCO 2 nonuniform dissolution were strongly correlated.…”

Effect of Saturation and Image Resolution on Representative Elementary Volume and Topological Quantification: An Experimental Study on Bentheimer Sandstone Using Micro-CT

“…Macroscopic modelling of fluid reaction and transport in porous media also requires finding the model that can accurately describes the average porescale conditions (Battiato et al 2009, Battiato andTartakovsky 2011). For applications related to carbon sequestration study, precise measurements of water-CO 2 interfacial area contributes to the investigation of the mass transfer coefficients of CO 2 (Miller et al 1990;Wu et al 2017;Patmonoaji and Suekane 2017). Accurate measurements of interfacial area can also be useful for obtaining estimates of in-situ contact angles under the thermal equilibrium assumption (Blunt et al, 2019), and directly discerning wettability state (Garfi et al, 2020b).…”