A Novel Experimental Study on Density‐Driven Instability and Convective Dissolution in Porous Media

Abstract

Geological carbon dioxide (CO2) sequestration (GCS) in deep saline aquifers is a promising solution to mitigate the impact of anthropogenic CO2 emissions on global climate change. CO2 dissolved in formation water increases the solution density and can lead to miscible density‐driven downward convection, which significantly accelerates the dissolution trapping of injected CO2. Experimental studies on miscible density‐driven convection have been limited. In the laboratory, we found an empirical linear correlation between reflected green light intensity and solute concentration, which enabled in situ measurements of solute concentrations in the spatial and temporal domains and consequently the mass flux across the top boundary of the porous medium. Using the novel experimental techniques, we determined the critical Rayleigh‐Darcy number and critical time scales for the onset of density‐driven instability and convective dissolution. This is the first study to determine these critical system parameters using laboratory experiments.

Scaling CO2–brine mixing in permeable media via analogue models

“…2010; Guo et al. 2021), MEG doped with sodium iodide and sodium chloride in quasi-two-dimensional (Q-2-D) and three-dimensional (3-D) porous media (Wang et al. 2016), and an aqueous solution of propylene glycol (PPG) and deionised water in Hele-Shaw cells (Backhaus et al.…”

“…In a Q-2-D porous medium, Guo et al. (2021) obtained , for , while in 3-D porous media, Wang et al. (2016) found , for .…”

Co-injection of CO2 and Nanoparticles Enhance Sequestration Potential in Subsurface Aquifers

“…As the CO 2 dissolves into the underlying brine, the CO 2 -saturated brine becomes denser than the native brine, and the density difference causes instability and triggers convection. Dense CO 2 -saturated brine migrates downward, while light native brine rises, and the natural convection of these two fluids generates convective fingers [7]. The downward migration of the CO 2 -saturated brine significantly enhances the mass transfer of CO 2 and reduces the time required for total dissolution.…”

“…The downward migration of the CO 2 -saturated brine significantly enhances the mass transfer of CO 2 and reduces the time required for total dissolution. More importantly, relative to the native brine that fills the pore spaces, the negative buoyancy of the CO 2 -saturated brine may reduce the risk of leakage along geological faults, which is of considerable concern relative to longterm sequestration security [7]. Recently, a method has been proposed to accelerate the dissolution of CO 2 and brine and reduce the risk of leakage with co-injection of CO 2 with nanoparticles (NPs).…”

Reservoir characterization and multiphase flow property in the upper Minnelusa sandstone: Implication for geological carbon storage

“…The presence of elevated concentration of greenhouse gases in the atmosphere have been linked to climate change, so reduction in their emissions into atmosphere is pressing. Geological carbon storage (GCS) in deep saline aquifers stands alone as a strategy in mitigating greenhouse gas emissions into atmosphere (Guo et al, 2021). Their widespread geographically makes them an attractive subsurface storage system.…”