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Dynamics of CO 2 Density‐Driven Flow in Carbonate Aquifers: Effects of Dispersion and Geochemistry
Author(s) -
Erfani Hamidreza,
Babaei Masoud,
Niasar Vahid
Publication year - 2021
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2020wr027829
Subject(s) - convective mixing , dispersion (optics) , dissolution , aquifer , carbonate , convection , carbon dioxide , geology , carbon sequestration , diffusion , mixing (physics) , fluid dynamics , flow (mathematics) , soil science , mineralogy , mechanics , groundwater , thermodynamics , materials science , chemistry , geotechnical engineering , physics , organic chemistry , quantum mechanics , optics , metallurgy
The dissolution of carbon‐dioxide (CO 2 ) in deep saline aquifers is an important trapping mechanism in carbon storage. This process is triggered by unstable high‐density CO 2 front, which later promotes density‐driven mixing, hydrodynamic dispersion of CO 2 , and favors the long‐term sequestration. In many former studies, effects of hydrodynamic dispersion and multispecies geochemical reactions have been ignored. This work elaborates the impacts of these simplifications on the dynamics of convective mixing by numerical simulations. Geochemical effects were studied by the implementation of rock‐fluid and fluid‐fluid interactions for a typical carbonate aquifer. Results show that accounting for the hydrodynamic dispersion decreases the convection onset time and increases the CO 2 dissolution flux, which is more significant in larger dispersivities and Rayleigh numbers. Results indicate that carbonate geochemical reactions intense the long‐term overall efficiency of the process, while decrease the total amount of sequestered carbon in the diffusion‐dominated period. Results also reinforce the importance of realistic geochemical representation and importance of spatial and temporal dependence of the reactions pathway, subsequent to the finger development for more detailed simulation of the CO 2 storage process.