CO 2 Dissolution Trapping Rates in Heterogeneous Porous Media

Gilmore, K. A. and Neufeld, J. A. and Bickle, M. J. (2020) CO 2 Dissolution Trapping Rates in Heterogeneous Porous Media. Geophysical Research Letters. ISSN 0094-8276 DOI https://doi.org/10.1029/2020GL087001

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Abstract

The rate of carbon dioxide (CO2) dissolution in saline aquifers is the least well‐constrained of the secondary trapping mechanisms enhancing the long‐term security of geological carbon storage. CO2 injected into a heterogeneous saline reservoir will preferentially travel along high permeability layers increasing the CO2‐water interfacial area which increases dissolution rates. We provide a conservative, first‐principles analysis of the quantity of CO2 dissolved and the rate at which free‐phase CO2 propagates in layered reservoirs. At early times, advection dominates the propagation of CO2. This transitions to diffusion dominated propagation as the interfacial area increases and diffusive loss slows propagation. As surrounding water‐filled layers become CO2 saturated, propagation becomes advection dominated. For reservoirs with finely bedded strata, ~10% of the injected CO2 can dissolve in a year. The maximum fraction of CO2 that dissolves is determined by the volumetric ratio of water in low permeability layers and CO2 in high permeability layers.

Item Type:	Article
Uncontrolled Keywords:	2020AREP; IA76
Subjects:	02 - Geodynamics, Geophysics and Tectonics
Divisions:	02 - Geodynamics, Geophysics and Tectonics 08 - Green Open Access 12 - PhD
Journal or Publication Title:	Geophysical Research Letters
Identification Number:	https://doi.org/10.1029/2020GL087001
Depositing User:	Sarah Humbert
Date Deposited:	02 Jun 2020 01:03
Last Modified:	02 Jun 2020 01:06
URI:	http://eprints.esc.cam.ac.uk/id/eprint/4754

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