Post-injection spreading and trapping of CO[subscript 2] in saline aquifers: impact of the plume shape at the end of injection
Author(s)MacMinn, Christopher W.; Juanes, Ruben
Post-injection spreading and trapping of CO2 in saline aquifers: impact of the plume shape at the end of injection
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We use an analytical model for the post-injection spreading of a plume of CO[subscript 2] in a saline aquifer under the action of buoyancy and capillary trapping to show that the spreading behavior is at all times strongly influenced by the shape of the plume at the end of the injection period. We solve the spreading equation numerically and confirm that, at late times, the volume of mobile CO[subscript 2] is given by existing asymptotic analytical solutions. The key parameters governing plume spreading are the mobility ratio, M, and the capillary trapping number, Gamma—the former sets the shape of the plume at the end of the injection period, and the latter sets the amount of trapping. As a quantitative measure of the dependence of the spreading behavior on the initial shape, we use a volume ratio. That is, we evolve the plume from a true end-of-injection initial shape and also from an idealized “step” initial shape, and we take the ratio of these mobile plume volumes in the asymptotic regime. We find that this volume ratio is a power-law in M, where the exponent is governed exclusively by Gamma. For conditions that are representative of geologic CO[subscript 2] sequestration, the ratio of mobile volumes between “true” and “step” initial plume shapes can be 50% or higher.
DepartmentMassachusetts Institute of Technology. Department of Civil and Environmental Engineering; Massachusetts Institute of Technology. Department of Mechanical Engineering
Springer Science + Business Media B.V.
MacMinn, Christopher, and Ruben Juanes. “Post-injection spreading and trapping of CO<sub>2</sub> in saline aquifers: impact of the plume shape at the end of injection.” Computational Geosciences 13.4 (2009): 483-491.
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