CO2 Storage in Deep Aquifers: Towards an Evaluation of Mineral Trapping
Fortier, Brice1, Magnier Caroline2, Teddy Parra2, Etienne Brosse2 (1) IFP-School, Rueil Malmaison, France (2) Institut Français du Pétrole, Rueil-Malmaison, France
The disposal of CO2 in deep saline aquifers is a promising technological option to mitigate the anthropogenic impact on climate. On the long term, in clastic sediments, it is expected that a part of the injected CO2 can be incorporated into minerals by dissolution of alumino-silicates and precipitation of carbonates. This mechanism is called mineral trapping. The study evaluates the influence of several parameters on the importance this process can induce in sandstones: mineral composition of the host rock and reservoir connectivity, associated petrophysical parameters, transport mechanism (diffusion vs. advective hydrodynamism).
A reaction-transport numerical code, Diaphore, is used to calculate the evolution of storage as soon as injected CO2 is dissolved in formation water. The model integrates the whole geological system in which the disequilibrium induced by CO2 injection progressively vanishes, as the system reaches a new equilibrium state. Typical sandstone compositions and transport scenarios are tested. The impact of several poorly constrained parameters on the simulation results, in particular part of the thermodynamical and kinetic data, or the feedback of mineral reactions on petrophysical properties, is investigated. Optimal conditions to maximize CO2 mineral trapping are explored and discussed.