Abstract
We study carbon capture and sequestration (CCS) over time scales of 2000 years by implementing a numerical model of reactive infiltration instability caused by reactive porous flow. Our model focuses on the mineralization of CO2 dissolved in the pore water—the geological carbon sequestration phase of a CCS operation—starting 10–100 years after the injection of CO2 in the subsurface. We test the influence of three parameters: porosity, mass fraction of the Ca-rich feldspar mineral anorthite in the solid, and the chemical reaction rate, on the mode of fluid flow and efficiency of CaCO3 precipitation during geological carbon sequestration. We demonstrate that the mode of porous flow switches from propagation of a planar front at low porosities to propagation of channels at porosities exceeding 10%. The channels develop earlier for more porous aquifers. Both high anorthite mass fraction in the solid phase and high reaction rates aid greater amounts of carbonate precipitation, with the reaction rate exerting the stronger influence of the two. Our calculations indicate that an aquifer with dimensions 500 m × 2 km × 2 km can sequester over 350 Mt solid CaCO3 after 2000 years. To precipitate 50 Mt CaCO3 after 2000 years in this aquifer, we suggest selecting a target aquifer with more than 10 wt% of reactive minerals. We recommend that the aquifer porosity, abundance of reactive aluminosilicate minerals such as anorthite, and reaction rates are taken into consideration while selecting future CCS sites.
Highlights
Carbon capture and permanent sequestration in the subsurface is becoming an important mechanism in carbon neutralization (Hosa et al, 2011; Odenberger et al, 2013; Celia, 2017)
We study carbon capture and sequestration (CCS) over time scales of 2000 years by implementing a numerical model of reactive infiltration instability caused by reactive porous flow
Our model focuses on the mineralization of CO2 dissolved in the pore water—the geological carbon sequestration phase of a CCS operation—starting 10–100 years after the injection of CO2 in the subsurface
Summary
Carbon capture and permanent sequestration in the subsurface is becoming an important mechanism in carbon neutralization (Hosa et al, 2011; Odenberger et al, 2013; Celia, 2017). Previous models of porous flow and laboratory experiments studied the efficiency of mass transfer as a function of two important dimensionless numbers: the Damköhler number (Da), representing the ratio between the rates of reaction and advection, and the Péclet number (Pe), representing the ratio between rates of advection and diffusion (Chadam et al, 1986; Riaz et al, 2006; Ghesmat et al, 2011; Szymczak and Ladd, 2013) These studies, ignored the crucial role of parameters such as the lithology and porosity of the aquifer on the efficiency of GCS. To model the deposition of solid carbonate resulting from the reaction between the H2CO3 rich fluid and the solid matrix, we carry out a series of 2D finite element simulations using a massively parallel open source software MuPoPP 1.2 (HierMajumder, 2020) running on the Oracle cloud computing platform In these simulations, we vary the dimensionless Damköhler (Da) and Péclet (Pe) numbers, aquifer porosity, and the initial concentration of the Ca bearing Da feldspar mineral phase anorthite (An) in the aquifer. These parameters influence (a) the mode of fluid transport by a transition from propagation of a planar front to channelized flow and (b) the amount of carbonate deposited in the solid phase after 2000 years of fluid flow
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
