CO2 migration in saline aquifers. Part 1. Capillary trapping under slope and groundwater flow

migration in saline aquifers. Part 1. Capillary trapping under slope and groundwater flow. Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Injection of carbon dioxide (CO 2) into geological formations is widely regarded as a promising tool for reducing global atmospheric CO 2 emissions. To evaluate injection scenarios, estimate reservoir capacity and assess leakage risks, an accurate understanding of the subsurface spreading and migration of the plume of mobile CO 2 is essential. Here, we present a complete solution to a theoretical model for the subsurface migration of a plume of CO 2 due to natural groundwater flow and aquifer slope, and subject to residual trapping. The results show that the interplay of these effects leads to non-trivial behaviour in terms of trapping efficiency. The analytical nature of the solution offers insight into the physics of CO 2 migration, and allows for rapid, basin-specific capacity estimation. We use the solution to explore the parameter space via the storage efficiency, a macroscopic measure of plume migration. In a future study, we shall incorporate CO 2 dissolution into the migration model and study the importance of dissolution relative to capillary trapping and the impact of dissolution on the storage efficiency. 1. Introduction Injection of carbon dioxide (CO 2) into geological formations is widely regarded as a promising tool for reducing global atmospheric CO 2 emissions (see e. To evaluate injection scenarios, estimate reservoir capacity and assess leakage risks, an accurate understanding of the subsurface migration of the plume of mobile CO 2 is essential. Much study has been done on this problem quite recently, including both theoretical modelling and numerical simulation. Numerical studies include Pruess & García (2002), Kumar et al. (2005) and Juanes et al. (2006), among many others; we review theoretical studies in more detail below. Here, we present a complete solution to a theoretical model for the subsurface migration of a plume of CO 2. The analytical nature of the solution offers insight into the physics of CO 2 migration and allows