How pressure buildup and CO[subscript 2] migration can both constrain storage capacity in deep saline aquifers

Abstract

A promising way to mitigate global warming is to sequester CO[subscript 2] in deep saline aquifers. In order to determine which aquifers are the best for sequestration, it is helpful to estimate how much CO[subscript 2] they can store. Currently, this is difficult because both the pressure buildup from injection and the volume of available pore space have been identified as constraints, but have not been compared to determine which is more important. In this study, we evaluate their relative importance using simple, but dynamic models of how pressure rises during injection and how CO[subscript 2] becomes trapped in the pore space. Our results show that the more important constraint depends on the properties of the aquifer and how the CO[subscript 2] is injected.