A simple but rigorous model for calculating CO2 storage capacity in deep saline aquifers at the basin scale

Abstract

Safely sequestering CO2 in a deep saline aquifer requires calculating how much CO2 the aquifer can store. Since offsetting nationwide emissions requires sequestering large quantities of CO2, this calculation should apply at the large scale of geologic basins. The only method to calculate storage capacity at the basin scale, however, is not derived from multiphase flow dynamics, which play a critical role in CO2 storage. In this study, we explain a new model to calculate basin-scale storage capacity that is derived from flow dynamics and captures the dynamic phenomena of gravity override and capillary trapping. Despite the fact that the model is dynamic, it is simple since it is a closed form expression with few terms. We demonstrate how to apply it on the Fox Hills Sandstone in the Powder River Basin.