Investigation of CO2 storage capacity in open saline aquifers with numerical models

Abstract

Accurate calculation of carbon dioxide (CO2) storage capacity in deep saline aquifers is a challenging task. However an assessment must be performed to determine whether there is sufficient capacity in a storage site for any CO2 sequestration project. We evaluated the CO2 storage capacity for a simplified reservoir system, which the layered potential storage formations are overlaid by sealing cap rock. This study aims at determining CO2 storage capacity for the injection of CO2 in opened saline formations using numerical simulation method. In this study, a 3D numerical model was developed for the investigation. Detailed processes for the storage capacity estimation are derived. The impact of injection strategy and the residual gas saturation on storage capacity was investigated. It is shown that both of the injection strategy and the residual gas saturation have a great impact on the spatial distribution of CO2 plume and the effective storage of CO2 in the reservoir. Simulation results also indicate that the injection well distribution may significantly influence the use of the formation porous space for CO2 storage. From this study, we may conclude that the most accurate way to estimate storage capacity is through construction of a basin scale three-dimensional numerical model for specific storage site by incorporating detailed geological information of the site and injection scheme used.