A comparison of volumetric and dynamic CO2 storage resource and efficiency in deep saline formations

Abstract

A reliable carbon dioxide (CO2) storage resource estimation method is crucial if carbon capture and storage in deep saline formations (DSFs) is to gain widespread deployment for reducing anthropogenic CO2 emissions to the atmosphere. Most of the published methodologies are based on a volumetric calculation and do not consider the effect of site-specific dynamic factors (e.g., injection rate, pressure interference). Several studies suggest these dynamic components may play the dominant role in storing CO2 in DSFs. In this study, CO2 storage resource estimates and efficiencies for two deep saline systems were calculated using volumetric and dynamic methodologies.Comparison of the results indicates that dynamic CO2 storage efficiency is time-dependent. For short injection lengths (∼50 years), an open system has an efficiency similar to a closed system, and volumetric storage resource estimates are too high. For long injection time frames (∼2000 years), the dynamic storage resource of open systems approaches the volumetric potential. These results suggest that volumetric assessments are reliable provided it is understood that it may take hundreds of wells and/or injection for hundreds of years to reach a formation's effective CO2 storage resource potential. Additionally, operational factors such as water extraction can increase CO2 storage resource and efficiency.