Enhancement of carbon dioxide storage efficiency using anionic surfactants

Abstract

The injection of carbon dioxide into aquifers under the cap rock involves high capillary pressure, resulting in reduced injection efficiency as the distance from the injection well increases. Capillary pressure, determined by the interfacial tension (σ) and contact angle (θ) between immiscible fluids, significantly influences this process. Previous studies examined surfactant properties such as the interfacial tension and contact angle, aiming to enhance carbon dioxide injection efficiency. Most of the existing research in this field has focused on the enhancement of oil recovery. Therefore, this study conducted micromodel experiments and pore network simulations to assess the impact of anionic surfactants, namely SDS and SDBS, on the efficiency of carbon dioxide injection into submarine aquifers. The results of micromodel experiments showed a substantial improvement in injection efficiency with higher injection rates and the incorporation of surfactants. However, no significant influence on injection efficiency was shown between surfactant concentrations of 0.01 wt% and 0.02 wt%. The numerical analysis showed that interfacial tension more influenced on injection efficiency than the contact angle. Moreover, the introduction of surfactants resulted in an increased relative fluid permeability, concomitant with increased injection efficiency. Consequently, the utilization of surfactants holds significant promise in increasing the injection efficiency of carbon capture and storage (CCS).