Evaluating CO2 storage strategies in saline aquifer: A simulation study on pressure, rate, and duration

Abstract

Carbon capture and storage (CCS) is a crucial strategy in reducing global CO2 emissions, with previous studies indicating it could contribute up to 20% of the necessary reductions by 2050. This paper presents a two-dimensional simulation model developed using CMG-GEM to evaluate CO2 storage potential in a saline aquifer. Seven scenarios were explored: varying injection pressures (15,000, 20,000, and 25,000 kPa), injection rates (5,000, 10,000, and 20,000 m³/day), and injection periods (1, 10, and 20 years). The model incorporated four CO2 trapping mechanisms: structural, residual gas, solubility, and mineral trapping. Results show higher pressures, increased injection rates, and extended injection periods generally improved CO2 storage. The optimal conditions were an injection pressure of 20,000 kPa, a rate of 10,000 m³/day, and a 20-year injection period, which struck the best balance between storage efficiency and operational feasibility. Over the 100-year simulation, the 20-year injection period achieved the highest CO2 mineralization. While structural and residual trapping was dominant early on, mineral trapping became increasingly important in the long term, highlighting the effectiveness of these mechanisms for CO2 sequestration in saline aquifers.