Interpretable metrics for optimizing CO2 storage performance: Integrated analysis of reservoir characteristics and injection dynamics on CO2 storage efficiency and distribution

Recent advancements in numerical simulations have significantly enhanced our understanding of critical factors influencing CO2 storage. However, there remains a gap in translating these insights into strategic decisions that optimize the efficacy and performance of CO2 storage operations. This study addresses this gap by developing interpretable metrics that integrate complex simulation data to provide actionable insights for enhancing efficacy and performance of storage.

The study focuses on four key performance metrics: Storage Efficiency Factor ($f_t$), CO2 Distribution Uniformity Index (CO2DUI), CO2 Plume Complexity Index (CO2PCI), and CO2 Sweep Efficiency (CO2SE). These metrics are systematically evaluated across diverse subsurface scenarios to understand their influence on CO2 storage dynamics. By examining the interaction between geological characteristics (e.g., depth, thickness, heterogeneity) and operational strategies (e.g., injection rates), the research provides profound insights into optimizing CO2 storage performance.

The findings reveal that shallower reservoir depths enhance storage efficiency ($f_t$) and distribution uniformity (CO2DUI) due to reduced injection pressures and increased buoyant forces resulting from lower CO2 density at lower pore pressure, facilitating better CO2 distribution. Conversely, deeper reservoirs, while challenging in terms higher energy requirements for CO2 injection, show improved sweep efficiencies at higher injection rates. Thinner reservoirs exhibit higher efficiency and uniformity but simpler plume structures, whereas thicker reservoirs display delayed uniformity that stabilizes over time due to larger pore volumes. The geological heterogeneity has minimal impact on the evaluated metrics, indicating robustness of current models against subsurface variability, but it marginally increases the complexity of the CO2 plume. Increasing injection rates consistently enhance all CO2 storage metrics, particularly in thinner and mid-thickness reservoirs, underscoring the critical role of injection strategy in optimizing CO2 sequestration. Based on the study’s findings, specific strategies for practical implementation are recommended.

These findings provide quantitative guidelines for CO2 storage optimization, emphasizing the importance of depth- and thickness-dependent operational parameters. The study introduces a comprehensive framework for evaluating and enhancing CO2 sequestration systems, offering practical insights for maximizing storage efficiency while maintaining reservoir integrity. This work represents a significant advancement in translating complex simulation data into actionable operational strategies for carbon storage projects.