In the quest to mitigate climate change, carbon capture and storage (CCS) has emerged as a critical technology, and a recent study published in the journal *Technologies* offers promising insights into optimizing offshore CCS methods. The research, led by Jiayi Shen from the Institute of Marine Structures and Naval Architectures at Zhejiang University, compares the performance of multi-layer and single-layer CO₂ injection methods in offshore saline aquifers, potentially revolutionizing the energy sector’s approach to carbon storage.
The study employs TOUGH-FLAC numerical simulations to evaluate four key indicators: CO₂ saturation, pore pressure, vertical displacement, and Coulomb Failure Stress (CFS). These metrics are crucial for assessing both the storage capacity of reservoirs and the mechanical stability of caprocks. The findings reveal that multi-layer injection significantly enhances CO₂ migration distance and reduces CFS values compared to single-layer injection.
“After just one year of injection, the combined CO₂ migration distance across two aquifers in our multi-layer case was 610 meters, which is substantially greater than the distances achieved with single-layer injection,” Shen explained. This increased migration distance is a game-changer for the energy sector, as it suggests that multi-layer injection could maximize the use of subsurface space, thereby increasing storage capacity and efficiency.
The research also highlights the advantages of deep saline aquifers. Higher overburden pressure in these deeper formations not only boosts CO₂ storage capacity but also mitigates the risk of caprock failures. Over a 30-year injection period, the study found that while the maximum CFS values were relatively low (0.591 and 0.567 for single-layer cases), the CO₂ migration distances were impressive, reaching 2400 meters and 2650 meters respectively.
The implications for the energy sector are profound. As the world seeks to decarbonize, the ability to store larger volumes of CO₂ more efficiently and safely is paramount. “Our findings indicate that the multi-layer injection method, particularly in deep saline aquifers, provides a safer and more efficient CO₂ injection approach for offshore CCS projects,” Shen noted. This could lead to more robust and scalable CCS solutions, supporting the energy sector’s transition towards a low-carbon future.
The study’s insights are timely, as industries and governments worldwide are investing heavily in CCS technologies. By optimizing injection methods, the energy sector can enhance the viability of CCS projects, making them more attractive for commercial investment and deployment. As the research suggests, the future of offshore CCS lies in leveraging multi-layer injection techniques, particularly in deep saline aquifers, to achieve safer and more efficient carbon storage.