Volume 62

Enhancement Strategies for Underground Hydrogen Storage and Recovery in Deep Saline Aquifers: Optimization of Well Configuration and Cushion Gas Lirong Dong, Miao Zhang, Yunqi Cui, Dexter Godwin

Abstract

Large-scale underground hydrogen storage (UHS) in deep saline aquifers is a critical enabler for balancing seasonal energy disparities and decarbonizing heating systems. This study presents a comprehensive numerical investigation into optimizing well configuration and cushion gas selection to enhance the performance of UHS in a dome-shaped anticline structure. The results demonstrate that vertical wells significantly improve storage performance compared to horizontal wells by enhancing gas mobility control, which reduces water production during hydrogen recovery. An optimized seven-well pattern with a spacing of 350 meters achieves a storage capacity 6.5 times greater than a single-well system over long-term cyclic operation, with a hydrogen recovery efficiency exceeding 90%. Furthermore, using methane as cushion gas effectively maintains hydrogen purity above 98% during the recovery phase, outperforming carbon dioxide and nitrogen due to superior density-driven segregation. The findings underscore the critical interplay between well network design and cushion gas management in maximizing storage capacity, deliverability, and hydrogen recovery purity. This work provides essential technical guidelines for the efficient and reliable design of aquifer-based hydrogen storage, contributing significantly to the development of large-scale renewable energy integration.

Keywords underground hydrogen storage, saline aquifer, well optimization, cushion gas, numerical reservoir simulation