Distinctive Reservoir Engineering Strategies: Comparing Underground Hydrogen Storage with CCS and Natural Gas Storage

Practical implementation of underground hydrogen storage faces several multiphysics challenges that must be addressed, including multiphase flow dynamics, microbial activity and geochemical reactions. Gas storage techniques, such as carbon dioxide (CO2) and natural gas storage, have been extensively investigated in literature. A key operational difference between UHS and both CO2 and natural gas storage is that H2 must not only be stored safely but also be produced back as a pure fluid and in its entirety. The central challenge lies in the different physical processes involved in UHS, which may significantly impact the fluid behaviour and thus the reservoir engineering approaches for field development. This work reviews and summarises critical findings from gas storage research to inform tailored reservoir engineering strategies for UHS, addressing the gap between theoretical understanding and practical implementation.