A technical review on underground hydrogen storage potential in porous media: A dynamic reservoir simulation approach

Stanley Uchenna Opara, Chinedu J Okere

As the global demand for energy continues to climb and the urgency for carbon-neutral alternatives grows, hydrogen becomes increasingly prominent as a clean energy source [1], [2]. The research reviewed underground hydrogen storage potentials, discussing the distinction between the working gas and cushion gas that are critical in maintaining pressure and optimal injection conditions. Emphasis on the similarities between underground hydrogen storage and underground gas storage was made. Various underground hydrogen storage facilities were outlined, necessitating specific criteria for adaptability. Depleted hydrocarbon deposits emerge as prevalent storage systems for hydrogen due to their existing infrastructure for gas injection and retrieval, presenting a cost-efficient conversion for underground gas storage while other geological storage options include salt domes and aquifers [3], [4]. Selection criteria for sites or structures for underground hydrogen storage demand a thorough geological and engineering analyses, considering factors such as reservoir pressure, depth, permeability, and structural integrity and adaptability. Furthermore, the need to prevent hydrogen leakage and adhere to technical, economic, and safety considerations was underscored, particularly in managing fracture pressures within the reservoir during gas injection or withdrawal.
The research methodology involved developing a hypothetical reservoir model to evaluate the factors and parameters facilitating efficient hydrogen injection and withdrawal for large-scale storage. The Computer Modelling Group (CMG) reservoir simulation software was used in the research to simulate hydrogen storage and transport in porous media. Some of the model's input variables included parameters such as reservoir porosity, permeability, temperature, compressibility, and bottomhole pressure. Sensitivity runs were done on injection pressure, bottomhole pressure, permeability, and porosity to establish the significant properties that impacted hydrogen storage and the extent of their impact.