Hydrogen Wettability and Geo-Storage Mechanics

Large-scale geo-storage of hydrogen relies on the interplay of rock–fluid interactions and subsurface mechanics. Wettability describes the affinity of geological surfaces for hydrogen relative to brine or other reservoir fluids; this property governs displacement of pore water, dictates capillary pressure–saturation relationships and ultimately determines storage capacity and containment security. At pore scale, contact angles and interfacial tensions control the distribution and trapping of hydrogen, influencing injection and withdrawal rates, residual saturation and recovery factors. Macro-scale storage efficiency emerges from the integration of these pore-scale processes through relative permeability functions and capillary pressure curves. Key parameters affecting hydrogen wettability include pressure, temperature, salinity, mineralogy, surface roughness and the presence of organic matter or cushion gases such as CH₄ or CO₂. Understanding these factors is essential to assess storage potential in aquifers, depleted hydrocarbon fields and salt caverns, and to ensure the long-term integrity of caprock seals. Advances in imaging and laboratory methods have begun to reveal the fundamental mechanisms controlling hydrogen flow and retention, providing the data required for robust reservoir simulation and safe operational design.

Research from Nature Portfolio

Recent studies have used high-resolution X-ray computed tomography to image hydrogen–water multiphase flow in heterogeneous sandstone cores under in situ pressure and temperature conditions. These experiments quantified capillary pressure and relative permeability during drainage and imbibition cycles, and derived receding contact angles for the hydrogen–brine–rock system. The work revealed complex displacement patterns, including gravity segregation, capillary barrier effects and finger formation, which contribute to residual hydrogen trapping. By linking micro-scale observations to continuum-scale transport functions, this research advances predictive models for underground hydrogen storage and informs the selection of reservoir formations and operational strategies.

Hydrogen Wettability and Geo-Storage Mechanics publication trend

The graph below shows the total number of articles in hydrogen wettability and geo-storage mechanics across all publications each year (not limited to Nature Index journals).

Technical terms

Wettability: The relative affinity of a solid surface for one fluid over another in a multiphase system, often expressed by contact angle measurements.

Contact angle: The angle at which a fluid–fluid interface meets a solid surface; indicates whether the surface is water-wetting or gas-wetting.

Capillary pressure: The pressure difference between two immiscible fluids in a porous medium, arising from interfacial tension and pore geometry.

Relative permeability: A measure of the ease with which each fluid phase flows through a porous medium in the presence of other phases.

Cushion gas: A secondary gas, such as methane or carbon dioxide, injected alongside hydrogen to maintain reservoir pressure and enhance storage performance.

References

1. A review of hydrogen/rock/brine interaction: Implications for Hydrogen Geo-storage. Progress in Energy and Combustion Science (2023).
2. Influence of organics and gas mixing on hydrogen/brine and methane/brine wettability using Jordanian oil shale rocks: Implications for hydrogen geological storage. Journal of Energy Storage (2023).
3. Surface interaction changes in minerals for underground hydrogen storage: Effects of CO2 cushion gas. Renewable Energy (2024).
4. Experimental characterization of H2/water multiphase flow in heterogeneous sandstone rock at the core scale relevant for underground hydrogen storage (UHS). Scientific Reports (2022).