Understanding the Feasibility of Hydrogen Storage in Depleted Hydrocarbon Reservoirs

This thesis quantifies geochemical, mineralogical, microstructural, and flow responses of reservoir and seal lithologies to evaluate the feasibility of underground hydrogen storage (UHS). Using laboratory experiments, synchrotron X-ray micro-CT, and reactive-transport modelling, it assesses H₂–rock–brine interactions in sandstone, claystone, limestone, and oil-saturated sandstone. Results show modest silicate reactivity (~15% normalized extent) but substantial carbonate and pyrite alteration (~35%), accompanied by up to ~25% hydrogen loss from reaction and diffusion. Synchrotron imaging links porosity evolution to mineral dissolution and oil-saturation patterns, with associated changes in flow properties. Collectively, the work improves understanding and quantification of H₂–rock–fluid interactions and provides parameters to inform safe, efficient UHS design—including containment, injectivity, and cycling performance.