Feasibility of UHS in Depleted Gas Fields: Progress on Subsurface Assessment of the H2RESTORE Project

The feasibility of underground hydrogen storage has been examined for depleted gas fields in the onshore part of the Otway Basin in SE Australia, as part of Lochard Energy’s H2RESTORE project. The subsurface part of the study involved dynamic simulations at pilot scale and commercial scale, and laboratory testing of the geochemical effects hydrogen on reservoir, seal and cement, and microbial effects on stored hydrogen. The pilot site, a small and steeply dipping structure, was found to be technically suitable even for an initial injection of 50 t of hydrogen, with a total of 81 t of hydrogen needed for three injection cycles. The commercial site, a large and gently dipping structure, was found to be technically suitable to meet the requirements of 500 MW electrical output, where the produced hydrogen goes into a turbine. The maximum quantity of stored hydrogen was 14,900 t, with a working volume of 6,500 t. The experimental studies of hydrogen interactions with samples from the reservoir, the seal and representative cement indicate that there is low risk to the formation integrity, seal capacity and cement integrity from abiotic geochemical reactions. Experiments on microbial interactions with field samples are still in progress.