Feasibility of underground hydrogen storage in a salt cavern in the offshore Polda Basin

Underground hydrogen storage (UHS) in halite caverns will become an essential technology to supplement energy supply networks. This study examines the feasibility of UHS in the offshore Polda Basin by integrating previous seismic interpretation, well data and regional geology information. The Mercury structure in the central – east Polda Basin has extensive halite accumulations (both vertically and laterally) and has been identified as an area with high UHS potential. The net halite thickness is more than 1000 m, while the total potential area is about 217 km². Well data from the Mercury 1 well show a low thermal gradient (1.7–2.1 °C/100m) and overburden pressure gradient of approximately 18 ppg, providing effective gas operation pressure for UHS. To illustrate the feasibility of UHS, a conceptual design of a halite cavern is provided for a depth range of 1650–2000 m. Caverns with diameters of 60 m and 100 m are estimated to have storage capacities of approximately 240 GWh and 665 GWh, respectively. Multiple halite caverns could be constructed within the extensive Mercury halite accumulation. Further investigation into the potential for salt accumulations in the onshore Polda Basin is recommended. Citation: Feitz A. J., Wang L., Rees S. & Carr L., 2022. Feasibility of underground hydrogen storage in a salt cavern in the offshore Polda Basin. In: Czarnota, K. (ed.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, https://dx.doi.org/10.26186/146501