Australia's geology - providing natural hydrogen for the future

Molecular hydrogen from geological sources (natural H2) is gaining an increasing share of exploration investment and activity globally. If found in commercially exploitable quantities, natural H2 could potentially support the transition to a low carbon economy. The origins of natural H2 are more varied and numerous than those for petroleum. Natural H2 of abiogenic origin is found in shallow reservoirs encompassing igneous, metamorphic and sedimentary rocks. This is particularly the case where Precambrian cratons underlay sedimentary basins. In Australia, an initial continent-wide natural H2 potential resource to a depth of 1 km was estimated without subsurface differentiation of rock types. Focusing here on Australia’s Kalgoorlie region in Western Australia, an area with known H2-rich natural gases, a 3D modelling study of hydrogen production from different types of Archean rocks ranging from ultramafics to granites to sedimentary rocks found that the rate of natural H2 production from both hydration and radiolytic H2 was 10.7 MMcf yr-1 from a rock volume with surface area of 104 km x 160 km and to a depth of 6 km. While the results from these initial studies are promising, continued development of natural H2 exploration strategies and resource estimates are required before the contribution of natural H2 to the global low carbon economy can be fully assessed.

Paper submitted for the 26th World Mining Congress (WMC 2023) 26-29 June 2023.