A Stratigraphic Reconstruction of Bulk Volatile Chemistry from Fluid Inclusions in: Glenorchy 1

Exploring for the Future (EFTF) is an Australian Government program led by Geoscience Australia (GA), in partnership with state and Northern Territory governments. The EFTF program (2016-2024) aims to drive industry investment in resource exploration in frontier regions of onshore Australia by providing new precompetitive data and information about their energy, mineral and groundwater resource potential. Under the EFTF program, GA’s National Hydrogen Project and in collaboration with Minerals Resources Tasmania (MRT) undertook a study of hydrogen and helium potential of south-east Tasmania with the sampling of cores from Glenorchy 1 in the surrounds of Hobart. This well was selected based on the availability of core and historic reports of hydrogen-rich natural gases from petroleum exploration wells in the region. Sampling of cores was done at MRT’s Core Repository in Hobart. Geoscience Australia commissioned a fluid inclusion stratigraphy (FIS) study on the downhole samples. Here, volatile components ostensibly trapped with fluid inclusions are released and analysed revealing the level of exposure of the well section to migrating fluids. Integration of thin section (TS) preparations reveal the extent of gas and fluid trapping within fluid inclusions while microthemometry (MT) gives an estimation of fluid inclusion trapping temperature. For Glenorchy 1, FIS analysis was performed on 173 cores between 6 m and 613.9 m base depth, together with 8 samples prepared for TS and 1 sample for MT. To support this study, lithostratigraphic tops were compiled by MRT. The results of the study are found in the accompanying documents.