The integrated use of seismic and gravity data can help to assess the potential for underground hydrogen storage in salt caverns in the offshore Polda Basin, South Australia. Geophysical integration software was trialled to perform simultaneous modelling of seismic amplitudes and traveltime information, gravity, and gravity gradients within a 2.5D cross-section. The models were calibrated to existing gravity data, seismic and well logs improving mapping of the salt thickness and depth away from well control. Models included known salt deposits in the offshore parts of the basin and assessed the feasibility for detection of potential salt deposits in the onshore basin, where there is limited well and seismic coverage. The modelling confirms that candidate salt cavern storage sites with salt thicknesses greater than 400-500 m should be detectable on low altitude airborne gravity surveys. Identification of lower cost onshore storage sites will require careful calibration of gravity models against measured data, rather than relying on the observation of rounded anomalies associated with salt diapirism. Ranking of the most prospective storage sites could be optimized after the acquisition of more detailed gravity and gradiometry data, preferably accompanied by seismic reprocessing or new seismic data acquisition.

The Exploring for the Future program Showcase 2023 was held on 15-17 August 2023. Day 3 - 17th August talks included: Geological Processes and Resources Session Large scale hydrogen storage: The role of salt caverns in Australia’s transition to net zero – Dr Andrew Feitz Basin-Hosted Base Metal Deposits – Dr Evgeniy Bastrakov Upper Darling Floodplain: Groundwater dependent ecosystem assessment – Dr Sarah Buckerfield Atlas of Australian Mine Waste: Waste not, want not – Jane Thorne Resource Potential Theme National-scale mineral potential assessments: supporting mineral exploration in the transition to net zero – Dr Arianne Ford Australia’s Onshore Basin Inventories: Energy – Tehani Palu Prioritising regional groundwater assessments using the national hydrogeological inventory – Dr Steven Lewis Assessing the energy resources potential in underexplored regions – Dr Barry Bradshaw You can access the recording of the talks from YouTube here: <a href="https://youtu.be/pc0a7ArOtN4">2023 Showcase Day 3 - Part 1</a> <a href="https://youtu.be/vpjoVYIjteA">2023 Showcase Day 3 - Part 2</a>

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. <b>Citation: </b>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

The Adavale Basin, home to the Boree Salt, is a potential option for underground hydrogen storage (UHS) due to its close proximity to industrial infrastructure, existing pipelines and significant renewable energy sources. This study builds upon a previously constructed 3D geological model to examine the feasibility of developing salt caverns for UHS. The study integrates well data and regional geology, as well as analyses on mineralogy, geochemistry and petrophysical and geomechanical properties of the Boree Salt. Results highlight that the Boree Salt is predominantly halite (96.5%), with a net salt thickness of ~540 m encountered in Bury 1, and has excellent seal properties. Furthermore, the formation overburden pressure gradient implies favourable conditions for storing hydrogen in the Boree Salt. To illustrate the feasibility of UHS, a conceptual design of a cylindrical salt cavern at depth intervals of 1600 – 1950 m is presented. A single 60 m diameter cavern could provide up to 203 GWh (or ~ 6000 tonnes) of hydrogen energy storage. Further investigation to improve our understanding on the Boree Salt extent is recommended.

Natural hydrogen is receiving increasing interest as a potential low-carbon fuel. There are various mechanisms for natural hydrogen generation but the reduction of water during oxidation of iron in minerals is recognised to be the major source of naturally generated H2. While the overall reaction is well known, the identity and nature of the key rate limiting steps is less understood. This study investigates the dominant reaction pathways through the use of kinetic modelling. The modelling results suggest there are a number of conditions required for effective H2 production from iron minerals. These include the presence of ultramafic minerals that are particularly high in Fe rather than Mg content, pH in the range of 8 to 10, solution temperatures in the 200 to 300oC range, and strongly reducing conditions. High reaction surface area is key and this could be achieved by the presence of finely deposited material and/or assemblages of high porosity or with mineral assemblages with surface sites that are accessible to water. Finally, conditions favouring the co-deposition of Ni together with FeO/Fe(OH)2-containing minerals such as brucite (and, possibly, magnetite) could enhance H2 generation

Carbon capture and storage (CCS) is a central component of many proposed pathways to reach net zero CO2 emissions by 2050. Even under conservative estimates, successful deployment of CCS projects at scale will require a substantial investment in the selection and development of new sequestration sites. While several studies have considered the potential costs associated with individual sequestration projects, and others have evaluated the costs of capture and sequestration in a generic manner, few have examined how regional differences in transport distances and reservoir properties may affect the overall costs of sequestration projects. In this abstract, we outline a new model to assess the costs associated with new carbon sequestration projects. The model evaluates the cost of CCS projects accounting for regional variations in transport distance and cost and well the storage properties of individual reservoirs. We present preliminary results from the modelling tool, highlighting potential opportunities for new CCS projects.

All commercially produced hydrogen worldwide is presently stored in salt caverns. In eastern Australia, the only known thick salt accumulations are found in the Boree Salt of the Adavale Basin in central Queensland. Although the number of wells penetrating the basin is limited, salt intervals up to 555 m thick have been encountered. The Boree Salt consists predominantly of halite and is considered to be suitable for hydrogen storage. Using well data and historical 2D seismic interpretations, we have developed a 3D model of the Adavale Basin, particularly focussing on the thicker sections of the Boree Salt. Most of the salt appears to be present at depths greater than 2000 m, but shallower sections are found in the main salt body adjacent to the Warrego Fault and to the south at the Dartmouth Dome. The preliminary 3D model developed for this study has identified three main salt bodies that may be suitable for salt cavern construction and hydrogen storage. These are the only known large salt bodies in eastern Australia and therefore represent potentially strategic assets for underground hydrogen storage. There are still many unknowns, with further work and data acquisition required to fully assess the suitability of these salt bodies for hydrogen storage. Recommendations for future work are provided. <b>Citation:</b> Paterson R., Feitz A. J., Wang L., Rees S. & Keetley J., 2022. From A preliminary 3D model of the Boree Salt in the Adavale Basin, Queensland. In: Czarnota, K. (ed.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, https://dx.doi.org/10.26186/146935

<div>This document provides metadata for the gross depositional environment (GDE) interpretations that have been generated in support of the energy resource assessments under the Australia’s Future Energy Resources (AFER) project.&nbsp;&nbsp;</div><div>The AFER projects is part of Geoscience Australia’s Exploring for the Future (EFTF) Program—an eight year, $225 million Australian Government funded geoscience data and precompetitive information acquisition program to inform decision-making by government, community and industry on the sustainable development of Australia's mineral, energy and groundwater resources. By gathering, analysing and interpreting new and existing precompetitive geoscience data and knowledge, we are building a national picture of Australia’s geology and resource potential. This will help support a strong economy, resilient society and sustainable environment for the benefit of all Australians. The EFTF program is supporting Australia’s transition to a low emissions economy, industry and agriculture sectors, as well as economic opportunities and social benefits for Australia’s regional and remote communities. Further details are available at http://www.ga.gov.au/eftf.&nbsp;</div><div>The GDE data sets provide high level classifications of interpreted environments where sediments were deposited within each defined play interval in the Pedirka, Simpson and Western Eromanga basins. Twelve gross depositional environments have been interpreted and mapped in the study (Table 1). A total of 14 play intervals have been defined for the Pedirka, Simpson and Western Eromanga basins by Bradshaw et al. (2022, in press), which represent the main chronostratigraphic units separated by unconformities or flooding surfaces generated during major tectonic or global sea level events (Figure 1). These play intervals define regionally significant reservoirs for hydrocarbon accumulations or CO2 geological storage intervals, and often also include an associated intraformational or regional seal.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</div><div>GDE interpretations are a key data set for play-based resources assessments in helping to constrain reservoir presence. The GDE maps also provide zero edges showing the interpreted maximum extent of each play interval, which is essential information for play-based resource assessments, and for constructing accurate depth and thickness grids.&nbsp;&nbsp;</div><div>GDE interpretations for the AFER Project are based on integrated interpretations of well log and seismic data, together with any supporting palynological data. Some play intervals also have surface exposures within the study area which can provide additional published paleo-environmental data. The Pedirka, Simpson and Western Eromanga basins are underexplored and contain a relatively sparse interpreted data set of 42 wells and 233 seismic lines (Figure 2). Well and outcrop data provide the primary controls on paleo-environment interpretations, while seismic interpretations constrain the interpreted zero edges for each play interval. The sparse nature of seismic and well data in the study area means there is some uncertainty in the extents of the mapped GDE’s.&nbsp;&nbsp;</div><div>The data package includes the following datasets:&nbsp;&nbsp;</div><div>Play interval tops for each of the 42 wells interpreted – provided as an ‘xlsx’ file.&nbsp;</div><div>A point file (AFER_Wells_GDE) capturing the GDE interpretation for each of the 14 play intervals in each of the 42 wells – provided as both a shapefile and within the AFER_GDE_Maps geodatabase.&nbsp;</div><div>Gross depositional environment maps for each of the 14 play intervals (note that separate GDE maps have been generated for the Namur Sandstone and Murta Formation within the Namur-Murta play interval, and for the Adori Sandstone and Westbourne Formation within the Adori-Westbourne play interval) – provided as both shapefiles and within the AFER_GDE_Maps geodatabase.&nbsp;</div><div>&nbsp;</div><div>These GDE data sets are being used to support the AFER Project’s play-based energy resource assessments in the Western Eromanga, Pedirka and Simpson basins.&nbsp;</div><div><br></div>

The Exploring for the Future program Showcase 2023 was held on 15-17 August 2023. Day 1 - 15th August talks included: Resourcing net zero – Dr Andrew Heap Our Geoscience Journey – Dr Karol Czarnota You can access the recording of the talks from YouTube here: <a href="https://youtu.be/uWMZBg4IK3g">2023 Showcase Day 1</a>

<div>This data package provides depth and isochore maps generated in support of the energy resource assessments under the Australia’s Future Energy Resources (AFER) project. Explanatory notes are also included.</div><div><br></div><div>The AFER project is part of Geoscience Australia’s Exploring for the Future (EFTF) Program—an eight year, $225 million Australian Government funded geoscience data and precompetitive information acquisition program to inform decision-making by government, community and industry on the sustainable development of Australia's mineral, energy and groundwater resources. By gathering, analysing and interpreting new and existing precompetitive geoscience data and knowledge, Geoscience Australia is building a national picture of Australia’s geology and resource potential. This will help support a strong economy, resilient society and sustainable environment for the benefit of all Australians. The EFTF program is supporting Australia’s transition to a low emissions economy, industry and agriculture sectors, as well as economic opportunities and social benefits for Australia’s regional and remote communities. Further details are available at http://www.ga.gov.au/eftf.</div><div><br></div><div>The depth and isochore maps are products of depth conversion and spatial mapping seismic interpretations by Szczepaniak et al. (2023) and Bradshaw et al. (2023) which interpreted 15 regional surfaces. These surfaces represent the top of play intervals being assessed for their energy resource potential (Figure 1). These seismic datasets were completed by play interval well tops by Bradshaw et al. (in prep), gross depositional environment maps, zero edge maps by Bradshaw et al. (in prep), geological outcrop data as well as additional borehole data from Geoscience Australia’s stratigraphic units database.</div><div><br></div><div>Depth and isochore mapping were undertaken in two to interactive phases; </div><div><br></div><div>1.&nbsp;&nbsp;&nbsp;&nbsp;A Model Framework Construction Phase – In this initial phase, the seismic interpretation was depth converted and then gridded with other regional datasets. </div><div><br></div><div>2.&nbsp;&nbsp;&nbsp;&nbsp;A Model Refinement and QC Phase – This phase focused on refining the model and ensuring quality control. Isochores were generated from the depth maps created in the previous phase. Smoothing and trend modelling techniques were then applied to the isochore to provide additional geological control data in areas with limited information and to remove erroneous gridding artefacts.&nbsp;</div><div><br></div><div>The final depth maps were derived from isochores, constructing surfaces both upward and downward from the CU10_Cadna-owie surface, identified as the most data-constrained surface within the project area. This process, utilizing isochores for depth map generation, honours all the available well and zero edge data while also conforming to the original seismic interpretation.</div><div><br></div><div>This data package includes the following datasets: </div><div><br></div><div>1)&nbsp;&nbsp;&nbsp;Depth maps, grids and point datasets measured in meters below Australian Height Datum (AHD, for 15 regional surfaces (Appendix A). </div><div>2)&nbsp;&nbsp;&nbsp;Isochore maps, grids and point datasets measured in meters, representing 14 surfaces/play internals (Appendix B).</div><div>&nbsp;</div><div>These depth and isochore maps are being used to support the AFER Project’s play-based energy resource assessments in the Pedirka and western Eromanga basins, and will help to support future updates of 3D geological and hydrogeological models for the Great Artesian Basin by Geoscience Australia.</div><div><br></div>