<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>

<div>Palynology preparations from 62 samples from several key wells in the Northern Territory section of the Pedirka Basin were examined for Geoscience Australia. The sampling was done by the Geological Survey of NT (see table 1 for sample listing). All resulting slides and remaining residue have been submitted to government. The samples were analysed quantitatively with the first 200 specimens in each sample counted and subsequent species simply recorded as present. In this summary report, the results are provided in tabulated form only. Details of the palynomorph assemblages are recorded on StrataBugs distribution charts, with each taxon expressed as a percentage of the entire assemblage (Appendix B). From this information, assignments are made to the palynostratigraphic scheme of Price (1997), as shown in Figures 1 and 2 and summarised in Appendix A.</div><div>Wells included are: Blamore-1, CBM 93-002, CBM 93-004, CBM 107-001, CBM 107-002, Hale River-1, Simpson-1, Thomas-1. </div><div>Also see accompanying report by Hannaford and Mantle, 2022: Palynological analysis of infill samples for selected wells in the South Australian section of the Pedirka Basin. eCat 147227</div>

<div>Palynology preparations from 50 samples from several key wells in the South Australian section of the Pedirka Basin were examined for Geoscience Australia. The sampling was done by Carey Hannaford under inspection number 5358 (see table 1 for sample listing). All resulting slides and remaining residue have been submitted to government. The samples were analysed quantitatively with the first 200 specimens in each sample counted and subsequent species simply recorded as present. In this summary report, the results are provided in tabulated form only. Details of the palynomorph assemblages are recorded on StrataBugs distribution charts, with each taxon expressed as a percentage of the entire assemblage (Appendix B). From this information, assignments are made to the palynostratigraphic scheme of Price (1997), as shown in Figures 1 and 2 and summarised in Appendix A.</div><div>Wells included are: Erabena-1, Macumba-1, Mokari-1, Oolarinna-1, Pandieburra-1, Poolowanna-1, Poolowanna-2, Walkandi-1. </div><div>Also see accompanying report by Hannaford and Mantle, 2022: Palynological analysis of infill samples for selected wells in the Northern Territory section of the Pedirka Basin.</div>

<div>The Pedirka, Simpson and western Eromanga basins in central Australia have undergone a chequered exploration history which has seen a total of only 42 wells drilled across a study area of ~210,000km2. Exploration initially focused on conventional hydrocarbons from the 1950s-1980s, before shifting towards coal seam gas (CSG) opportunities in the mid-2000s. Active petroleum systems have been proven in the region by a non-commercial oil discovery at Poolowanna 1 in 1977, and by several wells that showed evidence of residual oil columns. CSG exploration wells have confirmed the presence of thick, marginally mature coal intervals on the flanks of the basins, but are yet to evaluate the deeper troughs.</div><div>Geoscience Australia, the Northern Territory Geological Survey and the South Australian Department for Energy and Mining have been collaborating on the Australia’s Future Energy Resources project under the Australian government funded Exploring for the Future Program to undertake an assessment of the resource potential for conventional and unconventional hydrocarbons, and the geological carbon and storage (GCS) potential of the greater Pedirka region. </div><div>The project applied a play-based exploration approach to qualitatively assess the resource potential of the region. The Carboniferous to Cretaceous stratigraphic interval was divided into 14 plays which were evaluated for the presence of sediment-hosted energy resources through post-drill analysis, gross depositional environment mapping and common risk segment mapping. The analysis identified energy resources and GCS potential across multiple plays and locations within the study area. These results demonstrate, that while the region is underexplored, it should not be overlooked by future exploration activities.</div> Published in The APPEA Journal 2023. <b>Citation:</b> Iwanec Jeremy, Strong Paul, Bernecker Tom (2023) Underexplored but not forgotten: assessing the energy resources potential of the greater Pedirka Basin region through play-based mapping. <i>The APPEA Journal</i><b> 63</b>, S251-S256. https://doi.org/10.1071/AJ22150

<div>The “Australia’s Future Energy Resources” (AFER) project, funded under the Government’s “Exploring for the Future” (EFTF) program has been completed. The project’s four modules have evaluated a mixture of energy resource commodities, including natural gas, hydrogen, subsurface storage opportunities for carbon dioxide and hydrogen. They are complimented by several targeted basin inventories which outline the current geological knowledge of energy resources in underexplored, data-poor regions. Several publicly available data sets have been generated and published under the AFER project, including 3,750&nbsp;line-km of reprocessed 2D seismic data, acquired in the Pedirka and western Eromanga basins, of which key lines have been interpreted and integrated with geological and petrophysical well log data. Relative prospectivity maps have been produced for five energy resource commodities from 14&nbsp;play intervals to show the qualitative variability in prospectivity of these resources, including quantitative resource assessments where warranted. Results from the AFER project have helped to identify and geologically characterise the required energy resource commodities to accelerate Australia’s path to net zero emissions.</div> Presented at the Australian Energy Producers (AEP) Conference & Exhibition (https://energyproducersconference.au/conference/)

<div>Geoscience Australia’s Exploring for the Future program provides precompetitive information 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 leads to a strong economy, resilient society and sustainable environment for the benefit of all Australians. This includes supporting Australia’s transition to net zero emissions, strong, sustainable resources and agriculture sectors, and economic opportunities and social benefits for Australia’s regional and remote communities. The Exploring for the Future (EFTF) program, which commenced in 2016, is an eight year, $225m investment by the Australian Government. </div><div><br></div><div>As part of the EFTF Program, Geoscience has completed a multi-disciplinary study to investigate the energy resource potential of selected onshore basins within central Australia under the Australia’s Future Energy Resources (AFER) Project. The AFER Project has adapted the conventional hydrocarbon play-based exploration workflow, developed by the petroleum industry over several decades, to develop a similar approach for assessing unconventional hydrocarbon resource potential and CO2 geological storage prospectivity. Play-based exploration is a method of building and leveraging an understanding of a basin and its sediment-hosted resources by systematically evaluating a series of play intervals using the best available geological data and models. Each play interval represents a regionally significant reservoir/aquifer for one or more resources (e.g. hydrocarbons, groundwater, CO2 storage intervals) often with an associated seal/aquitard. Various ‘risk elements’ that are essential for a resource to exist can be mapped and qualified with a probability of geological success. These risk elements are then spatially integrated (stacked) to generate common risk segment (CRS) or ‘heat’ maps for each play interval that indicate areas of relatively high prospectivity versus relatively low prospectivity. Geological risk elements are evaluated using post-drill analysis of well control points, and geological maps generated from basin studies.</div><div><br></div><div>Common risk segment mapping, supported by post-drill analysis, has been undertaken by the AFER Project using the GIS-Pax Player Software, and assigned a geological probability of success (POS) using a ‘split risking’ system that involves assessing: </div><div>·&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Pg play, which is the POS that the risk element is effective somewhere within the map segment; </div><div>·&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Pg repeatability, which is the POS of future repeated effective discoveries for the risk element within the map segment (i.e. the inherent variability or heterogeneity of the risk element); and the </div><div>·&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Pg overall (Pg play x Pg repeatability). </div><div><br></div><div>This data package provides a spatial data set (CRS maps and post-drill analysis) capturing the AFER project’s assessment of hydrocarbon resources (conventional hydrocarbons, coal seam gas, and shale hydrocarbons) and the CO2 geological storage potential of the Pedirka and western Eromanga basins. The data package includes the following data sets:</div><div>1.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Common risk segment maps for conventional hydrocarbons, unconventional hydrocarbons and CO2 geological storage resources provided in ESRI© ArcGIS file geodatabase format (gdb).</div><div>2.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Common risk segment maps for conventional hydrocarbons, unconventional hydrocarbons and CO2 geological storage resources provided in ESRI© shape format (shp).</div><div>3.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Post-drill analysis data provided in ESRI© shape format (shp).</div><div>4.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Metadata forms documenting key information (abstract, data sources, lineage for related groups of map layers, keywords) for each group of related CRS maps and for the post-drill analysis results. </div><div><br></div><div>The product authors wish to acknowledge Tehani Palu (Geoscience Australia) for her internal peer review of the digital data package, Darren Ferdinando (Basin Science Pty Ltd) for his review of the conventional hydrocarbon common risk segment mapping, and Catherine Flowers (Geoscience Australia) for her technical support in developing the GIS products.</div><div><br></div><div><br></div>

<div>Understanding the hydrocarbon potential of Australia’s sedimentary basins is critical to ensuring the nation’s future energy security. The Pedirka and western Eromanga basins have proven petroleum potential with a sub-commercial oil discovery at Poolowanna 1 in the Poolowanna Trough and several wells drilled over the Colson Shelf and Madigan Trough showing evidence for residual oil zones. However, these basins remain relatively underexplored with only 42 petroleum wells drilled and relatively sparse 2D seismic data coverage. Geoscience Australia’s AFER Project has undertaken a qualitative and quantitative play-based assessment of the Pedirka and western Eromanga basins to enable a better understanding of their undiscovered hydrocarbon resources.</div><div><br></div><div>The AFER Project’s assessments are underpinned by new geological insights into the western Eromanga Basin and a supporting upscaled 3D geological model. A play-based common risk segment (CRS) mapping approach has been applied to eleven play intervals to delineate basin areas with relatively high prospectivity based on five geological risk elements: reservoir presence, reservoir effectiveness, top seal, trap presence, and hydrocarbon charge. Results from this qualitative component of the assessment indicate that the highest potential for future hydrocarbon discoveries is likely to be conventional oil resources across the Poolowanna Trough, Colson Shelf and Madigan Trough. The most prospective exploration targets are the Namur-Murta, Poolowanna and Peera Peera play intervals on a geological probability of success basis. The Peera Peera and Poolowanna play intervals have proven hydrocarbon charge from the Poolowanna 1 oil discovery but show poor reservoir quality (porosity <10%) in wells drilled across the Poolowanna Trough. These play intervals likely represent tight conventional oil exploration targets across their main play fairways in the Poolowanna Trough. The Namur-Murta interval has high reservoir qualities across all potentially prospective areas but has lower certainty regarding hydrocarbon charge with the most significant exploration result to date being a residual oil zone in the Madigan Trough. Moderate to high prospectivity for conventional oil is interpreted to occur in the Adori-Westbourne, Birkhead and Hutton play intervals over the eastern flanks of the Poolowanna Trough and western flanks of the Birdsville Track Ridge. The Walkandi, Upper Purni, Lower Purni and Crown Point play intervals are assessed as having moderate prospectivity for conventional oil over the Eringa Trough, Madigan Trough and Colson Shelf. </div><div><br></div><div>A quantitative assessment of the ‘Yet to Find’ hydrocarbon volumes has been undertaken to provide a play-level indication of the possible undiscovered conventional oil volumes. The risked volumes include a ‘Base Case’ that reflects the current exploration understanding of the basins, and a ‘High Case’ that reflects the potential impact of a new working petroleum system being discovered in the basins. The mean risked recoverable oil volume for the Base Case scenario total 22.2 MMbbl for the four plays evaluated (Namur-Murta, Poolowanna, Peera Peera and Lower Purni). About 70% of the risked mean volumes occur in the Poolowanna and Namur-Murta play intervals. Results from the High Case model highlight the significantly greater YTF potential across the basins if the geological requirement for a new working petroleum system eventuates from further exploration, with a total mean risked volume of 234.8 MMbbl for the three play intervals evaluated (Namur-Murta, Poolowanna and Lower Purni). Risked volumes are relatively evenly distributed across the three play intervals. &nbsp;&nbsp;</div><div><br></div><div>Unconventional hydrocarbons are evaluated as being less prospective than conventional hydrocarbons in the western Eromanga basin. Shale oil plays have not previously been explored but may be present within organic-rich shales from the Poolowanna and Peera Peera play intervals. These shale oil plays are evaluated as being moderately prospectivity due to their thin and heterogeneous character. Coal seam gas (CSG) wells drilled into the Upper Purni and Lower Purni play intervals have to date only demonstrated the presence of gas-undersaturated coal seams over the Andado Shelf. However, CSG is the most likely hydrocarbon resource type to produce hydrocarbons from the Pedirka Basin if future exploration can identify sweet spots where different geological conditions occur that are conducive to preserving high gas saturations.&nbsp;</div><div><br></div>

<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>

<div>Identifying potential basin areas for future Geological Storage of CO2 (GSC) exploration is essential to support Australia’s transition to a net zero emissions energy future. Geoscience Australia’s AFER Project has completed a play-based assessment of the GSC potential in the Pedirka and western Eromanga basins using regionally extensive aquifers containing saline to slightly brackish formation waters. There are currently no significant anthropogenic CO2 sources or associated storage projects in the assessment area. Understanding the area’s GSC potential does, however, assist in providing options for addressing CCS requirements in the central Australian region, including any future opportunities to remove anthropogenic CO2 using Direct Air Capture and Storage technologies. </div><div><br></div><div>The AFER Project’s assessments are underpinned by new geological insights into the basins and a supporting upscaled 3D geological model. A play-based common risk segment mapping approach has been applied to five potential storage (play) intervals to delineate basin areas with relatively high prospectivity based on four geological risk elements: injectivity, storage effectiveness, containment, and structural complexity. Results from this qualitative component of the assessment highlights a potentially prospective area for future GSC exploration extending across the Northern Territory, South Australia and Queensland. The most prospective interval on a geological probability of success basis is the Namur-Murta play interval. </div><div><br></div><div>Results from the qualitative GSC assessment have been used as a screening tool to delineate areas for quantitative modelling of the range of Estimated Ultimate Storage (EUS) volumes using deterministic and probabilistic methodologies. EUS volumes have been estimated in two model areas representing geological end members in storage interval heterogeneity and potentially prospective areas outside of the extents of current national parks. The EUS potential is high (10’s of gigatonnes) in the two model areas using both deterministic and probabilistic workflows, as expected for a regional assessment using very large pore volumes. Applying a geological probability of success based on injectivity and structural and stratigraphic containment reduces the volumes in the two model areas to a risked best estimate EUS of 13 Gt in the eastern area and a risked best estimate EUS of 2 Gt in the western area. Results from the quantitative assessment suggest that both model areas can support multiple industrial-scale CCS projects injecting 50 Mt CO2 over a 20-year period. However, heterogeneous reservoirs that extend over the eastern assessment area are likely to have greater storage efficiencies and an associated smaller project footprint of 29 km2 using three CO2 injection wells. Relatively homogenous reservoirs elsewhere in the assessment area have lower storage efficiencies due to a lack of intraformational seals within the Algebuckina Sandstone and have an associated larger project area of 49 km2 using three CO2 injection wells. Pressure management requirements are likely to be minimal in both model areas due to the thick and open nature of reservoirs. However, water production rates of up to 16,500 m3/day may be required where local lateral barriers to pressure dissipation occur. &nbsp;&nbsp;&nbsp;</div><div><br></div><div>Results from the AFER Project's GSC assessment demonstrate the value of applying a play-based exploration workflow for a regional-scale energy resource assessment. Estimating the geological probability of success to the presence and repeatability of four mappable risk elements associated with GSC resources allows both relative prospectivity maps and risked EUS volumes to be generated. Prospectivity maps and EUS volumes can in turn be readily updated as new geological data are collected to infill data and knowledge gaps. Geoscience Australia is building a national inventory of GSC resources using this play-based exploration approach, with qualitative assessments now completed under the EFTF and TEGI programs in seven basin areas from central and eastern Australia.&nbsp;</div><div><br></div>

<div>As part of the EFTF Program, Geoscience has completed a 4-year multi-disciplinary study to investigate the energy resource potential of selected onshore basins within central Australia under the Australia’s Future Energy Resources (AFER) Project. A key component of the AFER Project has been a qualitative and quantitative play-based assessment of hydrocarbon resources and geological storage of CO2 (GSC) potential within the Pedirka and western Eromanga basins (Bradshaw et al., 2024a). This study has provided a regional interpretive data set which includes regional seismic and well log interpretations (Bradshaw et al.&nbsp;2024b, 2024c); depth-structure and isochore maps for 14 play intervals (Iwanec et al., 2024); gross-depositional environment maps for 14 play intervals (Bradshaw et al., 2024c); and petrophysical analysis of wireline log data from 23 wells (Spicer et al., 2024). This report provides a high-level summary of the hydrogeology of Pedirka and western Eromanga basins as background information for the other assessments and some findings from the 3D models that may inform future understanding of the hydrogeology of these basins. </div><div><br></div><div>The assessment area extends over ~210,000 km2 across the Northern Territory, South Australia and Queensland (Figure 1). Much of the assessment area underlies national parks in South Australia and Queensland. No petroleum exploration access is allowed in the Munga Thirri Simpson Desert Conservation Park or the Witjira National Park (Dalhousie Springs area) in South Australia or Munga Thirri National Park in Queensland (Figure 1).</div><div><br></div><div>The AFER assessment area is situated within the Kati Thanda-Lake Eyre surface water catchment. The catchment’s arid climate and ephemeral river flow regime (Evans et al., 2024) makes groundwater a critical source of water for the environment, industry and communities, especially during dry periods. Groundwater dependent features in the region include water supplies for communities, industry and pastoral stations, as well as springs and other groundwater dependent ecosystems. Groundwater resources are managed by state and territory jurisdictions (see: NT Government, 2013; Queensland Government, 2017, SA Government, 2021). Across the three jurisdictions, the most important groundwater resources are those of the western Eromanga Basin (a part of Great Artesian Basin or GAB). In collaboration with state jurisdictions the Commonwealth provides a cross-jurisdictional policy framework for the GAB as well as the Lake Eyre surface water basin (DCCEEW, 2024). Key management goals include maintaining artesian pressures, water quality and viability of GAB dependent ecosystems, including springs.&nbsp;</div><div><br></div><div><br></div><div><br></div>