An assessment of tight, shale and deep coal gas prospectivity of the Cooper Basin has been undertaken as part of the Australian Government’s Geological and Bioregional Assessment Program. This aims to both encourage exploration and understand the potential impacts of resource development on water and the environment. This appendix presents a review of the regional petroleum prospectivity, its exploration, and the characterisation and analysis of shale, deep coal and tight gas in Carboniferous–Permian Gidgealpa Group of the Cooper Basin. The Cooper Basin is Australia’s premier onshore conventional hydrocarbon-producing province providing domestic gas for the East Coast Gas Market. As of December 2014, the Cooper and Eromanga basins have produced 6.54 Tcf of gas since 1969. The basins contain 256 gas fields as well as 166 oil fields that are currently in production. Gas is predominantly reservoired in the Cooper Basin, whereas the overlying Eromanga Basin hosts mainly oil. Hydrocarbon shows are found in the reservoir units throughout the succession. Recently, exploration targeting a range of unconventional plays has gained momentum. Unconventional play types within the mainly Permian Gidgealpa Group include shale gas associated with the Patchawarra Formation and the Roseneath and Murteree shales, tight and deep coal gas accumulations within the Toolachee, Epsilon and Patchawarra formations and additional tight gas plays in the Daralingie Formation and Tirrawarra Sandstone. To date, at least 80 wells have been drilled to test shale, tight and deep coal gas plays. Given the basin’s existing conventional production, and its processing and pipeline infrastructure, these plays are well placed to be rapidly commercialised, should exploration be successful. A prospectivity confidence mapping workflow was developed to evaluate the regional distribution of key unconventional gas plays within the Gidgealpa Group. For each play type, key physical properties were identified and characterised. The specific physical properties evaluated include formation extents, source rock properties (net thickness, TOC, quality and thermal maturity), reservoir characteristics (porosity, permeability, gas saturation and brittleness), regional stress regime and overpressure. Parameters for mappable physical properties were individually classified to assign prospectivity rankings. Individual properties were then multiplied together produce formation and play-specific prospectivity confidence maps. Non-mappable criteria were not integrated into the prospectivity mapping but were used to better understand the geological characteristics of the formations. Overall, both source and reservoir characteristics were found to be moderately to highly favourable for all play types assessed. Abundant source rocks are present in the Gidgealpa Group across the Cooper Basin. The Toolachee and Patchawarra formations are the richest, thickest and most extensive source rocks, with good to excellent source potential across their entire formation extents. Net shale, coal and sand thicknesses also demonstrate an abundance of potential reservoir units in the Gidgealpa Group across the basin. The predominantly fluvial Toolachee Formation is thickest in the Windorah Trough and Ullenbury Depression. Average effective porosity for assessed tight gas plays ranges from 6.7 % in the fluvio-deltaic to lacustrine Epsilon Formation to 7.8% in the Toolachee Formation. Based on an assessment of the brittleness of the shales and coaly shales, the Patchawarra Formation appears to be most favourable for hydraulic stimulation with an average Brittleness Index of 0.695, indicative of brittle rocks. This compares to the less brittle lacustrine Roseneath and Murteree shales have brittleness indices of 0.343 and 0.374, respectively. As-received total gas content is favourable, with averages ranging from 1.3 scc/g in the Patchawarra Formation to 1.6 scc/g for the Murteree Shale. The regional stress regime has an approximately east-west oriented maximum horizontal stress azimuth, resulting in predominantly strike-slip faulting to reverse faulting, depending on the depth, lithology and proximity of structures, e.g. GMI ridge. Significant overpressure is present at depths greater than 2800 m, especially in the Nappamerri and Patchawarra troughs. Overpressures are generally constrained to the Gidgealpa Group, with the Toolachee Formation being the youngest formation in which significant overpressure has been achieved. Based on a review of the geomechanical properties of the Cooper Basin sedimentary succession, it was found that stress variations within and between lithologies and formations are likely to provide natural barriers to fracture propagation between the gas saturated Permian sediments and the overlying Eromanga Basin. Prospectivity confidence maps were generated for six individual shale and deep coal plays and one combined tight gas play across the Gidgealpa Group. Comparison with key wells targeting shale, tight and deep coal gas plays, indicates that the prospectivity confidence mapping results are largely consistent with exploration activity to-date, with the highest prospectivity confidence for tight, shale and deep coal gas plays mapped in the Nappamerri, Patchawarra, Windorah, Allunga and Wooloo troughs and the southern Ullenbury Depression. Consequently, there is more confidence in the resultant maps in the southern Cooper Basin as more data was available here. Prospectivity confidence maps are relative, therefore a high prospectivity confidence does not equate to 100 % chance of success for a particular formation or play. The outputs of this regional prospectivity assessment identify areas warranting more detailed data collection and exploration and the assessment of potential impacts of resource development on water and the environment. The results also have the potential to encourage further exploration investment in underexplored regions of the Cooper Basin.

Geoscience Australia commissioned reprocessing of selected legacy 2D seismic data in the Pedirka-Simpson Basin in South Australia-Northern Territory as part of the Exploring for the Future (EFTF) program. 34 Legacy 2D seismic lines from the Pedirka Basin were reprocessed between May 2021 and January 2022 (phase 1). An additional 54 legacy 2D seismic lines (34 lines from Pedirka Basin, South Australia and 20 lines from Simpson Basin, Northern Territory) were reprocessed between November 2021 and June 2022 (phase 2). Geofizyka Toruń S.A. based in Poland carried out the data processing and Geoscience Australia with the help of an external contractor undertook the quality control of the data processing. The seismic data release package contains reprocessed seismic data acquired between 1974 and 2008. In total, the package contains approximately 3,806.9 km of industry 2D reflection seismic data. The seismic surveys include the Beal Hill, 1974; Pilan Hill, 1976; Koomarinna, 1980; Christmas Creek, 1982; Hogarth, 1984; Morphett, 1984; Colson 2D, 1985; Etingimbra, 1985; Fletcher, 1986; Anacoora, 1987; Mitchell, 1987; Bejah, 1987; Simpson Desert, 1979, 1984, 1986, 1987; Forrest, 1988; Eringa Trough, 1994; Amadeus-Pedirka, 2008 and covers areas within the Amadeus Basin, Simpson Basin, Pedirka Basin, Warburton Basin and Cooper Basin in South Australia and Northern Territory. The objective of the seismic reprocessing was to produce a processed 2D land seismic reflection dataset using the latest processing techniques to improve resolution and data quality over legacy processing. In particular, the purpose of the reprocessing was to image the structure and stratigraphic architecture of the Neoproterozoic to Late Palaeozoic Amadeus Basin, Triassic Simpson Basin, Cambrian–Devonian Warburton Basin, Permian–Triassic Pedirka Basin and Cooper Basin. All vintages were processed to DMO stack, Pre-stack Time Migration and Post-Stack Time Migration. <b>Data is available on request from clientservices@ga.gov.au - Quote eCat# 146309</b>

The Cooper Basin is a Pennsylvanian to Middle Triassic intracratonic basin in northeastern South Australia and southwestern Queensland (Gravestock et al., 1998; Draper, 2002). Exploration activity in the region has recently expanded with explorers pursuing a range of newly-identified unconventional hydrocarbon plays (Goldstein et al., 2012; Menpes et al., 2013; Greenstreet, 2015; Carr et al., 2016). In support of this on-going exploration activity, Hall et al. (2015a) presented a regional overview of the architecture, tectonic evolution and lithostratigraphy of the Cooper Basin. This data pack contains the supplementary material accompanying this report. Structural architecture, extent and thickness of key stratigraphic units were characterised through construction of a regional 3D geological model, designed to capture the groups and formations associated with the major play types in the basin (Hall et al., 2015a). Existing published Cooper Basin horizons (DMITRE, 2001, 2009; NGMA, 2001) were integrated with stratigraphic tops (DNRM, 2015; DSD, 2015) and new seismic data interpretations, ensuring seamless integration of datasets across the state border. Isopachs extracted from the 3D model were used to review the extent and true vertical thickness of each stratigraphic unit. The Permian Toolachee and Patchawarra formations in Queensland are shown to have a wider extent compared with previous studies. The boundaries of the Roseneath and Murteree shales were revised, although their distribution still remains uncertain in areas such as the Arrabury Depression. Lithofacies analysis published for South Australia (Sun & Camac, 2004) were integrated with new stratigraphic analysis in the Weena Trough (Morton, 2016) and new electrofacies mapping in Queensland to produce the first basin wide set of lithofacies maps for the Toolachee, Daralingie, Epsilon and Patchawarra formations (Hall et al., 2015a). The resulting net sandstone, siltstone, shale and coal thickness maps characterise the regional distribution of key source, reservoir and seal units across the basin. Maps of net coal and shale thickness demonstrate an abundance of potential source rock facies in the Toolachee and Patchawarra formations in all regions. Additional potential source rock facies can be found in the Roseneath and Murteree shales, as well as in coals and shales of the Daralingie and Epsilon formations. Net sandstone thickness maps highlight possible regional reservoir facies distribution. The model is designed to characterise the formations associated with the basin's key petroleum systems elements, providing a framework for regional scale petroleum systems analysis and resource assessment studies (Hall et al., 2015b; Kuske et al., 2015). While this work provides important insights into both the conventional and unconventional hydrocarbon prospectivity of the basin, it also has application for the assessment of other resources such as groundwater (e.g. Smith et al., 2015a, b, c).

The Cooper Basin is an upper Carboniferous-Middle Triassic intracratonic basin in northeastern South Australia and southwestern Queensland (Gravestock et al., 1998; Draper, 2002; McKellar, 2013; Carr et al., 2016; Hall et al., 2015a). The basin is Australia's premier onshore hydrocarbon producing province and is nationally significant in providing gas to the eastern Australian gas market. The basin also hosts a range of unconventional gas play types within the Permian Gidgealpa Group, including basin-centred gas and tight gas accumulations, deep dry coal gas associated with the Patchawarra and Toolachee formations, the Murteree and Roseneath shale gas plays and deep coal seam gas in the Weena Trough (e.g. Goldstein et al., 2012; Menpes et al., 2013; Greenstreet, 2015). The principal source rocks for these plays are the Permian coals and coaly shales of the Gidgealpa Group (Boreham & Hill, 1998; Deighton et al., 2003; Hall et al., 2016a). Mapping the petroleum generation potential of these source rocks is critical for understanding the hydrocarbon prospectivity of the basin. Geoscience Australia, in conjunction with the Department of State Development, South Australia and the Geological Survey of Queensland, have recently released a series of studies reviewing the distribution, type, quality, maturity and generation potential of the Cooper Basin source rocks (Hall et al., 2015a; 2016a; 2016b, 2016c; 2016d). Petroleum systems models, incorporating new Cooper Basin kinetics (Mahlstedt et al., 2015), highlight the variability in burial, thermal and hydrocarbon generation histories for each source rock across the basin (Hall et al., 2016a). A Geoscience Australia record 'Cooper Basin Petroleum Systems Analysis: Regional Hydrocarbon Prospectivity of the Cooper Basin, Part 3' providing full documentation of the model input data, workflow and results is currently in press. This work provides important insights into the hydrocarbon prospectivity of the basin (Hall et al., 2015b; Kuske et al., 2015). This product contains the working Cooper Basin Trinity-Genesis-KinEx petroleum systems model used to generate the results presented in these studies. This includes maps describing thickness, TOC and original HI for the following Permian source intervals: Toolachee Fm coals and coaly shales Daralingie Fm coals and coaly shales Roseneath Shale Epsilon Fm coals and coaly shales Murteree Shale Patchawarra Fm coals and coaly shales This model is designed for use as a regional scale hydrocarbon prospectivity screening tool. Model resolution is not high enough for this product to be used for sub-basin to prospect scale analysis, without further modification. However, the model provides a regional framework, into which more detailed prospect scale data may be embedded. The systematic workflow applied demonstrates the importance of integrated geochemical and petroleum systems modelling studies as a predictive tool for understanding the petroleum resource potential of Australia's sedimentary basins.

Across Australia, groundwater is a vital resource that supports and strengthens communities, culture, the environment and numerous industries. Movement of groundwater is complicated, taking place horizontally, vertically and across different timescales from weeks to millions of years. It is affected by changes in climate, human use and geological complexities such as the type, geometry and distribution of rocks. Understanding how all these factors interact is known as a groundwater conceptual model and it is an important first step. This groundwater conceptualisation includes the Cooper Basin and the overlying Eromanga and Lake Eyre basins as well as surface-groundwater interactions. Figure 1 shows the locations of the cross sections used to conceptualise groundwater in the Cooper Basin region. In the Cooper Basin this includes 1 aquifer in the Lake Eyre Basin, 5 aquifers in the Eromanga Basin and 1 aquifer in the Cooper Basin (Wainman et al., 2023a, b). Additional aquifers in the Permian sequence have not been included in this assessment, as they are yet to be fully investigated (Evans et al., 2020). Confidence for each aquifer was calculated for both salinity and water levels (Gouramanis et al., 2023a, b, c). The confidence for each aquifer was added to show the overall confidence for the basin. The level of knowledge across all aquifer is moderate to low. The groundwater conceptualisations summarises the groundwater flow and potential connectivity between aquifers. Figures also show the distribution of the aquifers and aquitards, average salinity, potential aquifer yield and confidence over an area of 50 km along the cross section lines.

Statements of existing knowledge are compiled for known mineral, coal, hydrocarbon and carbon capture and storage (CCS) resources and reserves in the Cooper Basin. This data guide illustrates the current understanding of the distribution of these key resource types within the Cooper Basin region based on trusted information sources. It provides important contextual information on the Cooper Basin and where additional details on discovered resources can be found. To date, mineral or coal deposits have not been found in the Cooper Basin, due to its depth. There are significant hydrocarbon resources found in the basin, including conventional and unconventional hydrocarbons. The Cooper Basin has been a major producer of oil and gas since the 1960s (Smith, Cassel and Evans, 2015). It is one of the largest sources of onshore hydrocarbon production in Australia. Some of the largest unconventional gas resources are contained in the basin. This is mostly basin-centred gas. The geology in the Cooper Basin is considered suitable for use in Carbon Capture and Storage (CCS) projects. The Cooper Basin and overlying Eromanga Basin contain 2 CCS projects that are currently being developed.

Publicly available geology data are compiled to provide a common information base for resource development, environmental and regulatory decisions in the Cooper Basin region. This data guide gives examples of how these data can be used and supports the data package that provides the existing knowledge of the key geological intervals of the Cooper Basin and the overlying Eromanga and Lake Eyre basins. The key geological intervals identified by the Trusted Environmental and Geological Information (TEGI) Program for resource assessment and groundwater system characterisation are termed play intervals and hydrostratigraphic intervals respectively. The Cooper Basin includes 7 plays, which are consolidated into 1 hydrostratigraphic interval. Overlying the Cooper Basin are 9 play intervals of the Eromanga Basin, which are consolidated into 7 hydrostratigraphic intervals and 1 Cenozoic play interval and 1 hydrostratigraphic interval for the Lake Eyre Basin. The geological groups and formations included in the play and hydrostratigraphic intervals are summarised in the stratigraphic charts of Wainman et al. (2023). Gross depositional, depth structure and thickness maps are provided with 3D model and cross-sections summarising the geology of the Cooper Basin and the overlying basins. The mapped depths and thicknesses of the key intervals are used to inform resource assessments and provide the framework for assigning groundwater data to hydrostratigraphic intervals.

Publicly available geological data in the Cooper Basin region are compiled to produce statements of existing knowledge for natural hydrogen, hydrogen storage, coal and mineral occurrences. This web service summarises mineral potential in the Cooper Basin region.

Publicly available baseline ecology data are compiled to provide a common information base for environmental, resource development and regulatory decisions in the Cooper Basin region. This web service summarises existing knowledge of the ecosystems and environmental assets in the Cooper Basin region.

Publicly available groundwater data have been compiled to provide a common information base to inform environmental, resource development and regulatory decisions in the Cooper Basin region. This web service summarises salinity, water levels, resource size, potential aquifer yield and surface water–groundwater interactions for the Lake Eyre Basin located within the Cooper Basin region.