This appendix provides a regional geological analysis and conceptualisation of the Cooper GBA region. It delivers information critical for the shale, tight and deep coal gas prospectivity assessment outlined in the petroleum prospectivity technical appendix (Lech et al., 2019), and for input into assessing the potential impacts on groundwater and surface water assets detailed in the hydrogeology (Evans et al., 2019) and hydraulic fracturing (Kear et al., 2019) technical appendices. The Cooper Basin is a Carboniferous to Triassic intracratonic basin in north-eastern South Australia and south-western Queensland. It has a total area of approximately 127,000 km2, of which about three quarters lies within Queensland and the remainder lies within South Australia. Section 2 provides a comprehensive inventory and review of existing open data and information for the Cooper GBA region relevant for the prospectivity assessment (see the petroleum prospectivity technical appendix (Lech et al., 2019)) and hydrogeological characterisation (see the hydrogeology technical appendix (Evans et al., 2019)). It includes discussion of the datasets incorporated in the data inventory. A broad range of datasets were utilised to develop a three-dimensional conceptualisation of the geological basin. These include: geographic and cultural datasets which details the location and nature of administrative boundaries, infrastructure and topography; and geological datasets such as surface geology and geological provinces, well and seismic data and geophysical data. A range of public domain publications, reports and data packages for the Cooper Basin are also utilised to characterise the basin architecture and evolution. Section 3 reviews the Cooper Basin’s geological setting and the GBA region’s basin evolution from pre-Permian basement to creation of the Cooper, Eromanga and Lake Eyre basins. Section 4 reviews the main structural elements of the Cooper Basin and how these relate to the basin’s stratigraphy and evolution. The base of the Cooper Basin succession sits at depths of up to 4500 m, and reaches thicknesses in excess of 2400 m. The Cooper Basin is divided into north-eastern and south-western areas, which show different structural and sedimentary histories, and are separated by a series of north-west–south-east trending ridges. In the south-west the Cooper Basin unconformably overlies lower Paleozoic sediments of the Warburton Basin, and includes three major troughs (Patchawarra, Nappamerri and Tenappera troughs) separated by ridges (the Gidgealpa–Merrimelia–Innamincka and Murteree ridges). The depocentres include a thick succession of Permian to Triassic sediments (the Gidgealpa and Nappamerri groups) deposited in fluvio-glacial to fluvio-lacustrine and deltaic environments. The north-eastern Cooper Basin overlies Devonian sediments associated with the Adavale Basin. Here the Permian succession is thinner than in the south-west, and the major depocentres, including the Windorah Trough and Ullenbury Depression, are generally less well defined. The Cooper Basin is entirely and disconformably overlain by the Jurassic–Cretaceous Eromanga Basin. In the Cooper GBA region the Eromanga Basin includes two major depocentres, the Central Eromanga Depocentre and the Poolowanna Trough, and exceeds thicknesses of 2500 m. Deposition within the Eromanga Basin was relatively continuous and widespread and was controlled by subsidence rates and plate tectonic events along the eastern margins of the Australian Plate. The Eromanga Basin is comprised of a succession of terrestrial and marine origin. It includes a basal succession of terrestrial sedimentary rocks, followed by a middle marine succession, then finally an upper terrestrial succession. The Lake Eyre Basin is a Cenozoic sedimentary succession overlying the Eromanga Basin, covering parts of northern and eastern South Australia, south-eastern Northern Territory, western Queensland and north-western New South Wales. The Lake Eyre Basin is subdivided into sub-basins, with the northern part of the Callabonna Sub-basin overlying the Cooper Basin. Here the basin is up to 300 m thick and contains sediments deposited from the Paleocene through to the Quaternary. Deposition within the Lake Eyre Basin is recognised to have occurred in three phases, punctuated by periods of tectonic activity and deep weathering. This technical appendix provides the conceptual framework to better understand the potential connectivity between the Cooper Basin and overlying aquifers of the Great Artesian Basin and to help understand potential impacts of shale, tight and deep coal gas development on water and water-dependent assets.

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 data guide gives examples of how these data can be used. The data package included with this data guide captures existing knowledge of Eromanga Basin aquifers and their properties, including salinity, water levels, resource size, potential aquifer yield and surface water interactions. The methods used to derive these data for all Eromanga Basin aquifers in the Cooper Basin region are outlined in the associated metadata files. These are described in groundwater conceptualisation models (Gouramanis et al., 2023). The Eromanga Basin overlying the Cooper Basin includes 5 broadly defined aquifer intervals: from deepest to shallowest, these are the Poolowanna, Hutton, Adori, Cadna-owie-Hooray and Winton-Mackunda aquifers. Compiled data are assigned to these intervals and used to characterise groundwater systems at the basin scale. The data were compiled for a point-in-time to inform decisions on potential resource developments in the Basin. The available historical groundwater data can be used to assess the potential effects on groundwater. The data can also be used for other purposes, such as exploring unallocated groundwater resource potential. Data to January 2022 are used for this compilation.

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 and water levels for the Cooper Basin located within the Cooper Basin region.

The potential for hydrogen production in the Cooper Basin region is assessed to provide a joint information base for hydrogen generation potential from renewable energy, groundwater, and natural gas coupled with carbon capture and storage (CCS). This web service summarises hydrogen potential 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 data guide gives examples of how these data can be used. The data package included with this data guide captures existing knowledge of Cooper Basin aquifers and their properties, including salinity, water levels, resource size, potential aquifer yield and surface water interactions. The methods used to derive these data for the Cooper Basin aquifer are outlined in the associated metadata files. These are described in groundwater conceptualisation models (Gouramanis et al., 2023). The Cooper Basin includes one broadly defined aquifer named the Nappamerri Group aquifer. Compiled data are assigned to these intervals and used to characterise groundwater systems at the basin scale. The data are compiled for a point-in-time to inform decisions on potential resource developments in the Basin. The available historical groundwater data can be used to assess the potential effects on groundwater. The data can also be used for other purposes, such as exploring unallocated groundwater resource potential. Data to January 2022 are used for this compilation.

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).

Geoscience Australia recently commenced work on a multi-year study of Australian petroleum source rocks to improve our understanding of the petroleum resource potential of Australia's sedimentary basins. The Permian source rocks of the Cooper Basin are the first to be characterised for this project. Quantifying the spatial distribution and petroleum generation potential of these source rocks is critical for understanding both the conventional and unconventional hydrocarbon prospectivity of the basin. 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., 2015; 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 contains reviews the distribution, type, quality, maturity and generation potential of the Cooper Basin source rocks. 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. - A 3D basin model, characterising regional basin architecture, was constructed through the integration of existing horizons with formation tops and seismic interpretations (Hall et al., 2015a; Hall et al., 2016d). - Source rock distribution, amount and quality were reviewed through the analysis of log data and source rock geochemical data (including data acquired from new sampling), characterising source rocks across the whole basin (Hall et al., 2016a; Hall et al., 2016e). - 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., 2016b in prep; Hall et al., 2016f). This GIS contains all data associated with the above reports and accompanying data packages, providing important insights into the hydrocarbon prospectivity of the basin (Hall et al., 2015b; Kuske et al., 2015). The broad extent of the Cooper Basin's Permian source kitchen and its large total generation potential, highlights the basin's significance as a world class hydrocarbon province. The systematic workflow applied here 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.

This seminar will showcase new results from the late Carboniferous to Middle Triassic Cooper Basin that challenge existing notions on its evolution, new insights on sediment dispersal pathways and consequently its resource potential. Topics that will be explored include how the Cooper Basin is similar to other failed rift basins and how depositional facies between each of the half-grabens/troughs are influenced by the relationship between sediment supply and the rate of creation of accommodation. Of note are new precise dates and carbon isotope data from the thick coals of the Patchawarra Formation suggesting prolonged and uninterrupted peat accumulation for millions of years during the latter stages of the late Palaeozoic ice age – no modern analogue exists to compare the conditions and longevity of these ancient mires. Come along to the talk to learn more about the Cooper Basin.

Publicly available data was compiled to provide a common information base for resource development, and environmental and regulatory decisions in the Cooper Basin. This web service summarises the geological storage of carbon dioxide prospectivity of the Cooper Basin.

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.