Geoscience Australia is leading a regional evaluation of potential mineral, energy and groundwater resources through the Exploring for the Future (EFTF) program. This stratigraphic assessment is part of the Onshore Basin Inventories project, and was undertaken to understand Devonian-aged depositional systems and stratigraphy in Queensland’s Adavale Basin. Such data are fundamental for any exploration activities. Maximising the use of existing well data can lead to valuable insights into the regional prospectivity of sedimentary basins. Data from 53 Adavale Basin wells have been used to evaluate subsurface stratigraphy, depositional environments and hydrocarbon shows across the basin. Stratigraphic data from 26 representative wells, where the well intersected at least three Devonian stratigraphic units, are used to generate chronostratigraphic time-space charts and two-dimensional well correlations within, and between, different (northern, north central, central, west central, east central and southern) parts of the basin. The primary objectives of the study are: • stratigraphic gap analysis to identify geological uncertainties and data deficiencies in the areas of interest, • integrate the well data with Geoscience Australia’s databases (i.e., Australian Stratigraphic Units, Time Scale, Geochronology, STRATDAT, RESFACS),the Geological Survey of Queensland’s Datasets and publicly available (published and unpublished) research data and information, • determine the lithostratigraphic unit tops, log and lithology characterisations, depositional facies, boundary criteria, spatial and temporal distribution and regional correlations, • integrate key biostratigraphic zones and markers with geochronological absolute age dates to generate a chronostratigraphic Time-Space Diagram of the basin. This work improves the understanding of the chronostratigraphic relationships across the Adavale Basin. The age of the sedimentary successions of the basin have been refined using geochronology, biostratigraphy and lithostratigraphic correlation. The chronostratigraphic and biozonation chart of the Adavale Basin has been updated and the stratigraphic, biostratigraphic and hydrocarbon shows datasets will be available for viewing and download via the Geoscience Australia Portal (https://portal.ga.gov.au/restore/15808dee-efcd-428e-ba5b-59b0106a83e3).

<div>Lateral variation in maturity of potential Devonian source rocks in the Adavale Basin have been investigated using nine 1D burial thermal and petroleum generation history models, constructed using existing open file data. These models provide an estimate of the hydrocarbon generation potential of the basin. Total organic carbon (TOC) content and pyrolysis data indicate that the Log Creek Formation, Bury Limestone and shale units of the Buckabie Formation have the most potential as source rocks. The Log Creek Formation and the Bury Limestone are the most likely targets for unconventional gas exploration.</div><div>&nbsp;</div><div>The models were constructed used geological information from well completion reports to assign formation tops and stratigraphic ages to then forward-model the evolution of geophysical parameters. The rock parameters, including facies, temperature, organic geochemistry/petrology, were used to investigate source rock quality, maturity and kerogen type. Suitable boundary conditions were assigned for paleo-heat flow, paleo-surface temperature and paleo-water depth. The resulting models were calibrated using bottom hole temperature and measured vitrinite reflectance data.</div><div>&nbsp;</div><div>The results correspond relatively well with published heat flow predictions, however a few wells show possible localised heat effects that differ from the overall basin average. The models indicate full maturation of the Devonian source rocks with generation occurring during the Carboniferous and again during the Late Cretaceous. Any potential accumulations may be trapped in Devonian sandstone, limestone and mudstone units, as well as overlying younger sediments of the Mesozoic Eromanga Basin. Accumulations could be trapped by localised deposits of the Cooladdi Dolomite and other marine, terrestrial clastic and evaporite units around the basin. Migration of the expelled hydrocarbons may be restricted by overlying regional seals, such as the Wallumbilla Formation of the Eromanga Basin. Unconventional hydrocarbons are a likely target for the Adavale Basin with potential either for tight or shale gas in favourable areas from the Log Creek Formation and Bury Limestone.</div> This Abstract was submitted/presented to the 2023 Australian Exploration Geoscience Conference 13-18 Mar (https://2023.aegc.com.au/)

Publicly available groundwater data have been compiled to inform environmental, resource development and regulatory decisions in the Adavale Basin region. This web service summarises salinity, water levels, resource size, potential aquifer yield and surface water–groundwater interactions for the Galilee Basin located within the Adavale Basin region.

Publicly available data was compiled to provide a common information base for resource development, environmental and regulatory decisions in the Adavale Basin. This web service summarises oil and gas prospectivity of the Adavale Basin.

Publicly available groundwater data have been compiled to provide a common information base to inform environmental, resource development and regulatory decisions in the Adavale 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 Adavale Basin region.

Publicly available geology data are compiled to provide a common information base for resource development and regulatory decisions in the Adavale Basin region. This web service summarises the geology of the Adavale Basin.

Publicly available groundwater data have been compiled to provide a common information base to inform environmental, resource development and regulatory decisions in the Adavale Basin region. This web service summarises salinity and water levels for the Adavale Basin located within the Adavale Basin region.

Publicly available groundwater data have been compiled to inform environmental, resource development and regulatory decisions in the Adavale Basin region. This web service summarises salinity, water levels, resource size, potential aquifer yield and surface water–groundwater interactions for the Eromanga Basin located within the Adavale Basin region.

Publicly available geology data are compiled to provide a common information base for resource development and regulatory decisions in the Adavale Basin region. This data guide gives examples of how the compiled data can be used. It supports a data package that presents core photographs, existing knowledge of the stratigraphy, and structural elements for the Adavale Basin and the overlying Galilee, Eromanga, Lake Eyre and other Cenozoic basins. Stratigraphic frameworks capture the geological groups and formations that make up the sedimentary sequence in the Adavale Basin region. The Adavale Basin includes 9 stratigraphic formations (Wainman et al., 2023). Overlying the Adavale Basin are the geological formations of the Galilee, Eromanga, Lake Eyre and other Cenozoic basins. The frameworks include the stratigraphic intervals used by the Trusted Environmental and Geological Information (TEGI) Program. From the base of the Adavale Basin to the top of overlying Cenozoic basins, the sedimentary sequence is categorised into 24 play intervals for resource assessment mapping and 12 hydrostratigraphic intervals for characterising groundwater systems (Wainman et al., 2023). Structural elements maps summarise where the sedimentary sequence has been deposited and later deformed by crustal movements. Structure information is used in assessing the geological potential for resources and interpreting groundwater flow and connectivity at the basin scale. The stratigraphic frameworks and structural elements provide the basic geological context for the Adavale Basin region resource and environmental assessments.

Publicly available data was compiled to provide a common information base for resource development, environmental and regulatory decisions in the Adavale Basin. This data guide gives an example of how these data can be used to create the components of a workflow to identify unconventional hydrocarbon resource opportunities. The data guide is designed to support the data package that provide insights on unconventional hydrocarbon resources in the Adavale Basin. The unconventional hydrocarbon assessment for the Adavale Basin includes tight gas, shale resources (shale oil and gas) and coal seam gas for 8 geological intervals, termed plays – these intervals have been defined by Wainman et al. (2023). The assessment captures data from well completion reports and government data sources (e.g. Queensland Petroleum Exploration Database (QPED) from the Geological Survey of Queensland (GSQ) Open Data Portal) along with the scientific literature to inform the components required for unconventional hydrocarbons to be present. Thirty-nine boreholes in the Adavale Basin were assessed with data used to map out gross depositional environments and their geological properties relevant for unconventional hydrocarbon assessments. The data are compiled at a point in time to inform decisions on resource development activities. The guide outlines the play-based workflow for assessing unconventional hydrocarbon resource prospectivity. Each of the elements required for a prospective unconventional hydrocarbon system is explained and mapped. These data were merged and spatially multiplied to show the relative assessment of unconventional hydrocarbon prospectivity across the basin, at both play interval and basin scale. As an example of assessments contained within the data package, this data guide showcases the tight gas prospectivity of the Buckabie Play interval.