<div>Geoscience Australia and CSIRO have collaborated, under the Exploring for the Future program, to investigate whether water-saturated residual oil zones (ROZs), sometimes associated with conventional Australian hydrocarbon plays, could provide a CO2 storage resource and enhance the storage capacity of depleted fields. This product is part of a larger project that includes, among others, a reservoir modelling component. </div><div>This report focuses on our petrophysical module of work that investigated the occurrence and character of ROZs in onshore Australian basins. Our findings demonstrate that ROZs occur in Australia’s hydrocarbon-rich regions, particularly in the Cooper-Eromanga Basin. ROZs with more than 10% residual oil saturation are uncommon, likely due to small original oil columns and lower residual saturations retained in sandstone reservoirs than in classic, carbonate-hosted North American ROZs. Extensive, reservoir-quality rock is found below the deepest occurring conventional oil in many of the fields in the Eromanga Basin, potentially offering significant CO2 storage capacity.&nbsp;</div><div>For more information about this project and to access the related studies and products, see: https://www.eftf.ga.gov.au/carbon-co2-storage-residual-oil-zones. </div><div><br></div>

<div>This Geoscience Australia Record reports on Interferometric Synthetic Aperture Radar (InSAR) processing over the Great Artesian Basin (GAB) to support an improved understanding of the groundwater system and water balance across the region. InSAR is a geodetic technique that can identify ground surface movement from satellite data at a regional scale and is therefore a valuable and widely used technique for measuring patterns in surface movement over time; including the movement of fluids (i.e. water or gas) beneath the surface.</div><div><br></div><div>This Record is the one of two Geoscience Australia Records that describe ground surface movement monitoring Geoscience Australia have undertaken in the GAB in recent years. Namely;</div><div>1.&nbsp;&nbsp;&nbsp;&nbsp;Ground surface movement in the northern Surat Basin derived from campaign GPS measurements. (Garthwaite et al., 2022).</div><div>2.&nbsp;&nbsp;&nbsp;&nbsp;InSAR processing over the Great Artesian Basin and analysis over the western Eromanga Basin and northern Surat Basin (this Record).</div><div><br></div><div>We have produced ground surface motion data products, which cover about 90% of the GAB for the period of time between January 2016 and August 2020. The data products were created using Sentinel-1 Synthetic Aperture Radar (SAR) data and an InSAR processing workflow designed for large spatial scale processing. The large spatial scale InSAR processing workflow includes using GAMMA software to (i) pre-process SAR images to align the pixels, (ii) generate interferograms and short temporal baseline surface displacement maps and PyRate software to (iii) combine these outputs in an inversion to form pixel-wise time series ground surface displacement data and fit ground surface velocities to the displacement data. The raw SAR data and these subsequent data products of the workflow are partitioned into overlapping frames; the final stage of the large scale processing workflow is to combine the partitioned data into a single map using a mosaicking algorithm. The results of this processing chain demonstrate the feasibility of developing a regional scale ground surface movement reconnaissance tool (i.e. subsidence and uplift). </div><div><br></div><div>We provide a summary of the processing chain and data products and a focused assessment for two case study areas in the western Eromanga Basin (South Australia) and northern Surat Basin (Queensland). Over these case study areas we examine the relationship between the InSAR derived ground surface movement and available groundwater level data. We also assess how land use types may influence the InSAR derived ground surface motion data by comparing the InSAR data to the “land types” over the region which we classify using a machine learning algorithm with Sentinel-2 optical imagery data. </div><div><br></div><div>From our analysis we observe little ground surface motion over the western Eromanga Basin. The surface movement rate over the entire area is estimated to be mostly within ±10 mm/yr. Groundwater level time series data from well monitoring sites in the area did not appear to have any significant trends either. However, large and broad scale ground surface motion (both uplift and subsidence) was observed in the InSAR processing results over the northern Surat Basin. A 75 km x 150 km scale uplift signal, with rates of up to 20 mm/yr, was located over an area we classified as cultivated land, where InSAR signals are likely to be influenced by near-surface cultivation activities (such as irrigation) rather than subsurface groundwater level changes. Furthermore, two approximately 75km x 75 km areas were identified which had subsidence signals of up to -20 mm/yr. Over the same area, groundwater level time series data show long-term negative trends in the water head level. For a more direct comparison between the InSAR results and the well data, we fitted a first order poroelastic model to transform the InSAR derived ground surface motion rates into modelled pore-pressure decline/groundwater drawdown rates. We compared the model to the groundwater time series data in the Walloon Coal Measures, Surat Basin, and found good agreement, which indicates that the observed subsidence signals could be attributable to pore-pressure decline due to the falling water head level.</div><div><br></div><div>We finally provide some preliminary analysis comparing our InSAR results to the results from an Office of Groundwater Impact Assessment (OGIA) InSAR study and a Geoscience Australia GPS land movement study to assist in validating the Geoscience Australia InSAR results. Overall, the comparisons are encouraging, showing a high correlation against the OGIA InSAR results and GPS results. Further work, is required to further validate our results and reduce uncertainty in our analysis process.</div>

The document summarises new seismic interpretation metadata for two key horizons from Base Jurassic to mid-Cretaceous strata across the western and central Eromanga Basin, and the underlying Top pre-Permian unconformity. New seismic interpretations were completed during a collaborative study between the National Groundwater Systems (NGS) and Australian Future Energy Resources (AFER) projects. The NGS and AFER projects are part of Exploring for the Future (EFTF)—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. The seismic interpretations build on previous work undertaken as part of the ‘Assessing the Status of Groundwater in the Great Artesian Basin’ (GAB) Project, commissioned by the Australian Government through the National Water Infrastructure Fund – Expansion (Norton & Rollet, 2022; Vizy & Rollet, 2022; Rollet et al., 2022; Rollet et al., in press.), the NGS Project (Norton & Rollet, 2023; Rollet et al., 2023; Vizy & Rollet, 2023) and the AFER Project (Bradshaw et al., 2022 and in press, Bernecker et al., 2022, Iwanec et al., 2023; Iwanec et al., in press). The recent iteration of revisions to the GAB geological and hydrogeological surfaces (Vizy & Rollet, 2022) provides a framework to interpret various data sets consistently (e.g., boreholes, airborne electromagnetic, seismic data) and in a 3D domain, to improve our understanding of the aquifer geometry, and the lateral variation and connectivity in hydrostratigraphic units across the GAB (Rollet et al., 2022). Vizy and Rollet (2022) highlighted some areas with low confidence in the interpretation of the GAB where further data acquisition or interpretation may reduce uncertainty in the mapping. One of these areas was in the western and central Eromanga Basin. New seismic interpretations are being used in the western Eromanga, Pedirka and Simpson basins to produce time structure and isochore maps in support of play-based energy resource assessment under the AFER Project, as well as to update the geometry of key aquifers and aquitards and the GAB 3D model for future groundwater management under the NGS Project. These new seismic interpretations fill in some data and knowledge gaps necessary to update the geometry and depth of key geological and hydrogeological surfaces defined in a chronostratigraphic framework (Hannaford et al., 2022; Bradshaw et al., 2022 and in press; Hannaford & Rollet, 2023). The seismic interpretations are based on a compilation of newly reprocessed seismic data (Geoscience Australia, 2022), as part of the EFTF program, and legacy seismic surveys from various vintages brought together in a common project with matching parameters (tying, balancing, datum correcting, etc.). This dataset has contributed to a consolidated national data coverage to further delineate groundwater and energy systems, in common data standards and to be used further in integrated workflows of mineral, energy and groundwater assessment. The datasets associated with the product provides value added seismic interpretation in the form of seismic horizon point data for two horizons that will be used to improve correlation to existing studies in the region. The product also provides users with an efficient means to rapidly access a list of core data used from numerous sources in a consistent and cleaned format, all in a single package. The following datasets are provided with this product: 1) Seismic interpretation in a digital format (Appendix A), in two-way-time, on key horizons with publically accessible information, including seismic interpretation on newly reprocessed data: Top Cadna-owie; Base Jurassic; Top pre-Permian; 2) List of surveys compiled and standardised for a consistent interpretation across the study area (Appendix B). 3) Isochore points between Top Cadna-owie and Base Jurassic (CC10-LU00) surfaces (Appendix C). 4) Geographical layer for the seismic lines compiled across Queensland, South Australia and the Northern Territory (Appendix D). These new interpretations will be used to refine the GAB geological and hydrogeological surfaces in this region and to support play-based energy resource assessments in the western Eromanga, Pedirka and Simpson basins.

This report, completed as part of Geoscience Australia’s Exploring for the Future Program National Groundwater Systems (NGS) Project, presents results of the second iteration of 3D geological and hydrogeological surfaces across eastern Australian basins. The NGS project is part of the Exploring for the Future (EFTF) program—an eight-year, $225 million Australian Government funded geoscience data and precompetitive information acquisition program. The program seeks to inform decision-making by government, community, and industry on the sustainable development of Australia's mineral, energy, and groundwater resources, including those to support the effective long-term management of GAB water resources. This work builds on the first iteration completed as part of the Great Artesian Basin Groundwater project. The datasets incorporate infills of data and knowledge gaps in the Great Artesian Basin (GAB), Lake Eyre Basin (LEB), Upper Darling Floodplain (UDF) and existing data in additional basins in eastern Australia. The study area extends from the offshore Gulf of Carpentaria in the north to the offshore Bight, Otway, and Gippsland basins in the South and from the western edge of the GAB in the west to the eastern Australian coastline to the east. The revisions are an update to the surface extents and thicknesses for 18 region-wide hydrogeological units produced by Vizy & Rollet, 2022. The second iteration of the 3D model surfaces further unifies geology across borders and provides the basis for a consistent hydrogeological framework at a basin-wide, and towards a national-wide, scale. The stratigraphic nomenclature used follows geological unit subdivisions applied: (1) in the Surat Cumulative Management Area (OGIA - Office of Groundwater Impact Assessment, 2019) to correlate time equivalent regional hydrogeological units in the GAB and other Jurassic and Cretaceous time equivalent basins in the study area and (2) in the LEB to correlate Cenozoic time equivalents in the study area. Triassic to Permian and older basins distribution and thicknesses are provided without any geological and hydrogeological unit sub-division. Such work helps to (1) reconcile legacy and contemporary regional studies under a common stratigraphic framework, (2) support the effective management of groundwater resources, and (3) provide a regional geological context for integrated resource assessments. The 18 hydrogeological units were constructed using legacy borehole data, 2D seismic and airborne electromagnetic (AEM) data that were compiled for the first iteration of the geological and hydrogeological surfaces under the GAB groundwater project (Vizy & Rollet, 2022a) with the addition of: • New data collected and QC’d from boreholes (including petroleum, CSG [Coal Seam Gas], stratigraphic, mineral and water boreholes) across Australia (Vizy & Rollet, 2023a) since the first iteration, including revised stratigraphic correlations filling data and knowledge gaps in the GAB, LEB, UDF region (Norton & Rollet, 2023) with revised palynological constraints (Hannaford & Rollet 2023), • Additional AEM interpretation since the first iteration in the GAB, particularly in the northern Surat (McPherson et al., 2022b), as well as in the LEB (Evans et al., in prep), in the southern Eromanga Basin (Wong et al., 2023) and in the UDF region (McPherson et al., 2022c), and • Additional 2D seismic interpretation in the Gulf of Carpentaria (Vizy & Rollet, 2023b) and in the western and central Eromanga Basin (Szczepaniak et al., 2023). These datasets were then analysed and interpreted in a common 3D domain using a consistent chronostratigraphic framework tied to the geological timescale of 2020, as defined by Hannaford et al. (2022). Confidence maps were also produced to highlight areas that need further investigation due to data gaps, in areas where better seismic depth conversion or improved well formation picks are required. New interpretations from the second iteration of the 18 surfaces include (1) new consistent and regionally continuous surfaces of Cenozoic down to Permian and older sediments beyond the extent of the GAB across eastern Australia, (2) revised extents and thicknesses of Jurassic and Cretaceous units in the GAB, including those based on distributed thickness, (3) revised extents and thicknesses of Cenozoic LEB units constrained by the underlying GAB 3D model surfaces geometry. These data constraints were not used in the model surfaces generated for the LEB detailed inventory (Evans et al., 2023), and (4) refinements of surfaces due to additional seismic and AEM interpretation used to infill data and knowledge gaps. Significant revisions include: • The use of additional seismic data to better constrain the base of the Poolowanna-Evergreen formations and equivalents and the top of Cadna-owie Formation and equivalents in the western and central Eromanga Basin, and the extent and thicknesses of the GAB units and Cenozoic Karumba Basin in the Gulf of Carpentaria, • The use of AEM interpretations to refine the geometry of outcropping units in the northern Surat Basin and the basement surface underneath the UDF region, and • A continuous 3D geological surface of base Cenozoic sediments across eastern Australia including additional constraints for the Lake Eyre Basin (borehole stratigraphy review), Murray Basin (AEM interpretation) and Karumba Basin (seismic interpretation). These revisions to the 18 geological and hydrogeological surfaces will help improve our understanding on the 3D spatial distribution of aquifers and aquitards across eastern Australia, from the groundwater recharge areas to the deep confined aquifers. These data compilations and information brought to a common national standard help improve hydrogeological conceptualisation of groundwater systems across multiple jurisdictions to assist water managers to support responsible groundwater management and secure groundwater into the future. These 3D geological and hydrogeological modelled surfaces also provide a tool for consistent data integration from multiple datasets. These modelled surfaces bring together variable data quality and coverage from different databases across state and territory jurisdictions. Data integration at various scale is important to assess potential impact of different water users and climate change. The 3D modelled surfaces can be used as a consistent framework to map current groundwater knowledge at a national scale and help highlight critical groundwater areas for long-term monitoring of potential impacts on local communities and Groundwater Dependant Ecosystems. The distribution and confidence on data points used in the current iteration of the modelled surfaces highlight where data poor areas may need further data acquisition or additional interpretation to increase confidence in the aquifers and aquitards geometry. The second iteration of surfaces highlights where further improvements can be made, notably for areas in the offshore Gulf of Carpentaria with further seismic interpretation to better constrain the base of the Aptian marine incursion (to better constrain the shape and offshore extent of the main aquifers). Inclusion of more recent studies in the offshore southern and eastern margins of Australia will improve the resolution and confidence of the surfaces, up to the edge of the Australian continental shelf. Revision of the borehole stratigraphy will need to continue where more recent data and understanding exist to improve confidence in the aquifer and aquitard geometry and provide better constraints for AEM and seismic interpretation, such as in the onshore Carpentaria, Clarence-Moreton, Sydney, Murray-Darling basins. Similarly adding new seismic and AEM interpretation recently acquired and reprocessed, such as in the eastern Eromanga Basin over the Galilee Basin, would improve confidence in the surfaces in this area. Also, additional age constraints in formations that span large periods of time would help provide greater confidence to formation sub-divisions that are time equivalent to known geological units that correlate to major aquifers and aquitards in adjacent basins, such as within the Late Jurassic‒Early Cretaceous in the Eromanga and Carpentaria basins. Finally, incorporating major faults and structures would provide greater definition of the geological and hydrogeological surfaces to inform with greater confidence fluid flow pathways in the study area. This report is associated with a data package including (Appendix A – Supplementary material): • Nineteen geological and hydrogeological surfaces from the Base Permo-Carboniferous, Top Permian, Base Jurassic, Base Cenozoic to the surface (Table 1.1), • Twenty-one geological and hydrogeological unit thickness maps from the top crystalline basement to the surface (Figure 3.1 to Figure 3.21), • The formation picks and constraining data points (i.e., from boreholes, seismic, AEM and outcrops) compiled and used for gridding each surface (Table 2.7). Detailed explanation of methodology and processing is described in the associated report (Vizy & Rollet, 2023).

<div>This Geoscience Australia Record summarises the collection, analysis and results of three Global Positioning System (GPS) campaign surveys conducted in 2015, 2016 and 2019 in the northern Surat Basin, Queensland, Australia. During each campaign, we collected at least seven continuous days of GPS observations at each of the 65 sites of a geodetic network established by Geoscience Australia in 2014. Our analysis of the collected GPS data reveals statistically significant downward vertical ground surface movement between 2015 and 2016, 2015 and 2019, or both, at 18 of the 65 geodetic sites. Two of the 18 sites have recorded downward vertical ground surface movement of more than 100 millimetres: SB36 near Miles (125 mm) and SB49 near Wandoan (218 mm). Further work is required to help better resolve the temporal and spatial pattern of ground surface movement in the northern Surat Basin. This could include further GPS campaign surveys, analysis of GPS data from continuously operating reference sites in south-east Queensland, and a detailed comparison of surface deformation observed with GPS and interferometric synthetic aperture radar (InSAR) data; extending on the work described in McCubbine et al. (2022).</div><div><br></div>

The Great Artesian Basin Research Priorities Workshop, organised by Geoscience Australia (GA), was held in Canberra on 27 and 28 April 2016. Workshop attendees represented a spectrum of stakeholders including government, policy, management, scientific and technical representatives interested in GAB-related water management. This workshop was aimed at identifying and documenting key science issues and strategies to fill hydrogeological knowledge gaps that will assist federal and state/territory governments in addressing groundwater management issues within the GAB, such as influencing the development of the next Strategic Management Plan for the GAB. This report summarises the findings out of the workshop.

This data package provides seismic interpretations that have been generated in support of the energy resource assessments under the Australia’s Future Energy Resources (AFER) project. Explanatory notes are also included. 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. The seismic interpretations build on the recently published interpretations by Szczepaniak et al. (2023) by providing updated interpretations in the AFER Project area for the Top Cadna-owie (CC10) and Top Pre-Permian (ZU) horizons, as well as interpretations for 13 other horizons that define the tops of play intervals being assessed for their energy resource potential (Figure 1). Seismic interpretations for the AFER Project are constrained by play interval tops picked on well logs that have been tied to the seismic profiles using time-depth data from well completion reports. The Pedirka and Western Eromanga basins are underexplored and contain relatively sparse seismic and petroleum well data. The AFER Project has interpreted play interval tops in 41 wells, 12 seismic horizons (Top Cadna-owie and underlying horizons) on 238 seismic lines (9,340 line kilometres), and all 15 horizons on 77 recently reprocessed seismic lines (3,370 line kilometres; Figure 2). Note that it has only been possible to interpret the Top Mackunda-Winton, Top Toolebuc-Allaru and Top Wallumbilla horizons on the reprocessed seismic lines as these are the only data that provide sufficient resolution in the shallow stratigraphic section to confidently interpret seismic horizons above the Top Cadna-owie seismic marker. The seismic interpretations are provided as point data files for 15 horizons, and have been used to constrain the zero edges for gross-depositional environment maps in Bradshaw et al. (2023) and to produce depth-structure and isochore maps for each of the 14 play intervals in Iwanec et al. (2023). The data package includes the following datasets: 1) Seismic interpretation point file data in two-way-time for up to 15 horizons using newly reprocessed seismic data and a selection of publicly available seismic lines (Appendix A). 2) Geographical layers for the seismic lines used to interpret the top Cadna-owie and underlying horizons (Cadnaowie_to_TopPrePermian_Interpretation.shp), and the set of reprocessed lines used to interpret all 15 seismic horizons (All_Horizons_Interpretation.shp; Appendix B). These seismic interpretations are being used to support the AFER Project’s play-based energy resource assessments in the Pedirka and Western Eromanga basins.

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

Publicly available groundwater data have been compiled to provide a common information base to inform environmental, resource development and regulatory decisions in the Galilee 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 Galilee Basin aquifers and their properties, including salinity, water levels, resource size, potential aquifer yield and surface water - groundwater interactions. The methods used to derive these data for all Galilee Basin aquifers in the Galilee Basin region are outlined in the associated metadata files. These are described in groundwater conceptual models (Hostetler et al., 2023). The Galilee Basin includes 3 broadly defined aquifer intervals: from deepest to shallowest, these are the Joe Joe Group, Betts Creek beds and Clematis aquifers. Compiled data have been 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 were 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 Galilee 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 Galilee Basin region.