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  • The hydrocarbon generative potential and the thermal maturity of source rocks in the offshore northern Perth Basin was reassessed based on existing and new geochemical data to get a better understanding of the basin's prospectivity. The study establishes for the first time that the main source of onshore accumulations, the Late Permian-Early Triassic Hovea Member, is well developed offshore and contains organic-rich sediments of oil-prone character. This finding shatters the long-held view that the Hovea Member was either absent or of poor quality offshore and provides a new perspective on the basin's prospectivity. The source potential of the Hovea Member varies spatially with best source rocks observed in the Beagle Ridge and Central Abrolhos Sub-basin. The Late Permian Irwin River Sequence and several Jurassic Sequences are also identified as prime potential source rocks offshore, mostly for their gas-generative potential. Oil-generative potential was identified in the Middle to Late Jurassic Yarragadee Sequence and possibly in the Middle Jurassic Cadda Sequence.

  • Hydrochemistry data for Australian groundwater, including field and laboratory measurements of chemical parameters (electrical conductivity (EC), potential of hydrogen (pH), redox potential, and dissolved oxygen), major and minor ions, trace elements, nutrients, pesticides, isotopes and organic chemicals. < <b>Value: </b>The chemical properties of groundwater are key parameters to understand groundwater systems and their functions. Groundwater chemistry information includes the ionic and isotopic composition of the water, representing the gases and solids that are dissolved in it. Hydrochemistry data is used to understand the source, flow, and interactions of groundwater samples with surface water and geological units, providing insight into aquifer characteristics. Hydrochemistry information is key to determining the quality of groundwater resources for societal, agricultural, industrial and environmental applications. Insights from hydrochemical analyses can be used to assess a groundwater resource, the impact of land use changes, irrigation and groundwater extraction on regional groundwater quality and quantity, assess prospective mineral exploration targets, and determine how groundwater interacts with surface water in streams and lakes. <b>Scope: </b>The database was inaugurated in 2016 with hydrochemical data collected over the Australian landmass by Geoscience Australia and its predecessors, and has expanded with regional and national data. It has been in the custodianship of the hydrochemists in Geoscience Australia's Minerals, Energy and Groundwater Division and its predecessors. Explore the <b>Geoscience Australia portal - https://portal.ga.gov.au/</b>

  • <div>The Birrindudu Basin is a region of focus for the second phase of the Geoscience Australia’s Exploring for the Future (EFTF) program (2020–2024). The Paleo to Mesoproterozoic Birrindudu Basin is an underexplored frontier basin located in northwestern Northern Territory and northeastern Western Australia. Interpretation of industry seismic data indicates it contains strata of similar age to the prospective McArthur Basin, South Nicholson region and Mount Isa Province, but remains comparatively poorly understood. Furthermore, much of the age of the stratigraphy of the Birrindudu Basin, particularly the younger stratigraphic units, and regional correlations to the greater McArthur Basin remains provisional and speculative.&nbsp;</div><div><br></div><div>This report presents data from Rock-Eval pyrolysis analyses undertaken by Geoscience Australia on selected rock samples to establish their total organic carbon content, hydrocarbon-generating potential and thermal maturity from 178 drill core samples from six drill holes intersecting units of the Birrindudu Basin including: 99VRNTGSDD1, 99VRNTGSDD2, WLMB001B, LBD2, LMDH4, and ANT003. </div><div><br></div>

  • <div>Geoscience Australia (GA) has produced a folio of 32 wells across the central and southeast regions. This folio covers the areas from Normanby 1 on the Normanby Terrace, through the Shipwreck Trough and Nelson Sub-basin, to Whelk 1 in the southeast. Composite logs for each well in the folio include wireline logs, petrophysical analysis, interpreted lithology, organic geochemical data, organic petrology data, and sequence stratigraphic markers. This folio also includes core-based depositional environment (DE) and gross depositional environment (GDE) interval interpretations which were used to constrain wireline interpretation of DE/GDE away from core control. The folio includes the digital data package used to construct each well composite. The new folio complements a recently published folio of northeast offshore Otway Basin wells, and both were designed as resource for exploration in the offshore Otway Basin.</div>

  • <p>The Roebuck Basin on Australia’s offshore north-western margin is the focus of a regional hydrocarbon prospectivity assessment being undertaken by the North West Margin Energy Studies (NWMES) section. This offshore program is designed to produce pre-competitive information to assist with the evaluation of the hydrocarbon resource potential of the central North West Shelf and facilitate exploration investment in Australia. <p>The recent oil and gas discoveries at Phoenix South 1 (2014), Roc 1 (2015-16), Roc 2 (2016), Phoenix South 2 (2016), Phoenix South 3 (2018) and Dorado 1 (2018) wells in the Bedout Sub-basin demonstrate the presence of a petroleum system in Lower Triassic strata. The current study aims to better understand this new petroleum system and establish its extent. <p>As part of this program, a range of organic geochemical analyses were acquired on two crude oils from the Phoenix South 1 ST2 well with these data released in this dataset.

  • <div>The Carrara Sub-basin, discovered in 2017 based on interpretation of 2D deep seismic surveys acquired by Geoscience Australia, is a large sedimentary depocentre in the South Nicholson region straddling the Northern Territory and Queensland. It was interpreted to contain up to 8 km of Paleoproterozoic to Cambrian rocks including stratigraphic equivalents to the Isa Superbasin, South Nicholson Group and Georgina Basin. In order to validate these stratigraphic interpretations and assess the resource prospectivity of the Carrara Sub-basin, the South Nicholson National Drilling Initiative (NDI) Carrara 1 stratigraphic drill hole was completed in late 2020 as a collaboration between the MinEx Cooperative Research Centre, Geoscience Australia and the Northern Territory Geological Survey. NDI Carrara 1 was drilled on the western flanks of the Carrara Sub-basin and reached a total depth of 1751&nbsp;m, intersecting ca. 630&nbsp;m of Cambrian Georgina Basin overlying ca. 1100&nbsp;m of Proterozoic carbonates, black shales and minor siliciclastics. More than 400 NDI Carrara&nbsp;1 physical samples were analysed as part of an extensive geochemical program, including Rock-Eval pyrolysis and compositional analyses of hydrocarbon shows, whose results and implications for energy prospectivity are summarised here.</div> This Abstract was submitted/presented to the 2022 Australian Organic Geochemistry Conference 27-29 November (https://events.csiro.au/Events/2022/October/5/Australian-Organic-Geochemistry-Conference)

  • This database contains geochemical data for samples analysed both for inorganic and organic geochemistry. Analytical data are sourced from Geoscience Australia's Inorganic Geochemistry Database (OZCHEM) and Organic Geochemistry Database (ORGCHEM), respectively. The data are joined on a unique sample number. Inorganic geochemical data cover the majority of the periodic table, with metadata on analytical methods and detection limits. Organic geochemical data include results of pyrolysis, derivative calculated values, and, where available, isotopic composition of carbonates (D13C) and isotopic composition of rock nitrogen (D15N). Further, there are provisions for delivery of isotopic data for kerogen (H, C, N) and oxygen (O) for carbonates. Where available, sample descriptions include stratigraphic unit names and ages, and lithology. Location information includes coordinates of the sampled feature (eg, borehole), coordinates of the sample and sample depth. Interpretation of the combined inorganic and organic geochemistry for organic-rich shales will facilitate comprehensive characterisation of hydrocarbons source rocks and mineral commodities source and trap environments. All are achieved within the frameworks of petroleum and mineral systems analysis. The initial data delivered by this service include 1785 samples from 35 boreholes from 14 geological provinces, including recently released data for 442 samples from the South Nicholson National Drilling Initiative Carrara 1 stratigraphic drill hole (Butcher et al., 2021; Carson et al., 2021). Many sampled boreholes are located within the polygon of the Exploring for the Future Barkly-Isa-Georgetown project. This dataset will be updated periodically as more data become available.

  • <p>The Roebuck Basin on Australia’s offshore north-western margin is the focus of a regional hydrocarbon prospectivity assessment being undertaken by the North West Margin Energy Studies Section (NWMES). This offshore program is designed to produce pre-competitive information to assist with the evaluation of the hydrocarbon resource potential of the central North West Shelf and attract exploration investment to Australia. <p>The recent oil and gas discoveries at Phoenix South 1 (2014), Roc 1 (2015-16), Roc 2 (2016), Phoenix South 2 (2016), Phoenix South 3 (2018) and Dorado 1 (2018) in the Bedout Sub-basin demonstrate the presence of a petroleum system in Lower Triassic strata. The current study aims to better understand this new petroleum system and establish its extent. <p>As part of this program, TOC and Rock-Eval pyrolysis analyses were undertaken by Geoscience Australia on selected rock samples from the well Roc 2 to establish their hydrocarbon-generating potential and thermal maturity.

  • In 2014, the surprise discovery of oil in the well Phoenix South 1 on Australia’s North West Shelf (NWS) heralded the Bedout Sub-basin as Australia’s new petroleum province. The well had initially targeted gas in Triassic reservoirs of the Keraudren Formation and Locker Shale but unexpectedly encountered oil instead. This has fuelled a revival of exploration in the area with subsequent wells Roc 1, Roc 2, Phoenix South 2 and Dorado 1 all successful in penetrating hydrocarbon columns. The Phoenix South 1 accumulation is significant as it demonstrates the occurrence of an effective oil-prone source rock within the Lower–Middle Triassic for the first time on the NWS. It also raised the possibility that a source rock analogue to the Hovea Member of the Lopingian–Lower Triassic Kockatea Shale, a well-established source of oil and gas in the northern Perth Basin, may also be effective on the NWS. In order to understand the origin of the Phoenix South 1 accumulation, its geochemical composition was compared to those of Triassic-sourced oils from the Perth Basin and petroleum fluids from the neighbouring Browse Basin, and Beagle and Dampier sub-basins.

  • The Roebuck Basin on Australia’s offshore north-western margin is the focus of a regional hydrocarbon prospectivity assessment being undertaken by the Offshore Energy Studies section. This offshore program is designed to produce pre-competitive information to assist with the evaluation of the hydrocarbon resource potential of the central North West Shelf and facilitate exploration investment in Australia. The recent oil and gas discoveries at Phoenix South 1 (2014), Roc 1 (2015-16), Roc 2 (2016), Phoenix South 2 (2016), Phoenix South 3 (2018), Dorado 1 (2018), Dorado 2 (2019) and Dorado 3 (2019) wells in the Bedout Sub-basin demonstrate the presence of a petroleum system in Lower Triassic strata (Thompson, 2020; Thompson et al., 2015 and 2018). The current study aims to better understand this new petroleum system and establish its extent. As part of this program, a range of organic geochemical analyses were acquired on petroleum fluids from the Roc 1 and Roc 2 wells with these data released in this report.