Organic geochemistry
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<div>The soil gas database table contains publicly available results from Geoscience Australia's organic geochemistry (ORGCHEM) schema and supporting oracle databases for gas analyses undertaken by Geoscience Australia's laboratory on soil samples taken from shallow (down to 1 m below the surface) percussion holes. Data includes the percussion hole field site location, sample depth, analytical methods and other relevant metadata, as well as the molecular and isotopic compositions of the soil gas with air included in the reported results. Acquisition of the molecular compounds are by gas chromatography (GC) and the isotopic ratios by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). The concentrations of argon (Ar), carbon dioxide (CO₂), nitrogen (N₂) and oxygen (O₂) are given in mole percent (mol%). The concentrations of carbon monoxide (CO), helium (He), hydrogen (H₂) and methane (C₁, CH₄) are given in parts per million (ppm). Compound concentrations that are below detection limit (BDL) are reported as the value -99999. The stable carbon (<sup>13</sup>C/<sup>12</sup>C) and nitrogen (<sup>15</sup>N/<sup>14</sup>N) isotopic ratios are presented in parts per mil (‰) and in delta notation as δ<sup>13</sup>C and δ<sup>15</sup>N, respectively.</div><div><br></div><div>Determining the individual sources and migration pathways of the components of natural gases found in the near surface are useful in basin analysis with derived information being used to support exploration for energy resources (petroleum and hydrogen) and helium in Australian provinces. These data are collated from Geoscience Australia records with the results being delivered in the Soil Gas web services on the Geoscience Australia Data Discovery portal at https://portal.ga.gov.au which will be periodically updated.</div>
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The Cooper Basin is Australia's premier onshore hydrocarbon producing province and hosts a range of conventional and unconventional gas play types. This study investigates the petroleum generation potential of the basin's major Permian source rocks, to improve regional understanding of the basin's hydrocarbon prospectivity. Source rock distribution, thickness, present-day amount of total organic carbon (TOC), quality (Hydrogen Index) and maturity were mapped across the basin, together with original source quality maps prior to the on-set of generation. Results of the source rock property mapping and basin-specific kinetics were integrated with 1D burial and thermal history models and a 3D basin model to create a regional pseudo-3D petroleum system model for the basin. The modelling outputs quantify the spatial distribution of both the maximum possible hydrocarbon yield, as well as the oil/ gas expelled and retained, for ten Permian source rocks. Monte Carlo simulations were used to quantify the uncertainty associated with hydrocarbon yields and to highlight the sensitivity of results to each input parameter. The principal source rocks are the Permian coal and coaly shales of the Gidgealpa Group, with highest potential yields from the Patchawarra Formation coals and coaly shales. The broad extent of the Cooper Basin's Permian source kitchen and its large total generation potential (P50 scenario >2000 bboe) highlights the basin¿s significance as a world-class hydrocarbon province. The difference between the P90 (~800 bboe) and P10 (>4000 bboe) scenarios demonstrate the range of uncertainties inherent in this modelling.
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<div>Geoscience Australia’s Exploring for the Future program provides precompetitive information 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 leads to a strong economy, resilient society and sustainable environment for the benefit of all Australians. This includes supporting Australia’s transition to a low emissions economy, strong resources and agriculture sectors, and economic opportunities and social benefits for Australia’s regional and remote communities. The Exploring for the Future program, which commenced in 2016, is an eight year, $225 m investment by the Australian Government. </div><div>As part of this program, Geoscience Australia led two deep crustal reflection seismic surveys in the South Nicholson region, revealing the existence of the Carrara Sub-basin, a large sedimentary depocentre up to 8 km deep, beneath the Georgina Basin (Carr et al., 2019; 2020). The depocentre is believed to contain thick sequences of highly prospective Proterozoic rocks for base metals and unconventional hydrocarbons. To confirm geological interpretations and assess resource potential, the National Drilling Initiative, NDI Carrara 1 stratigraphic drill hole was completed in late 2020, as a collaboration between Geoscience Australia, the Northern Territory Geological Survey (NTGS) and the MinEx CRC (Geoscience Australia, 2021). NDI Carrara 1 is located on the western flank of the Carrara Sub-basin on the South Nicholson seismic line (17GA-SN1) (Figure 1.1; Figure 1.2), reaching a total depth of 1751 m, intersecting sedimentary rocks comprising ca. 630 m of Cambrian calcareous shales of the Georgina Basin and ca. 1100 m of Proterozoic carbonates and siliciclastics that include black shales of the Carrara Sub-basin.</div><div>This report presents data on selected rock samples from NDI Carrara 1, conducted by the Mawson Analytical Spectrometry Services, University of Adelaide, under contract to Geoscience Australia. These results include bulk carbon isotope ratios (δ13C) of bitumens and isolated kerogens. In addition, a selection of 10 samples was analysed at Geoscience Australia for comparison purposes.</div><div><br></div>
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<div>The fluid inclusion stratigraphy database table contains publicly available results from Geoscience Australia's organic geochemistry (ORGCHEM) schema and supporting oracle databases for Fluid Inclusion Stratigraphy (FIS) analyses performed by FIT, a Schlumberger Company (and predecessors), on fluid inclusions in rock samples taken from boreholes. Data includes the borehole location, sample depth, stratigraphy, analytical methods and other relevant metadata, as well as the mass spectrometry results presented as atomic mass units (amu) from 2 to 180 in parts per million (ppm) electron volts.</div><div> Fluid inclusions (FI) are microscopic samples of fluids trapped within minerals in the rock matrix and cementation phases. Hence, these FIS data record the bulk volatile chemistry of the fluid inclusions (i.e., water, gas, and/or oil) present in the rock sample and determine the relative abundance of the trapped compounds (e.g., in amu order, hydrogen, helium, methane, ethane, carbon dioxide, higher molecular weight aliphatic and aromatic hydrocarbons, and heterocyclic compounds containing nitrogen, oxygen or sulfur). The FI composition can be used to identify the presence of organic- (i.e., biogenic or thermogenic) and inorganic-sourced gases. These data provide information about fluid preservation, migration pathways and are used to evaluate the potential for hydrocarbon (i.e. dry gas, wet gas, oil) and non-hydrocarbon (e.g., hydrogen, helium) resources in a basin. These data are collated from Geoscience Australia records, destructive analysis reports (DARs) and well completion reports (WCRs), with the results being delivered in the Fluid Inclusion Stratigraphy (FIS) web services on the Geoscience Australia Data Discovery Portal at https://portal.ga.gov.au which will be periodically updated.</div>
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<div>The Proterozoic basins of northern Australia have been the focus of regional hydrocarbon prospectivity studies undertaken by the Exploring for the Future program dedicated to increasing investment in resource exploration in northern Australia. As part of this program, a compilation of the compound-specific isotopic compositions of linear alkanes in source extracts, oils and oil stains from 21 boreholes of the greater McArthur Basin has been completed. The samples were analysed in Geoscience Australia’s Isotope and Organic Geochemistry Laboratory and the stable carbon and hydrogen isotopic data of individual alkanes are released in this report. </div>
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The Cooper Basin is a Pennsylvanian to Middle Triassic intracratonic basin in northeastern South Australia and southwestern Queensland (Gravestock et al., 1998; Draper, 2002; Carr et al., 2016). 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). In support of this ongoing exploration activity in the region, Hall et al. (2016a) reviewed the Cooper Basin source rock geochemistry and maturity based on a compilation of updated and quality controlled publically available total organic carbon (TOC), Rock-Eval pyrolysis and vitrinite reflectance data. This is the first study of its kind to be undertaken for the Cooper Basin as a whole and builds on the previous work of Boreham & Hill (1998) in South Australia. This data pack contains the supplementary material accompanying this report. The distribution, quantity, quality and thermal maturity of the organic matter were described for all formations within the Pennsylvanian¿Permian Gidgealpa Group and collectively for the formations within the Triassic Nappamerri Group (Hall et al., 2015a, 2016a). Where possible, data were also analysed by lithology. The total organic carbon (TOC) and Rock-Eval pyrolysis data were used to investigate source rock quality, maturity and kerogen type. Original Hydrogen Index (HIo) values for each formation and lithology were determined through the analysis of a subset of low maturity samples and through application of a maturity correction based on Cooper Basin-specific kinetics (Deighton et al., 2003; Mahlstedt et al., 2015). Where data density permits, maps of present day TOC content and both present day HI and original HI were created, showing the spatial variation in the amount and quality of the source rock present now and prior to the onset of hydrocarbon generation. This data pack includes all TOC and Rock Eval data for the Cooper Basin stratigraphic evaluated in Hall et al. (2016a). It also includes the grids of present day TOC for the shale and/or coaly shale intervals, along with the grids of present day and original HI by formation. These datasets quantify the spatial distribution, quantity and quality of the source rocks and provide important insights into the hydrocarbon prospectivity of the Cooper Basin (Hall et al., 2015b; Kuske et al., 2015). This was the first study to be completed as part of the Australian Petroleum Source Rock Mapping project, a new work program being undertaken at Geoscience Australia to improve our understanding of the petroleum resource potential of Australia's sedimentary basins.
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<div>The Roebuck Basin on Australia’s offshore north-western margin is the focus of regional energy exploration activity. Drilling in the Roebuck Basin resulted in oil and gas discoveries at Phoenix South 1 (2014), Roc 1 (2015–2016) and Dorado 1 (2018) in the Bedout Sub-basin (Figure 1‑2) and demonstrated the presence of a petroleum system in Lower Triassic strata. These discoveries have been evaluated for development and production with infill drilling at Roc 2 (2016), Phoenix South 2 (2016), Phoenix South 3 (2018), Dorado 2 (2019), and Dorado 3 (2019). Recent drilling by Santos (2022) has resulted in the discovery of oil at Pavo 1 (2022) and hydrocarbon shows at Apus 1 (2022).</div><div><br></div><div>To complement this industry work, Geoscience Australia’s Offshore Energy Systems program produces pre-competitive information to assist with the evaluation of the energy and resource potential of the central North West Shelf, including both hydrogen and helium resources, and to attract exploration investment to Australia. As part of this program, determination of the molecular and noble gas isotopic composition of natural gases from selected petroleum wells in the Roebuck Basin were undertaken by Smart Gas Sciences, under contract to Geoscience Australia, with results from these analyses being released in this report. This report provides additional gas data to determine the sources of natural gases in the Roebuck Basin and build on previously established gas-gas correlations. Noble gas isotopic data can be used in conjunction with carbon and hydrogen isotopic data to determine the origin of both inorganic and organic (hydrocarbon) gases. This information can be used in future geological programs to determine the source and distribution of hydrogen and helium in natural gases and support acreage releases by the Australian Government.</div><div><br></div>
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A regional hydrocarbon prospectivity study was undertaken in the onshore Canning Basin in Western Australia as part of the Exploring for the Future (EFTF) program, an Australian Government initiative dedicated to driving investment in resource exploration. As part of this program, significant work has been carried out to deliver new pre-competitive data including new seismic acquisition, drilling of stratigraphic wells and the geochemical analysis of geological samples recovered from exploration wells. A regional, 872 km long 2D seismic line (18GA-KB1) acquired in 2018 by Geoscience Australia (GA) and the Geological Survey of Western Australia (GSWA), images the Kidson Sub-basin of the Canning Basin. In order to provide a test of geological interpretations made from the Kidson seismic survey, a deep stratigraphic well, Barnicarndy 1, was drilled in 2019 in partnership between Geoscience Australia (GA) and the Geological Survey of Western Australia (GSWA) in the Barnicarndy Graben, 67 km west of Telfer, in the South West Canning Basin. Drilling recovered about 2100 m of continuous core from 580 mRT to the total driller’s depth (TD) of 2680.53 mRT (Normore and Rapaic, 2020). An extensive analytical program was carried out to characterise the lithology, age and depositional environment of these sediments. This included detailed organic geochemistry including isotopic and biomarker analyses of core samples. In order to determine the possible presence of organic contaminants in core samples that may jeopardise interpretation of results, manufactured products used during drilling and sample processing were identified as potential sources of hydrocarbon contamination and were investigated for their hydrocarbon content. In addition, in order to test if any hydrocarbon contamination was occurring due to contact with these manufactured products, water samples from the sumps and surface samples of drill muds from specific depths were collected and analysed as well.
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<div>The onshore Canning Basin in Western Australia was the focus of a regional hydrocarbon prospectivity assessment undertaken by the Exploring for the Future (EFTF) program dedicated to increasing investment in resource exploration in northern Australia, with the objective being to acquire new data and information about the potential mineral, energy and groundwater resources concealed beneath the surface. Significant work has been carried out to deliver new pre-competitive data in the region including new seismic acquisition, drilling of a stratigraphic well, and geochemical analysis from historic exploration wells.</div><div><br></div><div>As part of this program, determination of the molecular and noble gas isotopic composition of natural gases from selected petroleum wells in the Canning Basin were undertaken by Smart Gas Sciences, under contract to Geoscience Australia, with results from these analyses being released in this report. This report provides additional data to determine the sources of natural gases in the Canning Basin and build on the availability of existing gas data, gas-gas correlations and gas-oil correlations. Noble gas isotopic data can be used in conjunction with carbon and hydrogen isotopic data to determine the origin of both inorganic and organic (hydrocarbon) gases. This information can be used in future geological programs to determine the source and distribution of hydrogen and helium in natural gases and support exploration programs.</div>
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<div>A regional hydrocarbon prospectivity assessment has been undertaken of the offshore Otway Basin by the Offshore Energy Systems Section. This program was designed to produce pre-competitive information to assist with the evaluation of the hydrocarbon resource potential of the offshore Otway Basin and attract exploration investment to Australia. The inboard part of the basin is an established hydrocarbon province with onshore and shallow-water offshore discoveries, whereas the outboard deep-water region, where water depths range from 500 to 6300 m, is comparatively underexplored and considered a frontier area.</div><div><br></div><div>As part of this program, molecular and noble gas isotopic analyses were undertaken by Smart Gas Sciences, under contract to Geoscience Australia on available gas samples from the Waarre Formation in the Shipwreck Trough in the offshore eastern Otway Basin, with data from these analyses being released in this report. This report provides additional compositional information for gases in the Waarre Formation reservoirs and builds on previously established gas-gas correlations and gas-oil correlations. Noble gas isotopic data can be used in conjunction with carbon and hydrogen isotopic data to determine the origin of both inorganic and organic (hydrocarbon) gases. This information can be used in future geological programs to determine the source and distribution of hydrogen and helium in natural gases and support acreage releases by the Australian Government.</div><div><br></div><div><br></div>