Exploring for the Future (EFTF) is an ongoing multiyear initiative by the Australian Government, conducted by Geoscience Australia, in partnership with state and Northern Territory government agencies and other partner research institutes. The first phase of the EFTF program (2016-2020) aimed to improve Australia’s desirability for industry investment in resource exploration in frontier or ‘greenfield’ regions across northern Australia. As part of the program, Geoscience Australia employed a range of both established and innovative techniques to gather new precompetitive data and information to develop new insight into the energy, mineral and groundwater resource potential across northern Australia. To maximise impact and to stimulate industry exploration activity, Geoscience Australia focussed activities in greenfield areas where understanding of resource potential was limited. In order to address this overarching objective under the EFTF program, Geoscience Australia led acquisition of two deep crustal reflection seismic surveys in the South Nicholson region, an understudied area of little previous seismic data, straddling north-eastern Northern Territory and north-western Queensland. The first survey, L210 South Nicholson 2D Deep Crustal Seismic Survey acquired in 2017, consisted of five overlapping seismic lines (17GA-SN1 to SN5), totalling ~1100 line-km. Survey L210 linked directly into legacy Geoscience Australia seismic lines (06GA-M1 and 06GA-M2) in the vicinity of the world-class Pb-Zn Century Mine in Queensland. The results from survey L210 profoundly revised our geological understanding of the South Nicholson region, and led to the key discovery of an extensive sag basin, the Carrara Sub-basin, containing highly prospective late Paleoproterozoic to Mesoproterozoic rocks with strong affinities with the adjacent Mount Isa Province and Lawn Hill Platform. To complement and expand on the outstanding success of the South Nicholson survey and to continue to explore the resource potential across the underexplored and mostly undercover South Nicholson and Barkly regions, a second seismic survey was acquired in late 2019, the Barkly 2D reflection survey (L212). The Barkly seismic survey comprises five intersecting lines (19GA-B1 to B5), totalling ~813 line-km, extending from the NT-QLD border in the south-east, near Camooweal, to the highly prospective Beetaloo Sub-basin in the north-west. The survey ties into the South Nicholson survey (L210), the recently acquired Camooweal 2D reflection seismic survey by the Geological Survey of Queensland and industry 2D seismic in the Beetaloo Sub-basin, leveraging on and maximising the scientific value and impact on all surveys. The Barkly reflection seismic data images the south-western margin of the Carrara Sub-basin and identified additional previously unrecognised, structurally-disrupted basins of Proterozoic strata, bounded by broadly northeast trending basement highs. Critically, the survey demonstrates the stratigraphic continuity of highly prospective Proterozoic strata from the Beetaloo Sub-basin into these newly discovered, but as yet unevaluated, concealed basins and into the Carrara Sub-basin, further attesting to the regions outstanding potential for mineral and hydrocarbon resources. This survey, in concert with the South Nicholson seismic survey and other complementary EFTF funded regional geochemical, geochronology and geophysical data acquisition surveys, significantly improves our understanding of the geological evolution, basin architecture and the resource potential of this previously sparsely studied region.

NDI Carrara 1 is a deep stratigraphic drill hole (~1751m) completed in 2020 as part of the MinEx CRC National Drilling Initiative (NDI) in collaboration with Geoscience Australia and the Northern Territory Geological Survey. It is the first test of the Carrara Sub-basin, a depocentre newly discovered in the South Nicholson region based on interpretation from seismic surveys (L210 in 2017 and L212 in 2019) recently acquired as part of the Exploring for the Future program. The drill hole intersected approximately 1100 m of Proterozoic sedimentary rocks uncomformably overlain by 630 m of Cambrian Georgina Basin carbonates. This report presents inorganic geochemical analyses undertaken by Geoscience Australia on selected rock samples, collected at roughly 4 m intervals.

A comprehensive geochemical program was carried out on rock samples collected in the NDI Carrara 1 drill hole, the first stratigraphic test of the newly discovered Carrara Sub-basin located in the South Nicholson region of northern Australia. The drill hole recovered continuous core from 284 m to total depth at 1750 m and intersected approximately 1120 m of Proterozoic sedimentary rocks, unconformably overlain by 630 m of Cambrian Georgina Basin carbonate-rich rocks. Total organic carbon (TOC) contents from Rock-Eval pyrolysis highlight the potential for several thick black shales to be a source of petroleum for conventional and unconventional plays. Cambrian rocks contain an organic-rich section with TOC contents of up to 4.7 wt.% and excellent oil-generating potential. The Proterozoic section is overmature for oil generation but mature for gas generation, with potential for generating gas in carbonaceous mudstones showing TOC contents up to 5.5 wt.% between 680 and 725 m depth. A sustained release of methane (up to 2%) recorded during drilling from 1150 to 1500 m suggests potential for an unconventional gas system in the Proterozoic rocks from 950 to 1415 m depth, which exhibit favourable organic richness and thermal maturity. The Proterozoic rocks, which are comparable in age to the sediment-hosted deposits of the Century Mine, contain local occurrences of lead, zinc and copper sulfide minerals providing hints of mineralisation. The combined geochemical results offer the promise of a potential new resource province in northern Australia. <b>Citation:</b> E. Grosjean, A.J.M. Jarrett, C.J. Boreham, L. Wang, L. Johnson, J.M. Hope, P. Ranasinghe, J.J. Brocks, A.H.E. Bailey, G.A. Butcher, C.J. Carson, Resource potential of the Proterozoic–Paleozoic Carrara depocentre, South Nicholson region, Australia: Insights from stratigraphic drilling, <i>Organic Geochemistry</i>, Volume 186, 2023, 104688, ISSN 0146-6380, DOI: https://doi.org/10.1016/j.orggeochem.2023.104688.

<div>This study aims to understand both the burial and thermal history of the Carrara Sub-basin to further develop an understanding of possible geo-energy resources, particularly that for unconventional resources such as shale gas. A 1D and 2D model were developed using data from the above mentioned seismic and drilling campaigns, combined with previously published knowledge of the basin. This work contributes to Australia’s Future Energy Resources (AFER) Project, specifically the Onshore Basin Inventories study, which aims to promote exploration and investment in selected underexplored onshore basins. Inventory reports and petroleum systems modelling are being undertaken in select basins to highlight the oil and gas potential in underexplored provinces and to increase the impact of existing datasets.</div><div><br></div>

NDI Carrara 1 is a deep stratigraphic well completed in 2020 as part of the MinEx CRC National Drilling Initiative (NDI), in collaboration with Geoscience Australia and the Northern Territory Geological Survey. It is the first stratigraphic test of the Carrara Sub-Basin, a newly discovered depocentre in the South Nicholson region. The well intersected Proterozoic sediments with numerous hydrocarbon shows, likely to be of particular interest due to affinities with the known Proterozoic plays of the Beetaloo Sub-basin and the Lawn Hill Platform, including two organic-rich black shales and a thick sequence of interbedded black shales and silty-sandstones. Alongside an extensive suite of wireline logs, continuous core was recovered from 283.9 m to total depth at 1750.8 m, providing high-quality data to support comprehensive analysis. Presently, this includes geochronology, geochemistry, geomechanics, and petrophysics. Rock Eval pyrolysis data demonstrates the potential for several thick black shales to be a source of hydrocarbons for conventional and unconventional plays. Integration of these data with geomechanical properties highlights potential brittle zones within the fine-grained intervals where hydraulic stimulation is likely to enhance permeability, identifying prospective Carrara Sub-basin shale gas intervals. Detailed wireline log analysis further supports a high potential for unconventional shale resources. Interpretation of the L210 and L212 seismic surveys suggests that the intersected sequences are laterally extensive and continuous throughout the Carrara Sub-basin, potentially forming a significant new hydrocarbon province and continuing the Proterozoic shale play fairway across the Northern Territory and northwest Queensland. This abstract was submitted and presented at the 2022 Australian Petroleum Production and Exploration Association (APPEA), Brisbane (https://appea.eventsair.com/appea-2022/)

NDI Carrara 1 is a deep stratigraphic drill hole completed in 2020 as part of the MinEx CRC National Drilling Initiative (NDI) in collaboration with Geoscience Australia and the Northern Territory Geological Survey. It is the first test of the Carrara Sub-Basin, a depocentre newly discovered in the South Nicholson region based on interpretation from seismic surveys (L210 in 2017 and L212 in 2019) recently acquired as part of the Exploring for the Future program. The drill hole intersected approximately 1120 m of Proterozoic sedimentary rocks unconformably overlain by 630 m of Cambrian Georgina Basin carbonates. Continuous cores recovered from 283 m to a total depth of 1750 m provide samples of the highest quality for a comprehensive geochemical program designed to inform on the energy and mineral prospectivity of the Carrara Sub-basin. Total Organic Carbon (TOC) contents from Rock-Eval pyrolysis of the Cambrian and Proterozoic sections demonstrate the potential for several thick black shales as source rocks and unconventional plays. Evidence for retained hydrocarbons included bituminous oil stains in centimetre-scale vugs within the Cambrian Georgina Basin and several oil bleeds within the Proterozoic section. The latter also contains surface gas with up to 2% methane concentrations measured within carbonaceous mudstones. Geochemical analyses of hydrocarbon shows highlight the occurrence of several petroleum systems operating in this frontier region. The results at NDI Carrara 1 offer the promise of a new exciting resource province in northern Australia.

Exploring for the Future (EFTF) is an Australian Government initiative that gathers new data and information about potential mineral, energy and groundwater resources. Commencing in 2016 with a focus on northern Australia, an EFTF extension to 2024 was recently announced, with expanded coverage across mainland Australia and Tasmania. The EFTF energy component aims to improve our understanding of the petroleum potential of frontier onshore Australian basins and has acquired significant pre-competitive datasets, including the recently drilled Barnicarndy 1 deep stratigraphic well in Western Australia’s Canning Basin (in partnership with the Geological Survey of Western Australia), and NDI Carrara 1 deep stratigraphic well in the South Nicholson region of the Northern Territory (in partnership with the MinEX CRC). These are the first stratigraphic wells drilled in a petroleum basin by Geoscience Australia since the formation in 2001 from its predecessor agencies. Both wells were sited along two-dimensional, deep crustal seismic surveys acquired by Geoscience Australia as part of EFTF, and provide stratigraphic control for the imaged geology. The sedimentary fill intersected by the Barnicarndy 1 and NDI Carrara 1 wells were cored and logged with a broad suite of wireline tools, providing substantial new data in two frontier basins. These data provide insights into regional stratigraphy and local lithology. Geochronology, petrographic, organic and inorganic geochemistry, petrophysical rock properties, petroleum systems elements, palaeontological, and fluid inclusion studies have been undertaken upon which inferences on regional prospectivity can made in these data-poor regions. Moving into the next phase of EFTF, these wells provide a template for new pre-competitive data acquisition by Geoscience Australia, expanding our knowledge of frontier regions making them attractive for new investment and exploration.

The first phase of the Australian Government's Exploring for the Future (EFTF) was a multi-year (2016-2020) $100.5 million initiative to increase northern Australia's desirability as a destination for industry investment to stimulate ‘greenfield’ resource exploration. In order to support this fundamental objective of the EFTF program, Geoscience Australia conducted acquisition of a diverse range of new precompetitive datasets across northern Australia, focussing on regions of unrecognised mineral, energy and groundwater resource potential. The Barkly 2D Deep Crustal Reflection Seismic Survey (L212) was acquired in 2019 as a major objective of the EFTF program in partnership with, and co-funded by, the NT Government under the Resourcing the Territory initiative. The Barkly Seismic Survey extends from the newly discovered Carrara Sub-basin in the South Nicholson Basin region to the south-eastern margins of the Beetaloo Sub-basin (Fomin, T., et al. 2019). The Barkly Seismic Survey images interpreted Paleoproterozoic to Mesoproterozoic successions extending from the Carrara Sub-basin to the highly prospective Beetaloo Sub-basin of the McArthur Basin. These successions are concealed by a persistent cover of up to 600 m of Paleozoic Georgina Basin sediments. Interpretation of the Barkly Seismic Survey established three informal geological domains, each defined by structural elements and/or basin characteristics (Southby et al, 2021). This data set contains an exported set of XYZ points from interpreted horizons (Southby et al 2022,) on the Barkly Seismic Survey (L212) in both two way time (TWT ms on PreSTM_19ga lines) and depth (m) re-interpreted on depth indexed PreSDM_19GA lines. The coordinate reference system for this dataset is WGS 1984 Australian Centre for Remote Sensing Lambert. Seismic reference datum is 350 m. The seismic reference datum are described in the EBCDIC headers of the SEGY files for each of the survey lines. Fomin, T., Costelloe, R.D., Holzschuh, J. 2019. L212 Barkly 2D Seismic Survey. Geoscience Australia, Canberra. https://pid.geoscience.gov.au/dataset/ga/132890 Southby, C., Rollet, N., Carson, C., Carr, L., Henson, P., Fomin, T., Costelloe, R., Doublier, M., Close, D. 2021. The Exploring for the Future 2019 Barkly Reflection Seismic Survey: Key discoveries and implication for resources. Geoscience Australia, Canberra. https://pid.geoscience.gov.au/dataset/ga/145107 Southby, C., Carson, C.J., Fomin, T., Rollet, N., Henson, P.A., Carr, L.K., Doublier, M.P., Close, D. 2022. Exploring for the Future - The 2019 Barkly Reflection Seismic Survey (L212). RECORD: 2022/009. Geoscience Australia, Canberra. http://dx.doi.org/10.11636/Record.2022.009

NDI Carrara 1 is a deep stratigraphic drill hole (~1751m) completed in 2020 as part of the MinEx CRC National Drilling Initiative (NDI) in collaboration with Geoscience Australia and the Northern Territory Geological Survey. It is the first test of the Carrara Sub-basin, a depocentre newly discovered in the South Nicholson region based on interpretation from seismic surveys (L210 in 2017 and L212 in 2019) recently acquired as part of the Exploring for the Future program. The drill hole intersected approximately 1100 m of Proterozoic sedimentary rocks uncomformably overlain by 630 m of Cambrian Georgina Basin carbonates. This report presents petrology and clay speciation XRD conducted on of 6 selected volcaniclastic rocks taken from NDI Carrara 1 between ca. 1579 m and ca. 1653 m depth. Petrology and XRD was undertaken by Microanalysis Australia (under contract to Geoscience Australia as part of the Exploring for the Future program). Borehole completion report can be found at https://portal.ga.gov.au/bhcr/minerals/648482

<div>NDI Carrara 1 is a 1750 m stratigraphic drill hole completed in 2020 as part of the MinEx CRC National Drilling Initiative (NDI) in collaboration with Geoscience Australia under the Exploring for the Future program and the Northern Territory Geological Survey. It is the first stratigraphic test of the Carrara Sub-basin, a recently discovered depocentre in the South Nicholson region. The drill hole intersected Cambrian and Proterozoic sediments consisting of organic-rich black shales and a thick sequence of interbedded black shales and silty sandstones with hydrocarbon shows. A comprehensive analytical program carried out by Geoscience Australia on the recovered core samples from 283 m to total depth at 1751&nbsp;m provides critical data for calibration of burial and thermal history modelling.</div><div>Using data from this drilling campaign, burial and thermal history modelling was undertaken to provide an estimate of the time-temperature maxima that the sub-basin has experienced, contributing to an understanding of hydrocarbon maturity. Proxy kerogen kinetics are assessed to estimate the petroleum prospectivity of the sub-basin and attempt to understand the timing and nature of hydrocarbon generation. Combined, these newly modelled data provide insights into the resource potential of this frontier Proterozoic hydrocarbon province, delivering foundational data to support explorers across the eastern Northern Territory and northwest Queensland.</div> <b>Citation:</b> Palu Tehani J., Grosjean Emmanuelle, Wang Liuqi, Boreham Christopher J., Bailey Adam H. E. (2023) Thermal history of the Carrara Sub-basin: insights from modelling of the NDI Carrara 1 drill hole. <i>The APPEA Journal</i><b> 63</b>, S263-S268. https://doi.org/10.1071/AJ22048