Exploring for the Future is a four year $100.5 million initiative by the Australian Government conducted in partnership with state and Northern Territory government agencies and universities that aims to boost northern Australia's attractiveness as a destination for investment in resource exploration. The acquisition of deep crustal seismic reflection data in the Kidson Sub-basin (Canning Basin) between the Kiwirrkurra community and Marble Bar in northern Western Australia was a major EFTF deliverable, and was completed in August 2018. This paper presents the preliminary geological interpretation of the sedimentary succession imaged by the Kidson Sub basin seismic line.

A key focus of the Exploring for the Future program was the Kidson Sub-basin, a large, underexplored and poorly understood depocentre in the southern part of the Canning Basin of Western Australia. The Canning Basin hosts proven petroleum systems and has recently become an area of interest for unconventional hydrocarbon exploration. Several formations within deeper basin depocentres are under investigation. Unconventional petroleum resource evaluation is generally dependent on an understanding of both local and regional stresses, as these exert a control over subsurface fluid flow pathways, as well as the geomechanical properties of reservoir units. Gaps exist in our understanding of these factors within the Canning Basin, and particularly the Kidson Sub-basin where wellbore coverage is sparse. This study identifies a generally NE–SW-oriented regional maximum horizontal stress azimuth from interpretation of borehole failure in five petroleum wells, and a broadly strike–slip faulting stress regime from wireline data and wellbore testing. Variations in stress regime at different crustal levels within the basin are highlighted by one-dimensional mechanical earth models that show changes in the stress regime with depth as well as by lithology, with a general shift towards a normal faulting stress regime at depths greater than ~2.5 km. <b>Citation:</b> Bailey, A.H.E. and Henson, P., 2020. Present-day stresses of the Canning Basin, WA. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.

The Ordovician to Cretaceous Canning Basin of Western Australia is an underexplored prospective onshore petroleum basin with proven petroleum systems currently producing on a small-scale. The Canning Basin has recently become a site of interest for unconventional hydrocarbon exploration, with several formations within deeper basin depocentres being investigated for resources and estimates that suggest it may have the largest shale gas potential in Australia. Modern petroleum resource evaluation generally depends on an understanding of both local and regional stresses, which are a primary control over the formation and propagation of induced fractures. Presently, there are significant gaps in our understanding of these factors within the Canning Basin. This study characterises the regional stress regime of the onshore Canning Basin and presents detailed models of present-day stress within the subsurface. These allow for the identification of significant stress heterogeneities and natural barriers to fracture propagation. Wireline data interpretation reveals a variable present-day state of stress in the Canning Basin. An approximately NE-SW regional present-day maximum horizontal stress orientation is interpreted from observed wellbore failure in image logs, in broad agreement with both the Australian Stress Map and previously published earthquake focal mechanism data. One-dimensional mechanical earth models constructed for intervals from 15 Canning Basin petroleum wells highlight the relationship between lithology and stress. This study describes significant changes in stress within and between lithological units due to the existence of discrete mechanical units, forming numerous inter- and intra- formational stress boundaries likely to act as natural barriers to fracture propagation, particularly within units currently targeted for their unconventional resource potential. Broadly, a strike-slip faulting stress regime is interpreted through the basin, however, when analysed in detail there are three distinct stress zones identified.: 1) a transitional reverse- to strike-slip faulting stress regime in the top ~1 km of the basin, 2) a strike-slip faulting stress regime from ~1 km to ~3.0 km depth, and 3) a transitional strike-slip to normal faulting regime at depths greater than ~3.0 km. This study is a component of the Australian Government’s Exploring for the Future (EFTF) initiative, which is focused on gathering new data and information about the resource potential concealed beneath the surface across northern Australia. Appeared online in the Australian Journal of Earth Sciences 17 Feb 2021

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.

This report presents the results of an elemental and carbon and oxygen isotope chemostratigraphy study on three historic wells; Kidson-1, Willara-1 and Samphire Marsh-1, from the southern Canning Basin, Western Australia. The objective of this study was to correlate the Early to Middle Ordovician sections of the three wells to each other and to wells with existing elemental and carbonate carbon isotope chemostratigraphy data from the Broome Platform, Kidson and Willara sub-basins, and the recently drilled and fully cored stratigraphic Waukarlycarly 1 well from the Waukarlycarly Embayment.

<p>The Paleozoic Canning Basin is a large (~720 000 km2) frontier province with several proven petroleum systems. Recent oil production from the Ungani field on the southern edge of the Fitzroy Trough has boosted the small-scale production of crude oil and gas discovered in the 1980s on the Lennard Shelf and flanking terraces (e.g. Blina, Boundary, Lloyd, Sundown, West Kora, West Terrace). Determining the paleo-depositional environments within the epicontinental seaway is essential to characterise source rock formation and distribution, and hence assist future exploration strategies.</p> <p>This study of diagnostic biomarker hydrocarbons derived from the coloured carotenoid pigments of photosynthetic organisms (including plants, algae, cyanobacteria and photosynthetic bacteria) was designed to extend the geochemistry of the Ordovician-, Middle to Late Devonian- and Early Carboniferous-sourced oils of the basin published by Edwards et al. (2013) and Spaak et al. (2017, 2018), and implemented by GeoMark Research. The focus was to clarify the paleo-depositional environment of their marine source rocks and the extent of water stratification, and to expand upon the diversity of the contributing organic matter. The oils on the Lennard Shelf and those on the southern side of the Fitzroy Trough (e.g. Ungani and Dodonea 1) preserve a diverse range of biomarkers, including both saturated and aromatic C40 carotenoid-derived compounds (Figure 1) due to minimal secondary alteration. All analysed oils contain the saturated biomarker beta-carotane, derived from algae and cyanobacteria that flourish in sunlit oxygenated water. In addition, the oils also contain aromatic carotenoids produced by photosynthetic green sulphur bacteria, which inhabit the photic zone of euxinic water columns (e.g. Summons & Powell, 1986; French et al., 2015). Paleorenieratane is the dominant C40 aromatic carotenoid in the Ordovician (Dodonea 1, Pictor) and Late Devonian-sourced oils (Blina 1, 2, 4 and Janpam North 1; Figure 1). Oils on the Lennard Shelf generated by Lower Carboniferous source rocks have variable distributions of carotenoids with isorenieratane either in similar concentration to paleorenieratane (Point Torment 1, Sundown 2), absent (West Kora 1) or, in the case of Terrace 1, in lower abundance relative to paleorenieratane. Paleorenieratane, isorenieratane and renieratane are absent in oils from Wattle 1 ST1 and Mirbelia 1. Chlorobactane, also derived from green sulphur bacteria, is present in many of the analysed oils (and is the dominant peak in Point Torment 1), whereas okenane (derived from purple sulphur bacteria) was not detected. The exception is the Late Ordovician (Sandbian) Cudalgarra 1 oil that contains a low concentration of okenane, and in which isorenieratane predominates over paleorenieratane. The aromatic carotenoid distribution in oil from Ungani 2 is similar to those from both Terrace 1 and Blina (Figure 1).</p> <p>The association of these saturated and aromatic carotenoids in Paleozoic Canning Basin oils provides evidence for long-term restricted circulation and the development of shallow chemoclines in an epicontinental seaway centred along the Fitzroy Trough and Gregory Sub-basin in which oxygenated surface water frequently overlaid deeper, anoxic, sulphidic (euxinic) water also within the photic zone.</p> <p>REFERENCES Edwards, D.S., Boreham, C.J., Chen, J., Grosjean, E., Mory, A.J., Sohn, J., Zumberge, J.E., 2013. Stable carbon and hydrogen isotopic compositions of Paleozoic marine crude oils from the Canning Basin: comparison with other west Australian crude oils. In: Keep, M., Moss, S. (Editors), The Sedimentary Basins of Western Australia IV, Perth, WA. Edwards, P., Streitberg, E., 2013. Have we deciphered the Canning? Discovery of the Ungani oil field. In: Keep, M., Moss, S. (Editors), The Sedimentary Basins of Western Australia IV, Perth, WA. French, K.L., Rocher, D., Zumberge, J.E., Summons, R.E., 2015. Assessing the distribution of sedimentary C40 carotenoids through time. Geobiology 13, 139–151, 10.1111/gbi.12126. Spaak, G., Edwards, D.S., Allen, H.J., Grotheer, H., Summons, R.E., Coolen, M.J.L., Grice, K., 2018. Extent and persistence of photic zone euxinia in Middle–Late Devonian seas – insights from the Canning Basin and implications for petroleum source rock formation. Marine and Petroleum Geology, 93, 33–56. Spaak, G., Edwards, D.S., Foster, C.B., Pagès, A., Summons, R.E., Sherwood, N., Grice, K., 2017. Environmental conditions and microbial community structure during the Great Ordovician Biodiversification Event; a multi-disciplinary study from the Canning Basin, Western Australia. Global and Planetary Change, 159, 93–112. Summons, R.E., Powell, T.G., 1986. Chlorobiaceae in Palaeozoic seas revealed by biological markers, isotopes and geology. Nature 319, 763–765.</p>

<div>The onshore Canning Basin in Western Australia was the focus of a regional hydrocarbon prospectivity assessment undertaken by the Exploring for the Future&nbsp;(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>

Exploring for the Future Roadshow- Regional petroleum systems visualised in the EFTF Data Discovery Portal. A summary of petroleum systems of the Canning Basin and regional Meso- and Paleoproterozoic basins of northern Australia, and an introduction to the EFTF Data Discovery Portal

Late Devonian mass extinctions attributed to extensive anoxia and/or euxinia of the oceans are associated with widespread deposition of organic-rich shales. Also in the epeiric waters of the Canning Basin (Western Australia), photic zone euxinia (PZE) prevailed during the Givetian–Frasnian, with geochemical evidence for PZE on the northern (Lennard Shelf)–, and southern (Barbwire Terrace) margins of the Fitzroy Trough. On the Lennard Shelf, shales record episodic pulses of PZE associated with high algal activity due to enhanced nutrient supply, whereas a restricted marine setting on the Barbwire Terrace is thought to be the main driver for the development of persistent PZE and associated bacterial predominance. Structural evidence indicates that the Fitzroy Trough was a confined basin during the Late Devonian with the possibility of limited ocean circulation. Widespread PZE is expected to have developed in the poorly mixed water column, if the basin received sufficient nutrient supply for enhanced primary production. Notwithstanding the presence of anoxia during deposition of potential source rocks, only two small Devonian-sourced oil fields and numerous oil shows have been found in the Canning Basin. Biomarker assemblages show that the oils produced from the Lennard Shelf fields (i.e. Blina-1, Blina-4 and Janpam North-1) have substantially different molecular compositions to the minor oil recovered from Mirbelia-1 on the Barbwire Terrace. A correlation was established between the Lennard Shelf oils and rock extracts from the Gogo Formation at Blina-1 and McWhae Ridge-1 based on their hopane, sterane and carotenoids abundances. A definitive source correlation was not obtained for the Mirbelia-1 oil, but it did show some genetic affinity to the Givetian–Frasnian extracts from the Barbwire Terrace, suggesting that local source rocks are developed in the region. <b>Citation:</b> Gemma Spaak, Dianne S. Edwards, Heidi J. Allen, Hendrik Grotheer, Roger E. Summons, Marco J.L. Coolen, Kliti Grice, Extent and persistence of photic zone euxinia in Middle–Late Devonian seas – Insights from the Canning Basin and implications for petroleum source rock formation, <i>Marine and Petroleum Geology</i>, Volume 93, 2018, Pages 33-56, ISSN 0264-8172, https://doi.org/10.1016/j.marpetgeo.2018.02.033.

High-precision radiometric dating using Chemical Abrasion-Isotope Dilution Thermal Ionisation Mass Spectrometry (CA-IDTIMS) has allowed the recalibration of the numerical ages of Permian and Triassic spore-pollen palynozones in Australia. These changes have been significant, with some zonal boundaries in the Permian shifting by as much as six million years, and some in the Triassic by more than twice that. Most of the samples analysed came from eastern Australian coal basins (Sydney, Gunnedah, Bowen, Galilee) where abundant volcanic ash beds occur within the coal-bearing successions. The recalibrations of these widely used palynozones have implications for the dating of geological events outside the basins from where samples were obtained. Our revised dates for the Permian palynozones can now be applied to all Permian basins across Australia, including the Perth, Carnarvon, Canning and Bonaparte basins (along the western and northern continental margins), the Cooper and Galilee basins (in central Australia), and the Bowen, Gunnedah and Sydney basins (in eastern Australia). Revised regional stratigraphic frameworks are presented here for some of these basins. The impact of an improved calibration of biostratigraphic zones to the numerical timescale is broad and far-reaching. For example, the more accurate stratigraphic ages are the more closely burial history modelling will reflect the basin history, thereby providing control on the timing of kerogen maturation, and hydrocarbon expulsion and migration. These improvements can in turn be expected to translate in to improved exploration outcomes. We have initially focused on the Permian and provide preliminary results for the Triassic, but intend to expand recalibrations to include Jurassic, Cretaceous and Paleozoic successions beyond the Permian. Preliminary data indicates that significant changes to these calibrations are also likely.