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 a stratigraphic well, 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 a partnership between Geoscience Australia (GA) and the Geological Survey of Western Australia (GSWA) in the Barnicarndy Graben, 67 km west of Telfer, in the southwest Canning Basin. Drilling recovered about 2100 m of continuous core from 580 mRT to the driller’s total depth (TD) of 2680.53 mRT. An extensive analytical program was carried out to characterise the lithology, age and depositional environment of these sediments. This data release presents organic geochemical analyses undertaken on rock extracts obtained from cores selected from the Barnicarndy 1 well. The molecular and stable isotope data carbon and hydrogen will be used to understand the type of organic matter being preserved, the depositional facies and thermal maturity of the Lower Ordovician sedimentary rocks penetrated in this well. This information provides complementary information to other datasets including organic petrological and palynological studies.

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

Geoscience Australia’s Exploring for the Future (EFTF) program has established new techniques to collect onshore pre-competitive datasets on an unprecedented scale. The Exploration Incentive Scheme (EIS) is a Western Australian Government initiative that aims to encourage exploration for the long-term sustainability of the state’s resources sector. Integration of EFTF and EIS datasets has improved understanding of the geology across northern Australia, and the associated energy, mineral and groundwater resources potential. The onshore Canning Basin covers approximately 530 000 km2, and has proven prospectivity for conventional oil and gas, mainly in the northern part of the basin. Potential exists for unconventional resources that remain largely unexplored and untested. Gas resource assessments suggest that the basin has significant potential for recoverable shale gas and tight gas. Even with exploration continuing along the flanks of the Fitzroy Trough, the Canning Basin remains one of the least explored Paleozoic basins in the world (DMIRS, 2020). Australia’s longest onshore seismic line, 18GA-KB1, acquired in the southern Canning Basin addresses a long standing data gap across the Kidson Sub-basin and Waukarlycarly Embayment that assists with the resource evaluation of this frontier region. The Kidson Sub-basin covers 91 000 km2 and has a sag basin architecture. Preliminary interpretation of the seismic data indicates that the sedimentary basin is approximately 6 km deep, and includes a conformable package of Ordovician–Devonian siliciclastic, carbonate and evaporite facies of exploration interest. The Carboniferous succession is interpreted as not being present. Located on the western end of the seismic line, the newly drilled deep stratigraphic well Waukarlycarly 1 penetrated 2680.53 m of Cenozoic and Paleozoic strata and provides stratigraphic control for the geology imaged in the Waukarlycarly Embayment. A comprehensive elemental and δ13C isotope chemostratigraphy study assists with stratigraphic correlations within Ordovician sedimentary strata across the region (Forbes et al., 2020a, b). Oil and gas discoveries throughout the Canning Basin were generated from Paleozoic marine source rocks, deposited under stratified oxic and euxinic water columns. Three distinct petroleum systems, the Ordovician (Larapintine 2), Late Devonian (Larapintine 3) and latest Devonian–early Carboniferous (Larapintine 4), are recognized based on the geochemical character of their associated fluids and each display strong stratigraphic control (Carr et al., 2020). Widespread generation of gas from Paleozoic sources is evident from molecular analyses of gases recovered from petroleum wells and fluid inclusions (Boreham et al., 2020). Currently the Larapintine 2 Petroleum System is deemed most prospective system in the Kidson Sub-basin.

The discovery of strategically located salt structures, which meet the requirements for geological storage of hydrogen, is crucial to meeting Australia’s ambitions to become a major hydrogen producer, user and exporter. The use of the AusAEM airborne electromagnetic (AEM) survey’s conductivity sections, integrated with multidisciplinary geoscientific datasets, provides an excellent tool for investigating the near-surface effects of salt-related structures, and contributes to assessment of their potential for underground geological hydrogen storage. Currently known salt in the Canning Basin includes the Mallowa and Minjoo salt units. The Mallowa Salt is 600-800 m thick over an area of 150 × 200 km, where it lies within the depth range prospective for hydrogen storage (500-1800 m below surface), whereas the underlying Minjoo Salt is generally less than 100 m thick within its much smaller prospective depth zone. The modelled AEM sections penetrate to ~500 m from the surface, however, the salt rarely reaches this level. We therefore investigate the shallow stratigraphy of the AEM sections for evidence of the presence of underlying salt or for the influence of salt movement evident by disruption of near-surface electrically conductive horizons. These horizons occur in several stratigraphic units, mainly of Carboniferous to Cretaceous age. Only a few examples of localised folding/faulting have been noted in the shallow conductive stratigraphy that have potentially formed above isolated salt domes. Distinct zones of disruption within the shallow conductive stratigraphy generally occur along the margins of the present-day salt depocentre, resulting from dissolution and movement of salt during several stages. This study demonstrates the potential AEM has to assist in mapping salt-related structures, with implications for geological storage of hydrogen. In addition, this study produces a regional near-surface multilayered chronostratigraphic interpretation, which contributes to constructing a 3D national geological architecture, in support of environmental management, hazard mapping and resource exploration. <b>Citation: </b>Connors K. A., Wong S. C. T., Vilhena J. F. M., Rees S. W. & Feitz A. J., 2022. Canning Basin AusAEM interpretation: multilayered chronostratigraphic mapping and investigating hydrogen storage potential. In: Czarnota, K (ed.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, https://dx.doi.org/10.26186/146376

Exploring for the Future (EFTF) is a $225 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. A complementary initiative, the Exploration Incentive Scheme (EIS) is a Western Australian State-Government initiative that aims to encourage exploration in Western Australia for the long-term sustainability of the State’s resources sector. The Kidson Sub-basin seismic survey (18GA-KB1 or L211) was acquired as part of EFTF and the EIS, as a collaboration between Geoscience Australia and the Geological Survey of Western Australia (Resource Strategy Division). The 872 km long seismic line was acquired in an east-southeast to west-northwest orientation, on the road between the Kiwirrkurra community in the east, to approximately 20 km from Marble Bar, near the West Australian coast. The primary aims of the seismic survey were to better understand the subsurface geology, crustal architecture and spatial extents of basin and basement terrains. Crucially, the seismic survey was planned to address a lack of coherent seismic data across the Kidson Sub-basin, onshore Canning Basin and to increase the resource prospectivity of the region. The seismic survey imaged the following subdivisions of the Canning Basin: the Wallal Embayment Barnicarndy Graben, Anketell Shelf, and the Kidson Sub-basin, The survey also imaged several pre-Phanerozoic basement terrains, and several seismically distinct, mid to-lower crustal tectonic provinces. This report comprises a summary of the basement and basin geology, mineral and energy systems of the area, and an interpretation of the newly acquired seismic data.

The onshore Canning Basin in Western Australia is the focus of a regional hydrocarbon prospectivity assessment being undertaken by the Exploring for the Future (EFTF) program; an Australian Government initiative dedicated to increasing investment in resource exploration in northern Australia. The four-year program led by Geoscience Australia focusses on the acquisition of new data and information about the potential mineral, energy and groundwater resources concealed beneath the surface in northern Australia and parts of South Australia. As part of this program, significant work has been carried out to deliver new pre-competitive data including new seismic acquisition, drilling of a stratigraphic well, 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, Waukarlycarly 1, was drilled in 2019 in partnership between Geoscience Australia (GA) and the Geological Survey of Western Australia (GSWA) in the South West Canning Basin. The Waukarlycarly 1 stratigraphic well was drilled in the Waukarlycarly Embayment, 67 km west of Telfer and provides stratigraphic control for the geology imaged by the Kidson seismic line (Figure 1). The well was drilled to a total drillers depth (TD) of 2680.53 mRT and penetrated a thin Cenozoic cover overlying a Permian fluvial clastic succession that includes glacial diamictite. These siliciclastics unconformably overlie an extremely thick (>1730 m) interpreted Ordovician succession before terminating in low-grade metasediments of Neoproterozoic age. Log characterisation, core analysis, geochronology, petrographic and palaeontological studies have been carried out to characterise the lithology, age and depositional environment of these sediments. As part of this comprehensive analytical program, magnetic susceptibility and bulk density analyses were undertaken by Geoscience Australia on selected rock samples.

This Geoscience Australia Record reports the findings of the Canning Basin Petroleum Systems Modelling Project. The southern, frontier portions of the Canning Basin have numerous potential hydrocarbon play opportunities, in particular unconventional gas plays, which remain untested. Of particular interest are Ordovician-aged petroleum systems. Geoscience Australia in collaboration with the Geological Survey of Western Australia acquired an 872 km long 2D seismic line across the south and south-west Canning Basin in 2018, and drilled the 2680 m stratigraphic hole Barnicarndy 1 in the Barnicarndy Graben to further develop the understanding of hydrocarbon prospectivity in these frontier regions. As part of the Exploring for the Future program Geoscience Australia contracted GNS Science to construct ten 1D petroleum systems models and one 2D model across the frontier southern parts of the basin. The aim was to combine interpretation of the newly acquired seismic data with interpretation of legacy and new well data, in particular organic geochemical data, to improve the understanding of the burial and thermal history, trap formation, generation and migration of hydrocarbons in the southern, frontier parts of the Canning Basin. This Record is a compilation of the work completed by GNS Science International Limited and the reports containing new data collected and analyzed relevant to the petroleum systems modelling.

<div>Geoscience Australia’s Onshore Basin Inventories project delivers a single point of reference and creates a standardised national basin inventory that provides a whole-of-basin catalogue of geology, petroleum systems, exploration status and data coverage of hydrocarbon-prone onshore Australian sedimentary basins. In addition to summarising the current state of knowledge within each basin, the onshore basin inventory reports identify critical science questions and key exploration uncertainties that may help inform future work program planning and decision making for both government and industry. Volume 1 of the inventory covers the McArthur, South Nicholson, Georgina, Wiso, Amadeus, Warburton, Cooper and Galilee basins and Volume 2 expands this list to include the Officer, Perth and onshore Canning basins. Under Geoscience Australia’s Exploring for the Future (EFTF) program, several new onshore basin inventory reports are being delivered. Upcoming releases include the Adavale Basin of southern Queensland, and a compilation report addressing Australia’s poorly understood Mesoproterozoic basins. These are supported by value-add products that address identified data gaps and evolve regional understanding of basin evolution and prospectivity, including petroleum systems modelling, seismic reprocessing and regional geochemical studies. The Onshore Basin Inventories project continues to provide scientific and strategic direction for pre-competitive data acquisition under the EFTF work program, guiding program planning and shaping post-acquisition analysis programs.</div>

Although the Canning Basin has yielded minor gas and oil within conventional and unconventional reservoirs, the relatively limited geological data available in this under-explored basin hinder a thorough assessment of its hydrocarbon potential. Knowledge of the Paleozoic Larapintine Petroleum Supersystem is restricted by the scarcity of samples, especially recovered natural gases, which are limited to those collected from recent exploration successes in Ordovician and Permo-Carboniferous successions along the margins of the Fitzroy Trough and Broome Platform. To address this shortcoming, gases trapped within fluid inclusions were analysed from 121 Ordovician to Permian rock samples (encompassing cores, sidewall cores and cuttings) from 70 exploration wells with elevated mud gas readings. The molecular and carbon isotopic compositions of these gases have been integrated with gas compositions derived from open-file sources and recovered gases analysed by Geoscience Australia. Fluid inclusion C1–C5 hydrocarbon gases record a snapshot of the hydrocarbon generation history. Where fluid inclusion gases and recovered gases show similar carbon isotopes, a simple filling history is likely; where they differ, a multicharge history is evident. Since some fluid inclusion gases fall outside the carbon isotopic range of recovered gases, previously unidentified gas systems may have operated in the Canning Basin. Interestingly, the carbon isotopes of the fluid-inclusion heavy wet gases converge with the carbon isotopes of the light oil liquids, indicating potential for gas–oil correlation. A regional geochemical database incorporating these analyses underpins our re-evaluation of gas systems and gas–gas correlations across the basin. <b>Citation:</b> Boreham, C.J., Edwards, D.S., Sohn, J.H., Palatty, P., Chen, J.H. and Mory, A.J., 2020. Gas systems in the onshore Canning Basin as revealed by gas trapped in fluid inclusions. 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.

<p>The Early Paleozoic, specifically the Middle Ordovician, marks a significant period in Earth's history due to the appearance and diversification of life on land. Plant megafossil records indicate vascular plants first appeared in the Early Silurian and by Devonian times had diversified rapidly (e.g. Wellman and Gray, 2000; Steemans et al., 2009; Kenrick et al., 2012; Strother, 2016). However non-vascular plants (bryophytes) predating vascular plants are rarely preserved as body fossils and the bryophyte microfossil record in the lowermost Palaeozoic is scarce. This lack of fossil data severely limits our understanding of life in the earliest non-marine environments and the origin of land plants. <p>In comparison to microfossils, molecular fossils (biomarkers) are more ubiquitous in the sedimentary record and have a higher preservation potential, thus providing a powerful tool to track terrestrial signals when microfossils are either scarce or absent. Molecular proxies such as long chain n-alkanes have been used extensively in both modern and ancient environments to identify terrestrial contributions to the organic matter (e.g. Eglinton and Hamilton, 1967; Ficken et al., 2000; Hautevelle et al., 2006). Furthermore, the isotopic composition of these molecules can be used to further distinguish between sources (e.g. Bird et al., 1995; Sikes et al., 2009; Rouillard et al., 2016). That being said, only relatively few studies have combined palynological evidence with geochemical proxies to assess geochemical signatures of early land plants. <p>This work presents biomarker and palynological data of the Middle Ordovicianupper Goldwyer Formation which records the earliest occurrence of land plant microfossils (cryptospores) in Australia. The higher-molecular-weight n-alkane distributions and their isotopic compositions recorded in the upper Goldwyer show high resemblances to modern day bryophytes and aquatic macrophytes. Retene, a biomarker conventionally used as a proxy for gymnosperms, was also identified in some extracts. The presence of retene in Middle Ordovician (this work) and Silurian (Romero-Sarmiento et al., 2010) rocks indicates conifers are not the sole source of this compound. <p>Linking biomarkers and palynology has shown to beuseful in the study of early land plants where fossil records are sparse. Molecular and isotopic proxies distinctive of these plants can provide a more complete record of the geographical distribution of early land plants, providing useful information to understand their early evolution. <p>Bird, M.I., Summons, R.E., Gagan, M.K., Roksandic, Z., Dowling, L., Head, J., Fifield, L.K., Cresswell, R.G., Johnson, D.P., 1995. Terrestrial vegetation change inferred from n-alkane δ13C analysis in the marine environment. Geochimica et Cosmochimica Acta 59, 2853-2857. <p>Eglinton, G., Hamilton, R.J., 1967. Leaf epicuticular waxes. Science 156, 1322-1335. <p>Ficken, K.J., Li, B., Swain, D.L., Eglinton, G., 2000. An n-alkane proxy for the sedimentary input of submerged/floating freshwater aquatic macrophytes. Organic Geochemistry 31, 745-749. <p>Hautevelle, Y., Michels, R., Malartre, F., Trouiller, A., 2006. Vascular plant biomarkers as proxies for palaeoflora and palaeoclimatic changes at the Dogger/Malm transition of the Paris Basin (France). Organic Geochemistry 37, 610-625. <p>Kenrick, P., Wellman, C.H., Schneider, H., Edgecombe, G.D., 2012. A timeline for terrestrialization : consequences for the carbon cycle in the Palaeozoic. Philosophical Transactions of the Royal Society B: Biological Sciences 367, 519-536. <p>Romero-Sarmiento, M.F., Riboulleau, A., Vecoli, M., Versteegh, G.J.M., 2010. Occurrence of retene in upper Silurian-lower Devonian sediments from North Africa: origin and implications. Organic Geochemistry 41, 302-306. <p>Rouillard, A., Greenwood, P.F., Grice, K., Skrzypek, G., Dogramaci, S., Turney, C., Grierson, P.F., 2016. Interpreting vegetation change in tropical arid ecosystems from sediment molecular fossils and their stable isotope compositions: a baseline study from the Pilbara region of northwest Australia. Palaeogeography, Palaeoclimatology, Palaeoecology 459, 495-507. <p>Sikes, E.L., Uhle, M.E., Nodder, S.D., Howard, M.E., 2009. Sources of organic matter in a coastal marine environment: Evidence from n-alkanes and their delta13C distributions in the Hauraki Gulf, New Zealand. Marine Chemistry 113, 149-163. <p>Steemans, P., Herisse, A. Le, Melvin, J., Miller, M. a, Paris, F., Verniers, J., Wellman, C.H., 2009. Origin and radiation of the earliest vascular land plants. Science (New York, N.Y.) 324, 353. <p>Strother, P.K., 2016. Systematics and evolutionary significance of some new cryptospores from the Cambrian of eastern Tennessee, USA. Review of Palaeobotany and Palynology 227, 28-41. <p>Wellman, C.H., Gray, J., 2000. The microfossil record of early land plants. Philosophical Transactions of the Royal Society B: Biological Sciences 355, 717-732.