The Canning Basin is a large intracratonic basin in Western Australia that remains one of the least explored Paleozoic basins in the world. Recent resource assessments have renewed interest in the basin, in particular for unconventional gas within Ordovician organic-rich shales, although these proposed plays remain untested. Exploring for the Future (EFTF) is a program dedicated to exploring Australia’s resource potential and boosting investment. Launched in 2016 with $100.5 million in funding from the Australian Government, it initially focused on northern Australia. Geoscience Australia and the Geological Survey of Western Australia collected new, pre-competitive datasets in the frontier Kidson Sub-basin to better understand its energy resource potential. Here we present an overview of the regional petroleum systems with a focus on the modelled Ordovician section within the Kidson Sub-basin and Barnicarndy Graben (previously Waukarlycarly Embayment). Three Larapintine petroleum systems are recognised in the Ordovician (L2), Devonian‒earliest Carboniferous (L3), and Carboniferous (L4) successions of the Canning Basin. Integration of petroleum systems with interpretation of the Kidson Sub-basin seismic survey 18GA-KB1 shows that the Ordovician section is extensive, and hence, the Larapintine 2 Petroleum System is of most exploration interest across this frontier region. Ordovician organic-rich units are known within the Nambeet (Tremadocian–Floian), Goldwyer (Dapingian–Darriwilian) and Bongabinni (Sandbian) formations; however, only Nambeet and Goldwyer source rocks are considered to be present within the Kidson Sub-basin. Oil and gas shows occur within Ordovician and Silurian reservoirs, of which many are sub-salt. The range in the geochemical profile of shows from Goldwyer, Nita and Sahara reservoirs implies generation from numerous source units within the Goldwyer and Bongabinni formations. The origin of oil and gas shows within the Nambeet and Willara formations, including those in Patience 2 in the Kidson Sub-basin, is unknown but imply the presence of multiple lower Ordovician source units and include the Nambeet Formation. Within the Kidson Sub-basin, Kidson 1 is located closest to the main depocentre, whereas other wells are proximal to shelves and margins. In general, these latter wells return discouraging hydrocarbon potential pyrolysis parameters as a consequence of their sub-optimal location for source rock development and thermal maturation history. Kidson 1 penetrates the Goldwyer Formation and has TOC contents that are considered more representative of source rock richness (although diesel contamination is present) within the depocentre. Data paucity is the key limitation in resource evaluation for the Kidson Sub-basin, as such, an evaluation with volumetrics is not possible. 1D petroleum systems models of ten wells located in either the Kidson Sub-basin, Willara Sub-basin or Barnicarndy Graben were constructed to resolve whether potential source rocks were capable of hydrocarbon generation. The models demonstrate maturation of Ordovician source rocks resulting in near-complete transformation during Permian to Triassic deposition and burial. A 2D petroleum systems model constructed along the regional 2D seismic line 18GA-KB1 predicts full maturation of Larapintine 2 source rocks in the deeper parts of the Kidson Sub-basin. Expulsion and migration is considered to have taken place during the Permian‒Triassic, with potential accumulations trapped by evaporitic and fine-grained units of Ordovician and Silurian age.

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.

Laboratory results for fluid inclusion gas analysis in GA's Isotope and Organic Geochemistry Laboratory under GSWA Approval G004119

Geoscience Australia’s Exploring for the Future Program is investigating the mineral, energy and groundwater resource potential of sedimentary basins and basement provinces in northern Australia and parts of South Australia. A key challenge in exploring Australian onshore sedimentary basins is that these are often areas with limited seismic data coverage to image the sub-surface structural and stratigraphic architecture. Consequently, well logs are often the main data sets that are used to understand the sub-surface geology. Where good seismic data coverage is available, a considerable amount of time is generally required to undertake an integrated interpretation of well and seismic data. The primary aim of this study is to develop a methodology for visualising the three-dimensional tectonostratigraphic architecture of sedimentary basins using just well data, which can then be used to quickly screen areas warranting more detailed studies of resource potential. A workflow is documented which generates three-dimensional well correlations using just well formation tops to visualise the regional structural and stratigraphic architecture of the Amadeus, Canning, Officer and Georgina basins in the Centralian Superbasin. A critical step in the workflow is defining regionally correlatable supersequences that show the spatial linkages and evolution through time of lithostratigraphic units from different basin areas. Thirteen supersequences are defined for the Centralian Superbasin, which were deposited during periods of regional subsidence associated with regional tectonic events. Regional three-dimensional correlation diagrams have been generated to show the spatial distribution of these supersequences, which can be used as a reconnaissance tool for visualising the distribution of key stratigraphic elements associated with petroleum, mineral and groundwater systems. Three-dimensional well correlations are used in this study to redefine the Centralian Superbasin as encompassing all western, northern and central Australian basins that had interconnected depositional systems driven by regional subsidence during one or more regional tectonic events between the Neoproterozoic and middle Carboniferous. The Centralian Superbasin began to form during a series of Neoproterozoic rift-sag events associated with the break-up of the Rodinia Supercontinent at about 830 Ma. Depositional systems in the Amadeus and Officer basins were partially disconnected by an emergent Musgrave Province during these early stages of superbasin evolution. Subsequent regional uplift and erosion of the superbasin occurred during the late Neoproterozoic–early Cambrian Petermann Orogeny. The Officer and Amadeus were permanently disconnected by the uplifted Musgrave Province following this major orogenic event. Rejuvenation of the Centralian Superbasin occurred during middle–late Cambrian extension and subsidence resulting in the generation of several new basins including the Canning Basin. Subsidence during the Ordovician Larapinta Event created an intracontinental seaway that episodically connected the Canning, Amadeus, Georgina and Officer basins to the proto-Pacific Ocean in the east. Fragmentation of the Centralian Superbasin began at the onset of the Alice Springs Orogeny during the Rodingan Event when the uplifted Arunta Region disconnected the Amadeus and Georgina basins. The Rodingan Movement initially disconnected depositional systems between the Canning and Amadeus basins, which promoted the development of a large evaporitic depocentre over the southern Canning Basin. However, these basins subsequently reconnected during the Early Devonian Prices Creek Movement. Complete fragmentation of the Centralian Superbasin occurred during the Late Devonian–middle Carboniferous Pillara Extension Event when the Canning and Amadeus basins became permanently disconnected. Widespread uplift and erosion at the culmination of the Alice Springs Orogeny in the middle Carboniferous resulted in final closure of the Centralian Superbasin.

The Ordovician is an important period in Earth’s history with exceptionally high sea levels that facilitated the Great Ordovician Biodiversification Event. This crucial biological event is regarded as the second most significant evolutionary event in the history of Paleozoic life, after the Cambrian radiation. The present study integrates palynological, petrographic, molecular and stable isotopic (δ13C of biomarkers) analyses of cores from five boreholes that intersected the Goldwyer Formation, Canning Basin, Western Australia, to determine depositional environments and microbial diversity within a Middle Ordovician epicontinental, tropical sea. A major transgression was detected in the laminated shales of the lower Goldwyer Formation (Units 1+2) which were deposited in anoxic bottom waters, as confirmed by low (<1) Pristane/Phytane ratios, and elevated dibenzothiophene and gammacerane indices. A second, less extensive, flooding event is recorded by shallow marine sediments of the upper Goldwyer Formation (Unit 4). Cores of these sediments, from two wells (Solanum-1 and Santalum-1A) are bioturbated and biomarkers indicate relatively oxygenated conditions, as well as the presence of methanotrophic bacteria, as determined from the high 3-methylhopane indices. Typical Ordovician marine organisms including acritarchs, chitinozoans, conodonts and graptolites were present in the lower and upper Goldwyer Formation, whereas the enigmatic organism Gloeocapsomorpha prisca (G. prisca) was only detected in Unit 4. The presence of G. prisca was based on microfossils and specific biosignatures presenting an odd-over-even predominance in the C15 to C19 n-alkane range. Cryptospores were identified in Unit 4 in the Theia-1 well and are most likely derived from bryophytes, making this is the oldest record of land plants in Australian Middle Ordovician strata. Biomarkers in some samples from Unit 4 that also support derivation from terrestrial organic matter include retene, benzonaphthofurans and δ13C-depleted mid-chain n-alkanes. This research contributes to understanding Ordovician marine environments from a molecular perspective since few biomarker studies have been undertaken on age-equivalent sections. Furthermore, the identification of the oldest cryptospores in Australia and their corresponding terrestrial biomarkers contributes to understanding the geographical evolution of early land plants.

This report presents the results of scanning electron microscopy (SEM) analyses on 2 core samples from the GSWA Waukarlycarly 1 stratigraphic well drilled in the Canning Basin. The well was drilled as part of a co-funded collaboration between Geoscience Australia (GA) and the Geological Survey of Western Australia (GSWA) aimed at gathering new subsurface data on the potential mineral, energy and groundwater resources in the southern Canning Basin. The collaboration resulted in the acquisition of the Kidson Deep Crustal Seismic Reflection Survey in 2018; and the drilling of deep stratigraphic well GSWA Waukarlycarly 1, located along the Kidson Sub-basin seismic line within the Waukarlycarly Embayment in 2019 (Figure 1). GSWA Waukarlycarly 1 reached a total depth of 2680.53 m at the end of November 2019 and was continuously cored through the entire Canning Basin stratigraphy. Coring was complemented by the acquisition of a standard suite of wireline logs and a vertical seismic profile. The work presented in this report constitutes part of the post well data acquisition. The purpose of the SEM analysis was to determine mineralogy and textural relationships between grains, verify the presence of organic material at the micro-scale, document i) the presence of diagenetic alterations to the detrital mineral assemblage and ii) eventual distribution of visible pores.

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.

<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.

Pyrolysis and bulk kinetic studies were used to investigate the hydrocarbon generation potential and source rock facies variability of the marine organic-rich rocks from the Middle Ordovician (Darriwilian) Goldwyer Formation in the Canning Basin, Western Australia. Rock Eval pyrolysis results for the analysed immature to mid-mature calcareous mudstones imply that the upper Goldwyer Sequence I samples contain oil-prone Type I kerogen, while the lower Goldwyer Sequence III samples comprise on average Type II/III oil- and gas-prone kerogen. This is supported by the pyrolysis gas chromatography (Py-GC) results that show the presence of homogenous organofacies in the Goldwyer Sequence I that comprise aliphatic molecular signatures, possibly attributed to the selective preservation of the lipid fraction derived from <i>Gloeocapsomorpha prisca</i> (<i>G. prisca</i>). The heterogeneous organofacies of the Goldwyer Sequence III contains aromatic moieties that are present in similar abundance as the aliphatic compounds. The calcareous claystones of the Goldwyer Sequence I have the capacity to generate paraffinic oil with low wax contents, whereas those of the Goldwyer Sequence III have generative potential for paraffinic-naphthenic-aromatic (P-N-A) low wax oils and gas and condensate. The temperature for hydrocarbon generation for the Type I kerogen, assuming a constant geological heating rate of 3^oC/Ma, is estimated to occur over a narrow interval between 145^oC and 170^oC for the Goldwyer Sequence I samples. Generation from the Type II/III kerogen occurs from 100°C to 160°C in the Goldwyer Sequence III samples which are significantly thermally less stable than observed for the Goldwyer Sequence I samples. The kinetics results for both sequences were used in standard thermal and burial history plots to evaluate their transformation ratio and hydrocarbon generative potential. This provided a basin-specific kinetic input for burial history modelling and a better constraint for kerogen transformation and hydrocarbon generation on the Broome Platform. <b>Citation:</b> Lukman M. Johnson, Reza Rezaee, Gregory C. Smith, Nicolaj Mahlstedt, Dianne S. Edwards, Ali Kadkhodaie, Hongyan Yu,; Kinetics of hydrocarbon generation from the marine Ordovician Goldwyer Formation, Canning Basin, Western Australia,<i> International Journal of Coal Geology</i>, Volume 232, <b>2020</b>, 103623, ISSN 0166-5162, https://doi.org/10.1016/j.coal.2020.103623.

This report presents the results of scanning electron microscopy (SEM) and mercury porosimetry analyses on 1 whole core sample from the GSWA Waukarlycarly 1 stratigraphic well drilled in the Canning Basin. The well was drilled as part of a co-funded collaboration between Geoscience Australia (GA) and the Geological Survey of Western Australia (GSWA) aimed at gathering new subsurface data on the potential mineral, energy and groundwater resources in the southern Canning Basin. The collaboration resulted in the acquisition of the Kidson Deep Crustal Seismic Reflection Survey in 2018; and the drilling of deep stratigraphic well GSWA Waukarlycarly 1, located along the Kidson Sub-basin seismic line within the Waukarlycarly Embayment in 2019 (Figure 1). GSWA Waukarlycarly 1 reached a total depth of 2680.53 m at the end of November 2019 and was continuously cored through the entire Canning Basin stratigraphy. Coring was complemented by the acquisition of a standard suite of wireline logs and a vertical seismic profile. The work presented in this report constitutes part of the post well data acquisition. The purpose of the SEM analysis was to determine mineralogy and textural relationships between grains, verify the presence of organic material at the micro-scale, document i) the presence of diagenetic alterations to the detrital mineral assemblage and ii) eventual distribution of visible pores. Additionally, mercury injection capillary pressure porosimetry (MICP) was used to assess interconnected porosityand pore size distribution.