Well and seismic correlation schemes exist for the Western Australian and South Australian parts of the Officer Basin but there are inconsistencies between the western and eastern regions. Hence, as part of the Exploring for the Future Officer-Musgrave Project, a chemostratigraphic correlation has been determined for the sedimentary fill of the Officer Basin with emphasis on Neoproterozoic to Cambrian rocks. The correlations have been developed on whole rock inorganic geochemical data obtained from the analysis of 10 study wells which span the basin from Western Australia and into South Australia. A total of 8 chemostratigraphic mega-sequences (MS) are recognised across the basin, that in turn are subdivided into a total of 24 chemostratigraphic sequences. MS1 to MS6 include the Neoproterozoic to Cambrian sedimentary rocks and are the focus of this study. The Neoproterozoic–Cambrian mega-sequences MS1 to MS4 broadly correspond to the previously defined Centralian supersequences CS1 to CS4 and provide robust well-control to the regional seismic correlations. Confidence in the correlation of these old rocks are important since they contain both potential source and reservoir rocks for petroleum generation and accumulation. MS7 is equivalent to the Permian Paterson Formation, while MS8 is equivalent to the Mesozoic section. The elemental data has also been used to elucidate aspects of the petroleum system by characterising reservoirs and identifying fine-grained siliciclastics deposited in anoxic environments which may have source potential. This work is expected to further improve geological knowledge and reduce the energy exploration risk of the Officer Basin, a key focus of this program. <b>Citation:</b> Edwards D.S., Munday S., Wang L., Riley D. & Khider K., 2022. Neoproterozoic and Cambrian chemostratigraphic mega-sequences of the Officer Basin; a regional framework to assist petroleum and mineral exploration. In: Czarnota, K. (ed.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, https://dx.doi.org/10.26186/146285

<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>

A key challenge in exploring Australian onshore sedimentary basins is limited seismic data coverage. Consequently, well logs are often the main datasets that can be used to understand the subsurface geology. The primary aim of this study was to develop a methodology for visualising the three-dimensional (3D) tectonostratigraphic architecture of sedimentary basins using well data, which can then be used to quickly screen areas warranting more detailed studies of resource potential. This project has developed a workflow that generates 3D well correlations using sequence stratigraphic well tops to visualise the regional structural and stratigraphic architecture of the Amadeus, Canning, Officer and Georgina basins in the Centralian Superbasin. Thirteen Neoproterozoic‒Paleozoic supersequence tops were interpreted in 134 wells. Three-dimensional well correlations provide an effective regional visualisation of the tectonostratigraphic architecture across the main depocentres. This study redefines the Centralian Superbasin as encompassing all western, northern and central Australian basins that had episodically 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 Neoproterozoic extension, and underwent several phases of partial or complete disconnection and subsequent reconnection of depositional systems during various regional tectonic events before final separation of depocentres at the culmination of the Alice Springs Orogeny. Regional 3D correlation diagrams have been generated to show the spatial distribution of these supersequences, which can be used to visualise the distribution of stratigraphic elements associated with petroleum, mineral and groundwater systems. <b>Citation: </b>Bradshaw, B., Khider, K., MacFarlane, S., Rollet, N., Carr, L. and Henson, P., 2020. Tectonostratigraphic evolution of the Centralian Superbasin (Australia) revealed by three-dimensional well correlations. 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.

Led by Geoscience Australia, Exploring for the Future (EFTF) is a A$225 million Australian Government program dedicated to exploring Australia’s resource potential and boosting investment. The EFTF program energy component aimed to attract industry investment by delivering a suite of new precompetitive geoscience data in prospective Australian sedimentary basins. Through EFTF, Geoscience Australia has acquired significant amounts of new geomechanical data from underexplored onshore sedimentary basins with identified hydrocarbon prospectivity, from both legacy and newly acquired samples. These data were acquired to build a better understanding of basin sediment rock properties, particularly looking at the reservoir and seal potential of postulated unconventional and conventional targets. Four major datasets are presented herein, representing prospective intervals from the Paleozoic Canning Basin of Western Australia, the Neoproterozoic-Paleozoic Officer Basin of South Australia and Western Australia, the Paleo-Mesoproterozoic South Nicholson region of the Northern Territory and northwest Queensland, and the Paleo-Mesoproterozoic Birrindudu Basin of the Northern Territory and Western Australia. Additionally, the Paleo-Mesoproterozoic McArthur Basin of the Northern Territory is represented by a small number of analyses. Tests include unconfined compressive strength tests, laboratory ultrasonic measurements, single and multi-stage triaxial tests and Brazilian tensile strength tests. These datasets are a precompetitive resource that can facilitate investment decisions in frontier regions, helping to identify elements of conventional and unconventional hydrocarbon systems as well as providing essential data to assess geological storage opportunities. <b>Citation:</b> Bailey Adam, Dewhurst David, Wang Liuqi, Carson Chris, Anderson Jade, Butcher Grace, Henson Paul (2024) Exploring for the Future: new geomechanical data in frontier Australian basins. Australian Energy Producers Journal 64, 155-168. https://doi.org/10.1071/EP23029

As part of the Exploring for the Future (EFTF) program, a chemostratigraphic framework for the Officer Basin was developed that correlates inorganic geochemical sequences between exploration wells. The Officer Basin spans 525,000 km² across Western Australia and South Australia, where it remains an unproven frontier basin which has seen little exploration. The objective of this study was to undertake a bulk rock elemental chemostratigraphy study on ten historic wells in order to better correlate the Neoproterozoic and Cambrian sections. Ten study wells, five from Western Australia and five from South Australia, were selected, and core (241) and cuttings (1,245) samples were acquired from their respective state core libraries. All samples were analysed using Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), resulting in quantitative data for 50 elements. The approximate proportions of dolomite, clastics, halite and anhydrite for the samples were derived using stoichiometric geochemical calculations. Halite was identified in some formations based on mud log and wireline data, but was not always preserved in the cuttings samples. This non-detection of halite resulted in poor matches between the wireline gamma ray (GR) and ChemGR profiles for halite-bearing units in some wells (e.g. Dragoon-1, Mulyawara-1, and Yowalga-3). Key element and ratios utilised to subdivide the strata were principally chosen to highlight changes in sediment provenance, climatic, and organic matter changes, as they typically have the best correlation potential over a greater distance. The stratigraphy within the study wells has been subdivided into eight chemostratigraphic mega-sequences referred to as MS1 to MS8, which are further subdivided into a total of twenty-four sequences. Mega-Sequences MS1 to MS4 broadly correspond to the published Neoproterozoic–Cambrian Centralian Supersequences (CS1 to CS4). While overall there is broad agreement between these two schemes, there are also sections where the stratigraphy has been reassigned. For example, within Kutjara-1, the section previously assigned to Centralian Supersequence CS2, and equivalent to the Cryogenian Tapley Hill Formation, is assigned to Mega-Sequence MS3 (not MS2). Within MS4, the lithostratigraphically defined members of the Observatory Hill Formation show some significant variation to the chemostratigraphy, with differences occurring within sequences MS4-S3, MS4-S4 and MS4-S5 (e.g. Birksgate-1; Trainor Echo-1). Mega-Sequence MS6 encompasses the Mount Chandler Sandstone in Trainor Echo-1 in the east and the lithological lateral equivalent Lennis Sandstone in Lungkarta-1/ST1 and Yowalga-1 in the west; however, these two argillaceous sandstones are chemically distinct. Carbonate-containing samples from three wells (Birksgate-1, Yowalga-3, and Giles-1) were analysed for their δ13Ccarb and δ18Ocarb isotope signature using Isotope-Ratio Mass Spectrometry (IRMS), with results from the least altered carbonates being of sufficient quality to attempt preliminary age dating. Comparison of the Officer Basin isotope data to global type sections enabled tentative correlation of the Yowalga-3 carbonates to the Tonian and late Ediacaran, and the Birksgate-1 carbonates to the early Cambrian. The geochemistry analyses from 10 basin-wide wells provide a robust dataset that has been used to confirm which sections correlate within the existing lithostratigraphic and sequence stratigraphic framework. This study also highlights where further work needs to be undertaken to elucidate the spatial and temporal relationships of some Cryogenian and early Cambrian sections across the entire basin, given that rocks of these ages contain both potential source and reservoir rocks for petroleum generation and accumulation.

The Officer Basin in South Australia and Western Australia is the focus of a regional stratigraphic study being undertaken by the Exploring for the Future (EFTF) program, an Australian Government initiative dedicated to increasing investment in resource exploration in Australia. This data release provides new data and discusses the results from a new commissioned petrographic study of rock samples from five wells of the Officer Basin including: GSWA Vines 1, Yowalga 3, Birksgate 1, Giles 1, and Munta 1. Data includes petrography, XRD, thin section scans and photos, as well as petrographic summaries

<div>This report details results and methodology from two hydrochemistry sampling programs performed as part of Geoscience Australia’s Musgrave Palaeovalley Project. The Musgrave Palaeovalley Project is a data acquisition and scientific investigation program based around the central west of Australia. It is aimed at investigating groundwater processes and resources within the Cenozoic fill and palaeovalleys of the region. This project, and many others, have been performed as part of the Exploring for the Future (EFTF) program, an eight-year, $225 million Australian Government funded geoscience data and precompetitive information acquisition program.</div><div>Data released here is from 18 bores sampled for groundwater and tested for a range of analytes including field parameters, major and minor elements, isotopes and trace gases. The sampling methods, quality assurance/quality control procedures, analytical methods and results are included in this report.</div>

The Officer Basin spanning South Australia and Western Australia is the focus of a regional stratigraphic study being undertaken as part of the Exploring for the Future (EFTF) program, an Australian Government initiative dedicated to increasing investment in resource exploration in Australia. Despite numerous demonstrated oil and gas shows, the Officer Basin remains a frontier basin for energy exploration with significant uncertainties due to data availability. Under the EFTF Officer-Musgrave Project, Geoscience Australia acquired new geomechanical rock property data from forty core samples in five legacy stratigraphic and petroleum exploration wells that intersected Paleozoic and Neoproterozoic aged intervals. These samples were subjected to unconfined compressive rock strength tests, Brazilian tensile strength tests and laboratory ultrasonic measurements. Petrophysical properties were also characterised via X-ray computerised tomography scanning, grain density and porosity-permeability analysis. Accurate characterisation of static geomechanical rock properties through laboratory testing is essential. In the modern exploration environment, these datasets are a precompetitive resource that can simplify investment decisions in prospective frontier regions such as the Officer Basin. Appeared in The APPEA Journal 62 S385-S391, 13 May 2022

The Neoproterozoic–Paleozoic Officer Basin, located in South Australia and Western Australia, remains a frontier basin for energy exploration with significant uncertainty due to a paucity of data. As part of Geoscience Australia’s Exploring for the Future (EFTF) program, the objective of this study is to derive the petrophysical properties and characterise potential reservoirs in the Neoproterozoic–Cambrian sedimentary succession in the Officer Basin through laboratory testing, and well log interpretation using both conventional and neural network methods. Laboratory measurements of forty-one legacy core samples provide the relationships between gas permeability, Klinkenberg corrected permeability, and nano-scale permeability, as well as grain density, effective and total porosity for various rock types. Conventional log interpretation generates the volume fraction of shale, effective and total porosity from gamma ray and lithology logs. Self-organising map (SOM) was used to cluster the well log data to generate petrophysical group/class index and probability profiles for different classes. Neural network technology was employed to approximate porosity and permeability from logs, conventional interpretation results and class index from SOM modelling. The Neoproterozoic-Cambrian successions have the potential to host both conventional and tight hydrocarbon reservoirs. Neoproterozoic successions are demonstrated to host mainly tight reservoirs with the range in average porosity and geometric mean permeability of 4.77%-6.39% and 0.00087-0.01307 mD, respectively, in the different sequences. The range in average porosity and geometric mean permeability of the potential Cambrian conventional reservoirs is 14.54%-26.38% and 0.341-103.68 mD, respectively. The Neoproterozoic shales have favourable sealing capacities. This work updates the knowledge of rock properties to further the evaluation of the resource potential of the Officer Basin. Published in The APPEA Journal 2022 <b>Citation:</b> Wang Liuqi, Bailey Adam H. E., Carr Lidena K., Edwards Dianne S., Khider Kamal, Anderson Jade, Boreham Christopher J., Southby Chris, Dewhurst David N., Esteban Lionel, Munday Stuart, Henson Paul A. (2022) Petrophysical characterisation of the Neoproterozoic and Cambrian successions in the Officer Basin. <i>The APPEA Journal</i><b> 62</b>, 381-399. https://doi.org/10.1071/AJ21076

The Neoproterozoic to Middle Ordovician sediments of the Officer Basin, Australia are difficult to correlate, in part because biostratigraphic studies of acritarchs and stromatolites are localised, isotopic studies are rare, and seismic models are technically challenged by the occurrence of basaltic and halite prone-sections. Hence, the chemostratigraphic framework presented here provides an independent stratigraphic model for the Neoproterozoic to Middle Ordovician sediments of the Officer Basin. A total of six chemostratigraphic mega-sequences have been geochemically defined and assigned to the stratigraphy; these have been further subdivided into twenty-eight chemostratigraphic sequences. The chemostratigraphic zonation has been established upon elemental changes attributed to provenance and climatic variation which can be used for correlation as they convey regional, rather than local, changes in sedimentation. The elemental data reveals that there is lateral variation within the established lithostratigraphy (e.g., within the members of the Observatory Hill and Hussar formations), which is suggestive of localised sediment source input to different areas of the basin. Presented to the 2022 Central Australian Basins Symposium IV (CABS) 29-30 August (https://agentur.eventsair.com/cabsiv/)