This report represents the first output from a study designed to understand and identify residual oil zones in Australia, with the aim of developing this potential resource using CO2 –EOR techniques. This work is part of the Residual Oil Zone (ROZ) module in the Exploring For The Future (EFTF) programme, which runs from 2020-2024. The work presented here is a collaborative study between Geoscience Australia and CSIRO. ROZ potentially represent a new and viable oil resource for Australia, while at the same time providing an additional CO2 storage avenue through application of CO2 enhanced oil recovery (CO2-EOR). These water-saturated reservoirs, which contain a moderate amount of residual oil and resemble water-flooded conventional oil fields, can be associated with conventional fields (brownfields) or occur with no associated main pay zone (greenfields). Both types of ROZ are currently produced commercially through CO2-EOR in the Permian Basin, USA, and are of growing interest internationally, but our understanding of ROZ in the Australian context is lacking. The first section of this report identifies and discusses the key parameters and factors that influence the efficiency with which ROZ can be produced. These include fluid-rock and fluid-fluid interactions, which may affect injectivity and sweep of hydrocarbons. We also discuss the effects of reservoir heterogeneity as it relates to flow dynamics and also the effects of pore space configuration. The first section concludes with a discussion of CO2 storage associated with ROZ development. In the second section, we discuss two different injection strategies with which to develop ROZ; carbonated brine injection and water alternating gas injection. The final section outlines details of the workflow that will be applied in the EFTF ROZ module over the coming years. Our proposed workflow is a three pronged approach which involves core flooding experiments, pore scale modelling and petrophysical analysis to identify potential ROZ in key Australian basins. In addition to plain CO2 injection, two other promising EOR techniques namely CO2-WAG and carbonated brine injection are also considered in this workflow. The main objectives of this workflow are to: • assess and identifying estimated oil recovery potential from a target ROZ by either of three EOR injection strategies, • identify the best injection strategy for a ROZ • identify the CO2 storage and utilization potential

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

<div>As a resource to enhance exploration in the offshore Otway Basin, Geoscience Australia (GA) has produced a new well folio that extends the scope of a previous release by including 32 key wells from the central and southeast regions. This folio covers the areas from Normanby 1 on the Normanby Terrace, through the Shipwreck Trough and Nelson Sub-basin, to Whelk 1 in the south. The previous well composites included wireline logs for petrophysical analysis, interpreted lithology, organic geochemistry and organic petrology data, and well markers. This folio includes all of these attributes with the addition of core-based depositional environment (DE) and gross depositional environment (GDE) interval interpretations which were subsequently used to constrain wireline interpretation away from core control. The core/wireline lithological interpretation along with further seismic and biostratigraphic data informed well marker locations and enabled a better regional correlation across the basin. The folio provides the complementary datasets used to construct each well composite. Presented at the Australian Energy Producers (AEP) Conference & Exhibition (https://energyproducersconference.au/conference/)

Geoscience Australia’s Exploring for the Future program provides precompetitive information to inform decision-making by government, community and industry on the sustainable development of Australia's mineral, energy and groundwater resources. By gathering, analysing and interpreting new and existing precompetitive geoscience data and knowledge, we are building a national picture of Australia’s geology and resource potential. This leads to a strong economy, resilient society and sustainable environment for the benefit of all Australians. This includes supporting Australia’s transition to net zero emissions, strong, sustainable resources and agriculture sectors, and economic opportunities and social benefits for Australia’s regional and remote communities. The Exploring for the Future program, which commenced in 2016, is an eight year, $225m investment by the Australian Government. This package contains data generated in the field as part of stratigraphic drilling operations in the Delamerian region of the western New South Wales during 2023 funded through the Exploring for the Future program. A range of geological, geophysical and geochemical data are included, as well as associated borehole information such as core photographs. The data can be viewed and downloaded via the Geoscience Australia Portal - https://portal.ga.gov.au/. The data that is available is from several databases which are associated to this record. <i>These data are published with the permission of the CEO, Geoscience Australia. </i>

<div>NDI Carrara 1 is a deep stratigraphic borehole that was drilled in 2020 under the MinEx CRC’s National Drilling Initiative (NDI) program in collaboration with Geoscience Australia and the Northern Territory Geological Survey. NDI Carrara 1 is the first stratigraphic test of the recently described Carrara Sub-basin, a Proterozoic aged depocentre located in the South Nicholson region of northwest Queensland and the Northern Territory. The borehole was drilled to a total depth of 1751 m and penetrated a succession of Cambrian aged Georgina Basin carbonate and siliciclastic rocks that unconformably overly a thick succession of Proterozoic age siliciclastic and carbonate-rich sediments. Although drilled on the western flank of the Carrara Sub-basin, NDI Carrara 1 did not penetrate to basement. Interpretation of the L210 deep-crustal seismic survey suggests that further Proterozoic sedimentary packages known from the northern Lawn Hill Platform in northwest Queensland are likely to be found underlying the succession intersected in NDI Carrara 1. The borehole was continuously cored from 283 m to total depth, and an extensive suite of wireline logs was acquired. Geoscience Australia and partners have undertaken an extensive analytical program to understand the depositional, structural, and diagenetic history of the sediments intersected in NDI Carrara 1. This program includes a targeted petrophysical study that aims to characterise the physical properties of these Proterozoic rocks through laboratory analysis of core samples, the results of which are summarised in this data release.</div><div><br></div><div>This data release provides data from new X-ray Computerised Tomography (XCT) scanning and gas porosity and permeability testing for 32 samples from NDI Carrara 1. Additional low permeability tests were undertaken on select samples that were identified as being ultra-tight (permeability <1 μD). These tests were performed at the CSIRO Geomechanics and Geophysics Laboratory in Perth, during January to June 2022. The full results as provided by CSIRO to Geoscience Australia are provided as an attachment to this document.&nbsp;</div>

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 data from new digital photography, X-ray Computerised Tomography (XCT) scanning, unconfined compressive strength (UCS) and tensile strength, laboratory ultrasonic testing, and gas porosity and permeability experiments for 41 samples from five legacy stratigraphic and petroleum exploration boreholes drilled within the Officer Basin. Additional low permeability tests were undertaken on select samples that were identified as being ultra-tight (permeability <1 µD). These samples were analysed at CSIRO Geomechanics and Geophysics Laboratory in Perth during April to June 2021.

<div>This report presents new data from X-ray Computerised Tomography (XCT) scanning, gas porosity and permeability testing, and grain density measurements of 79 of 82 samples from the Birrindudu and McArthur basins. Three plugs could not be recovered from the whole core section. Plugs were taken from depths of interest from drill holes Manbulloo S1, Hidden Valley S2, Broughton 1, ANT003, 99VRNTGSDD1, 99VRNTGSDD2, Lamont Pass 3 and WLMB001B.</div><div><br></div><div>These tests were performed in 2023 by CSIRO in Perth. The full results as provided by CSIRO to Geoscience Australia are provided as an attachment to this document.&nbsp;This work was conducted as part of the Exploring for the Future Program (Officer–Musgrave–Birrindudu module).</div><div><br></div>