In October/November 1990 the Australian Bureau of Mineral Resources (BMR) carried out an 18 day combined water column geochemical and high resolution seismic survey on the Vulcan Sub-basin region of the Timor Sea. This report presents the results of the water column geochemical (direct hydrocarbon detection or DHD) aspects of that program. During the program, 2730 km of DHD data were obtained along 44 lines over the Vulcan Sub-basin, the Ashmore Platform and the Londonderry High. Ten water bottom hydrocarbon anomalies were detected during the program. Seven of these anomalies fell into two distinct groupings, which were associated with: - the Skua field and surrounding fault blocks, - the intersection of the NE-trending Vulcan Sub-basin/Londonderry High Boundary Zone with a prominent NW-trending transfer fault zone. The composition of the hydrocarbon anomalies within the Skua grouping was generally consistent with them having an oil-prone, Late Jurassic source,, and is thus compatible with the known composition of the hydrocarbons in the Skua accumulation. The composition of the other grouping was more consistent with a gas/condensate source; they may have originated from more gas prone Permo-Triassic source rocks on the edge of the Londonderry High. The remaining anomalies were all very weak, and may have been due to biogenic activity. The data indicate that the DHD technique can be useful at a prospect level within the Timor Sea (for example, it did remotely detect the Skua accumulation). The types of accumulations which are most easily detected using DHD are those with a significant gas cap, a relatively shallow (<2000 m) reservoir, and faulting which extends from the reservoir horizon to near the seafloor. Furthermore, the data suggest that transfer fault zones provide important pathways for hydrocarbon migration in this region.

No abstract available

Geoscience Australia has recently completed a survey searching for evidence of natural hydrocarbon seepage in the offshore northern Perth Basin, off Western Australia. The survey formed part of a regional assessment of the basin's petroleum prospectivity in support of ~17,000 sq km of frontier exploration acreage release in the region in 2011. Multibeam bathymetry, sub-bottom profiler, sidescan sonar and echosounder data were acquired to map seafloor and water column features and characterise the shallow sub-surface sediments. A remotely operated vehicle (ROV) was used to observe and record evidence of seepage on the seafloor. 71 sediment grabs and 28 gravity cores were collected and are currently being analysed for headspace gas, high molecular weight biomarkers and infaunal content. Survey data identified an area of high 'seepage' potential in the northernmost part of the study area. Recent fault reactivation and amplitude anomalies in the shallow strata correlate with raised, high-backscatter regions and pockmarks on the seafloor. A series of hydroacoustic flares identified with the sidescan sonar may represent gas bubbles rising through the water column. The ROV underwater video footage identified a dark-coloured fluid in 500 metres water depth proximal to the sidescan flares which may be oil that naturally seeped from the seafloor. The integration of the datasets acquired during the marine survey is indicative of natural oil seepage and provides additional support for the presence of an active petroleum system on this part of the continental margin.

Over the last 10 years there has been a rapid expansion in the coal seam gas industry in Australia. Exploration and production of coal seam gas is primarily focused on sedimentary basins along Australia's eastern seaboard. To provide a sound basis for a national assessment of coal seam gas resources, Geoscience Australia is identifying and mapping the distribution of coal in Australia's onshore sedimentary basins into a single Geographical Information System (GIS). Data are being collated for the three key geological time periods for coal, i.e. the Permian-Triassic, Jurassic-Cretaceous and Cenozoic. Information is being sourced from a wide range of publications and publicly available datasets and includes the distribution, thickness and depth of coal measures, and key attributes such as thermal maturity/rank, water content, porosity/permeability and depositional environment. Other relevant national datasets such as basin polygons, wells, mines and cultural data are also being compiled. While national in scale, work to date has focused on coal measures in the key eastern Australian basins, such as the Permian coals of the Bowen, Gunnedah, Sydney and Galilee basins, and the Jurassic Walloon Coal Measures in the Surat and Clarence-Moreton basins. The GIS forms a fundamental tool for Geoscience Australia's national unconventional hydrocarbon resources assessment. This compilation for the first time provides a single, national-scale coal basins dataset for use by government, industry and the public, reflecting Geoscience Australia's role to improve the information available to support the exploration and management of Australia's hydrocarbon resources. Abstract presented to 2012 Eastern Australasian Basins Symposium (EABS) IV Conference

Sandstone deposits are important sources of uranium, accounting for approximately 20 percent of global production, largely through in situ leach (ISL) mining. Most of this production has come from deposits in the western US, Niger and Kazakhstan. In Australia, sandstone-hosted uranium is being produced from the Beverley deposit in the Frome Embayment of South Australia, and a second ISL mine is under development at Honeymoon in the same region. Such deposits form where uranium-bearing oxidised ground waters moving through sandstone aquifers react with reducing materials. The locations of ore zones and the sizes of mineral deposits depend, amongst other factors, on the abundance and the reactive nature of the reductant. Hence the nature and abundance of organic material in the ore-bearing sedimentary sequence may be of critical importance in the formation of sandstone uranium deposits. In sandstones rich in organic material (containing debris of fossil plants or layers of authigenic organic material) the organic materials either reduce uranium directly with bacteria as a catalyst, or result in production of biogenic H2S. In sandstones relatively poor in organic material, that the reduction can be caused either by the introduction of hydrocarbons and/or H2S from oil/gas fields within underlying sediments; or by H2S produced from the interaction of oxidised ground water with pyrite in the sandstone aquifer. This paper outlines the geology of the world-class sandstone uranium deposits in the Chu-Sarysu and Syr-Darya Basins in the south-central portion of Kazakhstan, which are hosted by sandstones relatively poor in organic matter. It highlights the crucial role of that hydrocarbons appear to have played in the formation of these and other large sandstone type uranium deposits. Based on the model developed, it is concluded that there is considerable potential in Australia for discovery of large sandstone hosted uranium mineralisation, including in little explored regions underlain by basins with known or potential hydrocarbons.

In 2010 the Australian Government offered for the first time a large exploration block for acreage release in the frontier Mentelle Basin. This large sedimentary basin (36, 000 m2) is located about 150 km to the west of Cape Leeuwin. It lies beneath the continental slope off the Yallingup Shelf and the Naturaliste Though, a bathymetric saddle, separating the Australian margin from the Naturaliste Plateau. Water depths range from 500-1500 on the continental slope to almost 4000 m in the central part of the Naturaliste Trough. To enable petroleum prospectivity assessment of this frontier basin in 2008-09 Geoscience Australia acquired 2570 km of industry standard seismic, as well as gravity and magnetic data during the Southwest Margins seismic survey 310. Interpretation of the new seismic data resulted in mapping of the main structures and supersequences and led to a better undertsanding of the Mentelle Basin geology. Petroleum prospectivity assessment of the Mentelle Basin confirmed that the Mentelle Basin has a significant potential to become a new petroleum province. The work undertaken by Geoscience Australia team suggests that the Mentelle Basin has at least one active petroleum system. The basin is likely to contain multiple source rock intervals associated with coals and carbonaceous shales, as well as regionally extensive reservoirs and seals within fluvial, lacustrine and marine strata. A wide range of play types have been identified in the Mentelle Basin, including faulted anticlines and highside fault blocks, sub-basalt anticlines and fault blocks, drape and forced fold plays, and a large range of stratigraphic and unconformity plays.

On the eve of London's Olympic year this title is apt as Australia's first petroleum well in more than 2 km of water is drilled, exploration has pushed to the very margins of the continent and is more widely spread across the onshore basins than at any time since in the early 1980s. In the year 2000, Sydney's Olympic year, Australia had one LNG project exporting 6.9 million tonnes and total energy exports were worth A$25.7 billion including A$7.6 billion for crude oil, A$2.7 billion for LNG and A$10.8 billion for coal. In the intervening decade Australia has asserted itself as the energy powerhouse in the Asian region, LNG exports have nearly tripled, two LNG hubs are in operation and three new LNG projects are under construction. In 2010, the export value of energy commodities included A$11 billion for crude oil, A$9.5 billion for LNG and about A$50 billion for coal.

Legacy product - no abstract available

During April/May 1988, the BMR research vessel 'Rig Seismic' carried out a 21 day geochemical and sedimentological research program in the Otway (17 days) and Gippsland (4 days) Basins. Light hydrocarbon gases (C1-C6) were measured in sediments at 342 locations on thecontinental shelf and upper continental slope. Thermogenic hydrocarbons were identified in near-surface sediments at forty-two locations in the Otway (32) and Gippsland (10) Basins. The major results from the Otway Basin include: 1. Evidence of thermogenic hydrocarbon sediments was found at seven locations on the Crayfish Platform, seven locations on the Mussel Platform and eighteen locations in the VolutaTrough. 2. Wet gas contents ([C2-C4/C1-C4] x 100), which provide some indication of both hydrocarbon source type and maturity,are highest on the basin margins, i.e. the Crayfish and Mussel Platforms. Wet gas contents were consistently lower in the Voluta Trough. 3. Total C1-C4 gas concentrations were higher in the Voluta Trough than on the basin margins, probably because of more intense near-surface faulting in the trough. 4. The geochemical data, when integrated with thermal maturation modelling and well data, suggest that the principal liquidhydrocarbon source rocks are located at the base of the Early Cretaceous Otway Group (i.e. basal Pretty Hill Sandstone). The Late Cretaceous Sherbrook Group appears to be gas-prone. Preliminary data from the Gippsland Basin identify ten locations which show evidence of thermogenic hydrocarbons in near-surface sediments.

Car traverses were made in several directions over an area of 30 miles square with Coorabin as a centre, with the object of delimiting, if possible, the margins of the coal basin. The results of the geological survey are summarised herein.