Oil and gas discoveries in Australia's offshore basins are concentrated on the North West Shelf (Northern Carnarvon, Browse and Bonaparte basins) and Bass Strait (Gippsland, Otway and Bass basins). While discoveries have been made in a few regions outside these areas (e.g. Perth Basin), a large proportion of Australia's offshore basins remain exploration frontiers. However, the decline in oil production from the North West Shelf and Bass Strait basins since 2000 has led to an increasing exploration interest in the frontier basins. In order to improve our knowledge of the offshore frontiers and encourage exploration to these areas, from 2003-2011, Geoscience Australia was funded by the Australian Government to undertake a series of pre-competitive data acquisition and analyses programs in frontier basins around the Australian margin. This Record presents a comprehensive inventory of the geology, petroleum systems, exploration status and data coverage for 35 frontier basins, sub-basins and provinces, that draws on the results of those pre-competitive data programs, as well as exploration results and the geoscience literature. The Record also provides an assessment of the critical science and exploration questions and issues for each area. The results of each basin assessment are summarised in a prospectivity ranking. The availability of data and level of knowledge in each area is reflected in a confidence rating for that ranking. While the prospectivity of some areas is widely acknowledged to be high (e.g. Ceduna Sub-basin), the perception of prospectivity in many basins is negatively affected by the amount or quality of data available; in these basins, the acquisition of new data or targeted research could make a significant difference to the understanding of petroleum potential and likelihood of success. Therefore, recommendations for future work that could assist in addressing key knowledge or data gaps are included in each basin assessment.

The Bremer Sub-basin, which forms part of the Bight Basin off the southern coast of Western Australia, is a deep-water (100-4000 m water depth) frontier area for petroleum exploration. No wells have been drilled to test the sub-basin's petroleum potential, with company exploration limited to a regional seismic survey by Esso Australia Ltd in 1974. Early studies identified the Bremer Subbasin as a series of Middle Jurassic-Early Cretaceous half graben, which contain potentially prospective structures for trapping hydrocarbons. However, a lack of sub-surface geological data, along with the deep-water setting, discouraged exploration of this area for over 30 years. In 2003, the Bremer Sub-basin was identified as a key frontier area in Geoscience Australia's New Oil Program where new exploration opportunities might occur. Subsequently, Geoscience Australia's Bremer Sub-basin Study commenced in 2004 with an aim to determine if the sub-basin formed under suitable geological conditions to generate and trap large volumes of hydrocarbons.

AGSO's 1995-96 Petrel Sub-basin Study was undertaken within AGSO's Marine, Petroleum and Sedimentary Resources Division (MPSR) as part of MPSR's North West Shelf Project. The study was aimed at understanding the stratigraphic and structural development of the basin as a framework for more effective and efficient resource exploration. Specifically, the study aimed to: - define the nature of the major basement elements underlying the Petrel Sub-basin and their influence on the development of the basin through time, - determine the nature and age of the events that have controlled the initiation, distribution and tectonic evolution of the basin; - define the nature and age of the basin fill, and the processes that have controlled its deposition and deformation; and, importantly, - determine the factors controlling the development and distribution of the basin's petroleum systems and occurrences.

The study provides a comprehensive analysis of the natural gases from the Bonaparte, Browse, Carnarvon and Perth basins (in 4 modules). Geochemical analyses for the molecular and carbon isotope composition were performed on 96 gases and associated liquids, and these data are interpreted in a geological context. Additional non-exclusive data from the AGSO database have been used for correlation/interpretation purposes. The study addresses factors influencing the composition of gaseous and other light hydrocarbons in natural gas (and associated oil accumulations) including; - primary source and maturity controls, - secondary alteration processes, e.g. migration fractionation, water washing, biodegradation, and - multiple charge histories, including deep dry gas inputs.

The Bight Basin Sampling and Seepage Survey (SS01/2007), was undertaken in February-March 2007 as the final data acquisition activity of the Commonwealth Government's New Petroleum Program (2003-2007). The survey was designed to address two key petroleum systems issues in the Bight Basin. In order to assist in our understanding of the distribution of source rocks in the basin, the survey aimed to sample the distal facies of potential source intervals of Albian-Santonian age at locations on the seaward edges of the Ceduna and Eyre Terraces. Secondly, the survey aimed to investigate the presence of active petroleum systems by sampling and obtaining geophysical data at potential natural hydrocarbon seepage sites across the Ceduna Sub-basin. Nine areas of interest were identified for surveying in the eastern Bight Basin, including areas where the targeted Albian-Santonian section outcrops on the seafloor, and areas where there was seismic and other geophysical and remotely sensed evidence of possible hydrocarbon seepage. The survey, took place from 24 February-17 March 2007 using the Marine National Facility vessel R/V Southern Surveyor. The survey successfully sampled all nine targeted areas and collected 37 dredge hauls, 69 gravity cores and 15 grab samples, as well as 4600 km of swath data, and 2400 km of sub-bottom profile data. The Bight Basin Sampling and Seepage Survey was very successful in addressing the most critical of its objectives, recovering samples from the exposed up-dip northwestern edge of the Ceduna Sub-basin that provide the first evidence for a world-class marine Cretaceous source rock in the Bight Basin.

The offshore Gippsland Basin is Australia's major producing hydrocarbon province. Acreage has historically been tightly held, and opportunities for new players in this highly prospective basin have been limited. However, recent relinquishments have allowed the Australian Federal and Victorian State Governments to offer three potential permits to petroleum exploration companies and consortia. The Bureau of Mineral Resources Petroleum Group, in collaboration with the Victorian Department of Manufacturing and Industry Development's Petroleum Branch, has produced a hydrocarbon prospectivity package for the Southeast Gippsland Basin, with particular emphasis on the three areas to be released. The package takes the form of this BMR Record 1991/9. The Package covers regional geology, geophysics, palaeogeography, and hydrocarbon play concepts, together with a new structural interpretation for the Gippsland Basin developed at BMR. In addition, for each release area the package covers previous exploration, local geology and play concepts, reservoir geology and engineering, and geohistory. Prospects and leads are described in detail, and the text is complemented by some 80 Plates and Figures.

This arcview GIS data package is the third in a series of 3 of new potential field data and interpretations for the Great Australian Bight developed by AGSO and Desmond Fitzgerald & Associates. This data package encompasses an interpretation of primary and derived datasets in GIS format, and includes two reports in PDF format, on basement architecture and on regional petroleum geology of the Great Australian Bight.

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No abstract available