The Eyre Sub-basin of the Great Australian Bight Basin comprises a series of half-grabens with a maximum sediment thickness in the order of 6 000 m. It is bounded to the north by high-standing basement with a sedimentary cover about 550 m thick. To the west, sedimentary cover gradually thins and onlaps rising basement. To the south, a high- standing basement ridge separates the sediments within the Eyre Sub-basin from those of the Great Australian Bight Basin proper. The sedimentary pile apparently thickens south of the basement ridge where water depth increases to more than 1 400 m.The high basement trend bounding the sub-basin to the south plunges gradually to the east where it is eventually broken up by faulting. Seismic data from the eastern end of the sub-basin show progressive down-faulting of basement and increasing sediment thickness to the south.Jerboa 1 was drilled on a tilted basement fault block. It penetrated 1 739 m of sedimentary section, which is believed to be a condensed sequence representative of most of the total sedimentary fill of the sub-basin. Middle to Late Jurassic (Callovian-Kimmeridgian) sediments were encountered above basement, and the sequence continued almost unbroken into the Late Cretaceous (Cenomanian). Minor unconformities occur between the non-marine Aptian sequence and the overlying marine Albian, and between the Albian and Cenomanian. A major unconformity separates the Cenomanian from the overlying Tertiary section, interpreted to have been deposited after the separation of Australia from Antarctica.

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Jurassic and Cretaceous clastics of the Western Papuan Basin provide reservoir and source potential for hydrocarbon accumulation. Early Jurassic coarse clastics from sources in the south and west cover a wide stable platform area, while finer grained equivalents were deposited in a deepening trough along the east and northeast margins. A Middle Jurassic transgression deposited a thick shale unit over most of the basin, followed by a return to sand and silt deposition in the Late Jurassic-Early Cretaceous. Eocene/Miocene structuring in the north formed the Omati Trough which filled with deep water Miocene carbonates. This was followed by shallow water carbonates which cover the Western Papuan Basin. Mountain ranges to the north and northeast were the source for thousands of feet of poorly sorted Plio- Pleistocene sediments which were dumped in the rapidly subsiding Aure Trough and spread as a veneer over the remainder of the Papuan Basin.Geochemical studies indicate that adequate source rocks exist within the Mesozoic shales and these reach maturity at a depth of about 2700m. The Mesozoic shales correlate more closely with the various oil and condensate seeps than do the Miocene carbonates which are generally too immature over much of the basin to be considered as a significant oil source.The stable platform, except for the Omati Trough, has undergone very little tectonic movement since the Triassic and this has severely restricted the formation of structural traps suitable for hydrocarbon entrapment. Better structuring exists to the east of a Mesozoic hinge-line running approximately north- south just offshore from the present-day coastline, but lack of good Mesozoic reservoir sands in this area limits the hydrocarbon prospects. The most prospective area is the structured margin of the Omati Trough, where tilted fault blocks provide traps for hydrocarbons generated from the underlying shales of the Cretaceous and Jurassic, but difficult terrain and high exploration costs make for high risk exploration.

The Kingfish field, currently Australia's largest producing oil field, lies 48 miles offshore southeastern Victoria in 250 ft of water. The field occurs within a large, essentially, east-west trending topographic high on the Latrobe unconformity surface sealed by fine grained clastics of the Upper Eocene Gurnard and Oligocene Lakes Entrance Formations. The reservoir itself is formed by Lower Eocene sediments of interdeltaic origin.The discovery well, Kingfish 1, was spudded on 6 April 1967. This well indicated the severity of a suspected seismic velocity gradient, a function of high velocity channel deposits in Miocene sediments overlying the crest of the Latrobe unconformity surface. Additional seismic coverage and two outpost wells provided sufficient structural and stratigraphic control to define a commercial oil field having a maximum of 270 ft of vertical relief over an area of some 28 sq mi at the oil-water contact of 7,566 ft subsea.Following completion of the 42 well development drilling program for the A and B platforms the Kingfish oil field was put on stream on 21 April 1971. Proved and probable reserves have been initially estimated at 1,060 MM STB. The field has flowed oil at rates in excess of 180,000 STB/D for a cumulative production to the end of 1972 of 83 MM STB.