REVIEW OF THE PALAEOZOIC STRATIGRAPHY AND PETROLEUM POTENTIAL OF NORTHERN SOUTH AUSTRALIA

Abstract

The Amadeus, Warburton, Officer, Adavale, Arckaringa, Pedirka, Cooper and Great Artesian Basins form a complex system of overlapping basins in central Australia. Cambrian rocks are widespread in the Amadeus, Warburton and possibly the Officer Basins and are marked by the major role of carbonate deposition. Gas and oil shows are known from the Amadeus and Warburton Basins. In South Australia their reservoir potential lies in shoreline clean-up of generally dirty marine sandstones and porosity-permeability associated with archaeocyathid bioherms or dolomitization of limestones.

The Ordovician rocks follow the widespread distribution of the Cambrian rocks and are distinctive for thick quartzites and graptolitic shales. In South Australia, the Warburton and Officer Basins may have facies developed which are similar to the Pacoota and Stairway Sandstones, the reservoir rocks for the Amadeus Basin gas and oil fields. Large anticlinal structures have recently been suggested by S.A. Mines Department geophysical work in the Officer Basin which enhances the potential.

Red beds are distinctive in the Devonian System. Deposition apparently spilt into the peri-Musgrave Block area and the Adavale Basin to Innamincka area. A thickness of over 3 000 metres of Devonian rocks was drilled in the Officer Basin which contained some reservoir rock lithology. The petroleum potential in South Australia is relatively unattractive.

Some 3.4 trillion cu ft of deliverable gas reserves have been established already in the Permian sediments of the Cooper Basin which are up to 900 m thick. The Early Permian sediments of the Pedirka Basin which may be at least 500 m thick may hold similar petroleum potential.