PETROLEUM POTENTIAL OF THE ERINGA TROUGH IN SA AND THE NT

Abstract

The Eringa Trough occupies an area of over 8,000 km2 in SA and the NT and contains an estimated 1,500 m of Permo-Carboniferous and over 1,000 m of Mesozoic sediments. Early Permian depositional history of this frontier region is similar to that of the Cooper Basin in northeastern SA. The Eringa Trough has limited seismic coverage and sparse petroleum and mineral exploration drillholes are located on the trough margins. Interpretation of 255 km of new seismic and reprocessed data has delineated a number of undrilled prospects.

Excellent quality reservoirs are present. Early mature to mature, Permian and Jurassic source rocks occur, including good to excellent Type-II kerogens within an equivalent of the Jurassic Birkhead Formation. Apatite fission track analysis of Permian and Jurassic sediment shows palaeo-temperatures were approximately 30-40°C higher than at present and that cooling occurred within the last 60 Ma. This suggests that Permian and Jurassic sediments in the deeper parts of the Eringa Trough have experienced temperatures suitable for petroleum generation.

An integrated evaluation of the Eringa Trough in SA and the NT has resulted in a greater understanding of this frontier area which has the potential for significant commercial petroleum discoveries.