RECENT EXPLORATION AND HYDROCARBON POTENTIAL OF THE ROMA SHELF, QUEENSLAND

Abstract

The probability of finding additional gas reserves on the Roma Shelf within Authority to Prospect 336P and Petroleum Leases 3-13 is assessed as being very high. There is a 50 per cent probability that 80 billion cubic feet (2250 million cubic metres) will be found and a 20 per cent probability that 290 billion cubic feet (8170 million cubic metres) will be discovered.

Recent seismic information together with geologic models developed for the Roma Shelf, Queensland have refined the settings of various plays of this important hydrocarbon province. Despite the large number of wells drilled in the region, it is still relatively unexplored considering the small size of economic accumulations and when compared to other sedimentary basins containing similar play types, elsewhere in the world.

Modern regional seismic coverage has lead to an improved understanding of the basin's structural history. Tectonic events such as strike-slip faulting and compression commencing in the Early Carboniferous and continuing into the Tertiary have formed several structural traps in the area.

Recognition of the importance of reservoir horizons such as the Lower Triassic Rewan Formation and the Upper Permian Tinowon Formation has added to the prospectivity of this area.

Recent exploration has been highly successful with 67 per cent of the exploration drilling resulting in new field discoveries. This success rate has stemmed from finer spaced grids of high resolution seismic which has provided accurate prospect mapping. Refinements to exploration concepts have also resulted from an integrated geological and geophysical approach.