WOODADA 1—A DISCOVERY IN THE PERTH BASIN

Abstract

The year 1980 saw the first significant gas discovery to be made in the Perth Basin in many years. The basin has been explored sporadically since about 1960. West Australian Petroleum Pty Ltd made discoveries in the Dongara area in 1966-68 and production is still underway from these fields. Subsequent discoveries in the Perth Basin have been disappointing on test. The basin has a history of sandstone reservoirs with either limited areal extent, poor porosity, poor permeability, or all three. However, ample source, seal and trapping structures have been proven in numerous wells.

The Woodada discovery well was drilled in a previously untested part of the basin with the nearest deep exploration well some 20 km away. The discovery well flowed gas at a maximum rate of 33.4 MMcf/D through a 1 in choke. The well is significant, in that large quantities of gas with minor condensate were tested from a Permian carbonate reservoir not previously considered or tested as a potential reservoir. A step out well, offset 1.2 km, flowed at a similar rate. The discovery may thus herald the opening of a new and vigorous phase of exploration in the Perth Basin.