THE NORTH PAARATTE GAS DISCOVERY

Abstract

The North Paaratte 1 gas discovery well was drilled, in November 1979, on the Port Campbell High in the Otway Basin to test a discrete structural closure 3.5 km from the Frome-Broken Hill Port Campbell 1 well, which discovered gas in non-commercial quantities in 1959. A number of other minor gas flows have been encountered in wells drilled since 1959 in the vicinity, but none have beeen commercial.

A rate of flow of 9.6 MMcf/D was substained on production testing of the North Paaratte discovery well. This is the first discovery to have possible commercial significance in the Otway Basin, which has attracted a moderate level of exploration effort for the past 25 years.

The gas at North Paaratte is reservoired in the Waarre Sandstone of earliest Late Cretaceous age; the probable source of the gas being the underlying Early Cretaceous Otway Group. The structure relies on faulting for closure and is sealed by the Belfast Mudstone, which drapes over the fault block.

Post-drill seismic surveys were carried out to map the area of closure and a step-out well to determine the extent of the gas reserve is programmed for early 1981.