The Tern Gas Field case history

Abstract

The Tern Gas Field is located 110 km offshore in the Petrel Sub-Basin of the Bonaparte Basin in northern Australia. The Tern structure was discovered in 1966 when the first seismic survey was recorded in the area. Subsequently, gas was encountered in the Late Permian sandstones of the Hyland Bay Formation when Tern 1 was drilled in 1971. Further seismic studies detailed the Tern structure and Tern 2 located 10 km south-east of the discovery well confirmed the existence of the gas field in 1982. The presence of an amplitude anomaly in the seismic response (bright spot) was recognised when a modern seismic survey was recorded in 1980. Since then, different seismic projects have enabled an accurate mapping of the field whilst the significance of the anomaly was investigated.