Longtom—confirmation of a New Play in Offshore Gippsland

Abstract

The Longtom gas field was discovered in 1995, when the Longtom–1/ST1 wildcat well in the northern part of the offshore Gippsland Basin encountered dry gas in tight sandstones towards the base of the Latrobe Group, in what is now called the Admiral Formation of the Emperor Subgroup. In 2004 the Longtom–2/ST1 exploration well confirmed significant vertical and lateral extension of these prospective gas sands, and also provided very encouraging production test and core data. The recent Longtom–3 wells have demonstrated the viability of this new play by confirming significant lateral continuity of the thicker gas sands and demonstrating high gas flow rates. The history of the field’s discovery and appraisal illustrates how a multi-disciplinary and interactive approach, guided by innovative seismic inversion techniques and real-time petrophysical data, resulted in the successful planning and execution of the Longtom–3 drilling and evaluation program. The results of the wells and the outline of the field development plan illustrate how Longtom represents new production potential in this mature basin.

Fault seal analysis in ‘branched’ fault traps, eastern Gippsland Basin

“…Thus, the successful pooling of hydrocarbons in fault traps is problematic within the study area although possible, as has been demonstrated in the Flounder Field (ESSO, 1988). Other exceptions exist in the Golden Beach and Emperor Subgroups as have been demonstrated in the Kipper and Longtom Fields (Lanigan et al, 2007;Sloan et al, 1992).…”