RESERVOIR POTENTIAL OF THE CATHERINE SANDSTONE, DENISON TROUGH, EAST-CENTRAL QUEENSLAND

Abstract

The Denison Trough is a deep elongate sub-basin, located along the western margin of the Permian and Triassic Bowen Basin in east-central Queensland. Gas is produced commercially from several small fields in the area, mainly from the Aldebaran Sandstone. The Catherine Sandstone, a Late Permian unit lying in the central part of the Trough, has produced gas in a limited number of petroleum wells, but is generally not a primary target for exploration. This paper aims to provide a stratigraphic and sedimentological framework for the formation, and to develop ideas relevant to its future exploration potential. Data are derived from measured outcrop sections and from cored intersections of the unit in stratigraphic bores and petroleum wells. Facies analysis has identified fluvial channel, lagoon, tidal inlet, shoreface to foreshore, offshore-transition and offshore depositional environments. The overall depositional setting has been interpreted as a wave-dominated coastline cut by fluvial channels, and passing basinward into an open marine shelf. Analysis of geometry and petrophysical characteristics suggests that tidal inlet facies and high-energy shoreface subfacies have the greatest reservoir potential within the Catherine Sandstone. Both are best developed in the northern half of the Denison Trough; gas production from the Catherine Sandstone in the area has been derived exclusively from intervals of high-energy shoreface subfacies. Further potential from these rocks is suggested, with the Catherine Sandstone and equivalents providing exploration targets of the future.