Comparing Basin-Centred Gas Prospectivity in the Bowen-Surat Basin (Queensland, Australia) With the Deep Basin of Western Canada and the Piceance Basin of Utah

Abstract

The Western Canada Sedimentary Basin contains some of the best-documented basin-centred gas accumulations in the world. The “Deep Basin” concept was first advanced here in the 1970's, and now encompasses huge tight gas resources in Triassic through Upper Cretaceous clastic reservoirs. A variety of drilling and completion strategies have been designed to exploit specific reservoirs and groups of reservoirs. The Piceance Basin produces gas from very thick tight Cretaceous reservoirs, composed of marginal marine to channelized tight sandstones, interbedded with finer-grained clastics. Closely-spaced vertical wells are drilled to efficiently access stacked discontinuous reservoir sandstones. The Bowen-Surat Basin of Queensland is a well-known petroleum province because of a long history of relatively shallow conventional oil and gas production from Mesozoic reservoirs, and more recently prolific coal-seam gas (CSG) production from the Jurassic Walloon Coal Measures. Regional seismic and a small number of recent exploration wells now demonstrate immense gas and liquids potential in deeper Triassic and Permian clastic reservoirs in the central Taroom Trough, which share many key features with the western Canada Deep Basin and Rocky Mountain basins, including the Piceance Basin. Three comparisons stand out: The Permian Tinowon Formation is a thick, overpressured reservoir section dominated by shallow marine and deltaic sandstones that offers reservoir properties, continuity, and gas volumes comparable to the Triassic Montney Formation of the WCSB; Upper Permian through Lower Triassic reservoirs of the Bowen Basin can be compared to the Cretaceous Deep Basin section in western Canada – both contain several hundred metres of marine to marginal marine sediments, including shoreface, deltaic, channel and coal measure deposits, deposited in settings controlled largely by changes in relative sea level; Lower to Middle Triassic reservoirs of the Bowen Basin (Rewan Formation, Showgrounds Sandstone) are like the thick Cretaceous Mesaverde Group succession of the Piceance Basin – both sections consist of dominantly marine facies at the base, grading upward to fluvial-dominated strata characterized by discontinuous tight sandstones interbedded with finer clastic rocks. Future exploration and development in Bowen-Surat Basin reservoirs will be supported by consideration of successful exploration and development strategies employed for their North American analogues.

AAPG Datapages/Search and Discovery Article #90259 ©2016 AAPG Annual Convention and Exhibition, Calgary, Alberta, Canada, June 19-22, 2016