Publication Name: Eastern Australian Basins Symposium 2001
Authors: T. Nakanishi and S.C. Lang
Date Published: November 2001
Number of Pages: 33
Reference Type: Magazine Article
Abstract:
Exploration and development in the Cooper-Eromanga Basin have been predominantly focused on structural traps. However, the future for exploration and field development lies in exploration for stratigraphic traps. Using advanced visualisation techniques on open file 3D seismic survey data from the Pondrinie and Packsaddle fields on the Packsaddle Ridge, we characterised possible stratigraphic traps in the Toolachee and Poolowanna Formation. The key to the analysis lies in a genetic-stratigraphic framework using sequence stratigraphic concepts as applied to non-marine basins. Two types of possible stratigraphic traps are extracted from the Pondrinie 3D survey:I. an isolated fluvial channel belt in a transgressive systems tract of the Toolachee Formation, and
2. transgressive fluvial channel sandstones in the incised valley of the Poolowanna Formation.
To rank these stratigraphic traps, the confidence values for the existence of geological chance factors (reservoir, top seal, lateral seal, bottom seal and the appropriate spatial arrangement of these factors) were estimated according to the distributions of the possible reservoir and seal rocks within each genetic-stratigraphic interval. Using this ranking methodology, the isolated fluvial channel play of the Toolachee Formation was ranked higher than the incised valley fill play of the Poolowanna Formation. We proposed that this evaluation procedure for
stratigraphic trap explorations should provide consistency with the ranking of the conventional play types and assist the selection of an economically effective portfolio from an exploration prospect inventory.