Publication Name: The Sedimentary Basins of WA
Authors: Alan Stein
Publication Volume: 1
Date Published: July 1994
Number of Pages: 26
Reference Type: Book Section
Abstract:
The Rankin Platform on Australia's North West Shelf is, and will continue to be, a major source of gas and condensate to expanding markets in Australia and Asia. Based on current figures, recoverable reserves are estimated to be in excess of 25 TCF of gas, 700 MMBBL of condensate and 200 MMBBL of oil. The focus of exploration to date has been upon the leading edge of the Rankin Platform which forms a prominant structuralfeature within the Carnarvon Basin. The internal parts of the platform remain virtually unexplored. Conventionally the Rankin Platform has been viewed as the 'stable margin' of the Carnarvon Basin which subsided rapidly during the Jurassic and Early Cretaceous. This analysis of the flexural and isostatic response of the platform to rifting suggests that it was not stable and that it underwent deformation, mostly uplift, associated with subsidence in the adjoining basin. Using mathematical models from analogous basin settings it is predicted that some of the frontal parts of the platform have undergone in excess of one and a half kilometres of uplift, and that the effects of rift-related uplift extend back onto the platform, with exponentially decreasing effect, for as much as 30 km. A corollary of this structural model is the identification of new plays on the unexplored parts of the platform which upgrade the exploration potential for oil.