ABSTRACT: Petroleum Play Concepts in the Devonian-Carboniferous of the Northern Canning Basin, Western Australia

JACKSON, M. JIM, JOHN M. KENNARD, PETER N. SOUTHGATE, PHIL E. O'BRIEN, and MIKE J. SEXTON, Bureau of Mineral Resources, Geology and Geophysics, Canberra, Australian Capital Territory, Australia.

The Devonian-Carboniferous of the northern Canning basin has been subdivided into sixteen sequences. These were deposited in a Givetian-Frasnian reef-rimmed platform, characterized by reciprocal lowstand clastic and highstand carbonate sedimentation, and a Famennian-Tournasian ramp complex. The reef and ramp sequences show cycles of backstepping and rapid progradation related to second-order relative sea level oscillations.

Three petroleum plays are recognized. The most promising reef play is the transgressive-highstand Frasian pinnacle and barrier reefs deposited during platform drowning and back-stepping. These are likely to be sourced and sealed by onlapping shales. Most previous, largely unsuccessful, exploration of the reef complex has been within structurally enhanced targets in the advancing Famennian platform. An exciting new stratigraphic play is the extensive lowstand basin floor fans, developed off the platform edge, in the late Frasian and Famennian. Potential reservoirs include turbidite sand sheets within basin floor fans, and channels sands flanked by levee complexes within overlying slope fans. Potential source rocks and seals are provided by interbedded shales and turbidites at the base f the overlying prograding complex. Up-dip pinchouts of the fans provide an obvious stratigraphic trap. A second new and untested stratigraphic play is the highstands in the rapidly prograding Famennian-Tournasian Ramp Complex. Prime reservoirs are ooid and bioclastic bars and shoal complexes on the inner shelf. Outer ramp shaly facies represent potential source rocks. Potential seals are provided by progradational inner shelf and coastal facies or the transgressive shales of overlying sequences. Creative exploration might provide the rewards that the Canning basin has so long promised, but not yet fulfilled.

AAPG Search and Discovery Article #91015©1992 AAPG International Conference, Sydney, N.S.W., Australia, August 2-5, 1992 (2009)