Publication Name: The North West Shelf Australia
Authors: J. Bentley
Date Published: July 1988
Number of Pages: 26
Reference Type: Book Section
Abstract:
The Candace Terrace is part of a broad shelf area which flanks the Barrow-Dampier rift. The eastern boundary ofthe Candace Terrace is formed by the Sholl Island Fault, a major listric fault which developed during the Palaeozoic. The western limit occurs at the Flinders Fault System, a complex set of faults formed during Jurassic rifting.Wells have penetrated sediments dating back to the Early Carboniferous. Late Carboniferous deformation and subsequent glaciation were followed by rapid deposition of glacigene sediments in an infra-rift basin. Shallow marine environments predominated through the Permian. A transgression in the Early Triassic resulted in basinal shale deposition. Submarine canyon systems were subsequently incised on the Candace Terrace. A regressive sequence of Late Triassic fluviodeltaic deposition was curtailed by the Early Jurassic Rift-onset Unconformity. Following the major tectonism of the Mid Jurassic Breakup, a thin cover of Cretaceous and Tertiary sediments blanketed the Candace Terrace.
Source rocks have been identified in the Triassic lower Locker Shale and Permian Kennedy Group but these are immature on the Candace Terrace. Migration from mature Jurassic Dingo Claystone in the depocentre relies on a tortuous migration path through the Flinders Fault System. Potential reservoirs are found in the Cretaceous Birdrong Sandstone, Triassic Mungaroo Formation, Permian Kennedy and Byro groups and Carboniferous Quail Formation. Several play types have been recognised, including rollover into the Sholl Island Fault, tilted fault blocks adjacent to the Flinders Fault System and a structural/ stratigraphic concept involving lateral seal against an incised submarine canyon.
No significant hydrocarbon shows have been recorded on the Candace Terrace but only two of the four wells drilled were located within structural closure.