Depositional And Diagenetic Controls On Reservoir Quality In The Early Permian Moogooloo Sandstone, Southern Carnarvon Basin.
Wilson, Richard Arthur Lee
Honours Degree, 1991
University of Adelaide
The offshore extension of the Fitzroy Graben contains a highly structured Palaeozoic section, resulting from an early rifting phase in the Devonian, later modified by Permo-Triassic dextral wrenching and structural inversion during the Miocene collision of Australia and Indonesia. A relaxation phase associated with the Miocene event has resulted in crestal growth faulting of major anticlinal structures. The present day basin geometry reflects an asymmetric half-graben, bounded to the north by a NN-SE trending fault and subjected to two or more phases of NNN-SSE trending compression.
Permian and Carboniferous rocks are present at drillable depths and, consist of sediment accumulated within a glacially influenced deltaic environment followed, by a marine shelf environment. This latter formed in response to a transgression caused by melting of the ice. Within this Late Palaeozoic sedimentary package, thick (100m+) reservoir units of moderate quality are expected together with currently mature source rocks. The quality of the latter is not well known but may improve basinward (west).
Seismic mapping indicates the presence of several large structural traps sealed by Early Permian shelf deposits and associated with regional high trends. This region may be classed as "high risk/high reward", and awaits further evaluation of burial, thermal and diagenetic histories before being considered as prospective for commercial hydrocarbons.