--> Utilising BP's 3-D Seismic to Give New Insights Into the Great Australian Bight

International Conference & Exhibition

Datapages, Inc.Print this page

Utilising BP's 3-D Seismic to Give New Insights Into the Great Australian Bight

Abstract

The Cretaceous-aged deltaic systems (White Pointer; Tiger and Hammerhead) of the Ceduna Sub-Basin within the Bight Basin off the present-day south coast of Australia represent one of the largest underexplored basins in Australia. A new, high-quality 3D seismic volume covering 12,100km2, shot using 8km streamers by BP as part of on-going exploration activity, has provided significant new insight into the basin. The Bight Basin began to form during the mid-late Jurassic as Antarctica and Australia rifted. Separation of India from Antarctica towards the end of the Barremian resulted in the cessation of movement between Antarctica and Australia and the basin entered a thermal sag phase. The basin, and potentially a large proportion of the Australian landmass was flooded during the Aptian. This allowed the deposition of marine mud-prone facies in the clastic-starved Bight Basin. Subsequent base-level fall during the Cenomanian resulted in a major clastic influx in to the basin, with Apto-Albian muds forming a break in mechanical stratigraphy along which the White Pointer listric faults formed during Cenomanian loading could detach. During the deposition of the Tiger delta, major uplift and rotation of a Distal High beyond the White Pointer compressional zone occurs. This structuration is roughly coincident with the shift in Tiger depocentre and may represent renewed extension before eventual continental break up at the end of the Santonian. The Santonian breakup surface forms a significant erosive event across the basin. Post break-up, the deposition of the Hammerhead delta progrades southwards then aggrades. A regional unconformity is present at the top of the Hammerhead that represents clastic shut-off in the basin and the deposition of cold-water carbonate. Understanding the deposition, accommodation space generation and fault movement is key understanding the evolution of these reservoir systems. Detailed mapping and seismic facies work has potentially revealed a complex and diverse petroleum system with multiple reservoirs and structural styles that open up new play potential throughout the Bight.