8th October 2019
Abstract
Speaker: Ian Cockerill
Tittle: Dorado. An overview of the largest oil discovery on the Northwest Shelf of Australia in the last 30 years.
The Dorado field was discovered by Quadrant Energy (now Santos) and partners Carnarvon Petroleum in August 2018. Carnarvon Petroleum released a 2C Gross Contingent Resource of 186 million barrels of oil and condensate and 552 Bscf of Gas (20 August 2018) making Dorado the largest oil discovery made on the Northwest Shelf in the last 30 years and far exceeding the pre-drill (gross, Pmean) estimate of 125 million barrels of oil equivalent.
Dorado is located in the Bedout sub-basin 160km north of Port Hedland in approximately 90m of water. The reservoirs are at a depth of around 4000m in the Caley, Baxter, Crespin and Milne clastic units of the Lower Triassic Keraudren Formation.
The Bedout sub-basin covers an area of approximately 15,000km2. Six wells were drilled in the basin between 1971 and 1983 including what was originally interpreted to be a tight gas discovery in the Phoenix-1 and Phoenix-2 wells. Despite the early indications of a proven petroleum system, exploration drilling in the area didn’t return until 2014 with the Phoenix South discovery. The Roc discovery followed in 2016 and Dorado (2018) has rounded up a record of 100% geological success for exploration drilling in this renewed period of activity in the Bedout.
The Dorado prospect was a new stratigraphic play concept for the sub-basin, targeting high amplitude seismic events of the Lower Keraudren Formation terminating against a deep incising canyon. The shale-filled Dorado canyon provides the side seal to Dorado. Multiple prospects have been identified on trend from Dorado on the east-west trending canyon system. The Dorado canyon, and other canyons yet to be tested, have the potential to extend on to neighbouring open acreage some of which were made available in the Australian 2018 Acreage Release.
The 22,000km2 Capreolus 3D Survey owned by TGS covers Dorado, all of the discoveries made in the Bedout sub-basin and the majority of the most prospective part of the Bedout sub-basin. RISC has interpreted this survey and this presentation will describe the Dorado play and highlight other untested plays within this exciting emergent province of the Northwest Shelf of Australia.
