Carnarvon Petroleum Limited (ASX:CVN) and Quadrant Energy expect to start drilling the Dorado-1 well targeting gas and liquids on the North West Shelf by the end of May.
The Ensco 107 jackup drilling rig has left Singapore and is heading to the Dorado location off Western Australia’s northwest coast.
It will be the second well in the current program of Carnarvon and Quadrant with drilling at the nearby Phoenix South-3 well now underway.
The primary objective of the Dorado-1 well is to assess the gas and liquids potential in the Caley Member.
It will be less than 20 kilometres from and up-dip of the successful Roc-1 and Roc-2 wells.
The Roc-2 well also tested the deliverability of the reservoir through a well test that achieved around 55 million scf per day of gas and an associated condensate rate of 3,000 barrels per day.
On location by mid-May
Carnarvon expects the rig to be on location by mid-May with drilling to start by the end of the month.
It is expected to take around 60 days to complete and be at the top of the primary objective in around 35 days.
Based on the results at Roc and Phoenix South, Dorado is considered as a probable gas prospect, with significant associated condensate.
There is also the possibility for the structure to contain a substantial oil accumulation.
This is due to the known presence of oil-prone source-rocks in the section at Roc, and the possibility that gas at Roc has displaced the oil up-dip into Dorado.
Up-dip of Roc discoveries
As the Dorado-1 well will be up-dip of the Roc discoveries, the overall chance of success of this prospect is enhanced.
The Dorado structure at the Caley interval is estimated to contain a gross mean recoverable prospective resource of 545 Bscf of gas and 30 million barrels of associated condensate, which is equivalent to 125 million barrels of oil.
Seismic line showing the incised Dorado Canyon which defines the Dorado trap.
Multiple secondary targets have been identified in the Crispin and Milne members, and these will also be assessed by the Dorado-1 exploration well.
The Dorado structure is clearly defined on 3-D seismic.
A shale-filled canyon, the Dorado Canyon, which has incised into the Caley and Milne sediments, creates a large trap geometry in the target levels, bounded to the west, south and east.
Similar shale-filled canyon trap geometries have proven effective in a number of gas fields in Victoria’s Gippsland Basin.