Carnarvon Petroleum said that the Ensco 107 jackup drilling rig has started to move from Singapore to drill the Dorado-1 well offshore Western Australia.
The rig is expected on location in mid May 2018 with drilling anticipated to commence before the end of May. The well is expected to take around 60 days to complete and be at the top of the primary objective in around 35 days.
The primary objective of the Dorado-1 well is to assess the gas and liquids potential in the Caley Member. As depicted in Figure 2 (see link below), the Dorado well is less than 20km from and updip 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/day of gas and an associated condensate rate of 3,000 barrels per day.
The Dorado-1 well, being up-dip of the Roc discoveries, enhances the overall chance of success of this prospect.
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 (being 125 million barrels of oil equivalent (“boe”), gross, Pmean).
Multiple secondary targets have been identified by Carnarvon in the Crispin and Milne members (see Figure 3 in link below) and these will also be assessed by the Dorado-1 exploration well. See the recently released volumetric strategy update (ASX 23 April 2018) for details on these targets.
The Dorado structure is clearly defined on3-D seismic. The 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 (see Figure 1 and 2 in link below).
Similar shale-filled canyon trap geometries have proven very effective in a number of gas fields in the Gippsland Basin in Victoria.
The Dorado prospect is considered by Carnarvon as a probable gas prospect, with significant associated condensate, based on the results at Roc and Phoenix South. However, it should be noted that there is the possibility for this structure to contain a substantial oil accumulation.
This is due to the known presence of oilprone source-rocks in the section at Roc, and the possibility that gas at Roc has displaced the oil up dip into Dorado.