Drilled down-dip about 2 km (1.2 mi) from the Dorado-1 discovery, the well encountered 85 m (279 ft) of net reservoir in the primary Caley Formation. An oil-water contact was intersected at 4,003 m (13,133 ft) measured depth, with 40 m (131 ft) of net oil pay encountered. An additional 11 m (36 ft) of pay was encountered in the Upper Caley sands.
Preliminary well site analysis indicates this upper zone is oil-bearing but is subject to further analysis to confirm the hydrocarbon phase, the company said.
A further 32 m (105 ft) of net pay was encountered in the underlying Baxter and Milne sandstones, with no fluid contacts intersected. Both sands, the company said, are currently interpreted to be gas bearing, but the Milne hydrocarbons will require further analysis to confirm the hydrocarbon phase.
The well result has increased confidence in the presence of large hydrocarbon columns in the Baxter and Milne reservoirs, Santos said.
Wireline pressure testing has confirmed that all the reservoirs are in pressure communication with the equivalent intervals in Dorado-1. Hydrocarbons have also been recovered from each reservoir interval via wireline sampling.
Initial indications are that fluid compositions are similar to the light oils and gases that were sampled in Dorado-1, where condensate yields ranged from 190 to 245 b/MMcf in the Upper Caley, Crespin and Milne Formations, and from 70 to 90 b/MMcf in the Baxter Formation.
Santos Managing Director and CEO Kevin Gallagher said: “This is a great result which indicates the Dorado discovery is larger than anticipated and which significantly de-risks a future development.
“The value of the discovery is greatly enhanced by the high-quality reservoirs and fluids and the shallow-water setting, which should facilitate a cost-competitive development.”
Dorado-2 is in petroleum permit WA-437-P about 160 km (99 mi) north of Port Hedland. Operator Santos has 80% interest and Carnarvon Petroleum has 20%.
The jackup Noble Tom Prosser drilled the well in a water depth of 91 m (299 ft) and reached a total depth of 4,573 m (15,003 ft).
Once wireline logging operations are completed, the well will be P&A'd as planned, and the rig will move to the Roc South-1 exploration well before returning to drill Dorado-3.