The confirmation was made through the drilling of the Dorado-2 appraisal well about 160km north of Port Hedland and 2km away from the Dorado-1 discovery


Image: The Dorado discovery was made in the WA-437-P permit in the Bedout Basin. Photo: courtesy of D Thory/Pixabay.

Santos and its partner Carnarvon Petroleum said that the drilling of the Dorado-2 appraisal well has confirmed the pre-drill expectations of the Dorado discovery offshore Western Australia.

The Dorado discovery, which was made in July 2018 through the drilling of the Dorado-1 well, is contained in the WA-437-P permit in the Bedout Basin.

Dorado-2 is the first appraisal well of the Dorado discovery

The Dorado-2 well, which is the first appraisal of the Dorado discovery, was drilled using the Noble Tom Prosser jack-up drilling rig, in a water depth of 91m and up to a total depth of 4,573m.

Planned as a down-dip appraisal well, Dorado-2’s objective was to delineate the hydrocarbon contacts in the Caley, Baxter and Milne Members of the Lower Keraudren Formation.

The appraisal well encountered an oil-water contact in the Caley reservoir, which was the primary target. According to Carnarvon, high-quality oil was drawn from the reservoir and reservoir properties were found to be excellent and on part to those discovered during the drilling of the Dorado-1 well.

Results from the Caley formation provide key definition of the facilities required for developing the oil field and also in giving confidence for moving ahead with the first phase of development, said Carnarvon.

In the Baxter reservoir, which was the secondary target, as expected, condensate rich gas was drawn from the appraisal well. The wireline logging also confirmed that a hydrocarbon column was intersected by Dorado-2 with no gas-water contact found.

Carnarvon said that samples collected from the Milne reservoir were recorded as oil bearing on the rig. The company said that no water contact was intersected in the Milne section in the appraisal well.

Dorado-2 is claimed to have intersected high quality and productive reservoirs in each of the targets.

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.

Santos said that after completion of wireline logging operations, Dorado-2 will be plugged and abandoned and the Noble Tom Prosser rig will be deployed to the Roc South-1 exploration well and later on will be used for drilling the Dorado-3 well.

The company is the operator of the WA-437-P permit with a stake of 80% while Carnarvon holds the remaining stake of 20%.