Santos will in May spud the appraisal well Dorado-2, testing the world-class Dorado offshore oil discovery in Western Australia. The company will then drill the Roc South-1 and Dorado-3 wells.

Carnarvon, Santos’ partner in the project, said in its quarterly report on Monday that the Dorado-2 appraisal well was expected to begin in May 2019 and would be the first of three wells planned in the 2019 drill campaign by the two companies.

Noble’s Tom Prosser drill rig was contracted for the program and is currently drilling in the Carnarvon Basin before it moves to the Dorado location. The Tom Prosser was previously used on the Roc-1 discovery in 2016.

The Dorado-2 well is targeting the hydrocarbon columns in a down-dip location from the Dorado-1 discovery. This will provide more information on the extent of the hydrocarbon accumulations and further calibrate the reservoir and fluid properties.

Carnarvon said that the Roc South-1 exploration well was added to the drill program and will be drilled immediately following the completion of the Dorado-2 well.

Joint development for Roc and Dorado?

Roc South is within close proximity to Dorado, just 13 kilometers away from the Dorado crest and is estimated by Carnarvon to contain 74 million barrels of oil equivalent. The prospect has a relatively high chance of success of 63% and given its proximity to Dorado. Success could result in this structure being developed alongside the Dorado field.

Following Roc South-1, the final firm well of the 2019 drill campaign will be the Dorado-3 appraisal well.

Dorado-3 plans to include drill stem tests will assist with reservoir performance and obtain fluid samples required for the design of the Dorado production facilities.

“The results from these wells will also be instrumental in preparing for a Final Investment Decision (FID) which the joint venture is targeting for late in the 2020 calendar year,” Carnarvon said.

The original oil discovery at the Dorado field was made in mid-2018 by Quadrant Energy. The company was later bought by Santos for $2.15B. The Dorado-1 well had been targeting gas, but instead struck a find believed to be W. Australia’s largest oil discovery in years.

Image source: Noble Corporation