Santos spuds second well with Noble rig off Australia

Santos spuds second well off Australia using Noble rig

Australian energy giant Santos has kicked off drilling operations on the second well in its campaign offshore Western Australia, using a Noble-owned jack-up rig.

Noble Tom Prosser rig; Source: Carnarvon

Following the recently completed drilling of the Pavo-1 well, which resulted in a material oil discovery, the Noble-owned rig mobilised to the Apus-1 well location earlier during the week with expectations to begin drilling operations within a week.

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The Apus-1 well is located in the Bedout Basin in the WA-437-P exploration permit, which is operated by Santos with an 80 per cent interest while Carnarvon Energy holds the remaining 20 per cent interest. The prospect straddles the boundary between the WA-437-P and WA-438-P exploration permits, with the resource interpreted to extend into WA-438-P. As Carnarvon holds a 30 per cent interest in this permit, this results in an average interest of ~25 per cent.

Apus-1 well location map; Source: Carnarvon
Apus-1 well location map; Source: Carnarvon

In an update on Friday, Santos’ partner, Carnarvon, informed that drilling had started at the Apus-1 well, located around 27 kilometres southwest of the successful Pavo-1 well. Based on the company’s statement, the Noble Tom Prosser rig started operations at Apus-1 with the drilling of the surface hole down to around 175 metres Measured Depth (MD), and the installation of the surface conductor.

After the setting of the surface conductor, the 17 ½” hole will be drilled down to around 850 metres MD and the 13 ⅝” casing will be set and cemented in place while the rig will then drill ahead in the 12 ¼” hole to approximately 2,200 metres MD before setting the 9 ⅝” liner. The firm explains that no hydrocarbons are anticipated to be intersected in these hole sections.

Following the setting of the 9 ⅝” liner, the rig will drill ahead in the 8 ½” hole section through the expected reservoir interval, Carnarvon elaborated within its statement. The Apus-1 well is targeting a large structure with two potential reservoir intervals.

Furthermore, Carnarvon has estimated a gross mean combined recoverable volume of 235 million barrels of liquids and 408 billion cubic feet of gas in the Caley and Milne sands within the Apus structure, which includes Apus West and Apus East.

The target reservoirs have been proved in the Dorado and Pavo discoveries, with the Caley Formation sands having been flow tested at equipment limits of around 11,000 barrels of oil per day in the Dorado-3 well in 2019. The Apus-1 well location is 31 kilometres southeast of the Dorado field.

Carnarvon sees Apus as an attractive prospect, ascribing an estimated one-in-four (23 per cent) geological probability of success.

Earlier this week, Santos made what was described as an important step on the path towards a final investment decision on the Dorado project, which is expected in mid-2022.