Anzon Australia Ltd is to join the joint venture partners for drilling the offshore Canterbury well Cutter-1, likely to spud in early October.

Sydney-based upstream oil and gas company Anzon announced that it has reached agreement to acquire Arrowhead Energy Ltd's 15% interest in PEP 38259, which contains the Cutter prospect off Oamaru.

The permit is operated by Perth-based Tap (New Zealand) Pty Ltd which holds a 40% interest, while Sydney-based AWE New Zealand Pty Ltd holds a 25% interest and Adelaide-based Beach Petroleum Ltd 20%. Beach holds an 8.9% shareholding in Anzon.

The Diamond Offshore semi-submersible drilling vessel Ocean Patriot is scheduled to be mobilised to Canterbury when it completes a Nexus Energy well in Bass Strait late next month.

According to Diamond Offshore's current website rig schedule, after Ocean Patriot drills Cutter-1, the rig will head back to Bass Strait for one well before returning across the Tasman to begin a series of eight wells about late November for AWE in offshore Taranaki, including the four Tui field development wells.

Tap says Cutter-1 will test the oil potential of the Shag Point Formation reservoirs in a large four-way dip closure in the northern part of the permit area. Reserve potential for the prospect is in the range of 70-80 million barrels of recoverable oil.

The hydrocarbon potential of the basin was demonstrated by the Galleon-1 well, drilled within the permit in 1985 some distance south of Cutter-1, which encountered a 21 m gas column that flowed at rates up to 10 MMcf of gas per day, with associated condensate of 2240 bpd.

Cutter-1 will take about a month to drill to a depth of around 3000m in 75m deep waters.

Timaru will be shorebase for the support vessel and helicopter supporting the Ocean Patriot. Drill pipe is already stacked at the port.