Sydney-headquartered AWE this morning said the semi-submersible Ocean Patriot drilling rig had spudded Tieke-1 at 2.30am today and that by 6am the rig was preparing to run and cement 30-inch conductor casing at a measured depth of 229m.

The well will be drilled to a planned total depth of 3600m, in water 122m deep. It is expected to take 18 days on a trouble-free basis.

Tieke-1 is only about 8km from the Tui oil pool and is in the Tui Area licence, PMP 38158, roughly 40km offshore.

Following completion of operations at Tieke-1, the Ocean Patriot will start drilling the first of four development wells on the $US225 million ($A292 million) Tui Area oil project.

Tieke-1 and the second scheduled near-field appraisal well, Taranui-1, could more than double total Tui Area reserves, currently estimated at 27.9 million barrels, with Tieke delivering up to 15MMbbl.

Tieke and Taranui are less than 15km from the Tui floating processing, storage and offtake vessel site, so any discovery could be quickly brought to production by tying in to the Umuroa FPSO.

The PMP 38158 partners are AWE (42.5%), New Zealand Oil & Gas (through its subsidiary Stewart Petroleum) (12.5%), Mitsui E & P New Zealand (35%) and Pan Pacific Petroleum (through its subsidiary WM Petroleum) (10%).