Wellington-headquartered NZOG this morning said that the Kupe South-7 well had intersected the top of the Paleocene-aged Farewell Formation reservoir last weekend.

However, the string became stuck when making a connection after drilling of the 8½-inch section had reached a depth of 3454m below the rotary table, the company said.

A fishing assembly was now being run in-hole in an attempt to recover the stuck pipe, NZOG said.

The jack-up Ensco Rig 107 had earlier drilled the Kupe South-6 and 8 wells to depths of 3385m and 3834m respectively.

Both had confirmed commercial hydrocarbons in the Farewell formation.

Origin is doing the Kupe development drilling on a "batch-drilling" basis, drilling each section of the three wells sequentially from the same top-hole location.

The Kupe partners are operator Origin Energy (50%), Genesis Energy (31%), New Zealand Oil & Gas (15%), and Mitsui E&P NZ (4%).