Taranaki's Kupe gas and condensate field is substantially bigger than originally thought.
The field's owners said yesterday they had revised upwards by 16.5 per cent Kupe's estimated recoverable reserves.
It is now estimated the field's proved-plus-probable (2P) reserves total 394 petajoules equivalent (PJE) - comprising 281 petajoules of sales gas,627,000 tonnes of LPG and 14.7 million barrels of condensate. Previous estimates had put the field's 2P reserves at 338 PJE.
One petajoule of gas is sufficient to heat 5000 homes for a year.
Kupe operating company Origin Energy said the field's original estimate of reserves was based on a study conducted by the previous operator in 2000.
But these had now been revised upwards after a major reinterpretation exercise that included reprocessing of seismic survey information. This exercise had been carried out as part of studies to establish the most efficient means of commercially developing the field.
All this is now being incorporated into an overall development plan aimed at the Kupe field annually supplying about 20 petajoules of sales gas, 1.7 million barrels of condensate and 45,000 tonnes of LPG.
Kupe is the subject of a major front-end engineering and design project, which is involving the designing of offshore and onshore production facilities, and the obtaining of resource consents.
Origin Energy said that subject to Government approvals, the joint-venture owners of Kupe expected to make final investment decisions in the fourth quarter of this year to proceed with development of the field.
First gas is expected to be produced in late 2007.
"The joint-venture parties are encouraged by this upwards reserves revision and by the potential for the Kupe project to play a significant role in helping New Zealand meet its ongoing energy needs," it said.
New Zealand Oil & Gas (NOG) has a 15 per cent stake in the joint venture, Origin Energy Kupe owns 50 per cent, Genesis Energy 31 per cent and Mitsui 4 per cent.
A 9c rise in the NZOG share price and its options just prior to yesterday's announcement prompted the NZX to question the company about its disclosure of the news.
The shares closed up 6c, or 7 per cent, to 93c yesterday.
More power
* Kupe gas field is now believed to be 16 per cent bigger than first thought. * That is the equivalent of about 56 petajoules of extra energy. * One petajoule of gas is sufficient to heat 5000 homes for a year.
