Managing director Richard Tweedie told PetroleumNews.net this morning that Todd Energy planned to drill two more appraisal wells in the Mangahewa field, probably early next year, and to link them into the Mangahewa-McKee production process.
He said that McKee - where some gas is reinjected to maintain reservoir pressures and increase oil recovery - and Mangahewa have been producing about 9 petajoules of sales gas a year.
This will increase to 11-12PJ once Mangahewa-3 comes onstream and is forecast to increase to over 15PJ per year by 2009-10.
Depending on the success of Mangahewa-4 and 5 next year, a major upgrade of the 24-year-old McKee production station might be necessary to enable the plant to handle even more gas, Tweedie told PNN.
In December, Tweedie said Mangahewa-3 had discovered "a lot more gas", although he declined to specify how much more had been found and in which intervals.
But Todd Energy says the field could contain up to 250PJ of undeveloped reserves - much more than previous owner Fletcher Challenge Energy's initial estimates of about 100PJ of recoverable gas.
Gas and liquids are separated at the Mangahewa-2 wellsite, with liquids processed at the nearby McKee production station.
Mangahewa-2 currently produces from only one of several Eocene-aged tight gas intervals in the PMP 38150 lease.
Todd yesterday officially opened the first cogeneration plant at McKee - a $NZ5 million ($A4 million) project that will produce about 2MW of electricity by using waste gas that was previously flared.
Most electricity generated would be used onsite, but some would be sold via the grid. All of the steam produced would be used onsite.
Tweedie said a second cogeneration scheme for the Mangahewa field is planned to be operational by the end of this year, producing up to 9MW of electricity and more associated exhaust heat.
Associate Energy Minister Harry Duynhoven said Todd's existing and planned cogen plants would enable the McKee and Mangahewa fields to run more efficiently.
The plants should also encourage other exploration and production companies to use similar small and isolated gas finds around the country for local electricity generation and waste heat utilisation.
