Field owner Maui Development Ltd announced the planned inspection and maintenance program yesterday and said it estimated 75-90 percent of maximum gas deliverability could be maintained throughout most of that month. However, further supply constraints could be possible, particularly during November 16-22, it warned.
The work would require the phased, partial shutdown of facilities throughout the month, with the most critical period being the November 16-22 period, when the Maui B platform would be isolated during the replacement of the emergency shutdown valve in the pipeline from Maui A-B and on to the onshore Oaonui production station.
"MDL is working closely with the Crown and major gas users to co-ordinate maintenance activity so that the effects of reduced gas supply will be minimised," MDL chairman Lloyd Taylor said from Wellington.
The program would not adversely affect residential and most commercial and industrial users, as supply should be more than enough for those customers. "However, the electricity sector may be required to co-ordinate its generating capacity, to minimise the impact of reduced gas availability in thermal power generation," Taylor warned.
MDL would provide a further update on shutdown plans in late October, taking into account progress in well work-overs and reservoir performance during the next two months.
New Zealand's largest gas user, Methanex Corporation, is looking at rescheduling a planned shutdown at its small Waitara Valley plant, but admits it might be forced to close the larger Motunui complex for a few days.
"At present we are not sure of all the implications of the planned work on Maui. We hope to reschedule our planned turnaround for the valley plant to roughly coincide with the Maui shutdown," said Methanex manufacturing director Harvey Weake today.
"However, there is the potential for Motunui to come down for a few days," he added.
The month-long maintenance turnaround at the small valley plant, which produces about 520,000 tonnes of methanol a year, had been scheduled to start in late October, but that could be delayed by a week or so.
While Weake did not comment on the impact of the Maui shutdown on overall production, any closure of the larger Motunui complex, which produces over two million tonnes of methanol a year, would hit Methanex harder.
Natural Gas Corporation spokesman Keith FitzPatrick said NGC was still assessing what the shutdown would mean for its thermal power stations and delivery capability to its large gas customers. "It's too early, we have not yet drawn any conclusions."
Contact Energy said it expected to supply gas customers on a 'business as usual' basis during the maintenance program and that the outage would coincide with a planned 10-12 week maintenance program at the company's 380MW gas-fired Otahuhu B plant in south Auckland.
The 23-year-old Maui field is now starting to show its age. Taylor said that with the Maui field well into its third and final production decade, the impacts of field depletion and increased facilities maintenance "places a premium on energy industry co-operation to ensure that the inherent energy supply chain risks are identified and managed in advance."
