New Zealand's biggest oilfield, Maari, off the Taranaki coast, will be shut down for three months, losing millions of dollars in production, while up to US$70 million (NZ$89m) of repairs are done to its floating tanker ship.
One of the partners in the field, Horizon Oil, said its share of lost production would be about US$5 million (NZ$6.3m) for the three months, implying deferred production of about US$50m for the Maari field.
Some of the cost of the remedial work on the floating production ship, Raroa, should be recovered through insurance, Horizon said.
The joint venture partners in Maari, led by operator OMV, said the floating production station would be disconnected from the field and towed to a suitable port.
A new swivel, which allows the ship to swing around its mooring, would be installed after a "bearing malfunction" was found in the existing swivel.
OMV has not decided which port would be used to carry out the work, but it will need to be able to handle the large 250 metre- long ship and have a crane to lift the 12-tonne swivel. There is likely to be some local engineering work involved in the repairs, but it is unclear how much of the total cost will involve importing the new swivel and mooring lines.
The joint venture partners in Maari, led by Austrian oil giant OMV, bought the converted supertanker, Raroa, only in March this year.
A spokesman for OMV said the repairs would cost more than US$60m, while another field partner, Horizon, said it would cost US$70m.
Just as Maari is being shut down, the Maari joint venture is starting to drill a new well nearby, Manaia-2, using the drilling rig Kan Tan IV. Another rig, Ensco- 107, is expected to start work on the Maari field early next year.
Raroa is what is known as a floating processing, storage and offloading ship - an FPSO - and it has been sitting above the Maari field since 2009, when the field first started production. The field is about 80km off the Taranaki coast.
In the past financial year, Maari produced about 3.2 million barrels, but the field is naturally declining and has had problems with downhole pumps, so average daily production is unclear. But it appears the joint venture partners may miss out on hundreds of thousands of barrels of production in the next three months.
The Raroa is being prepared for disconnection from the field and removal of all the remaining crude on board, which was expected to take several weeks. During the field shutdown, construction work is being done ahead of bringing in new wells and the upgrade of the Maari wellhead platform.
OMV said while there would be a greater than expected deferral of production from doing all the upgrade work together, the decision made long-term sense.
The Maari field facilities would be "fully upgraded" before the new wells came on stream next year. Kan Tan IV is drilling the first of those now, and the Ensco rig will drill more next year.
Raroa's main job is to separate raw production from Maari's wells into oil, gas and water and then store the oil for offloading to visiting conventional tankers.
- © Fairfax NZ News
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