There is no risk of oil leaking into the sea off Taranaki due to a crack in the Maari oil platform, the company which manages the oil field says.
A 1.4m crack was discovered about 4m below the water line on one of the horizontal struts of the OMV-operated Maari wellhead platform.
The platform, located 80km off the Taranaki coast in about 100m deep water, is being evacuated as a result of the discovery. Thirteen of the 34 staff left yesterday with more scheduled to leave today and the remainder tomorrow.
The company said in a statement to the Herald that there was no risk of oil leaking and that the cracked strut was not connected in any way to the oil production system.
"Oil production ceased yesterday as part of the planned shut down of the facility."
The company said that the crack was caused by "fatigue associated with the combined action of wind and wave", adding that the company carries out inspections regularly to check for fatigue. The previous inspection was in May.
OMV senior vice president for Australasia Gabriel Selischi said the crack was identified this week as a result of scheduled underwater checks that began on November 1.
"We have taken expert external advice which confirms there is no risk to people or the environment. There are 12 horizontal struts and the six levels of the structure are supported by four structural legs, consolidated by 20 vertical cross-members. So the platform is very flexible, and has a high level of built-in redundancy," Selischi said.
"Level 3 of this platform is the most exposed to the pressures generated by wind and wave action. That's why, as operator, we undertake regular checks."
Bad weather expected this weekend and New Zealand's heightened earthquake risk were factors in the company's precautionary approach.
"Work has started on stabilising the crack and we are actively monitoring it meantime. We've engaged specialist advisors to assist in this work, and have been keeping WorkSafe and Maritime New Zealand fully informed," Selischi said.
"Production was due to be shut in on 5 December to allow for the completion of a water injection flow-line installation, so support vessels and equipment will shortly be on hand."
Maritime New Zealand said in a statement that it was ensuring that OMV was fully compliant with their responsibilities around the environment. It was satisfied that the company was acting appropriately at this stage.
"We support OMV's move to shut down production, which means the well is shut down and the oil pipelines are flushed out. This means there is very little likelihood that any oil spill could occur."
"OMV have confirmed that there is very little risk to either the environment or workers and no oil spill has been reported."
The cause of the crack was not known and was being investigated. It would likely take some time to resolve.
OMV New Zealand is one of the country's largest liquid hydrocarbon producers, the third largest gas producer, and a major explorer in a number of offshore basins around New Zealand, particularly the Taranaki Basin.
It has been active in New Zealand since 1999 when it acquired shares in the Maari oil discovery, which it developed and now operates.