Operator Cnooc has confirmed that its Buzzard oil field has been shutdown for the second time this month after a pipework defect repair was found to be “compromised”.

Buzzard was shutdown on October 4 after a defect was found during an inspection.

It restarted production on Sunday.

The asset was shutdown again on Wednesday after it was discovered that the repair work on the topside pipe was not sufficient.

The Buzzard field is the largest contributor to the Forties crude oil grade, pumping around 150,000 barrels of oil per day.

A spokeswoman for Cnooc Petroleum Europe Limited, a wholly-owned subsidiary of Cnooc Limited, said that the firm “confirms it took a safe, temporary shutdown of its Buzzard installation at around 9:05am on 16 October”.

She added: “A defect on topsides pipework was repaired last week and production safely restarted.

“A routine follow-up inspection identified that the integrity of the repair was subsequently compromised.

“There is no harm to people, the environment or the asset.

“An alternative repair option is being progressed. Normal operations are expected to resume once the repair is complete.”

Buzzard is currently the largest producer in the UK according to the Oil and Gas Authority’s website, followed by BP’s Schiehallion field.

Discovered in 2001, it is one of the largest finds in UK waters of the last two decades and started production in 2007.

Cnooc holds a 43% stake in Buzzard.