China's CNOOC shut down the 150,000 barrel per day Buzzard oilfield in the British North Sea to repair pipework on the platform, a spokesman said on Friday.
Buzzard plays a role in global oil pricing as it is the main contributor to the Forties crude stream, the largest of the five North Sea oil grades that underpin the Brent crude oil futures benchmark.
The spokesman said he could not confirm how long the work would last.
(Reporting by Shadia Nasralla; Editing by Susan Fenton)