Ineos has confirmed deliveries of crude from its major North Sea pipeline are under force majeure after it shut down the entire system due to a cracked pipe.
The firm discovered a hairline crack in the pipe near Netherely, south of Aberdeen, last week, and it shut down the huge Forties pipeline system on Monday. It now expects the pipeline to be shut for "weeks rather than days".
Ineos, which only recently bought the pipeline from BP, said no further growth in the crack had been recorded for 48 hours, allowing it to halve the precautionary safety cordon to 150m.
"At this stage it is still too early to say how long the repair will take to complete, but it is expected to be a matter of weeks rather than days," Ineos said, adding that a number of repair options were currently being assessed and developed.
"We can confirm that formal force majeure has been declared on relevant contracts and we continue to work closely with our customers during this period, as well as local communities, government and other stakeholders."
"We apologise to our customers and the local community for the issues that this creates and we are working hard to minimise the impact of the pipeline closure as far as possible."
The Forties pipeline system, which was built by BP in 1975 as one of the largest in the North Sea, is about 100 miles long and transports around 450,000 barrels of oil a day, which is about 40 per cent of UK production.
It carries oil from the North Sea to be processed at the Grangemouth refinery, which Ineos also owns.
Under force majeure a company's contractual obligations are suspended in the wake of situations that lie beyond its control, and Reuters reported that it is extremely rare in the North Sea.