The timeframe to repair Britain's Forties crude oil pipeline in the North Sea remains 2-4 weeks.

LONDON, Dec 19 (Reuters) - The timeframe to repair Britain's Forties crude oil pipeline in the North Sea remains two to four weeks, its operator Ineos said on Tuesday, adding that repair options were still being assessed.

The system, which carries around 450,000 barrels per day of Forties crude to Britain, along with a third of the UK's total offshore natural gas output, has been closed since Dec. 11 after a crack was found.

"There's a number of options that we're pursuing," Ineos spokesman Richard Longden said. "The timescale stays the same - two to four weeks from the 11th."

(Reporting by Alex Lawler, editing by Louise Heavens)