The Forties Echo platform in the North Sea has been shut after being hit by a supply vessel, a spokesman for operator Apache North Sea said on Monday.
Fifteen workers were taken off the platform and transferred to the nearby Forties Bravo platform following the collision, which happened at about 0840 GMT on Monday morning, the spokesman said. Another 15 remain on the platform.
The spokesman also confirmed there had been no leak of hydrocarbons, but was unable to give a restart date for production.
Apache North Sea, part of Apache Corp, is investigating the extent of any damage but there was no structural risk to the rig, he added.
"An initial visual inspection has been carried out from the platform's standby vessel and a specialist inspection team is being mobilized to assess the damage to the platform," Apache said in a statement.
The Forties oil field is located 110 miles north-east of Aberdeen, in the UK sector of the central North Sea.
Forties is one of the four crude streams that underpins the Brent crude oil futures benchmark.
(Reporting by Claire Milhench and David Sheppard; Editing by David Holmes)