A breach in the rig's riser, 65m under the deck, allowed water-based mud and yellow chemicals in.

The chemicals were not environmentally hazardous.

"The safety distance to the reservoir is good, which means there is no risk of hydrocarbon flowing. All safety systems are intact," Lundin managing director Norway Torstein Sanness said.

"No one was affected by this incident and all 88 persons on board the rig are safe."

The company's emergency response organisation is coordinating support services and has contacted all relevant authorities.