Statoil said only security staff remained on the Floatel Superior, an offshore facility housing rig workers in the North Sea. The company said it used three helicopters to airlift 326 workers off the platform, leaving 48 people behind to handle emergency measures.
"A hole was discovered in the rig's ballast tank," the company said. "Water seepage caused a 3-4 degree tilt that was speedily rectified and rig stability was re-established."
The accommodation rig was disconnected from the Njord platform when the listing occurred. Crude oil production wasn't influenced by the incident, the company said, because the drilling platform in the North Sea was closed for maintenance.
The company said the damaged rig would be towed to land for repairs "in due course." No update was provided for when production operations at the Njord platform would resume.
Norway is the largest oil producer in Europe and the second-largest exporter of natural gas after Russia.