Chevron North Sea’s Alba Northern platform was shut down after “low levels” of a potentially-deadly gas were detected.
A spokesman for the oil company said it took action yesterday as a “precautionary measure” after an alarm went off during routine well operations in the vicinity of drilling activity.
He added: “As per routine procedures, the well was secured and all 139 personnel on board were called to muster and safely accounted for.
“The platform returned to full operations following muster”.
Sources claimed people had to be evacuated from the drilling floor and there were problems finding enough sets of emergency breathing apparatus for everyone, but this was flatly denied by the spokesman.
The Alba Northern Platform is about 130 miles north-east of Aberdeen in the central North Sea.
Meanwhile, nearly 80 people evacuated from one of Shell’s North Sea platforms late on Sunday were still being kept safely elsewhere last night.
The oil major moved dozens of people from its Brent Bravo platform during Storm Imogen after concerns were raised over structural damage on one of Bravo’s legs.
Forty people were moved to Brent Charlie and 39 were switched to the nearby Brent Delta as a precaution, leaving 75 essential workers on Bravo.
A spokesman for Shell yesterday said: “Shell UK can confirm that an incident occurred on Sunday evening on its Brent Bravo platform, located approximately 115 miles north east of Lerwick.
“Personnel on the platform were called to muster following damage to one of the structure’s legs. As a precaution, all non-essential personnel were moved to other nearby Brent platforms.
“Relevant authorities have been notified.”
Last month, a separate storm left scaffolding dangling from the operator’s Brent Delta platform.
Shell’s spokesman confirmed it would manage a “controlled drop” of the damaged equipment before recovering it from the seabed.
The Brent Field was discovered off the north-east coast in 1971. Since production began in 1976, it has been one of the world’s largest oil and gas producers.