The body of father-of-two Ross Flett, 35, was discovered by colleagues on the Transocean Rather drilling rig on Sunday.
It is not clear how he died and his employer confirmed it had started its own inquiry into the circumstances.
Mr Flett, from Portessie, Moray, had worked for Transocean since 2007 as a ballast control operator -keeping the rig steady as drilling took place.
A former pupil of Buckie High school, Mr Flett was a keen Celtic football supporter.
A spokesman for Transocean, which has an office in Aberdeen, said: "The company has started an inquiry into the circumstances leading to the incident."
The American-owned firm has offices in nearly 20 countries globally, including Angola, Nigeria and the Cayman Islands.
The Transocean Rather was sited close to Labuan island, a remote area of Malaysia.
Gordon MacDonald, who is one of the representatives for the Buckie ward on Moray Council, said last night: "It's a real tragedy that someone so young has died. Everyone's feelings are with the family right now."