The patient was being transported to Bergen after being picked up at the facility by the CHC Helikopter Service aircraft at around 8am on Wednesday in an ambulance operation, Norwegian TV channel TV2 reported.
The 37-year old Swedish man fell out of the helicopter at an altitude of around 600 meters.
The victim was found after around an hour of the search and rescue operation being conducted.
He was pronounced dead on the scene.
A CHC spokesman said,“This is the kind of tragedy we have never experienced before.”
The patient was accompanied on board by a medical attendant, two pilots, a rescue worker, and a lift operator.
“We have decided to follow up with the involved parties and the installation has been informed about the incident,” said a Statoil spokesman.
The incident is being investigated by both companies, and the local police.