The fire occurrred on the North Apoi platform of Funiwa oil facility on Monday and has forced a shut down of the facility, Ruuters reports.
The company said officials were still trying to account for all those working there and that it was investigating the cause of the fire.
“Chevron Nigeria Limited (CNL) … confirms a fire incident on the K. S. Endeavor jack-up rig. The incident occurred in the early hours of Monday,” Chevron spokesman Scott Walker said in an emailed statement.
“We are still investigating the incident and are working to fully understand what happened,” he added, but did not provide any casualty figures.
The rig is run on Chevron’s behalf by contractor Fode Drilling Co., Walker said.
Officials with Fode, which has offices in London and Jenkintown, Pennsylvania, could not be immediately reached for comment Monday.
Nnimmo Bassey, who runs an environmental watchdog group in Nigeria, said he had received reports from locals nearby that the fire was an industrial incident.
“Workers were trying to contain the gas pressure and they didn’t succeed,” Bassey said.
Nigeria is the fifth-largest crude oil exporter to the U.S. It produces about 2.4 million barrels of crude oil a day. Chevron, based in San Ramon, California, produced an average of 524,000 barrels of crude oil a day from Nigeria in 2010.
The company has exploration rights to about 2.2 million acres across Nigeria’s delta and offshore.