Norway's Petroleum Safety Authority (PSA) on 26 September urged oil companies to be more vigilant over unidentified drones seen flying near Norwegian offshore oil and gas platforms, warning they could pose a risk of accidents or deliberate attacks.
The warning came after the country's largest oil and gas firm, Equinor, recently said it had notified authorities of sightings of drones of unknown origin flying near some of its platforms.
"We would urge increased vigilance, a review of emergency preparedness measures and incident response, and information sharing," the PSA said in a letter to operators.
The safety watchdog said unidentified drones posed a risk to helicopters that transport offshore workers, could become an ignition source in areas with explosion hazard, or could be used for deliberate attacks.
Newspaper Stavanger Aftenblad reported last week that unidentified drones had been observed at least at six Equinor installations, including at its giant oilfield Johan Sverdrup.
On 20 September, a drone was observed some 50 m away from Equinor's Heidrun platform in the North Sea, breaching the 500-m security perimeter, the newspaper reported.
"There have been observations of drones at some of our installations on the Norwegian continental shelf," a spokesperson for Equinor told Reuters, declining to elaborate.
Equinor has reported the incidents to the Norwegian authorities, including the PSA and police.