Shell has shut in production at its Brutus platform in the US Gulf of Mexico following a 2100-barrel spill near the Glider field.
The leak has been isolated, and no injuries have been reported, Shell said.
The spill was discovered at around 7:55 am local time on Thursday when a Shell helicopter spotted a sheen near Green Canyon Block 248, home of the Glider field.
Glider, which is produced through four wells and a subsea manifold, is one of the fields tied in to the Brutus tension-leg platform in Green Canyon 158.
The TLP is moored in 2900 feet of water.
The cause of the spill is believed to be a release of oil from subsea infrastructure, a Shell spokeswoman said.
“Shell is determining the exact cause of the release by inspecting the subsea equipment and flowlines in the Glider field,” Shell said.
“There are no drilling activities at Brutus, and this is not a well control incident.”
The spill created a sheen measuring two miles by 13 miles, about 97 miles south of Port Fourchon, Louisiana, according to the US Bureau of Safety and Environmental Enforcement (BSEE).
A BSEE inspector conducted a flyover of the area and is currently on location at the platform. BSEE will lead the incident investigation and the US Coast Guard will lead in monitoring response efforts.
A Coast Guard aircrew also conducted a flyover assessment of the spill.
Shell said it is working with the Coast Guard and the National Oceanic Atmospheric Association “to define the best approach to contain and clean up the sheen”.
“No release is acceptable, and safety remains our priority as we respond to this incident.”
Brutus came online in 2001 with a nameplate capacity of 100,000 barrels of oil and 150 million cubic feet of gas per day.
Capacity was increased to 130,000 bpd a year later after the TLP was shut down due to valve failures in the production processing system.
The TLP’s current production was not immediately known, but is thought to be below capacity.