Hurricane Isaias: a quarter of Gulf of Mexico oil output shut in as Shell and Chevron evacuate platforms, October 2026

Hurricane Isaias has shut in about a quarter of the oil produced in the US Gulf of Mexico, and the count was taken before the two largest producers began halting their main platforms. The federal offshore regulator reported on Wednesday, October 7, 2026 that 25.08% of Gulf oil output and 16.37% of gas output were shut in. That evening Shell said it was evacuating all personnel and shutting in production at its Mars, Olympus, Ursa, Vito and Appomattox hubs, a statement that reached the MoveSurge news feed at 19:48:07 ET, three minutes after Chevron said it had begun shutting in four of its operated facilities. A few hours later the National Hurricane Center upgraded Isaias to a hurricane.

Where Isaias is heading

At 10:00 p.m. CDT on October 7 the storm was about 460 miles south-southwest of the mouth of the Mississippi River, moving east-northeast at 9 mph. Half an hour later the hurricane center said reconnaissance aircraft had found 75 mph winds, making Isaias a hurricane. The forecast has it peaking at about 110 mph, Category 2 strength, before reaching the northern Gulf Coast late Friday or early Saturday, October 9 or 10, and the center said rapid intensification was a distinct possibility.

• Hurricane warning: Ocean Springs, Mississippi, to the Bay/Gulf County line in Florida.
• Tropical storm warning: from the Jefferson/Plaquemines Parish line in Louisiana to west of Ocean Springs, and east of the Bay/Gulf County line to the Aucilla River in Florida.
• Storm surge warning: from the mouth of the Mississippi River to the Steinhatchee River, Florida, with 5 to 7 feet of surge possible from Ocean Springs to Indian Pass, including Mobile Bay.

How much Gulf output is offline

The Marine Minerals Administration, which took over the work of the former Bureau of Safety and Environmental Enforcement in July, counted 8 of 371 manned platforms evacuated on October 7, together with 2 of 11 rigs that are not dynamically positioned, and 1 of 17 dynamically positioned rigs moved off location. Reuters put the oil shut-in at 511,619 barrels a day. A day earlier the count had been 185,120 barrels a day, or 9.24% of oil output and 3.36% of gas. The Gulf produced about 2.05 million barrels a day in September, roughly 15% of US crude output.

Shell's full shut-in came after the October 7 count. Three of the five hubs it named, Appomattox, Vito and Olympus, were built for a combined 375,000 barrels of oil equivalent a day at peak, and Mars and Ursa add more. Those are design figures that include gas and do not describe current output, but they indicate that the next official count is likely to be well above 25%. Chevron said four of its operated facilities were being shut in while its other five Gulf facilities kept producing normally. Neither company gave a volume. Earth Science Associates forecast mean losses over the storm of 11.17 million barrels of oil and 13.25 billion cubic feet of gas, compared with 7.12 million barrels for Tropical Storm Bertha in July.

How oil prices reacted

Early on October 7 Brent rose 1.04% to $101.63 and WTI 0.89% to $90.24, with Reuters citing both Isaias and Houthi strikes in the Middle East. By the settlement Brent had fallen 0.38% to $100.20 and WTI 1.3% to $88.28, because the International Energy Agency's faster release of emergency stocks outweighed the storm. In Asian trading on October 8, December Brent was up 2.1% at $102.34 and November WTI up 1.8% at $89.87, with Investing.com attributing the move to the Gulf disruption and to Iranian attacks on tankers near the Strait of Hormuz.

Reuters said up to six refineries could be affected, and refineries in the Gulf Coast states hold about half of the 18.2 million barrels a day of US refining capacity. No refinery had announced a shutdown by early October 8.

Timeline on the MoveSurge news feed

1. October 7, 04:52 ET: the hurricane center reported that the depression had become Tropical Storm Isaias.
2. October 7, 10:44 ET: Chevron said it was tracking the storm's expected path.
3. October 7, 16:49 ET: the hurricane center said Isaias was rapidly intensifying.
4. October 7, 19:45 ET: Chevron began shutting in production at four Gulf facilities.
5. October 7, 19:48 ET: Shell said it was evacuating and halting Mars, Olympus, Ursa, Vito and Appomattox, and moving non-essential staff from Stones.
6. October 8, 00:04 ET: hurricane warnings were issued for parts of the northern Gulf Coast.