About 9% of Gulf oil output is shut in as forecasters expect a hurricane by Thursday

Some Gulf of Mexico oil output is already offline and companies are moving workers to shore as a newly formed tropical depression, forecast to become a hurricane by Thursday, heads toward offshore fields that pump about 15% of U.S. crude.

The Marine Minerals Administration, the Interior Department agency that oversees drilling in what the federal government calls the Gulf of America, estimated on Tuesday that about 185,000 barrels a day of oil had been shut in, or 9.24% of current Gulf production, along with 3.36% of natural gas output. The figures reflect one company's reports as of 11:30 a.m. Central time, and the agency did not name the company. At that point no workers had been evacuated from any of the 371 staffed production platforms, and none of the 17 rigs that hold position with thrusters had moved off location. By TickerGrove's calculation, the agency's numbers put current Gulf oil output at about 2 million barrels a day.

Shell said Tuesday it had begun evacuating nonessential workers from six offshore production sites: Stones, Mars, Olympus, Ursa, Vito and Appomattox. Chevron said nonessential staff were being moved off its Gulf platforms but that production from the fields it operates remained at normal levels.

The forecast: a hurricane over the central Gulf

As of 10 p.m. Central time Tuesday, the National Hurricane Center placed Tropical Depression Nine about 605 miles southwest of the mouth of the Mississippi River, with top sustained winds of 35 mph, drifting east at 5 mph. Forecasters expect it to become a tropical storm early Wednesday and a hurricane on Thursday, pass north of Mexico's Yucatan Peninsula, then turn north and approach the U.S. northern Gulf Coast on Friday. The official forecast has it peaking at 100 mph over the central Gulf, which would make it a Category 2 hurricane.

The center said the risk of dangerous wind and storm surge is increasing from Louisiana to the Florida Panhandle and that watches could be needed on Wednesday. It also said confidence in the track is below average, and that strong wind shear near the coast means the storm will likely reach its peak before it gets there. From Friday through the weekend, 3 to 6 inches of rain is forecast from southeastern Louisiana to the Florida Panhandle, with local totals of up to 10 inches.

The storm would be named Isaias once it reaches tropical-storm strength. If it becomes a hurricane, it would be the first of the 2026 Atlantic season.

What it means for oil and gasoline

Brent crude, the global benchmark, rose 95 cents, or 0.9%, to $101.53 a barrel in Asian trading, and U.S. crude gained 0.9% to $90.25, according to cnbc.com market data at about 11:10 p.m. Eastern time. Gasoline futures rose about 2%, roughly twice crude's gain. Traders were also weighing attacks by Yemen's Houthis on Saudi Arabia, with oil already trading near $100.

The offshore fields in the storm's path also produce about 5% of the country's natural gas, and as many as six refineries could be affected. Refineries in Gulf Coast states account for about half of the country's 18.2 million barrels a day of refining capacity. Tim Waterer, chief market analyst at KCM Trade, called the storm an "unwelcome complication for crude, raising the prospect of production and refining disruptions at a time when the market already has enough supply-side headaches."

Shutting in wells ahead of a storm is a standard safety step, and it is reversed once the danger passes. The agency says undamaged facilities come back online as soon as inspections are complete, while damaged ones can take longer. When Hurricane Ida hit Louisiana in 2021, more than 90% of Gulf oil production was shut at one point and 279 platforms were evacuated, according to federal figures at the time.

The agency updates its shut-in and evacuation figures at 1 p.m. Central time each day. The hurricane center's next full advisory is due at 4 a.m. Central time Wednesday.