DALLAS (Bloomberg) — Oil and natural gas companies accelerated evacuations from rigs and production platforms in the Gulf of Mexico as Tropical Storm Gustav may enter the region as a hurricane this weekend.

ConocoPhillips said it stopped oil and natural-gas production at its only offshore platform in the Gulf and will begin evacuations today. Royal Dutch Shell Plc, Europe's largest oil company, said it has begun shutting its offshore oil and gas operations and plans to evacuate all offshore workers.

Gustav may halt 1.2 million barrels of a day of crude oil production and 7.2 billion cubic feet of natural gas output if it strikes the central Gulf Coast, said Angela Montoya, a meteorologist at Weather Insight LP in Houston.

ConocoPhillips will evacuate about 20 non-essential staff from the Magnolia platform about 150 miles southeast of Lake Charles, Louisiana, Houston-based ConocoPhillips said in a statement posted on its website. Magnolia had daily output equivalent to 33,000 barrels of oil in 2006.

Another 58 workers will be taken off the platform by August 30, based on the predicted path of the storm, ConocoPhillips said.

Royal Dutch Shell Plc plans to evacuate 300 offshore workers yesterday, after evacuating 400 yesterday, Shell said in a press release. Another 600 employees will be pulled out by Saturday.

Production from Shell's fields in the Gulf could be cut as early as today, Robin Lebovitz, a Shell spokeswoman, said in an e-mailed statement. The company operates fields that pump 510,000 barrels of oil equivalent a day, according to Shell's website.

Exxon Mobil Corp., the world's biggest oil company, began identifying which workers will be evacuated from oil and natural-gas platforms because of the storm.

The Irving, Texas-based company's output hasn't been affected by the preparations, which include readying offshore installations for high winds and battering waves, Exxon Mobil said in an advisory on its website yesterday morning.

Petroleo Brasileiro SA will evacuate six non-essential workers from the EC373 platform in the Gulf.

The evacuations were scheduled to happen yesterday or today, Petrobras, as the company is known, said yesterday in an e-mailed statement.

Transocean Inc., the largest offshore oil driller, evacuated about 190 non-essential workers from five of its 11 offshore drilling rigs in the Gulf, according to an e-mail from spokesman Guy Cantwell.

Diamond Offshore Drilling Inc., the world's second-largest deepwater oil driller by market value, said some non-essential personnel have been evacuated and it is securing rigs in preparation for the storm.

"We will have evacuated virtually all personnel by the end of the day Saturday assuming the storm continues on its projected path and speed," said spokesman Les Van Dyke, in an e-mail.