Nov. 10 (Bloomberg) -- The Louisiana Offshore Oil Port, used by import tankers too large for U.S. harbors, remained closed for a third day by high seas as the storm Ida was downgraded and all warnings were discontinued.

Unloading at the port may resume today or tomorrow, based on forecasts, Barb Hestermann, a spokeswoman, said today in a telephone interview. The port is making normal deliveries from its onshore storage tanks, she said. The storm didn’t affect Chevron Corp.’s Mississippi refinery, according to a Pascagoula police department dispatcher who declined to provide her name.

Energy companies in the U.S. idled about 30 percent of oil and 28 percent of natural-gas output in the Gulf of Mexico because of Ida, the first disturbance of the hurricane season to disrupt production, the federal government said yesterday.

“Ida passed directly over several high-volume facilities,” Scott Hanold, an analyst at RBC Capital Markets in Austin, Texas, wrote today in a note to clients. “Given its weakened state, we do not expect Ida to have caused any material damage to offshore oil and gas infrastructure.”

Platforms in the storm’s path included Mariner Energy Inc.’s Bass Lite, BP Plc’s Na Kika and Thunder Horse and the Devil’s Tower gas-processing facility owned by Williams Cos. and operated by Eni SpA, Hanold said.

Downgraded

Ida was downgraded from a tropical storm in an advisory from the National Hurricane Center issued before 10 a.m. New York time. The center of the weather system was about 30 miles (50 kilometers) east-southeast of Mobile, Alabama, with maximum sustained winds near 35 miles per hour, according to the center.

Crude oil for December delivery climbed for the second consecutive day, gaining 49 cents, or 0.6 percent, to $79.92 a barrel on the New York Mercantile Exchange at 10:52 a.m. in New York. Natural gas for December delivery dropped 18.3 cents, or 3.9 percent, to $4.487 per million British thermal units.

The Gulf produced an average of 1.3 million barrels of oil and 7 billion cubic feet of gas a day as of March, according to the Minerals Management Service, which is part of the U.S. Interior Department.

Era Helicopters LLC, which has 85 helicopters working in the Gulf of Mexico, today began bringing workers evacuated over the weekend back to offshore platforms, said Melanie Landry, communications coordinator. The Lake Charles, Louisiana, company will begin returning workers to platforms in the eastern Gulf once the storm system has passed, she said.

Offshore Drilling

Anadarko Petroleum Corp., which had daily output equivalent to about 105,000 barrels of oil shut down because of Ida, said today that it plans to return crews to production platforms today and tomorrow.

“We really aren’t anticipating finding any significant damage,” said John Christiansen, a company spokesman. “It’s been a blessing for everybody that operates in the Gulf and everybody that lives along the Gulf Coast that it’s been a very mild hurricane season.”

Houston-based Diamond Offshore Drilling Inc., which evacuated 70 to 80 people from its Ocean Saratoga rig in the Gulf of Mexico over the weekend, said it hopes to get workers back to the unit sometime today.

“Fortunately this was pretty much a non-event,” Les Van Dyke, a company spokesman, said today in a telephone interview. “I’m sure they’ll be going back out to the rig we evacuated today.”

Enterprise Products Partners LP said the Independence Hub production platform may resume operating today. The company may deploy workers to the hub, which was evacuated because of storm Ida, at about noon local time, said Rick Rainey, a spokesman for the partnership. Enterprise sent workers back to the West Delta and Viosca Knoll 817 platforms, he said.

To contact the reporter on this story: Aaron Clark in New York at aclark27@bloomberg.net

Last Updated: November 10, 2009 11:15 EST