The U.S. offshore safety regulator's daily update showed that 40 percent of Gulf oil output and 29 percent of natural gas production was locked in, slightly less than a day earlier.
The storm brought heavy seas with up to 20 foot (6 metre) waves and winds of 155 miles per hour (250 kph) in the Gulf on Wednesday as it churned towardS the Florida Panhandle. The storm produced drenching rains on Thursday over Georgia and the Carolinas.
Oil output was off by 680,000 barrels per day and natural gas production down by 744 million cubic feet a day, according to the Bureau of Safety and Environmental Enforcement. Its Thursday survey found workers had returned to 30 of the 89 production platforms that were unmanned a day earlier.
BHP Billiton Ltd is in the process of ramping up production at its Shenzi production platform and expects to resume output at its Neptune platform on Friday, spokeswoman Judy Dane said late Thursday.
Chevron and Exxon each were in the process of returning to normal operations at two production platforms that had evacuated some staff, the companies said. BP also was redeploying crews to four platforms after completing safety checks.
Restarting production can take several days. Producers lost about 2.39 million barrels of oil this week through Thursday as a result of shut-ins.
The Louisiana Offshore Oil Port, or LOOP, the largest privately-owned crude terminal in the United States, said it resumed Marine Terminal operations on Thursday.
Power outages were delaying fuel deliveries in Georgia to customers of Colonial Pipeline [COLPI.UL], the country's largest fuel network, its operator said on Thursday. Colonial said it was assessing damages and working to resume service.
U.S. West Texas Intermediate crude futures fell $2.20 to settle at $70.97 a barrel on Thursday, a loss of 3 percent as global stock markets fell, with investor sentiment made more bearish by a bigger-than-expected U.S. crude inventories build. [O/R]
Anadarko Petroleum Co said on Thursday it had expanded its shut-ins to three offshore platforms, and was waiting for safety reasons to return workers.
Gas production should reach 2.3 billion cubic feet per day (bcfd) on Thursday from a low of 2.2 bcfd on Tuesday, according to Refinitiv data. A week ago, energy firms were pulling 3.5 bcfd from offshore wells.
(Reporting by Gary McWilliams in Houston, Scott DiSavino and Stephanie Kelly in New York; editing by Marguerita Choy, Grant McCool and G Crosse)