Oil and gas firms work to restore output after Isaac

HOUSTON Aug 31 (Reuters) - Several U.S. Gulf Coast refineries remained shuttered or operating at reduced rates early on Friday following Hurricane Isaac as energy companies assessed offshore platforms and began returning workers to facilities.

Former Hurricane Isaac became a rainstorm as it moved north into the Midwest on Friday, but as of Thursday nearly 95 percent of U.S. oil production in the Gulf of Mexico and over 72 percent of natural gas output remained shut in, government figures showed.

Early comments from oil and gas companies in the region show offshore facilities, which supply 23 percent of U.S. oil production and 7 percent of U.S. natural gas output, weathered the storm without significant damage.

Major offshore producers including Royal Dutch Shell and Chevron Corp have said they plan to restaff offshore platforms starting on Friday, with an aim to restart idled production.

Oil traders are awaiting word from Phillips 66 about the status of its 247,000-barrels-per-day Alliance refinery in Belle Chasse, Louisiana, which remained shut on Thursday after the company said it had been affected by "some flooding" due to the storm.

Marathon Petroleum Corp said on Friday its 490,000-bpd refinery in Garyville, Louisiana, was operating at reduced rates following this week's storm.

The U.S. Coast Guard said the Port of Morgan City in Louisiana had reopened late on Thursday.

Utilities were working to restore electricity to hundreds of thousands of homes and businesses along the Gulf Coast.