Royal Dutch Shell Plc on Tuesday said it is beginning the process of redeploying personnel to its Auger platform in the Gulf of Mexico, while also assessing the full damage at its West Delta-143 (WD-143) offshore facility due to storm Ida.

As of Tuesday, about 88% of the U.S. Gulf of Mexico's offshore oil production remained shut after the storm, one of the most destructive to strike the region, made landfall on Aug. 29. 

The Appomattox, Mars, Olympus, Ursa, Auger, and Enchilada/Salsa facilities remain shut, Shell said in a statement, reiterating that about 80% of Shell-operated production is offline.

"Our inspections on board confirm that there is no significant structural damage to these Shell Deep Water assets impacted by the storm. Our crews will focus on making any necessary repairs in a safe, sustainable manner," Shell said.

Shell's Norco plant in Louisiana was still without power while assessment and repairs continue, the company said.

Sources told Reuters on Sunday that Shell plans to begin restarting the 230,611-barrel-per-day (bpd) Norco oil refinery in about two weeks.

The company also said it has re-staffed Shell Pipeline's Ship Shoal 28 asset.

"Platform startup will remain dependent on the availability of downstream infrastructure including pipelines and delivery locations," Shell said.

Meanwhile, redeployment to its Enchilada/Salsa assets continued, the company said.

West Delta-143, operated by Shell Pipeline, serves as the transfer station for all production from its assets in the Mars corridor in the Mississippi Canyon area of the Gulf of Mexico to onshore crude terminals.

Consultancy Energy Aspects last week estimated a production loss of 250,000 to 300,000 barrels per day of Shell's Mars medium sour crude, possibly for weeks.

This would put 12-15 million barrels of Mars that was to be exported in September-October at risk, prompting a scramble for alternatives from Chinese and Korean buyers, Energy Aspects added.

(Reporting by Arpan Varghese in Bengaluru, Gary McWilliams in Houston; Editing by Nick Zieminski and Alistair Bell) ((arpan.varghese@thomsonreuters.com;))