Shell’s Olympus platform produces oil and natural gas from the Mars field in the Gulf of Mexico off Louisiana's coast. The platform will be joined in the Mars-Ursa production area by Kaikias, a project that subsidiaries of Royal Dutch Shell and Mitsui Oil Exploration Co. are undertaking.

Offshore oil and gas operators in the Gulf of Mexico have evacuated platforms and rigs in response to tropical weather activity, according to the Bureau of Safety and Environmental Enforcement.

The bureau's hurricane response team is activated and monitoring the operators’ activities, according to a news release. The team will continue to work with offshore operators and other state and federal agencies until operations return to normal and the storm is no longer a threat to Gulf of Mexico oil and gas activities.

At least 15 platforms had been evactuated as of noon Wednesday, which is a little more than 2 percent of the 669 manned platforms in the Gulf. Production platforms are the structures located offshore from which oil and natural gas are produced. Unlike drilling rigs, which typically move from location to location, production facilities remain in the same location throughout a project’s duration.

Personnel have been also been evacuated from four rigs. Three rigs have moved out of the storm’s path as a precaution.

As part of the evacuation process, personnel activate applicable shut-in procedures, which can frequently be accomplished from a remote location. This involves closing the sub-surface safety valves located below the surface of the ocean floor to prevent the release of oil or gas.

BSEE estimates more than 30 percent of the current oil production in the Gulf of Mexico has been shut-in, which equates to 602,715 barrels of oil per day. In addition, more than 17 percent of the natural gas production in the Gulf has been shut-in.

After the storm has passed, facilities will be inspected and brought back on line.