The agency did not immediately identify the rigs by name.
"MMS is closely monitoring these rigs, and they have been relatively stationary for several hours," said Lars Herbst, regional director, MMS Gulf of Mexico Region. "We expect tugs to be on location to secure the rigs as soon as sea conditions allow."
The MMS conducts risk assessments of every mobile drilling rig location plan prior to hurricane season before granting approval of each plan. The assessments consider the proposed location's proximity to critical oil and gas infrastructure, condition of sea floor, and station-keeping capabilities of each specific rig.
Once the weather in the Gulf of Mexico clears, over flights by MMS staff, the U.S. Coast Guard and the oil and gas industry will begin in both fixed-wing aircraft and helicopters. These over flights will allow a preliminary survey of damage to both oil and gas production platforms and drilling rigs. Damage estimates cannot be confirmed until the structures are boarded and actual inspections take place.
Based on data from offshore operator reports submitted as of 11:30 a.m. CDT Saturday, personnel have been evacuated from a total of 611 production platforms, equivalent to 85.2 percent of the 717 manned platforms in the Gulf of Mexico. Production platforms are the structures located offshore from which oil and natural gas are produced. These structures remain in the same location throughout a project's duration unlike drilling rigs which typically move from location to location.
Personnel from 101 rigs have also been evacuated; this is equivalent to 83.5 percent of the 121 rigs currently operating in the Gulf. Rigs can include several types of self-contained offshore drilling facilities including jackups, submersibles and semisubmersibles.
From the operators' reports, it is estimated that approximately 99.7 percent of the oil production in the Gulf has been shut-in. As of June 2008, estimated current oil production from the Gulf of Mexico is 1.3 million barrels of oil per day. It is also estimated that approximately 98.5 percent of the natural gas production in the Gulf has been shut-in. As of June 2008, estimated current natural gas production from the Gulf of Mexico was 7.0 billion cubic feet of gas per day. Since that time, gas production from the Independence Hub facility has increased and current gas production from the Gulf is estimated at 7.4 billion cubic feet of gas per day.
As part of the evacuation process, personnel activate the shut-in procedure, which can also be accomplished from a remote location. This involves closing the safety valves located below the surface of the ocean to prevent the release of oil or gas. During Hurricanes Katrina and Rita, the shut-in valves functioned 100 percent of the time, efficiently closing in production from wells and resulting in no major spills from the Outer Continental Shelf. Shutting-in oil and gas production is a standard procedure conducted by industry for safety and environmental reasons.
The production percentages are calculated using information submitted by offshore operators in daily reports. Shut-in production information included in these reports is based on what the operator expected to produce that day. The shut-in production figures therefore are estimates, which the MMS compares to historical production reports to ensure the estimates follow a logical pattern.
Source: Energy Current