By Phaedra Friend Troy
The US Minerals Management Service has approved a new method to help contain the oil spill 5,000 feet below the water’s surface in the Gulf of Mexico.
The MMS has approved the use of a methanol injection to prevent the formation of gas hydrates in the ultra-deepwaters where the oil is spilling from the Macondo well.
The first oil containment dome, lowered into the Gulf of Mexico above the biggest oil leak was thwarted because of the formation of gas hydrates at the subsea level. These gas hydrates, similar to ice crystals, are a naturally occurring formation in ultra-deepwaters and Arctic regions.
The gas hydrates prevented the flow of the oil-water combination up the riser to the drilling rig above, and the original oil containment dome was parked on the ocean floor.
A second, smaller oil containment dome, referred to now as a “top hat” system, is being developed to cap the oil spill.
This system will cap the largest oil leak, where the damaged riser and the damaged drill pipe meet. A riser will then transport the oil-water contaminant to the Enterprise Drillship above, which will process the petroleum.
Within the "top hat" is where the methanol injection will be deployed to prevent the hydrates from forming and keep the riser line clear to transport the oil-water mixture.
Furthermore, the riser will be heated to promote the flow of oil from the ocean floor to the drillship above. This is a commonly used practice in ultra-deepwater production because the temperatures at these water depths tend to stymie the flow of oil.
The “top hat” oil containment system should be deployed mid-week.
Another smaller leak in the drillpipe was resolved through the use of ROVs last week.
A third oil leak remains at the Blowout Preventer (BOP). Nonetheless, should the “top hat” oil spill containment system work, a large portion of the oil spilling into the Gulf of Mexico should stop.