Oil sheen spreads after rig fire, collapse in gulf

April 27, 2010
Spilled oil from the BP PLC well drilled by Transocean Ltd.’s Deepwater Horizon semisubmersible rig spread to a 600-mile circumference rainbow sheen with areas of emulsified crude oil 36 miles off Louisiana, response officials said Apr. 27.

Paula Dittrick
OGJ Senior Staff Writer

HOUSTON, Apr. 27 -- Spilled oil from the BP PLC well drilled by Transocean Ltd.’s Deepwater Horizon semisubmersible rig spread to a 600-mile circumference rainbow sheen with areas of emulsified crude oil 36 miles off Louisiana, response officials said Apr. 27.

The cause of an Apr. 20 explosion and fire on the rig remains under investigation. The semi rig sank Apr. 22 on Mississippi Canyon Block 252.

Eleven crew members remain missing and presumed dead, and 17 people were injured with one person still in the hospital as of Apr. 26. A total of 115 people evacuated the rig to nearby supply vessels.

The drilling rig Development Driller III was being moved into position to drill a well to intercept the Macondo exploration well and inject a specialized heavy fluid to prevent flow of oil and gas. Workers then planned to permanently seal the original well.

BP and Transocean also are using remotely operated vehicles in an attempt to activate a seabed blowout preventer on the well. In addition, they are designing and building an underwater dome to contain the oil, which then would be moved by pipe to the surface.

The rig is resting on the ocean floor about 1,300 ft from the wellhead. Response officials estimate a total of 1,000 b/d of oil is being released.

“The safety of the people working offshore is our top priority and the improved weather has created better conditions for our response,” said BP Group Chief Executive Tony Hayward. “This, combined with the light, thin oil we are dealing with has further increased our confidence that we can tackle this spill offshore.”

National Oceanic and Atmospheric Administration experts have described the spilled oil as “very thin” and consisting of “97% sheen.”

Congressional inquiry requested
Three members of the US Senate requested a joint hearing of the Senate Commerce and Energy committees on offshore oil and gas safety oversight. Sens. Bill Nelson (D-Fla.), Frank R. Lautenberg (D-NJ), and Robert Menendez (D-NJ) made their request in an Apr. 26 letter.

“The explosion, ensuring fire, and continuing spill raise serious concerns about the industry’s claims that their operations and technology are safe enough to put rigs in areas that are environmentally sensitive or are critical to tourism or fishing industries,” the senators said in the letter.

They noted that the Deepwater Horizon incident was “certainly not an isolated incident.” The US Minerals Management service reports 509 fires caused at least 2 fatalities and 12 serious injuries on rigs in the gulf since 2006.

The US Coast Guard reported the Deepwater Horizon oil spill response team had recovered 1,152 bbl of an oil-water mixture. About 50 vessels, including skimmers, tugs, and barges continued recovery operations. More than 29,280 ft of boom was assembled to contain the spill with more was available if needed.

Some 29,140 gal of dispersant had been deployed and another 119,734 gal was available.

Five staging areas are in place and ready to protect sensitive shorelines. These areas include: Biloxi, Miss.; Pensacola, Fla.; Venice, La.; Pascagoula, Miss.; and Theodore, Ala.

A field operations response office was set up in Houma, La., and more than 1,000 people are involved in the response effort both on and offshore, USCG said on Apr. 27.

Contact Paula Dittrick at [email protected].