Engineers using submersible robots landed a 100-ton concrete-and-steel box over a blown-out oil well thousands of feet down on the Gulf of Mexico sea floor yesterday in a desperate attempt to stop the flow of crude.
The 40-by-24-foot box — essentially a giant spigot that will be attached to a tanker ship — is the best hope to cap the ruptured well that’s been spewing 200,000 gallons of crude oil a day in the worst environmental disaster in decades.
“It appears to be going exactly as we hoped,” said Bill Salvin, a spokesman for BP, which had leased the rig that exploded last month. “Still lots of challenges ahead, but this is very good progress.”
He compared the effort to “taking a four-story building and lowering it 5,000 feet and setting it on the head of a pin.”
No operation of this scale had ever been attempted.
The MC252 well, 50 miles off the Louisiana coast, has been gushing oil since an April 20 explosion on the Deepwater Horizon rig killed 11 workers and sent toxic oil toward a shoreline of marshes, shipping channels, fishing grounds and beaches.
The first sheen of oil reached the Chandeleur Islands, about 60 miles east of New Orleans, yesterday.
To stanch the flow, engineers used joysticks — like in a videogame — to guide their remote-operated submersible vehicles during the descent.
To properly place the box, known as a cofferdam, above the well, the engineers overcame pitch-black seas, shifting currents, metal-crushing undersea pressure and freezing temperatures.
At 5,000 feet, they are operating in an environment with the equivalent of 151 atmospheres or more than 2,200 pounds of pressure per square inch — enough to crumple a submarine like a beer can.
“This has never been done in 5,000 feet of water; it is a technology first,” BP chief executive Tony Hayward said. “The pressure and temperatures are very different here, so we cannot be confident that it will work.”
Engineers had feared the cofferdam could miss the leak and accidentally rupture another section of pipe, although that didn’t appear to have happened.
Once the cofferdam is properly secured, pressure will force the oil through the cofferdam’s piping into a freighter on the surface.
But, even so, only about 85 percent of the oil would be captured with the remainder still escaping in the sea.
Still, if the cofferdam works as planned, another one will be positioned over a second, smaller leak from the ruptured well that extends 18,000 feet deep.