Commercial fisherman Kevin Merrick hauls in his catch on a shrimp boat in Buras, La., on Sun., May 16.John Moore
After weeks of setbacks, engineers have had their first success trying to stem the flow of oil into the Gulf of Mexico, using robotic submarines to insert the end of a 1.5-km-long tube into the main leak on the ocean floor. The tube is designed to collect oil gushing from the well and guide it to a ship on the surface.
Workers, however, are watching nervously Monday to see if the experiment holds, and the next few days will determine how effective it will be in trying to slow one of the worst oil leaks in U.S. history.
The first encouraging signals came Sunday when natural gas, then oil, began flowing up the tube, which took the weekend to manoeuvre into place.
Officials with well owner BP cautioned that they don't know how much oil will make it up the tube, and how much will continue gushing out to sea. The tube has a 10-centimetre diameter, which is about one-fifth the size of the ruptured pipe into which it has been inserted, and a series of rubber stoppers to plug the gap.
"We have had some success in that we have managed to deploy this tool and we think we've got it working," BP spokesman David Nicholas said from the gulf. "But we're in very early days yet of trying to say: 'Is this is going to continue working. And exactly how much of the oil and gas is it going to take?' This is something that people haven't done before."
Engineers used eight robotic submersibles, known as remotely operated vehicles, or ROVs, to position the tube into place this weekend. The first natural gas began flowing to the ship on the surface early Sunday morning - an indicator that oil would soon follow. However, the company faced a setback before the oil could begin pumping when an ROV knocked the tube out of position. Sunday afternoon the apparatus was put back into place.
Mr. Nicholas described the process as similar to threading a needle.
"An ROV accidentally dislodged the tool, and so we had to take it out and put it back in again. And so we're now in the process of building the flow back up," Mr. Nicholas said.
The ruptured well has been gushing about 5,000 barrels of oil into the gulf each day since April 20. It is among the worst oil spills the United States has experienced and scientists estimate it will equal or surpass the 1989 Exxon Valdez disaster off the coast of Alaska by the time it is contained.
Researchers tracking the size of the spill said that huge underwater plumes of oil have been found in the gulf, some as big as 16 kilometres long and five kilometres wide.
Though the exact cause of the disaster is still unknown, it began when an explosion on an oil rig caused the riser - the large pipe connecting the rig to the ocean floor - to be severed. About 85 per cent of the oil is gushing from the mouth of the severed pipe, while the other 15 per cent is seeping from a kink in the riser at the well, which happened when the pipe collapsed.
For now, BP is putting most of its efforts toward dealing with oil gushing from the riser, and estimates that if the collector tube works, about 70 to 80 per cent of the oil seeping into the sea can be directed up to the ship. At the surface, the oil will be stored aboard a tanker, while natural gas will be flared off.
The company plans to deal with the well itself in the next week to 10 days, hoping to force a slurry of mud down a series of pipes leading into the well in order to slow the oil, and eventually cement it shut.
Failed efforts to stop the spill have humbled BP, and shown just how difficult it is to handle a rupture involving an ultra-deep-sea well. Last week, BP attempted to lower a structure down over the well that would stem the flow of crude, but ran into problems when it became clogged with crystals. The crystallization was caused by a reaction between water and natural gas at such extreme depths, BP said.
Ed Overton, an oil spill expert at Louisiana State University, said this spill has taken the oil industry into uncharted territory, as it explores ever deeper reserves under the sea.
"This is not easy by any stretch of the imagination and it's being done where you can't see very easy what's being done down there. But if it works, that would be wonderful. We sure need a break, I will tell you that," Mr. Overton said.
The longer-term plan for BP to plug the well at its base also involves drilling a relief well that will take pressure off the rupture. However, because the well is so far below the surface of the gulf, drilling a relief well has been slow and tedious.
"We're still months away - two or three months probably - from really getting the relief well in. And that's a lot of oil entering the gulf," Mr. Overton said. "The problem is some of these things you need to do in a hurry, you can't just sit around and plan and plan and take six months to do it. So it may not work the first couple of times."
Grant Robertson