BP wrestles with oil spill hitch in Gulf of Mexico
A relief well being drilled to stop the spill will not be finished for weeks
Engineers from the British oil firm BP are scrambling to find a way to contain oil leaking from a blown-out well on the bottom of the Gulf of Mexico.
A containment device lowered over the well to funnel oil to the surface had to be moved on Saturday after ice-like crystals began accumulating inside it.
Some 5,000 barrels (210,000 gallons) of oil a day has been flowing into the sea since an explosion on a rig last month.
Balls of tar have meanwhile begun washing up on an island off Alabama.
Bundles of absorbent material have been laid along the shore of Dauphin Island in an attempt to protect the resort area.
Samples of the tar will be analysed to ascertain whether they come from the massive oil spill off the coast of neighbouring Louisiana.
A massive effort to contain what threatens to become an environmental catastrophe has been under way since 20 April, when an explosion killed 11 workers and led to the eventual sinking of the Deepwater Horizon rig, 50 miles (80km) off Louisiana.
I wouldn't say it's failed yet. What I would say is what we attempted to do last night didn't work
Doug Suttles, BP
A sheen of oil began washing ashore on the Chandeleur Islands chain last week, and crews have been laying inflatable booms, spraying chemical dispersants and setting fire to the slick to try to protect local wildlife.
Although the Deepwater Horizon was operated by Transocean, it was leased by BP, which is responsible for cleaning the 3.5 million gallons that have so far leaked out of the well below, creating a slick covering about 2,000 sq miles (5,200 sq km).
The 98-tonne concrete-and-steel funnel lowered 5,000ft (1,500m) to the seabed had been BP's best hope to contain the main leak while it attempted to stop it altogether by drilling relief wells nearby.
But a build-up of gas hydrates - crystalline water-based solids resembling ice - inside the device blocked the exit at the top, and it had to be put aside until engineers could decide what to do.
HOW THE OIL FUNNEL WORKS
The funnel is a 40ft tall iron box, weighing 98 tonnes
It will be placed over the leak, 5,000ft down on the seabed
BP hopes it will collect 85% of the leaking oil and pipe it to the surface
"What we're working on now is we're gathering some data to help us with two things. One is another way to do containment, and the second is other ways to actually stop the flow," BP Chief Operating Officer Doug Suttles told the Reuters news agency on Sunday.
"On the containment side, we're working two options. One is a smaller dome - we call it the 'top hat', and the second is to try to find a way to tap into the riser, the piece of pipe the oil is flowing through, and take it directly from that pipe up to the ship on the surface."
BP's Doug Suttles explains hitch
The smaller containment dome would theoretically be less likely to get blocked by hydrates because it would contain less water. It could be ready to deploy on Tuesday or Wednesday. Tapping into the riser would be difficult, experts say.
Another solution might be to plug up the blow-out preventer at the well-head, which failed to cut the flow after the explosion on the rig last month, with a "junk shot" of rubber and another material, Mr Suttles said.
Meanwhile, a relief well is being drilled - considered a more permanent solution to the leak - but that is weeks from completion.
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