posted Jun 17, 2010 4:05 PM by Li Yu [ updated Jun 18, 2010 1:52 AM by Cesar Harada ]
Efforts to Suppress the Flow of Oil
Since a fire engulfed the Deepwater horizon rig
in the Gulf of Mexico on April 20, engineers have attempted a number of
techniques to slow or stop the torrent of oil leaking from the wellhead
5,000 feet below the surface.
June 16 Capturing More Oil
A second containment system has begun siphoning oil and gas from the
leaking well. BP estimates the system will carry 5,000 to 10,000 barrels
a day to the surface, supplementing the roughly 15,000 barrels
collected daily by a containment cap on top of the blowout preventer.
Using equipment originally put in place to inject heavy drilling mud
during the failed “top kill” procedure last month, the new system
extracts oil and gas directly from the blowout preventer, passes it
through a manifold on the seafloor and pipes it up to the Q4000 surface
The Q4000 has no storage capacity and will burn the oil and gas.
June 4 Beginning to Capture Some Oil
A cap placed over the upper portion of the leaking well was funneling
some oil and gas to a surface ship, though oil continued to billow from
under the lip and through four open vents on top of the device.
Methanol is being pumped into the cap to prevent the formation of icy
hydrates that could block the mile-long pipe rising from the cap.
Engineers hope to capture more oil by progressively closing the cap
May 31 Another Attempt to Cap the Well
After the failure of the top kill operation, BP began a new operation to
cap the well. The damaged pipe will be cut from the blowout preventer,
and a dome will be lowered over it to catch the spewing oil.
The new riser pipe will have a 6.625 inch
internal pipe to capture leaking oil and gas. Methanol and warm seawater
will be pumped down the riser to insulate the smaller pipe and prevent
the formation of ice crystals which caused the earlier containment dome
May 26 The Top Kill and Junk Shot
BP tried two more operations, called the “junk shot” and the “top kill,”
to stop the gushing oil. In the “top kill,” heavy drilling liquid is
pumped into the well until the weight of the liquid overcomes the
pressure of the rising oil. The “junk shot” involves injecting objects
like golf balls to clog the blowout preventer, the stack of valves at
the top of the well.
Source: BP technical briefings
May 16 ATTACHING A TUBE
After several unsuccessful attempts, BP inserted a mile-long tube into
the broken riser pipe to divert some of the oil to a drill ship on the
surface some 5,000 feet above the wellhead. The tube siphoned off about
22,000 barrels of oil over nine days, but was shut off once the “top
kill” operation began.
May 7 LOWERING A CONTAINMENT DOME
BP constructed a four-story containment dome, intended to control the
largest of the leaks. As the dome was lowered, crews discovered that
the opening was becoming clogged by an icy mix of gas and water. The
dome was set down on the seabed, 650 feet away from the leak, as
officials decided how to proceed.
May 2 DRILLING RELIEF WELLS
BP is drilling relief wells that may be used to plug its runaway well in
the Gulf of Mexico. Once one of the new wells intersects the existing
well, heavy drilling mud, followed by cement, will be used to stop the
oil from leaking.
April 30 CHEMICAL DISPERSANTS
BP officials began injecting chemical dispersants underwater, near the
source of the leaks. The dispersants, usually used on the water surface,
is intended to break up the oil before it rises. The full environmental
impact of the technique is unknown, but the E.P.A. has directed BP to
change to a less toxic chemical than it had originally chosen.
April 25 REPAIRING THE BLOWOUT PREVENTER
The quickest way to stop the leak would have been to activate the well’s
blowout preventer, a valve designed to seal off the well in an
emergency. But several efforts to activate the blowout preventer failed.
By JONATHAN CORUM, AL GRANBERG, MIKA GRONDAHL,
XAQUIN G.V., HAEYOUN PARK and GRAHAM ROBERTS