efforts to suppress the flow of oil

8/8/2019 Efforts to Suppress the Flow of Oil

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Efforts to Suppress the Flow of OilSince a fire engulfed the Deepwater horizon rig in the Gulf of Mexicoon April 20, engineers have attempted a number of techniques toslow or stop the torrent of oil leaking from the wellhead 5,000 feetbelow the surface.

Sep. 21The Bottom KillThe federal government has finally declared the Macondo well deadafter nearly five months of failed attempts and semi-successes byBP engineers to permanently plug the leaking well in the Gulf ofMexico.


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Aug. 14Making progress on the relief well

BP engineers continue developing a more specific plan on how tocomplete the bottom kill with minimal risk. When engineers pumped


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cement into the Macondo well's metal casing pipe during the statickill last month, it is possible that cement also entered the annulus,the space between the pipe and the bore hole.

Aug. 3The Static KillEngineers successfully pump mud through a valve on the blowoutpreventer and into the existing wells metal casing pipe in aprocedure similar to the failed top kill. They are able to pump mudslower and at lower pressure because a new cap atop the well hasstemmed the flow of oil. Mud forces the oil and gas back down intothe reservoir. Cement is also pumped in to seal the well.


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July 15Testing to See if the Well Is IntactA new capping assembly stops the flow of oil for the first time.Engineers begin monitoring pressure in the well to determine itsintegrity.


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hurricane.

July 10A Better CapBP replaces the cap put in place on June 3 with a tighter one thatcould potentially stop the flow of oil from the well. The new cap hassome of the same types of components as the blowout preventer.


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June 16Capturing More Oil

A second containment system begins siphoning oil and gas from theleaking well. BP estimates the system will carry 5,000 to 10,000barrels a day to the surface, supplementing the roughly 15,000barrels collected daily by a containment cap on top of the blowoutpreventer.Using equipment originally put in place to inject heavy drilling mudduring the failed top kill procedure last month, the new systemextracts oil and gas directly from the blowout preventer, passes itthrough a manifold on the seafloor and pipes it up to the Q4000surface vessel.

The Q4000 has no storage capacity and burns the oil and gas.


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June 3 Beginning to Capture Some Oil

A cap is placed over the top of the blowout preventer to funnel oiland gas to a surface ship. Methanol is pumped into the cap toprevent the formation of icy hydrates that could block the mile-longpipe rising from the cap. Oil continues to billow from under the lipand through four open vents on top of the device. Engineers areunable to close all the vents as originally planned.


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May 31 Another Attempt to Cap the WellEngineers position submarine robots to shear the collapsed riserpipe so that a domeline cap could be placed over the blowout

preventer to funnel some of the leaking oil to a tanker on thesurface.

The new riser pipe has a 6.625-inch internal pipe to capture leaking


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oil and gas. Methanol and warm seawater is pumped down the riserto insulate the smaller pipe and prevent the formation of icecrystals, which caused the earlier containment dome to fail.May 26The Top Kill and Junk ShotIn a procedure called the top kill, engineers pump heavy drilling

mud into the well with hopes that the weight of the fluid overcomesthe pressure of the rising oil. In another technique called the junkshot, objects including golf balls and pieces of rubber are injectedinto the blowout preventer. Both techniques fail to plug the leak.

May 16ATTACHING A TUBEAfter two false starts, BP engineers successfully insert a mile-long

tube into the broken riser pipe to divert some of the oil to a drill shipon the surface. Over nine days, the tube siphons off about 22,000barrels of oil, which is just a fraction of the total spill.May 7LOWERING A CONTAINMENT DOMEWorkers lower a four-story steel box over the larger leak. But whencrews discover that the domes opening is becoming clogged withan icy mix of gas and water, it is set aside on the seabed.


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May 2DRILLING RELIEF WELLSBP begins drilling the first of two relief wells that may later be usedto inject mud and cement into the existing well.


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April 30CHEMICAL DISPERSANTSCrews inject chemical dispersant into the oil as it flows from themain leak underwater. The dispersant, conventionally used on the

water surface, is intended to break the oil into small droplets,reducing its buoyancy. The full impact of chemical dispersants onthe underwater ecology is unknown. The E.P.A. later orders BP tochange to a less toxic chemical than originally used.


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April 25REPAIRING THE BLOWOUT PREVENTEROfficials use remotely operated submersibles to try to activate theblowout preventer, a stack of valves at the wellhead meant to sealthe well in the event of a sudden pressure increase. A crucial valvehad never fully deployed, and efforts to activate the device after theexplosion are unsuccessful.


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efforts to suppress the flow of oil

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