13 May 2010

BP Chooses Caution -- Revises Order of Oil Capture Methods

Excellent Local Response to Oil Spill Limits Enviro Damage

BP has revised the order of its seafloor oil capture approaches. As of late this afternoon, BP plans to attempt to thread a 6 inch suction pipe into the gushing 21 inch pipe on the seafloor, to divert the oil and gas flow to surface ships. The 6 inch pipe will be surrounded by a stopper to prevent hydrocarbons from flowing into the sea around the suction pipe. The attempt will begin tonight and take 12 hours to complete.

If that attempt is unsuccessful, BP intends to attempt the "top hat" small enclosure to cap the leaking pipe. Hydrocarbons would be funneled to the surface from inside the small dome. That method would likely be attempted over the weekend, if it becomes necessary.

The third approach -- the "top kill" or "junk shot" would not be attempted until next week, if the prior two approaches failed. If BP engineers have any other likely ideas to try before the relief wells are finished in 6 to 10 weeks, they have not made any announcements. So they -- and the rest of us -- are hoping that at least one of these approaches will succeed.
BP officials said Thursday they would thread a small tube into a jagged pipe on the seafloor to suck oil to the surface before it can spew into the Gulf and add to a disaster apparently set in motion by a long list of equipment failures.

Engineers will have to make sure the 6-inch-wide tube is inserted deep enough into the 21-inch-wide pipe so gas and seawater don't mix, which can form crystals that could clog the tube. They'll also have to thread the tube into the pipe without hitting debris around the riser.
The smaller tube will be surrounded by a stopper to keep oil from leaking into the sea. The tube will then siphon the crude to a tanker at the surface, though BP declined to estimate how much oil the tube will be able to collect.

Company spokesman Bill Salvin said engineers hope to start moving the tube into place Thursday night, but it will take 12 hours to get the tube fully hooked up. Another option is a small containment box called a "top hat," which is already on the seafloor and also would siphon oil to a tanker on the surface.

Officials are waiting to use the box until they know if the tube works, and how well it's working, Salvin said. Engineers still might consider trying to fill the leak with golf balls and other debris -- the "junk shot," though that won't be until at least next week. And a relief well is being drilled, but that is at least two months away. _al.com
Presumably something occurring at the wellhead caused engineers to revise the order in which they chose to try to stop the ongoing gusher. Perhaps the pressures they detected at the blowout preventer were higher than expected, or the varying proportion of gas to oil changed the equation, or some specific damage to the blowout preventer complicates one method or other, or some other factor so far not disclosed to the public makes this order of battle more favourable.

One cannot help but ask, "If threading a stoppered suction pipe into the leak is the preferable approach, why wasn't it tried much sooner?"

Clearly, engineers are making up the rules for this mile-deep oil recovery effort as they go.

All of this suggests that deep sea drilling has been waiting for just this type of disaster, in order to force engineers to think through all of the things that could go wrong -- and how to respond to each one. Clearly deep sea drilling engineers need some type of intense, realistic disaster simulator of the type that airline pilots must train on.

Because humans are definitely going deeper -- much deeper -- for fuels and minerals. And they had better learn how to deal with the pressures, cold, methane ice, and other hazards and complications of working in the deep sea environment.

Updated Oil Spill News:

Deep Horizon Response Website
Miami Herald oil spill coverage
USA Today Oil Spill


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“During times of universal deceit, telling the truth becomes a revolutionary act” _George Orwell

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