Jun
03
2010

The riser is cut, the top hat is coming back to the oil spill

After the failure of the "top kill" plan, BP stated that it would remove the broken riser from the blowout preventer on the leaking oil well—that is, they would cut off the long bent pipe from the machine that was supposed to stop an oil leak in the first place.

BP has now done just that, but, as usual, things didn't go quite as planned. Initially, BP engineers attempted to use a diamond-bladed saw to cleanly remove the riser, but the blade became stuck in the 21-inch steel pipe. Unable to free the blade and continue the operation, BP used a giant pair of shears to scissor off the riser. The shears worked, but the cut is not as clean as it would have been from the saw.

So what happens now? Well, the good news is that BP can move onto the next step of their containment plan. The bad new is that it doesn't seem like they're going to be using the original containment cap that was meant for this operation. (I take it this is because the riser was sheared instead of sawed?) Instead, they'll be using the "top hat." Remember the top hat? That was the plan after the huge containment dome plan failed, but apparently the top hat was sort of shoved aside while the tube-insertion plan was tried out. But now they're using it again.

I wonder how effective the top hat will be? When it was going to be deployed before, it was acknowledged that it would only capture a fraction of the oil from the leak it was placed over—just one of several leaks on the riser. Now that the riser has been cut, all the leaks have been consolidated... Anyway, BP isn't making any predictions about the effectiveness of the top hat here.

The other bad news is that the rate at which oil is leaking has probably increased now that the riser has been removed—perhaps by as much as 20%. The government's estimate prior to the removal of the riser was that perhaps 800,000 gallons of oil were leaking each day. That number could increase to almost a million gallons a day until the top hat is placed over the leak. (Considering that independent estimates have placed amount of oil leaking at over a million gallons a day even before the riser was cut, the flow rate could be much more than that, even.)

Hmm. Stay tuned.

Your Comments, Thoughts, Questions, Ideas

James R Richey's picture
James R Richey says:

We have vessels that been used for underwater exploration with hydrolectric arms.We should be using our salvage divers and the deep sea eguipment we have avaiable.

posted on Thu, 06/03/2010 - 2:14pm
JGordon's picture
JGordon says:

I'm not sure what you mean by "hydroelectric arms," but the oil spill response efforts have relied heavily on remotely operated vehicles (that have arms).

I think divers are out of the question, however. The leak is just too deep for divers. I believe the world record for a human diver is about 2000 feet, and that was in an atmospheric diving suit (and ADS is a big, hard-shelled, robotic-looking outfit). The leak is under 5000 feet of water—far deeper than the limits of our best diving equipment.

posted on Thu, 06/03/2010 - 3:02pm
Liza's picture
Liza says:

On the CNN homepage right now, there's very cool live footage of the capping operation. Fascinating.

posted on Thu, 06/03/2010 - 2:18pm

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