May
26
2010

BP will attempt to stop the oil spill today. Cross your fingers . . .

Later today, BP is going to attempt to block up the leaking oil well at the bottom of the Gulf of Mexico. They're going to pump heavy drilling mud, followed by cement, into the blowout preventer (the giant valve system that was supposed to stop the well from leaking in the first place). The heavy mud should slow down the oil after a while (it will probably get blasted out of the pipe at first), and then the cement will block up the flow. If it works, it should cap the well, and stop the leak entirely. If not, it's back to the drawing board. An earlier plan for capping the well involved injecting it with shredded junk first, but it looks like that might be off the menu, because of the risk that the junk could further damage the well equipment, and allow oil to escape even faster. So now it's just heavy mud and concrete.

Here's an animation of the process:

And here's a labeled illustration.

Hold your breath and cross your fingers...

Your Comments, Thoughts, Questions, Ideas

JGordon's picture
JGordon says:

The NY Times' article on the "top kill" well-clogging plan points out that it may be a few days before we know if the effort was successful. Also, while the method isn't new, it has never been tried in such deep water (this well was drilled under about 5000 of water), and the upward pressure of the oil at that depth may be too much for the heavy mud to counteract. We'll see, I guess.

posted on Wed, 05/26/2010 - 12:44pm
bryan kennedy's picture

Hmm, that's a bit confusing to me. Why is the upwards pressure of the oil greater at this depth? Is it because of the water column above? Does the hugh stack of water push on the sediment increasing the pressure that the oil is under?

posted on Wed, 05/26/2010 - 1:58pm
JGordon's picture
JGordon says:

I wondered about that too. I've seen that language used in a few different places, and maybe I'm just repeating something that doesn't actually have a basis in physical science. I'll look into it.

In the meantime, I found a link to watch the "top kill" operation live. It's not much to look at—I think it's just a camera mounted on the remote controlled equipment—but it's sorta interesting. Check it out here.

posted on Wed, 05/26/2010 - 2:29pm
JGordon's picture
JGordon says:

Yeah, I think you had the right idea, more or less.

I suppose "depth" is a little misleading here—the depth of the water certainly matters, and it makes working with the leaking well difficult (as we've seen), but it's the depth of the rest of the well (how much rock it goes through) that matters more. I seem to remember that the well the Deepwater Horizon was drilling is about 18,000 feet deep, with 5,000 feet of water on top of it. (Water weighs about half as much as an equal volume of rock, if we're eyeballing it.)

If you're measuring the pressure from a column of rock, you can add about one pound per square inch per foot (and, again, about half that for each foot of water). So the oil reservoir under the Deepwater Horizon drilling rig had about 21,500 pounds per square inch of pressure on it (or some large fraction of that). When a hole is opened in the reservoir (like a well), the pressure makes that oil "want" to shoot out the hole. Drillers counteract the pressure of the oil in the hole with heavy drilling mud, which pushes back on the oil, and with the equipment on the blowout preventer, which can control the pressure of the well by adjusting the size of the tube it flows through.

When there's gas in a reservoir, it is compressed by all the pressure being placed on it from above. When it starts to head up the well, though, and there's less stuff above it, the gas begins to expand, and when it expands it wants to move up even faster, and then it expands more... and so on. That's what they think happened on the Deepwater Horizon—gas came up the tube leading from the well, and exploded out on the rig. And because the blowout preventer wasn't working, the well was never shut off.

So with this leak, there's still all the pressure from the water and rock above the oil reservoir, and the equipment that's supposed to control the flow of the oil is all messed up, so everything is just rushing out.

Something like that, anyway. This blog explains the phenomenon in more detail. (And I could be rephrasing it poorly.)

posted on Wed, 05/26/2010 - 3:07pm
Steve Ackerman's picture

Here is a link that provides a satellite view of the oil slick.
http://cimss.ssec.wisc.edu/goes/blog/archives/5768

posted on Wed, 05/26/2010 - 3:18pm
JGordon's picture
JGordon says:

The "top kill" is maybe, knock-on-wood, sorta working?

It looks like drilling mud may be accumulating in the well hole, which is the first step to slowing down the oil enough that the well can be clogged with cement, although BP is cautioning that the operation "could fail at any moment," and is urging people to be patient.

posted on Thu, 05/27/2010 - 11:20am
JGordon's picture
JGordon says:

No, that failed.

BP announced on Friday (missed that one...) that despite pumping 30,000 barrels of drilling mud into the well, the oil couldn't be stopped, and so the attempt to "top kill" the well was a failure. Nuts.

Over the weekend, they've been working on yet a new plan, which sounds kind of like one of the first plans; they're putting another cap over the leak, to contain the spill, and siphon off some of the oil.

This time, they're going to be cutting off the remains of the riser pipe and the top of the blowout preventer assembly, to have a single, clean source of the leak. Then they will be lowering the "Lower Marine Riser Package (LMRP) Cap Containment System."

The LMRP is supposed to seal around the severed pipe, and it will send the oil up a riser to another drill ship. (The operation should look something like this.)

In the meantime, BP is continuing to drill a relief well to intercept the original borehole, which should allow them to clog it up. As of Friday, the relief well was at 12,090 feet (although they didn't say how deep it would have to be before it intercepted the original hole. Less than 18,000 feet, I suppose, seeing as how that was supposed to be the depth of the reservoir (I think).

posted on Mon, 05/31/2010 - 10:23am
Anonymous's picture
Anonymous says:

i think that if they really try hard enough they can do it, but i also think that the boats that run on coal and oil that they are usingis not helping at all. if anything it is making everything worse!

posted on Fri, 08/06/2010 - 9:46am

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