Comments on: What Am I Missing?

By: Bryan

Bryan — Tue, 11 May 2010 02:23:55 +0000

You are only talking about the gases and the hydrates, there is crude oil in the mix and that will be the plug. It becomes solid at temperature in Alaska, which are a good deal higher than liquid nitrogen. The water temperature is 50° and the pipe will ice coat when it gets down to 20°, even in sea water, as Alaskan fishermen can tell you.

I’m not saying it is certain, I’m saying it is worth a try because it is relatively cheap. If it works, it has the advantage of stopping the leak, not simply collecting it.

By: Badtux

Badtux — Mon, 10 May 2010 23:11:19 +0000

Uhm, except the pressure is being provided from deeper within the Earth, due to the pressure of the upper layers upon the oil-bearing layers, and the pipe does not have a constant volume because basically you are talking about the entire oil reservoir having a constant volume and you’re not cooling the entire reservoir, you’re cooling just the small extrusion of it that goes to the surface. So yes, in *general* cooling a gas will reduce its pressure but that isn’t going to work here.

And cooling a water pipeline at the surface is a completely different process altogether. The pressures are much lower to begin with (the average municipal water system provides about 80psi of pressure), as vs. the tens of thousands of PSI of pressure involved in this oil well, and you can typically get an insulated jacket around the pipe, and you’re in open air rather than two miles under the sea.

In short, you have the same issue as with the notion of simply burning off the oil — the water is just too efficient at carrying off heat (or bringing it, if you’re trying to cool things down). Remember that the boiling point of propane at sea level atmospheric pressure is -44F and the freezing point of propane at sea level is -305F. If you freeze just the hydrates, and not the propane and methane gases too, all that happens is that the pipe starts spitting out chunks of hydrates. If the pipe wasn’t under pressure that could clog the pipe like it did with the pipe coming out of the top of the coffer, but the pipe *is* under pressure…

In short: Not realistic, given the mix of gunk coming out of the well.

So what *is* realistic? Well, a heated coffer, probably. A *heavy* heated coffer. That’s the best solution I can come up with, anyhow. Why BP thought an unheated coffer would be good enough, I don’t know. Wait, BP. Thought. Err, nevermind :(.

-Badtux the Science Penguin

By: Bryan

Bryan — Mon, 10 May 2010 21:40:59 +0000

I saw that earlier, Jim. With the sucker 158 miles southwest of me I already think in terms of the Gulf, but it should help “inlanders”.

Actually I didn’t, Badtux, but given that temperature is proportional to pressure at the constant volume inside the pipe, it isn’t a problem, i.e. the pressure will go down with the temperature.

The idea is too simple for someone else not to have done it somewhere, so I checked and sure enough, it is a common method for temporarily plugging water mains when there is no shut off valve. It won’t be instantaneous, but it will work with the modifications for working at that depth.

Oh, yes, Elayne, they definitely don’t want to do anything that would prevent them from accessing all of that light, sweet [low sulfur] crud [no, that isn’t a misspelling].

By: Elayne Riggs

Elayne Riggs — Mon, 10 May 2010 20:34:47 +0000

What you may also be missing, as my husband pointed out, is that stopping the leak isn't really BP's priority - their priority is recovering as much oil as they can. So they're not interested in something that will stop the flow so much as something that will divert it so they can still get it. .-= last blog ..Silly Site o' the Day =-.

By: Badtux

Badtux — Mon, 10 May 2010 16:22:21 +0000

You’re missing the pressure thingy — the hydrates within the pipe are under pressure, and thus you would need extremely low temperatures in order to freeze them within the pipe, probably lower temperatures than are possible to attain so far down in the ocean due to the fact that water is an excellent conductor of heat. It’s easier to heat the inside of a cofferdam (which you can insulate against the outside ocean temperatures) than it is to cool the outside of a pipeline (which you *can’t* insulate against the outside ocean temperatures).

– Badtux the Science Penguin

By: Jim Bales

Jim Bales — Mon, 10 May 2010 15:30:17 +0000

Bryan, A three-cushion shoot here: I started with Jay Ackroyd at Eschaton, who pointed me to James Fallows at The Atlantic, who gives examples from Paul Rademacher's utility that allows you to display the outline of the spill over a map centered on any city you enter. Check out the utility -- it does a great (as in sobering) job of driving home the scale of the spill. Best, Jim