Wednesday, June 2nd, 2010 01:07 pm
the xkcd comic yesterday just confirms an question I had on Monday.

They keep trying rigid containment systems on the gulf oil spill gusher. (top hat etc, talking about explosive charges to close the hole again...)

would some science-type explain to me why a flexible containment system couldn't be dropped over the top of the gusher, and then the oil directed specifically to some other containment rig? (I mean aside from the whole it's a mile down in icy cold ocean waters and the flexible material might simply freeze and break under all the pressure...)

I'm thinking of something designed like a ginormous female condom, with weights on the wide open end to drop over the gusher, a gargantuan hose (or hoses) at the end to funnel the oil, and for the container, some of those ocean-going bags full of fresh-water that some idiot was trying to sell to southern California a few years ago.

Why can't this mess be contained & channeled, at least part of the time?

(in other related news, I just had a memory of Gary Larson's mosquito-cartoon, where one mosquito is swelled up like a balloon, and the other mosquito says, "Gladys! Pull up, you've hit an artery!" Maybe that comic is more related to this topic than I realized at first.)



Feel free to forward sciency friends here, I genuinely want to understand.
Wednesday, June 2nd, 2010 08:27 pm (UTC)
I'm not sure how a flexible system would help. They dropped a box and it filled up with slushy stuff. A flexible bag would fill up with slush just as fast as a box, wouldn't it?

p.s. - I may be an engineer but I'm certainly not a petroleum engineer, so I don't know what all the variables are. The temps and pressures are outside the zone I normally deal with and frequently stuff behaves non-linearly under pressure.
Wednesday, June 2nd, 2010 08:30 pm (UTC)
That's essentially what they are trying, in various forms. Here's a reality check for you. They are about 1 mile underwater. ~34 ft of water creates one atmosphere of pressure. So the pressure at the well head is 156 times the pressure you feel here in the Bay Area (assuming sea level). And the pressure behind the oil is enough to make it gush, so the oil is under a heck of a lot more pressure than 156 atmospheres. Ever try hold you thumb over the end of a hose?

The next problem is that there is a lot gas in with the oil, as the gas comes out it expands and hits to the cold ocean water (both cool it down). This forms ice crystals that keep clogging the pipes they are trying to use to pump the oil.

There are several spot along the original well pipe that are leaking. They managed to get a hose/pipe assembly around one of the smaller ones. It took the 3 days of slowly increasing the pumping rate before they managed to get most of the oil that small one. The problem is once the pipe clogs, you got to start over. So they would pump a little more and see if there were any sign of problems, them increase the rate (lather, rinse, repeat).

I'm also guessing that some of the caps, hoods, containment vessels they are using are being custom manufactured. So you got the whole design, production, delivery process that takes up time as well.

It's a mess. I want my electric car NOW dammit!
Edited 2010-06-02 08:30 pm (UTC)
Wednesday, June 2nd, 2010 08:44 pm (UTC)
Here's some reference pressures for you:

Household water pressure - 50-100psi = 5.5-7 atm
Household natural gas pressure - 1/4psi = .025 atm
Propane Tanks Pressure (when full) - 200psi = 14 atm

Wednesday, June 2nd, 2010 08:51 pm (UTC)
The mile-icy water thing, as you put it, really is a tremendous hurdle. The pressure at that depth is high enough that most "flexible materials" would be subject to forces that would squeeze them down to maybe 85% of the materials' "air size." Conventional rubber hoses simply won't do such a job...the shrinkage would cause them to pop off or rupture under such deep water. Also, keep in mind we're talking millions of gallons of oil...the bags probably don't hold even a small fraction of that. The right materials would also be difficult to come by to build it too...it would have to be something strong enough to withstand the pressure of the gushing oil and also resistant to salt-water corrosion. It would take months to design and build the apparatus and to properly test it, probably longer than it would take to drill another relief well.
Wednesday, June 2nd, 2010 10:27 pm (UTC)
My wonder is why this contingency wasn't planned for way ahead of time. Yes, they narrowed it down to the amount of risk but the result of this has shown itself to be very detrimental.
Wednesday, June 2nd, 2010 10:44 pm (UTC)
Wow, good answer. Very enlightening. Thank you.

Also, thank you labelleizzy for asking this question this way. It's so frustrating when all you hear are pundits and nobody knows any actual science.
Wednesday, June 2nd, 2010 11:05 pm (UTC)
As if everything else mentioned wasn't bad enough, there are also currents to contend with as well. It's not a simple matter of just dropping it down there - you have do some fighting just to get it there.

I'm thinking lately that an International Underwater Station, along the lines of the International Space Station, might be a good thing. The technical challenges of just getting down there are significant enough - getting down there and doing something (perhaps with more precision than the robots they're using) would be worthwhile.
Wednesday, June 2nd, 2010 11:53 pm (UTC)
putting people at that depth is no more useful than robots, for all the work has to be done by whatever robotics was sent down with them.

I am reminded of the throwaway explanation at the end of The Abyss where the lab is brought to the surface in a matter of seconds: "We should be dead."
Wednesday, June 2nd, 2010 11:55 pm (UTC)
Ask the same question about the residents of the Niger Delta. They've been enduring much more leaked oil for years, and the life expectancy is way down.
Thursday, June 3rd, 2010 12:16 am (UTC)
Now I kind of want to watch The Abyss all the way through.
Thursday, June 3rd, 2010 12:18 am (UTC)
Let us also not forget the trials endured by the "former submarine base" used as a lab in Deep Blue Sea.