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2010-05-08 Science & Technology

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Posted by KBK 2010-05-08 10:47|| || Front Page|| [11131 views ] Top

#1 Link doesn't work.

Posted by Canuckistan sniper 2010-05-08 12:12|| 2010-05-08 12:12|| Front Page Top

#2 Hm? Works from New Hampshire.

Posted by KBK 2010-05-08 12:18|| 2010-05-08 12:18|| Front Page Top

#3 Generally makes sense. I don't know about the explanation of the surface plug (cement just below the sea floor) - yes, cement generates heat when it cures, and yes, slushy methane occurs and could get melted. But that slushy gas (methane hydrate, or clathrate) is not deep below the seafloor, but fairly close to the sea floor, and in a zone of rock that already had several strings of casing and cement settings across it. Yes, a rapidly rising and expanding gas bubble does seem to have been the primary culprit - but where did it come from? Oil contains quite a lot of dissolved gas, and as pressure drops that gas comes out of solution and as the gas separates it will rise and expand faster than the oil. But neither oil nor gas was supposed to be inside the casing - which had been set, cemented, and supposedly tested - so should not have even been anywhere it could have been able to expand, exsolve gas, and make a bubble when the crew lightened the mud weight to set the surface plug. If the gas came from somewhere else it could have caused the explosion, but the oil should still be behind cemented pip, so somehow that cement (the cement near the bottom of the well) failed. And it should have been, and supposedly was, tested. It's all very strange to me - the tricky bits (drilling, casing, cementing) were all done, with nothing but fairly benign operations remaining (which is why the safety celebration was going on) when everything went to Hell.

Posted by Glenmore 2010-05-08 12:26|| 2010-05-08 12:26|| Front Page Top

#4 One of the better articles I've seen. Thanks, KBK.

Posted by Nimble Spemble 2010-05-08 13:38|| 2010-05-08 13:38|| Front Page Top

#5 It was a freak of nature, pure and simple. It happens.

Posted by newc 2010-05-08 17:56|| 2010-05-08 17:56|| Front Page Top

#6 Deep beneath the seafloor, methane is in a slushy, crystalline form

I very much doubt this is true. The writer is confusing clathrates which lie on the sea floor with gas under extreme pressure far below the sea floor.

Methane is in a slushy, crystalline form on the sea floor due to pressure and COLD. At the depths this drill was operating temps would be much hotter than the 4C temperature of the sea floor and far too hot for clathrates to form (I think?).

And if the gas pushed up oil as the article states then the gas must have been below the oil and hence could not have been from sea floor clathrates.

BTW, these gas bubbles under extreme pressure causing blowouts in very deep wells is a known problem. I was reading about it several weeks before this accident.

Posted by phil_b 2010-05-08 19:32|| 2010-05-08 19:32|| Front Page Top

#7 I find it less than credible that the heat of hydration of cement at that depth/temp/pressure could set it off....just SOP*

*SOP = seat of the pants observation. We use F'c = 8000 psi concrete that doesn't reach 110 (external) at surface enviro

Posted by Frank G 2010-05-08 19:56|| 2010-05-08 19:56|| Front Page Top

#8 Natural gas on oil wells of ANY depth can be a problem.

Posted by Besoeker 2010-05-08 19:58|| 2010-05-08 19:58|| Front Page Top

#9 Killed by a Party Cake?

As opposed to a Megladon Shark.

Posted by Clyde Unusonter1178 2010-05-08 23:44|| 2010-05-08 23:44|| Front Page Top

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