Question on fixing the Gulf of Mexico Oil Spill

[Bodhi]

Referring to the first attempt of British Petroleum's "top hat operation"...why do the deep-water methane hydrates crystallize inside the containment dome? What are all the factors of why this crystallization occurs (turning into solid component)?

peace,
D.

[DJSapp]

Referring to the first attempt of British Petroleum's "top hat operation"...why do the deep-water methane hydrates crystallize inside the containment dome? What are all the factors of why this crystallization occurs (turning into solid component)?

peace,
D.

My understanding in short: pressure @ 5000' and low temps. Placement of the top hat concentrated them to the point that surrounding salt water could not sufficiently warm/disperse the hydrates to keep them from crystallizing.

[Bodhi]

My understanding in short: pressure @ 5000' and low temps. Placement of the top hat concentrated them to the point that surrounding salt water could not sufficiently warm/disperse the hydrates to keep them from crystallizing.

Is the pressure from the methane gas that is coming out of the leak part of the factor as to why the methane hydrates are crystallizing?

peace,
D.

[runethechamp]

I thought crystallization comes from a sudden drop in pressure? You can but a beer or a can of coke in the freezer and the liquid is all fine in there, but the second you open it up, you get ice. I think the pressure drop causes more energy in the molecules, but that energy needs to come from somewhere. And since the temperature down there is probably 39.2, the way to crystals/ice is very short when a lot of heat is "drawn out" from the methane/surroundings.

[Mofro261]

Is the pressure from the methane gas that is coming out of the leak part of the factor as to why the methane hydrates are crystallizing?

peace,
D.

I don't think so, more the low water temperature and high pressure at 5000ft below sea level causes rapid ice formation in the presence of methane- the methane itself is trapped in a shell of ice while remaining a gas inside the frozen hydrate shell. This is occuring whether the collection dome is in place or not- but is a problem since the methane trapped ice is more boyant than water and as a solid it collects within the dome and want to displace it. As the temperature increases or the pressure is decreased, the ice melts and releases the methane gas.

[DJSapp]

I thought crystallization comes from a sudden drop in pressure? You can but a beer or a can of coke in the freezer and the liquid is all fine in there, but the second you open it up, you get ice. I think the pressure drop causes more energy in the molecules, but that energy needs to come from somewhere. And since the temperature down there is probably 39.2, the way to crystals/ice is very short when a lot of heat is "drawn out" from the methane/surroundings.

Mostly right. Increased pressure increases the freezing point, thus when you open your beer (or drill an uncontrolled well), the pressure is released therefore dropping the freezing point. When the superchilled fluid is disturbed (i.e. poured, shot out of a broken pipe) then the phase change can occur. During this time, the temperature in the molecules increases due to energy required to change phases. Counter-intutive that something can get warmer and freeze, but pressure releases are weird events.

Where it gets more complicated is with the immediate mixing with sea water (or contact with a beer glass), the crystals melt. The tophat slowed the mixing with seawater, thus keeping the crystals from melting.