I've been following this one pretty closely--and I suspect that one of the issues here may be pressure. Not just pressure from being a mile below the surface of the ocean, but the actual wellhead pressure of the oil coming up.

BP said the accident was caused by a 'pressure surge' and I've been trying to get my brain around what could cause such a pressure surge. There are a couple of things that I realize:
1) Wellhead pressure is not a static head pressure, i.e., pressure in the oil bearing formation is dependent upon the flotation (yes, flotation) of cap stone above it. Pressure changes within the formation can cause faulting of the stone above it, and with faults come shifting: partial collapse of this cap stone can dynamically raise the pressure of the formation perhaps an order of magnitude higher. Instead of 10,000 psi, you might get momentary spikes to 100,000 psi or more. No blow out protector on the planet could protect against that.

2) The pressence of methane clathrates (methane hydrate crystals) near the wellhead in sediments just beneath the ocean floor. Oil is coming up from a deep geologic formation perhaps 10,000 feet or more below bottom of the ocean and so it is hot (mayhbe near the boil point of water.) Hot oil heats the well casing, which begins to heat the rock and sediments around the pipe casing. This in turn causes strong thermal decomposition of the methane hydrates nearby. If enough methane hydrates decompose explosively, it could literally lift the concrete casing around the wellhead shearing pipes and control cables: thus the BOP failed to operate. Furthermore, the huge blow of gas which when it reached the surface would have interfered with the rigs ability to float: a partial collapse of the rig could have pinched the well casing which could have easily caused uncontrollable pressure oscillations in the pipe stand.

3) Clumps of methane hydrates already in the pipe from the initial drill process could have been forcefully expelled up the pipe column until the reduction in pressure and increased temperatures from the oil below caused them to explosively decompose within the pipe: boom. Once the blow out happened on the surface with the subsequent ignition of the original methane plume, pretty much everything else falls into place.

It's just an educated guess, but I suspect that something along these lines has occured.

The really scary thing to me--and nobody anywhere on the net has talked about it is: what is the condition of the concrete seal at the bottom of the ocean around the wellhead? If that thing is damaged and oil can leak around the well casing, then you can get an 'oil volcano' at the bottom of the ocean that no force on the planet can stop. Also freely flowing oil tends to carry a lot of sand with it, which over time can literally saw its way through a steel casing. Even if the casing isn't leaking now, how long before it does become comprimised? An oil volcano will stop leaking oil when the formation is depleted. Can we say: billion barrel spill? Ten years' length? That's scary!

-- Edited by GoogleNaut on Wednesday 12th of May 2010 04:05:56 PM

Looks like the oil volcano is still not capped.

I would say they need now to cable a demolition charge (cable tipped explosive) and feed it down well case. Use submersibles to guide cable down pipe use enough explosive to collapse sea bed in immediate area only. All other surrounding well rigs should be shut down all personal removed well pipes capped in preparation for blast. 

I stand corrected. BP's own live video feed as of 4:25 am PST shows the yawning pit of a totally uncontrolled gusher.

Damn!

http://www.bp.com/liveassets/bp_internet/globalbp/globalbp_uk_english/homepage/STAGING/local_assets/bp_homepage/html/rov_stream.html

I wish I could have done a frame grab.

Ty

Use closed circuit nitrogen lines--one set of insulated lines to bring down liquid nitrogen, the other set are larger diameter vent lines. Use a relatively small pressure drop between the two systems to control rate of liquid nitrogen consumption. Bring the vent lines all the way to the surface and vent the nitrogen there. Do not vent underwater.

Nitrogen lines must withstand 2300 psi hydrostatic pressure at depth, and allow for a 400 psi pressure difference between liquid and vent systems. Pumps liquid nitrogen at high rate down LN2 Riser and use one or more larger diameter Vent Risers to control boiloff at depth. If enough cooling is created, it should be able to create a plug of tar in the line.


However, I've found out some other very interesting data regarding this particular well.

The formation is at a depth of 13,000 feet below the ocean bottom, which is itself just under 5000 feet from the surface. This oil is an unusual mix of oil and natural gas--the petroleum industry uses a ratio called GOR (Gas/oil ratio) which for this well is 3000 (by volume.) By weight this works out to be about a 40%/60% by weight gas and oil mixture. The formation temperture is 180 degrees Fehrinheit, which is unusually low. The formation pressure is just about 12,000 psi. Any cap that is sealed in place must withstand this hydrostatic pressure once equilibrium is reestablished.

The gas and oil mixture is probably a supercritical fluid as methane is a terrific solvent for oil at 12,000 psi. The average specific density of this fluid in the drill pipe is on order of 0.62 g/ml.

Also, the formation may be water driven, which means that water is displacing the formations oil/gas mix from below--which means we've got a long wait before the formation depressurizes.

The expansion of the oil/gas mixture in the 13,000 foot rise up the drill stem is probably adiabatic, which means the mixture cools at it rises. No telling what the tempurature is when it exist the drill pipe on the sea floor, but BP reports that the oil is rising with a warm water plume that originates at depth: this indicates to me that the oil is still quite warm when it exits the drill stem.

I am learning a lot about this, and it is extremely interesting: we've got a hell of a problem on our hands...

http://adropofrain.net/2010/05/analysis-of-oilgas-behavior-pre-and-post-deepwater-horizon-blowout-bop/

This guy 'roger_rethinker' at theoildrum.com seems to know a lot about the oil indrusty--I am trying to get in touch with him.