Freeze the Flow

Short answer, no due to the high flow rate and discharge pressure.

At an absolute best case scenario, liquid nitrogen would still only work temporarily. I cannot think of a better near infinite heatsink than being at the bottom of the Gulf of Mexico.

"canisters, containers or whatever of liquid nitrogen"

It's the whatever's that get you. And how much N2 would you need to freeze a "large chunk of ice" that is 5,000 feet high, because unless you freeze a block of ice that extends about 1,000 feet into the air above sea level since oil floats, ice floats and methane sure as hell floats, what will stop the flow? Everything just keeps heading up.

You have no concept of the scope of this problem!

GA Lyn, Ice floats

Only thing to add is Rorschach has covered the difficulties of freezing the flow underground, at the pressure depth involved, in the Oil Spill thread.

This link may help you understand that.

The gas would expand as it heated (it won't be hot though) and induce a large flow of water (and gas) towards the surface. It may make matters worse. If it was done slowly (OK I like the idea of exploding things too) then a frozen plug may be able to form, or why couldn't the hydrates that blocked the funnel be induced to form and slow the leakage.

The oil would have to be cooled to something like -100°F to freeze it (wild guess). The hot oil at high pressure and flow will furnish such a large heat flux that it will most likely overcome the rate at which even cryogenic nitrogen can carry the heat away. This is only a qualitative estimate, but I suspect real numbers would bear it out.

Cannisters (thin ones)or will not reach the bottom or (thick ones) cannot unload.

I don't think your solution would create ice. At 5000 feet, the water pressure is ~2200 psi (15,170 kPa). The nitrogen would stay liquid. Without phase conversion, no heat will be removed from the surrounding water, and no ice would form.

Being less dense than water, the liquid nitrogen would rise, vaporizing (and possibly creating small ice pockets) on the way up. According to the most likely theory, this action (with methane from the well) is exactly what caused the initial explosion.

See this link.

http://www.youtube.com/watch?v=GHmhxpQEGPo

Only relief wells worked at similar situations in the past.

That's a great video

But I disagree with your conclusion, in the same way I disagree with going through a ritual of failed methods, before listening to why things work, so how to make 'unexpected' things workable.

E.g. a "junk shot" could work - but if you knew what made it work - and did the sums on this depth - you would know 'the usual way' won't.

But - if you did it "on the underlying principals of why it can work" - it will work.

On the bright side it looks like we have 9 months for BP to start seeking understanding from people who know how things work.

Oddly - how to plug this leak is already on another thread, and how to capture the spill is on yet another. But, as said, ritual must be exhausted before listening can begin.

Thanks for your reply and thoughts.

Another point is Management's decisions which is something you can not control by any mechanical / technical improvements and safeguards, no matter how "safe" you make it.

Of course, I can only report of what I read in this case. Apparently they were warnings of technical nature that management ignored and pushed ahead anyway as it wanted to have the well brought in asap as "it took to long already".

Since we hear nothing from the workers or reports of what let to this, it smacks of suppression of information.

Regardless of what the circumstances were in the present case, the human factor (management decisions) can never been taken out. For that reason it is impossible to say "it is a safe installation". (Or a safe nuclear plant, or safe airplane, or whatever.)

There is an English Company, Midland Cryrogentics, that has done work for BP in the past. They do line freezing with liquid nitrogen. They have various pipe jackets to encircle the broken pipe end and to contain a constant flow of liquid nitrogen into the pipe jackets. Hopefully, over time this freezing will slowly freeze the layer upon layer of oil in contact with the frozen pipe, reducing the inside diameter and ultimately sealing the oil with a build-up frozen plug. The plug could be maintained until the relief well is successful. No one has told me why this would not work. Granted, it will take time for the frozen oil to acculumate and close off the flow. It is already very cold at that depth. You would not need to chill the pipe and oil a great deal in order to accumulate laminar frozen (crystqalized)oil deposits of the interior of the pipe.

Comments solcited.

Schodowski@att.net

This sounds plausible. The OP description of exploding tanks and thus producing an impulse of cold and expecting it to hold back this pressure was not at all realistic. This gradual, well controlled approach could not just work, it could also give valuable information. By also adding a thermal probe into the downstream flow of oil along with the thermal probes for the feed and return of nitrogen a variety of extrapolations and predictions could be done. This will produce the least amount of a mechanical shock to the already damaged structure for the restriction will be gradual.

But what about the gorilla in the room, I wonder. What will be the complications of trying to pump a cryogenic fluid down to this depth and then getting the heated fluid back up to surface to remove the added heat? This though seems like an engineering hurdle that can be surmounted instead of hope that something can be done that won't make it worse. Also if this is actually a coaxial pipe with concrete between pipes (I'm not sure where I heard that, Rorschach maybe?), what effect will freezing concrete have on the pipe's integrity?

Other than my mentioned concerns, I like this idea!

I've used freeze plugs in the past, and they work very well in many situations. Controlled flow through a jacket is much more plausible than simply uncontrolled release of the N2 into the water in the vicinity of the wellhead. I can see some difficulties, but they're probably not insurmountable.

• The freeze plug system would require at least a mile of very well insulated tubing to get the nitrogen to the leak site and keep it from absorbing too much heat from the surrounding water.
• It would also be a good idea to add several thousand feet of return line, which would not need to be insulated. If the N2 were simply vented at depth, back pressure from the water would greatly reduce the flow rate, and therefore the heat transfer. It would not need to go all of the way back to the surface unless you wanted to analyze the return gas. The return line should be at least twice as large as the supply line to ensure an adequate flow rate of the gaseous nitrogen after phase change.
• The pipe jacket would have to be extremely well insulated. Water has a higher specific heat capacity than oil, and without good insulation, the heat absorbed by the N2 would come from the surrounding water instead of the oil.
• Lastly, they will need truly massive amounts of liquid nitrogen to keep the plug in place until permanent repairs are made. That will likely mean a cryogenic liquefaction plant on the surface support vessel. Skid-mounted package plants are available. Depending on the design of the support vessel, you may need a dedicated generator to supply the cryo plant. Those compressors take a LOT of power.

As I said, difficult but not impossible. Lots of weak points, but good contingency planning could make your suggestion work.

I've explained this previously - but as things get lost in the CR4 jumble;

Phase transition

Bottom pressure say 2200 psi ~= 150 atm.

Working system pressure? say +500 psi ~= 180 atm

Critical point (thermodynamics) - Wikipedia, the free encyclopedia

So at ~ 5 times it's critical pressure, what temperature is required for it to change state?

If it will not change state then no energy is absorbed.

Note; "Above the critical temperature a liquid cannot be formed by an increase in pressure, but with enough pressure a solid may be formed."

So pumping the liquid down presents the problem of it turning solid and/or evaporates turning solid.

Given all the above; how much heat can be extracted from the energy of the 'oil'?

The physics you describe are correct, but your assumptions are not. The nitrogen need not be at the same pressure as the seawater if it is contained in pipe. The liquid N2 is pumped down to the jacket in a heavy-walled pipe which can handle the pressure at the sea floor (say 200 atm). It circulates through the jacket, also designed for 200 atm.

The crucial design point here is that the N2 is NOT released at depth, but is piped back to the surface to vent. The return pipe is also good for 200 atm. With the vent above the surface, backpressure from the seawater is nonexistent. The backpressure from the gaseous N2 column in the return pipe is ~0.2 atm, well below the phase transformation point.

By keeping the N2 at significantly lower pressure than the water, phase transformation can and will take place, removing significant amounts of heat from the oil.

My apologies; I didn't realize the post 12 plan was to install a pressure proof jacket and fully insulated plumbing loop.

Naughty of me to assume.

Yes you seem to have ameliorated the bottom pressure aspect.

Why does keep jumping to mind?

Never mind; I'm sure your mile long "twice as large" return pipe will not exert significant back pressure; so change of state will be in the collar, not up the return pipe somewhere.

So how do you plan to install this?

I would install it using a manned submersible, NR-1 or something similar. However, the latest information I've seen indicates that the well casing is breached below the seabed. If that's the case, nothing you do above the seabed will stop the flow. Best options at this point are domes to catch what they can while they work on a sidebore to penetrate the casing below the break.