Okay, this may sound like i'm being stupid, but hey aren't we brainstorming... I am thinking along the lines of flubber... silly putty... stretch arm strong... or that floam stuff...
I am pretty sure silly putty does not freeze well, but if one of the other nearly liquid solids is still pliable at freezing temps... They have already cut the pipe, which means that those robot things should be capeable of working with some sort of caulking gun system with what ever nearly solid is the choice.
We have a slightly smaller, really long A$$ pipe, that has some sort of mechanism at the end of it like those butterfly nuts. We guide the long small pipe into the larger leaking pipe and then jerk it out engaging the mechanism to expand and creating a partial seal which would then be caulked with the nearly liquid solid.
I realize that there are a lot of innuendos here, as well as issues, but please hear me out...
Issue one would be that the "pressure and force" of the oil spewing out of the existing pipe might prevent the insertion of said smaller pipe. A feasable soultion would be to calculate that, fill the smaller pipe with oil (or a liquid with near the same density and other characteristics), position it, and when almost ready, turn massive pumps on to trump the larger pipe. I realize that this would in essence be pumping oil out and creating a worse situation, but if in the end the leak is completely sealed, then we are ahead of the game.
I guess the concept would work if the pipe was larger, but I kind of feel like that's already been tried and didn't work with the whole concrete funnel thing. You could have your little tree of BOP's and flanges and all that stuff ready on the smaller (or larger) pipe, and in essence turn the thing into a functioning rig again. Which would be issue two... these materials are not exactly readily available. (My solution to that one is... this is the freaking free world and then some that are experiencing the impacts, we should be able to get anything in less then a weeks time if the money is right)
If the pipe we were inserting was already filled with a liquid, would this not prevent the ice crystals from forming somehow?
And did I mention that Bruce Willis, Billy Bob Thorton, and Ben Affleck and the rest of the cast from Armageddon are the ones that have to preform said above operation?
The thing about all of the above, is that we could easily experiment with the senarios prior to implementing to see if they worked. Scaled models and the likes in pressure chambers with really rocking HVAC units.
Oh and about that cleaning up afterwards... we need to figure out how to infuse the booms with the dispursing chem and attach spill absorbant pads (the kind that doesn't soak up water) on the "outsides" of them. Pool all of the resources of every construction site on earth together since half of them use soil to soak up their leaks anyway, and circle the "spill".
Okay, since i'm just a lowly tech, all you PE's need to figure out how to implement the above
although I'm sure you guys will come up with WHY it won't work, which will make me feel better knowing that at least I tried this one out and I'll move on to the next idea.