And God took it off…
[QUOTE=geodude;35145]Thanks for catching this image. This observation may be the key to resolving several of the puzzles about this disaster. The mysterious second pipe would appear to be a section of the inner casing from the well which was blown up into the BOP and lower riser by the blowout. We may never know whether it was dislodged from the cement in its entirety or was torn in the middle and the upper section thrust upwards. Given that they had displaced the dense mud in the center casing with lower density seawater I would not be surprised if the differences with the elevated pressures outside the pipe from the gas kick caused it to mechanically fail, breaking the upper section loose to be thrust upwards like a rocket into the works. Given that the pressure differential would be greatest at depth, there might be a very long section of that casing trapped in the crumpled riser.
The presence of casing, with it’s higher rated steel, inside the BOP and riser would explain why the rams could not close even though it sounds like they were triggered. It would explain why the rams could not be fully closed manually in the days after the rig sank. It would certainly explain why they had such trouble with the diamond wire cutter. It might also help explain why the top kill did not work, since the open connection through the trapped casing section allowed for pressure release from a point somewhere below the BOP straight out to the riser. There was no way you would ever get mud pushed down very far below the bottom of the broken casing or it would just turn and shoot up the inner pipe (remember the mud jets from the riser?).
It might even help explain the two-toned character of the current flow, since the composition of the fluid at the base of the trapped casing section may be different from what’s coming out the outer pipe. The bottom of the pipe may be catching more or less of the exsolved gas than the average for the flow as a whole.
Let’s hope they can catch most of the oil until the relief wells get down. Otherwise this is going to be a loooong summer.[/QUOTE]