[QUOTE=A Cooke;35047]Alvis, that was a very useful link. So they were preparing to put another BOP on top and stopped drilling at one of the relief wells to progress prep of the BOP. I also note that the depth of bore hole is quoted at 18,000 feet, which is about 3 1/2 miles . Now all is on for an LMRP cap or hat.
I am sure that firing another BOP would create a force that would threaten the integrity of the bore. With 3 1/2 miles of fast moving oil column to try and stop in a matter of seconds, I would not be surprised if it knocked the whole assembly off the ocean floor. As Newton said, every force must have an equal and opposite reaction. This length is greater and, given the greater diameters quoted of 36" down to 9", the impulse to overcome movement of the column will have to be several times greater than 16,800,000 kgm/s I estimated based on 9" throughout and only 2 miles long. Stopping that freight train quickly was never going to be an option. The force (and pressure) needed would be huge.[/QUOTE]
OK, I don’t want to be critical, but I’ve seen this flawed theory on the oil drum and want to debunk it now. You are confusing what the mass is (force = mass * acceleration). The mass is not the mass in the column, it is the mass leaving the column. In other words, to find the force needed to stop the flow, you take the mass being ejected times its velocity and divide by the time you will take to stop it. This force is negligible compared to the reservoir pressure.