Quoting MD11Engineer (Reply 208): Isn´t there a fail safe circuit on the BOP, which wsill activate it automatically contact is lost with the rig |
The second "fail safe" is EDS which also activates the BOP and other functions is pretty much as you described.
Quoting okie (Reply 206): The Emergency Disconnect System did not work as well which would have cut the rig from the riser. |
We pretty much know that the BOP had been activated, once a signal has been sent the system is pretty much autonomous. The BOP works off the accumulators after it gets a signal, if you hear or see the word "Koomey" that is usually referring to the package that has, electric pumps, air operated pumps, controls, control valves.
With in a couple days of the blowout Transocean went in with
ROV's and connected an additional hydraulic source to the BOP and manually operated the valves they got no further improvement in the results of the BOP.
So we are back to some kind of internal damage of the BOP either:
1. Previous damage by not waiting for the BOP to open during a test or drilling operation.
2. There was damage to the internals of the BOP trying to close on the inertia of the pipe during the blowout.
3. The cement or part of the formation (rocks if you will) passing through the BOP with enough inertia to damage the BOP or jam it up.
4. There is a drill collar (a very massive section of drill string to add weight) in the BOP, that the BOP hydraulics do not have the power to collapse or cut through the drill collar.
There are back up systems galore but we are still on one section of pipe. If you have a second BOP or a taller one and never put two collars together (30 ft or so long each) then you would be able to know that you would always be able to close on a section of drill pipe instead of a collar or the band (coupling)
Okie