On the Deepwater Horizon disaster- BOPs, deadman switches and ROVs

[Merchant Marine]

The news has latched on to the idea that the spill would have been prevented by the installation of a remote switch on the BOP (Blow out Preventer), and that the owners of the DWH were negligent for not installing this.

I do not see how it could have helped the situation.

The blow-out preventer is a device that is clamped onto the drill pipe close to the well-head, near the ocean floor. It is a giant valve equipped with shear rams and hydraulically actuated. It is supposed to shear through the drill pipe and close the wellhead if there is an uncontrollable pressure release from the well. The DWH had three methods of actuating this valve.

1. By command from the drilling floor or the bridge, via wires run down the drill-pipe.
2. A deadman that activates if the signal from the rig is interrupted.
3. Manual valves on the BOP itself, designed to be actuated by ROV manipulators.

Obviously #s 1 and 2 failed. However the BOP has been activated by ROVs at this point.

It has quite obviously failed. There is speculation about why- damage from the blowout, mechanical failure, or perhaps it has worked over a tool joint that it was not designed to shear and has instead simply crimped the pipe.

However the statements that the DWH had no safety valve or was negligent in not having a sonic activation method is just noise. Drilling at 5,000 feet is very much on the edge of known limits, and this may have exposed a fatal flaw in the BOP design.

I hope this will at least give people some technical background. I'm not a rig-man but I know a very little bit.

[nosmokes]

1. crimping the pipe is one of the ways the BOP is designed to work

My understanding is the BOP cannot be activated b mechanically by the ROVs at this time. Whether that's due to failure of the BOP or the manipulator on the submersibles. I don't know for certain, but my understanding is that it(the BOP) was supposed to be equipped with wireless remote control as well as hard wired control panel, but I don't have any sort of documentation on that, just word of mouth.