Pressure gauges and a device known as a “blowout preventer” are the two biggest fail-safe tools used on oil rigs to determine if there is a potential problem and correct it. But none of these will function properly without adequate maintenance and monitoring.
Pressure readings are well-monitored on a system that is under high pressure. This should be a first indication of any problem and should be acted on immediately. The amount of pressure in the well is monitored, not only on the rig, but onshore at separate facilities. Other methods, including the “blowout preventer” are then checked and sometimes manually activated to correct the problem. In the event that the preventer is not activated manually, a mechanism known as a “Deadman”, presumably activates the preventer automatically.
The “blowout preventer” is the device that stands between normal operations and a potential disaster. It is designed to stop flow from a well that has a problem and, as the name suggests, prevent a major blowout of oil from the well. However, this safety mechanism must be checked on a regular basis to insure that all parts are functioning properly.
The preventer itself is composed of several distinct parts, including hydraulics, cutting tools that cut through steel in the well pipe to stop the oil flow, and batteries that power the control pod itself. All these factors of the preventer are designed to eliminate any potential problem, and are always assumed to be in working order. However, the real fail safe function is the testing and maintenance of these devices, prior to an actual emergency.
Hopefully, with a series of fail-safe devices, not all of them will fail to function at once, and problems can be corrected immediately. Unfortunately, if both gauges and “blowout preventer” fail at the same time, it is unlikely that the problem will be detected. This is very rare. It has been proposed that onshore controls be implemented to enable other operators to remotely shut down malfunctioning systems from a watch area separate from the offshore rig.
Fail-safe devices are only useful when maintained and tested on a regular basis, regardless of the time, effort, and cost in lost time that is involved. It is normal for all of these to be checked weekly. The discovery that there are malfunctions in any of these vital safety procedures and mechanisms after a disaster pretty much defeats the purpose.
http://www.osha.gov/SLTC/etools/oilandgas/drilling/wellcontrol.html
