[tommix2]

There is a valve to shut the oil off beneath the rig My information may be obsolete as I am retired from the business. But there is a huge device called a Blowout Preventer which is attached to the casing on the bottom. Weighs several hundred tons, has two stages of shutoff valves, remotely actuated, and finally as last resort can squeeze the drill pipe closed. The driller constantly watches the heavy drilling mud in the drill pipe to contain gas pressure from below. Mud system is 10,000 psi or more system because gas drilled into at deep levels may be high pressure.

The driller on the drill floor never takes his eyes off the pressure gages and is ready to instantly act to contain the gas pressure from below.

I worked for that company, Transocean, and I know all the crews are well trained and the equipment is the best. Don't know what might have gone wrong. They are drilling in deeper water nowadays which makes more complicated.

[HiTech RedNeck]

If something kills the driller, though, then what happens?... wouldn’t you think there would be an electronic fail safe on the system so if there is a rig demolishing catastrophe, the blowout prevention system would automatically kick in?

[KDD]

Update.

http://www.google.com/hostednews/ap/article/ALeqM5g5gnWbqZ9SqBHvSYqJeE2AT5KebwD9F8LKQ80