Blowout Preventer - Phil's Rambling Rants
I'm aware that one system died, and that the other system failed to function when commanded. The biggest problem is that during a test, someone screwed up and destroyed the seals inside the BOP. Chunks as big as you hand came up in the mud. But replacing the BOP requires you pull up ALL the pipe you've put down, change it out, and then put the pipe back before you can continue. BP decided to be cheap since the platform costs 1Million bucks a day to operate.
Then BP did the extreme dumb stunt of taking out the drilling mud before the cementing was finished. See, the weight of the mud keeps the oil and gas from escaping. Take it out, and nothing stops it from entering your pipe.
And you know how a percolator works, right? The steam bubbles expanding as they rise through a tube, filling the tube and pushing liquid ahead of them? Same thing happens to oil and natural gas. The methane bubbles are tiny at 90 atmospheres, but become enormous by the time they reach 1 atm. So if nothing balances the pressures in the tube, the bubbles enter and drive oil out at incredible pressures as the expanding bubbles rise.