2010

BP Blowout Preventer Failure

Engineers often see emergencies arise over and over again. Because of the frequency of recurrence, they develop safety systems. One example: sprinkler systems in public buildings. Fires are not uncommon, so sprinkler systems extinguish them automatically.

In the world of oil drilling, a common emergency is the blowout. Once a borehole has been drilled from the surface to the oil reservoir, the reservoir will frequently send oil and gas up the hole under pressure. If the pressure is moderate and consistent, it is manageable. But if the well kicks, creating a high-pressure surge, events can spiral out of control. The blowout preventer (BOP) is a piece of equipment engineers put in place to protect against surges.

The idea behind a ram-type blowout preventer: powerful hydraulic rams slide in from the side to close off the well. In some, shear plates cut through anything in the way as well. An annular-type BOP uses a rubber donut to seal around drill pipe. A well will have several blowout preventers in a stack attached to the wellhead. They may activate automatically, manually, or remotely.

What if the safety equipment fails? In one of the most famous cases, the well blew out at the site of the Deepwater Horizon rig in the Gulf of Mexico in 2010, ultimately releasing five million barrels of oil into the Gulf.

The blowout preventer was engineered to automatically seal the well in a case just like this. It should have activated and clamped the well shut. And it did try. One annular and three rams activated. But the engineers miscalculated. The blowout preventer completely failed at its assigned task.

What happened? A postmortem analysis is how engineers learn from mistakes to prevent repeats in the future. It appears that high-pressure flow from the well washed out rubber and metal pieces of the BOP. In addition, the sheer ram failed to sheer the drill pipe and seal. Other elements never activated. Using the results from the postmortem, engineers improve their designs, add redundancy, and eliminate points of failure.

SEE ALSO Oil Well (1859), Wamsutta Oil Refinery (1861), Seawise Giant Supertanker (1979).

Workers on board the Transocean Discoverer Inspiration in the Gulf of Mexico.