By ANDREW C. REVKIN
Dot Earth - New York Times blog
June 21, 2010, 11:47 am
The New York Times has published a detailed and devastating report on weak links in the design and operation of the blowout preventer that was the last line of defense against an uncontrolled seabed gusher like the one at BP’s Macondo Prospect well in the Gulf of Mexico.
The central component of blowout preventers is a powerful device called a blind shear ram that crimps the well pipe in an emergency. These complicated rams are controlled by shuttle valves that deliver hydraulic fluid. The reporting package includes an annotated trove of documents, including a risk analysis from 2000 identifying a shuttle valve in the preventer as the source of more than half of the total “failure likelihood.”
There’s a great package of explanatory graphics and animation. (Editor's NOTE: in the New York Times article HERE... including a video which demonstrates how the blind shear ram is designed to work)
The story shows how companies doing offshore oil drilling had shifted progressively to cutting the risk of failure by adding a second blind shear ram to blowout preventers. The well installed by the Deepwater Horizon team for BP did not have the twin rams. The story includes responses from BP and Transocean on the absence of the backup equipment.
There’s also a passage in the story vividly showing how industry pronouncements about the safety of deepwater drilling — which undoubtedly contributed to President Obama’s decision to support expanded oil and gas development off American coasts — were a smokescreen:
Last year, Transocean commissioned a “strictly confidential” study of the reliability of blowout preventers used by deepwater rigs.
Using the world’s most authoritative database of oil rig accidents, a Norwegian company, Det Norske Veritas, focused on some 15,000 wells drilled off North America and in the North Sea from 1980 to 2006.
It found 11 cases where crews on deepwater rigs had lost control of their wells and then activated blowout preventers to prevent a spill. In only six of those cases were the wells brought under control, leading the researchers to conclude that in actual practice, blowout preventers used by deepwater rigs had a “failure” rate of 45 percent.
For all their confident pronouncements about blowout preventers (the “ultimate failsafe device,” some called it), oil industry executives had long known they could be vulnerable and temperamental.
There’s much more in the package, which demonstrates the vital role of investigative teams who can take the time to dig deep. Let’s hope The Times and other media can find ways to invest in such efforts even as they race to find new sources of income in an online world where “ information wants to be free.”
