- Joined
- Feb 16, 2010
- Messages
- 44,019
- Reaction score
- 29,303
- Gender
- Female
- Political Leaning
- Liberal
ON THE GULF OF MEXICO – The deadly blowout of an oil rig in the Gulf of Mexico was triggered by a bubble of methane gas that escaped from the well and shot up the drill column, expanding quickly as it burst through several seals and barriers before exploding, according to interviews with rig workers conducted during BP's internal investigation.
As has been posted earlier on this subject, cement placed at the bottom of the well meant to act as a seal seems to be the culprit.
Based on the interviews, Bea believes that the workers set and then tested a cement seal at the bottom of the well. Then they reduced the pressure in the drill column and attempted to set a second seal below the sea floor. A chemical reaction caused by the setting cement created heat and a gas bubble which destroyed the seal.
There are safe guards and from interviews of the workers on the rig, the safeguards did not work.
Investigators looking into the cause of the explosion have been focusing on the so-called blowout preventer. Federal regulators told The Associated Press Friday that they are going to examine whether these last-resort cutoff valves on offshore oil wells are reliable.
Blowouts are infrequent, because well holes are blocked by piping and pumped-in materials like synthetic mud, cement and even sea water. The pipes are plugged with cement, so fluid and gas can't typically push up inside the pipes.
Instead, a typical blowout surges up a channel around the piping. The narrow space between the well walls and the piping is usually filled with cement, so there is no pathway for a blowout. But if the cement or broken piping leaves enough space, a surge can rise to the surface.
There, at the wellhead of exploratory wells, sits the massive steel contraption known as a blowout preventer. It can snuff a blowout by squeezing rubber seals tightly around the pipes with up to 1 million pounds of force. If the seals fail, the blowout preventer deploys a last line of defense: a set of rams that can slice right through the pipes and cap the blowout.
Deepwater Horizon was also equipped with an automated backup system called a Deadman. It should have activated the blowout preventer even if workers could not.
Based on the interviews with rig workers, none of those safeguards worked.
http://news.yahoo.com/s/ap/us_gulf_oil_spill
Last edited: