BlowOut Preventer (BOP)

NoseyMike2010

How are they suppose to work? I am just trying to understand what exactly happened in the Gulf of mexico.

bnt

In its simplest form, a blowout preventer is simply a remote-controlled valve that can cut off the oil flow. My understanding of what happened initially, based on reports like this, was that it was supposed to activate automatically, but failed to close completely, and then could not be activated manually. The root cause has not yet been identified - it's still a mile down - but there appears to be a hydraulic leak and questions about its maintenance (or lack thereof).

There are also questions about why there was a blowout in the first place, focusing on the concrete lining of the well. Some reports suggest that it failed tests that were already inadequate; and that the Schlumberger people doing the tests, upon hearing that BP was going to go ahead and tap the well regardless, ordered up a helicopter to get them the hell off that rig.

As for the cement, BP decided to use fewer centralizer devices to keep the final string of casing centered in the well hole. It has been reported that the cement contractor, Halliburton, recommended the use of 21 centralizers. BP elected instead to use only six.

An email from a BP official dated April 16—four days before the blowout—complained about the time it would take to install the recommended number of devices.

The congressmen allege that BP also failed to circulate heavy drilling mud through the well before going ahead with the cement job. It has been reported that the American Petroleum Institute recommends full circulation prior to cement work in an effort to reduce the possibility that mud will contaminate the cement and compromise its strength. The time required to circulate the heavy drilling mud according to recommendations was 12 hours.

It has also been alleged that BP decided not to proceed with a test that would verify the soundness of the cement. The Times reported yesterday that BP's own engineers ran computer models suggesting a good cement job was unlikely. A crew from Schlumberger Ltd., a company specializing in cement bond log tests, was on hand to conduct the necessary tests that would vouch for the strength, or lack thereof, of the cement job.

The test would have taken an additional 12 hours. BP elected not to proceed. The crew from Schlumberger vacated the Deepwater Horizon the morning of April 20, just hours before the disastrous blowout that killed 11 and injured several.

(source)