July 1, 2010

Perhaps a clue?

Part of the rationale for the deepwater drilling moratorium is that we've not identified the cause of the failure. We know that the drilling crew attempted to activate the shear rams of the blowout preventer. This action should have sheared the drill pipe and sealed the hole. It didn't, and we have failed to understand the reason the BOP stack failed.

Recent discoveries are suggesting a possible explanation.

At 15,000 feet below mudline, the string likely included heavyweight pipe or drill collars, possibly of 6-5/8 inch OD with very thick wall. If two of those were inside the BOP at the time the shear was engaged it could easily have exceeded maximum operating limits.
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3 Comments:

BCFD36 said...

If I remember the 60 Minutes story correctly, the blowout preventer was broken. The person who was the object of the story reported that large pieces of rubber came up the drill pipe and they were part of the preventer. And one of the control mechanisms was broken. A non-functioning or malfunctioning blowout preventer was the cause of the problem.

jeg43 said...

Until the reason/s the blowout preventer failed is known for sure, and a reliable fix is developed to prevent such failures, I feel the moratorium on deep water drilling should remain in place. Period. Everywhere on this planet.
We just can't stand any more gushers like this one.

Mule Breath said...

BCFD, the 60 Minutes story was and remains speculation. That the BOP was coming apart was only one of several scenarios that remain possible, but are as yet unproven.

Two things about the 60 Minutes theory unsustainable. First, the BOP was tested and functioned properly earlier in the same day as the blowout. Secondly, all of these stacks have treble safety features, including pipe rams, blind rams, and shear rams, so if one or even two fail, there is a third as fail safe.

As a sidebar, many rigs today are adding a second shear ram, so the safety features would be four deep.

Jeg, as I have already pointed out why I feel that is an unreasonably costly overreaction, I suppose we will just have to disagree on that point.