BP's Deepwater Horizon - Static Top Kill vs. Bottom Kill: Weighing the Risks - and Open Thread

The Oil Drum ^ | July 30, 2010 - 10:45am | aeberman

[Ernest_at_the_Beach]

Author's Note: Art Berman (aeberman) is an Oil Drum staff member and geological consultant whose specialties are subsurface petroleum geology, seismic interpretation, and database design and management. He has been interviewed on CNN and BNN about the Deepwater Horizon disaster. William Semple collaborated on this post. Mr. Semple is a drilling engineer and independent drilling consultant with 37 years of experience in the oil and gas industry. He worked for 16 years with a major oil company and has 24 years of experience as a drilling supervisor. He has been a guest contributor on The Oil Drum writing about the Deepwater Horizon (June 19, 2010).

A permanent solution to the BP Macondo blowout in the Gulf of Mexico may be achieved soon but there are risks. Admiral Thad Allen announced on Monday, July 26 that a static top kill would be attempted on August 2. The schedule may be accelerated to July 31 or August 1 according to an announcement today (July 29). The sealing cap has successfully stopped the flow of oil and gas from the well and the pressure continues to build slowly. Temperature at the wellhead has not increased, and seeps near the well are mostly nitrogen and biogenic methane unrelated to leakage. BP Senior Vice President Kent Wells’ technical update on July 21 explained these findings and showed how the well will be killed.

There are risks involved in both the top and bottom kill procedures. The purpose of this post is to describe those risks. There are two risks associated with the static top kill. First, it may not work at all and second, it may rupture the casing by pumping heavy mud under pressure (“bull heading”).

[justa-hairyape]

Skandi 2 ROV is water blasting the crude off the 3 Ram Stack. Man was that stuff thick. The leak apparently has not slowed.

[justa-hairyape]

Temperature at the wellhead has not increased, and seeps near the well are mostly nitrogen and biogenic methane unrelated to leakage. BP Senior Vice President Kent Wells’ technical update on July 21 explained these findings and showed how the well will be killed.

When Kent first announced that the tested gas was 15 % methane, he was referring to the leaks NEAR the well. Near the well is not AT the wellhead. In his July 21 recorded briefing he refers to the gas AT the well head not Near the well. So I think they are releasing that information in a confusing manner intentionally. Plausible deniability. The chance of the gas leaking from seeps Near the well having the same composition of methane 15 % as the leaks In the well head are remote.

[justa-hairyape]

From the Oil Drum article linked above.

The 16-inch pipe has a burst rating approximately equal to the current shut-in pressure of 6,900 psi (80% of rating), but the 22-inch pipe does not meet this standard.

[Marine_Uncle]

Don't sound good. But then the pressure has stabilized, and only creeps up well below what originally would have been expected. Perhaps the idea of doing the top kill first was to verify the soundness of the main well bore. If one successfully plugs it then the inner liner as well at the outer casings where not damaged. If one pours extremely large amount of drilling oil well beyond calculated cubic volume of the tube system, then there are cracks in the pipe down below leading to oil/gas pockets or worse.
I have to get ready for work shortly. So I will be out of things until later evening hours.

[justa-hairyape]

The news today on the radio was that the Relief Well is delayed because something fell into the well when they uncapped. Gonna be delayed.