BP Oil Leak: Good News, Bad News

First the good news, then the bad news. Well, first the bad news that precedes the good news.

BP has put a cap on the well, but a crucial test of the cap was delayed because of an unexpected leak. But basically, this is good news, the cap is on.

The cap is not closed … the well is still gushing oil. But once they close the third of three valves on the cap, the well will be sealed. Then over coming weeks or months, relief wells in the same oil deposit can extract enough underground oil to make this well less of a threat.

But …

There is a possibility that this could go terribly wrong. When the third valve (the “kill” valve) is shut, the pressure inside the well should increase. That is good. But, once the pressure increases, it is possible that the oil that is in this well will break through to a different geological zone than where it is currently confined. Then, leak out into the sea.

This is a bit like balloon that is losing air from the valve. If you plug the valve you stop the loss, but if the balloon explodes, then you are royally, totally, screwed. If something like that happens with the well, there will be, essentially, no way to stop the flow of oil into the gulf other than tapping a percentage of it off via the relief wells.

No one is sure how likely that nearly-worst-case-scenario is.

“I was gung-ho for this test and I remain gung-ho for this test,” said Adm Thad Allen, the US incident commander, on Wednesday.

But he warned that nobody wanted to make an “irreversible mistake”.

If the pressure testing fails, the well will be left open and oil capture to vessels on the surface will be resumed.

source

Comments

  1. #1 Thomas
    July 15, 2010

    Wouldn’t it be safer to just put the biggest pump they can come up with on the other end of the pipe to the surface and not seal the cap? As long as you pump hard enough you should suck in essentially all the oil as well as surrounding sea water. Sure, it’s inconvenient to have water in your oil, but under the circumstances that seems like a minor problem.

  2. #2 BioEngineerGreg
    July 15, 2010

    Thoma, the problem with that approach is the same thing that prevented the First Attempt from working. Remember the “Top Hat”? As this pumping system pulled in the oil/gas mixture as well as cold seawater it created a slurry in the pipeline to the surface. As this slurry rose, and the pressure correspondingly dropped, the seawater mixed with the methane (as it transitioned from liquid–> gas) and created the hydrate crystals which then clogged the pipeline. I’m not an expert on this stuff, but it seems to be critical to keep seawater out of the mixture when pumping to the surface from a mile below.

  3. #3 Russell
    July 15, 2010

    Unless you believe that the bore just happened to follow a particularly weak structure that runs all the way from the seabed to the reservoir, which strikes me as quite implausible, especially given the depth of the well, there is a depth at which a relief well can seal the well.

  4. #4 CherryBomb
    July 15, 2010

    Just one nit-picky thing. The relief wells are not for drawing oil from the reservoir. They are going to use a column of heavy mud in those to push down against the formation pressure, and then flood the whole area with cement to block off the original well from all contact with the porous rock that holds the oil and gas.

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