Darxus

BP: What reason do we have to believe the second hole won't blow?

BP: What reason do we have to believe the second hole won't blow?

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2009-09-29
Since I heard that BP's long term solution to the oil leak, which was going to take until August, involve drilling a second hole, I've wanted to know:

What reason is there to believe the second hole won't blow?


(Also, why don't they put an upside down funnel over the hole, with a valve at the top, and anchor it with cables?)
  • The ocean floor isn't flat, or smooth, or hard, so an upside down funnel wouldn't seal against the ocean floor. The oil would just spurt out around the base of the funnel.

    What would you anchor the cables to?
    • Big bolt thingies driven into the ocean floor.

      And just make the funnel big and thick enough that when you torque it down, the ocean floor flattens to seal it.


      My other idea is to take all of the lead, melt it into a ball, and drop it in place.
      • imagine trying to bolt into the sand at the beach.
        • So drill until you hit rock, and then screw in the bolts. If drilling the second hole is taking months, there's something there that will hold.
          • Then what? Do you imagine squishing the funnel down until it hits rock too? The squirting oil will just displace the sediment on the ocean floor around the funnel's rim.
      • You've got the entire weight of the water in the Gulf of Mexico pressing down on the earth's crust, which is pressing down against the oil pocket, which is spurting upward through a hole more than a foot across bored into the earth. It's like popping a pimple, only on a geological scale. I've heard numbers in the range of 40,000 PSI for the pressure there at the wellhead. We simply don't really know how to deal with pressures that great.
  • I'm not convinced anyone in the business is certain that the relief wells will completely stop the flow from the blowout bore, only because we've been told that this well is at a depth that's on the bleeding edge of undersea drilling experience/technology.
    But it's all about pressure, and relief wells have worked for similar blowouts, just by providing an alternate path for the oil while they try to seal off the blown out one.
    There are actually two relief wells being drilled, both are angled under the seabed so as to intersect with the main borehole *above* the actual oil reservoir. So it's like tapping into an existing pipe to divert the flow. How they have the technology to aim their drills that precisely, I have no idea, but that seems to be the plan: see slide 7 here (I found the other slides informative too): http://news.bbc.co.uk/2/hi/world/us_and_canada/10317116.stm
  • Since nobody else answered your actually questions:

    1. A relief well is not a well that you pump out of. A relief well is one you pump a denser liquid into. The hydrostatic pressure from the liquid pumped in can then be used to stop the flow of the oil. Once that happens you cap the whole thing with concrete.

    The problem with relief wells is they take months to drill. The Canadians solve this problem by mandating a relief well be drilled at the same time as a the primary well. Perhaps we can learn something from them.

    2. The upside down funnel idea was kind of like the first two things they tried the "pyramid" and I forget what they nick named the other one. The "cap" thing they currently have in place is something like that. It doesn't get everything though and lots of oil still gushes out.
    • #1 didn't really answer my main question. The first hole blew open. I don't see how having a different purpose makes the relief well any less likely to blow.
      • I guess it could blow, but as it isn't going to be open for every long. It will only be open long enough to stop the initial flow and then fill with concrete.
        • Yeah but why did the first one blow, and how is this different? How do you stop a 170,000 PSI flow, even for not very long?
          • You probably need to ask an engineer that. But my assumption would be that while drilling at this depth is dangerous, one blow out at that location doesn't mean another well must do the same thing. So while there is a risk of another blow out the probability of it happening during the time it takes to plug it with concrete is low.
            • Yeah what I've been looking for is a reason, not an assumption.
              • You might consider turning the question around. Is there any reason the next well must blow?
                • Not that I know of. But it's obviously very important to have reasons to believe it won't.

                  Also, you called my question "silly" and then answered it with an assumption.
      • They cut corners when they were drilling the first one, and the final cementing job was poor. This led to the explosion on Deepwater Horizon, its sinking, and the resulting blowout. The blowout preventer was faulty and/or didn't work, and there was another device (I forget what it's called) that many other countries require. The US doesn't require it, though, and at half a million dollars, it was deemed too expensive to use, and unnecessary, since the BOP was going to seal the well, right?

        Basically, we hope that they're not doing a slapdash job on the relief wells and are using more (and better) safety equipment.
  • What reason is there to believe the second hole won't blow?

    Because a lot of things went wrong with the first one, all at the same time. Theoretically, the new blow out preventer will have all hydrolic rams working (the old one had 1 ram that leaked fluid, so it didn't work, and another 1 was a dummy 'test part' that was never intended to work. That's 2 out of 4 rams that never fired).

    Assuming that they actually seal the well, that means that there won't be any rapidly expanding gas to rupture things, since the gas will all stay a mile below the surface where it's at roughly the same pressure.

    How many off-shore oil rigs are there? And how long have they been in use? Have you ever heard of this kind of thing happening before? No, because there are a lot of safeguards in place. They all have to fail at the same time. And since it hasn't happened before (at least not on this scale or depth) no one knows how to handle it.

    (Also, why don't they put an upside down funnel over the hole, with a valve at the top, and anchor it with cables?)

    Greed. They created a box (4 story building) that was intended to be dropped over the well. It was designed to sink into the mud of the ocean floor half way to prevent any leakage. But the nozzle at the top, where they were hoping to still collect oil, got clogged. I think if they decided to plug the well for good, it would be easier to stop the flow of oil. But most options they've tried so far aren't designed to stop the oil, just to allow it to be collected.
    • Thanks, that's somewhat comforting. I'd still prefer to hear that they've tested it in a simulated environment above ground a dozen times first.

      Yeah, I got the impression that they were trying more to collect the oil than to stop the leak. That's fucked up. And I don't even see why they care so much about collecting oil from this hole. Why don't they just drill another once this is fixed?
      • I'm sure some people still want to collect oil. However, I'm not convinced it'd be easier to fully stop the leak, given pressure stuff.
  • Here's what I'm worried about, regardless of what happens with the relief well: There are concerns that the entire thing is sort of like a hose with holes in it. We don't see much coming out of other breaks because the main leak hasn't been stopped yet. Once that's plugged, pressure will build up and new leaks will form. I can't remember who showed me this article, but I don't think it was you.

    There's also concern the is going to release methane gas bubble and cause an extinction event. http://is.gd/dntZt I have no idea how reliable any of those sources are so I'm not overly concerned about it, but it's one of those things that sounds semi-believable if you don't know anything about geology, which is my situation. (Sort of like how the "moon landing is a hoax" theories sound plausible if you don't know anything about the actual moon landing.)
    • Yeah, I posted that to [info]so_very_doomed yesterday.

      I think you may be getting carried away with your is.gd usage. That url is mostly the article's descriptive title, and you could have spent about as much time typing up a link to it which would allow me to hover over the link to see what site I would be going to. Which I like to see.
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