Posted on 05/31/2010 2:38:39 PM PDT by omega4179
Very interesting.
(Excerpt) Read more at bp.com ...
I observed the operations today for some time and have concluded that the pipe stub out above the point it is welded to the flange is bent slightly out of plumb.
They went in after jaws and made some vertical cuts around the perimeter. I think they will squeeze (or beat with a sledge hammer) so the tabs thus formed bend inward the very small distance to correct the minor out of plumb condition. The cut is not perfectly square but I don’t see that as a factor. The very small bend (kink)is the problem to my eye. Dimensionally, it is in my view quite small.
I’m starting to think that they intend on sealing around the outside of the flange, and not on the end of the pipe. I think that was their intention all along. That way there’s no need to guarantee a perfect cut... just to get enough of the pipe stub off to make room for the bell to fit down over it.
I have not seen anything though that shows the dimensions of that bell, or what its size is relative to the pipe-stub/flange.
My question (an area unknown to me) is regarding the compression of rubber at this depth. I would think a rubber o-ring would nearly/completely compressed at this depth, unless there is some super incredible rubber compound they are using... which would make gaskets a pretty unreliable thing... ???
Thanks for letting me know. It is at least somewhat good that they have an array of backup plans to ensure what the seal is. Though I still have not been able to see what shape the stub is in and even with the live feed it would be very hard to judge by looking at it, I imagine. Though I mean, anyone who knows anything about engineering knows that having these kinds of operations go exactly as according to plan is like winning the lottery five times in a row. When trying new procedures you can for sure count on something not being quite right. So I suppose we should try to take all the news of setbacks with a dose of salt.
That little rubber gasket the ROV is trying to fit around the pipe on one of the cams is kicking the ROVs ass right now. LOL
Here’s something I haven’t seen discussed. What about all the methane that caused the initial explosion? Is it still present in these plumes? I’m sure they’ve constructed the piping to handle any gas when they finally start to divert the oil topside.
I think I heard the reservoir pressure below the BOP was near 13,000 PSI while the pressure at the top was 8,000-9,000 PSI due to some obstructions inside the BOP. (partial closure, Junk blown up from down the well bore) It is all guesses.
Fumbles was involved along with 23 1/2 tons of hydraulic shear. When the diamond cut failed the resulting side pressure was threatening to topple the stack, so they had to get the riser completely off as fast as possible. So they called in Craw to cut it off. They have been doing small cuts and shaping all day to try and get it to a point the cap will go over it.
That sounds right but I think the pipe is much more oval than the pic we’re seeing indicates. The sealing ring will have to be a good bit larger than the pipe to slip over without damaging the seal. But I agree that looks like what they are trying to do. There must be some good reason that they don’t want to remove the stub along flange.
But I imagine the pressure could still be greater than they anticipate. A mistake in unbolting the flange could have even worse consequences because the force resulting from that could very well knock the whole BoP over and cause the complications to grow exponentially. I mean, I see it as a good potential idea but I also believe they have thought of doing that as well. I could be flat out wrong as I certainly wont pretend to be an oracle, but I do suspect they have more awareness of what can and should work then some people want to believe. To be sure, I think all of us could be overestimating how much we know about what is happening.
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They are going to inject methanol and warm sea water into the stream to prevent hydrate formation. They will vent any gas that gets through also. At least that is the plan.
I second that. Can hardly tear away to eat.
No doubt there is a darn good reason for not removing the flange. But it may also be that the planning for this never to into account the flange would be so easily worked on. The cap was being thought out and fabricated days ago. Maybe they are just sticking with their plan. I’m just thinking aloud. No claims whatsoever as to expertise. Far from it! These guys are awesome in my book. Even Fumbles!!
I think the methane is a liquid at the reservoir pressure of around 13,000 PSI and is therefore part of the oil stream but state changes to a gas and expands radically as the pressure drops, hope it’s built to handle it as well.
It could also be that the flange bolts extend down and hold something else together on the BOV.
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