Jun 02 2010
Put A Cork In The Pipe
Folks are rightfully pointing to a radical idea to stop the Gulf oil leak proposed by a young engineer in NY:
The Northport native, who started reading before she could walk and who at 18 broke a 300-year-old record to become the youngest-ever college professor, proposes surrounding a pipe with deflated automobile tires, inserting it into the leaking riser, and then inflating the wheels to form a seal.
While her plan will not work directly, it is along the right path. First off tires will not work, but a steel-belted balloon would. Also, you don’t fill it with air, you pump it with water at incredible pressure (the water pressure is too high at those depths). Theoretically the pipe should hold the pressure. The problem is getting the cork into the pipe. But if they used a sleeve over the pipe with vents to release the oil out the sides, then you can inflate the cork and then close the vents on the sleeve.
Here’s how you fix it.
You make a dual concenric pipe.
It has an incredibly tough inner section
and a rather soft outer section. The diameter of the outer section is an inch or two smaller than the riser and the pipe is
threaded at the top for connection to a hose to the surface.
Inbetween the strong inner pipe and the deformable outer pipe
are many concentric rings of high explosive.
The pipe is lowered into the riser. It is heavy enough and open enough to sink against the oil flow.
After the insert pipe is about 100 ft into the riser, the explosive is detonated forcing many concentric rings of soft aluminium to surge outwards
and dig into with great force against the old broken riser.
Now that that new threaded insert is wedged into place, a pipe to the surface can be screwed on.
Ths will work.
Good thinking, Daniel. What you’re describing is pretty close to what’s known as a Baker Bridge Plug (others make them, but Baker’s was the best) and back in the 80’s sometimes I would set 2 or 3 of those a day at various depths in a wellbore we were working on. We had an explosive-powered setting tool that hung off the end of our wireline that we used to position and then set them. They’ve been around for at least 50 years now, but good job to think of it on the fly like that.
Here’s the problem with using something like that in this case – first, you have to get down into the wellbore. They are in the process of sawing off the top of the bent riser so that at least the wellhead will be clear. Unfortunately, if the BOP’s are partially closed, then you can’t get past them and you’re stuck right there. (no one knows yet what’s happened inside that BOP stack) But say it’s open and the wellbore is clear – we *never* would have attempted to set a bridge plug in a well that was flowing, you could never have gotten into position. A little quick math – the top of the riser, when cut, has a 21 inch interior diameter. The pressure differential between the wellbore and outside seafloor pressure is reportedly 6,000 psi – that’s what’s blasting up into the sea. To get down against that flow, do a bit of quick math, area X differential pressure and you come up with a figure of roughly 2.1 MILLION pounds of force that will be required to push down into that hole.
That’s why top kill failed. *Maybe* a drillstring could be weighted heavily enough to get down against that, but if you could get a drillstring in the hole you could go all the way down and kill it with mud. This is why the automobile tire idea, while innovative, cannot work. There is no way to apply the 2.1 million pounds of force that would be required to push them into that wellbore – any less than that and they will be blown right back out instantly.
This is the reason everyone is having so much trouble coming up with a way to handle this – the pressures and forces at work here truly the greatest we have ever had to face from a technical perspective. The oil industry got so good at handling this kind of thing that some people forgot just how easily things can get out of control. And how hard it is to get them back once they’re gone.
Meant to add that AJ’s idea of a vented sleeve is very good for diverting the pressure while the plug is set, that’s the only way you can get into position on a flowing well – but the problem is still that you would have to have the weight of a drill string to push anything that size into the wellbore, which means putting a rig right back on top of the oil and gas that’s coming up from the depths. For obvious safety reasons, no one wants to do that.
The only real hope left is the relief well, still 2 months away from intersection. Can’t be sped up, because (if I understand correctly) the directional gyro in the steerable drilling assembly has to be pulled out, checked, and recalibrated daily or else the entire relief well can go off track. And then the entire effort will have been for nothing.
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WWS,
You can weight the device and use ballast containers to float it down to depth. Releasing the ballast tanks will then apply the counter pressure. Guiding is also an issue, bit of you have anchors in the sea floor with pullies for guiding it would work.
WWS,
At least I recognized the key challenge – pressure!
This entire episode with this well is a sham. There are plenty of able-bodied drillers and platforms who would plug it today for a share of future production – but for some reason the Federal Government insists on leaping into action and doing nothing to incent private industry to fix this thing.
We need some useless dead weight to plug the whole…. what about using Congress?
I’d settle for building a fabric tube, about 10 feet across and ~5,000 ft long. Drop one end over the whole wellhead, use the tube to direct the oil to the surface. Pump it into a tanker, ship it to a refinery. Repeat the pump/ship process as required.
Then drill the relief well as conditions permit.
Or we could use Obama’s ego to plug it…it’s certainly big enough.
It’s an intriguing idea; but it’s hard to really grasp just how hard every little step is – much harder than working in space, for instance. But like space, everything has to be done robotically.
Here’s an extremely well done blog post, complete with diagrams, as to just what a mess that BOP stack is right now.
If he is right (and his logic and diagrams look impeccable to me) then no kind of plugging operation can work, because there is still pipe stuck through the midde of the bop, stuck by the partially closed rams, and partly sliced through by the shear rams which failed to slice completely. Some of the oil is coming up through the inner, smaller diameter pipe, some is coming up around it – some may even be coming out of the base of the BOP, which is a Real Bad Thing if true.
http://www.theoildrum.com/node/6538
What this means is that *nothing* can go down into that well bore unless it can get inside that smaller, inner diameter pipe that’s stuck there – but that pipe is almost certainly partly crushed at the top, blocking entry. Even if you could get into that inner pipe, a plug would do no good because there’s no way to seal off the oil coming up around that inner pipe, and the oil we stopped from one pathway would just shift over to the other pathway, which there is no way to get to.
From an engineering point of view, it’s a perversely fascinating problem. It is a true Black Swan – the problem appears almost as though it has been designed to defeat every possible technological ability we have.
btw, I don’t think they should have used a diamond saw to separate that riser today, anyone who’s used a chainsaw knew that was going to get stuck. I would have gone with a double row of linear shaped charges wrapped around the riser pipe a couple feet above the BOP, myself. Nice, clean, fast – they make a very nice cut.
Next step, BP is going to try and drop a 70 ton containment dome over the wellhead and try to vacuum up the oil. Until the relief well comes, that’s about the last trick in the bag.
Thanks WWS,
What do you say about the idea of using 100,000 tons of
molten rock to plug the well?
I suggested this idea at the office early on only to be called
a typical American.
Then I heard it seconded by a Naval sub commander on Fox News.
The suggestion is to melt, not vaporize,
a large section of the sea bed and force it downwards with a compression wave.
The device would be a small-ish nuclear bomb set off a hundred feet above the well head.
I don’t know if this would work but the guy on Fox News said Russia has used this technique to solve their own problems.
What do you think?
If you set it off *above* the sea bed, you will probably create a tidal wave that will destroy large parts of most gulf coast cities, because even a smallish-bomb will still vaporize about a cubic mile of seawater.
The people who are suggesting the idea have noted that it would probably have to be placed at least 2,000 feet under the sea floor (have to drill another hole) or else we may just end up with a lot of oil spraying up out of a big undersea crater. No guarantee that the fused rock will stay in place as a cap if it’s too close to the surface.
It’s completely unpredictable, which probably makes it a bad idea. It *could* seal off the borehole; it also could fracture the undersea rock strata so badly that new oil leaks pop up in a thousand new places, right out of the sea bed, and then they could *never* be stopped. No one can know for sure, and since the relief well can stop it in two months, that’s still the best bet.