Loading
davidcatton

DC spike

by davidcatton Jun 22, 2010

Please Login to Comment

Hi DC, Just to disprove MarcusWolschon 's comment, I actually work in the oil business (though not in well control : unless I do something very wrong, I try to keep the well control specialists fat, lazy and sleeping in their bunks, not running around with a job to do).

I don't have access to any detailed information about the DWH disaster (nearly wrote "fiasco" there, but it hasn't quite descended to a technical fiasco ; yet. Wait until the hurricanes start hitting the relief wells while they're in the danger zones.) apart form what is in the public domain already, but it seems that you've identified several of the key problems with your design already.

How much pipe - and in what state - is in the BOPs? I don't think that anyone knows to any more accuracy than "enough to leave a gaping gap between the rams" and "pretty fucked" for the respective questions. Which means that for your system to work, then you've got to get a fairly substantial amount of pipe out of there.

"Chain down the spike" ... to what? Seriously - to what? You need something that can exert a downward force of something approaching a hundred tonnes at a significant angle from the vertical (because you're going to have to place it on the seabed at least some metres from the BOPs). If you want a scary sight, on my FaceBook page at [fiddles, not sure if this'll work] here http://www.facebook.com/profile.php?id=1501300611http://www.facebook.com/profil...
&
amp;v=wall
&
amp;story_fbid=136104726415741 followed a little later by this http://www.facebook.com/video/video.php?v=1151627319805http://www.facebook.com/video/... I have someone else's video from a rig which had a blowout, and which then had it's leaking BOP stack knocked over. Ugly. Don't want to do that.

So - when a floater has to abandon a well because of weather, drifting tankers, or whatever - how do we anchor a "hurricane packer" (illegitimate, un-known grandparent of your device) into a well? What we do is suspend a length of heavy weight drill pipe (drill "collars" actually ; details vary) BENEATH the sealing element. The weight then stays nicely centred and everything is in tension.

Which is great. But it means that [back of envelope calculations] something approaching a thousand feet of drill pipe will have to be cleared from the wellbore to make room to allow the bottom weight to be run in below your "spike". That's non-trivial. Very non-trivial.

[continuing]

Now, next problem : what shape is the void in the top of the well. If it's nice and simple, then it'll be a circle, into which your conical taper will fit, plug everything, and joy and happiness will spread over the surface of the Gulf, dispersing the sludge. BUT, if ANY of the 3 or 4 sets of "rams" (your diagram shows 3 sets of rams and an annular "Hydril", but most subsea stacks I've worked with have 4 sets of rams and two sets of "Hydrils" ; system-level redundancy in this decidedly un-reckless part of the industry) ... if ANY of the ram pairs are partly closed ... you'll have a slot to close, possibly with a semicircular hole in each of the rams. (You understand that the rams should be pushed together from each side of the stack, normally to close and seal around the pipe
<
i
>
without
<
/i
>
crushing it (because you'll need to pump through it later in the kill.

I don't think that anyone
<
i
>
knows
<
/i
>
what the positioning of the rams is (I've heard precisely nothing about being able to read any external "tell tales", if they exist ; having tell tales on a sub-sea stack may add leak paths to an already complex system. And tell tales do sometimes tell false tales.)

There is a family of techniques for trying to determine the answers to questions like this - you run lead-bottomed pipe repeatedly into the hole and try to interpret the marks left on the bottom of the block to build up a model of the shape of the top of the "fish". At this water depth, look at ar
ound a day each way for running such assemblies to the bottom and stabbing them into the BOPs. And your "containment cap" is on a different rig whose derrick/ equipment running apparatus is occupied with the containment equipment. Got some big choices there.

You're right about the use of somewhat
resilient or compliant materials as "packing elements" in seal assemblies. But they also have the distressing habit of getting worn away ("washed out") by flow of well fluids past them before they seal ... if they last that long. And at the rates this well is flowing, you can bet that it's going to
be "sanding" like buggery - the fluid flowing from the ground may contain as much as 1 or 2 % of sand in the oil, water and gas - and that's a really aggressive environment.

What else ... you wouldn't plug your DP with lead - you'd want to maintain some circulation path by which you could eventuall
y kill the well if the relief wells fail. Running stuff in hole without a pressure management path has a distressing habit of getting things stuck in the wrong place and making things worse.

Sorry to sound like I'm knocking you - I'm not. But this is a genuinely difficult problem in a technology w
ith a lot of experience of having tried all sorts of things over the years. The number of times over my 20 years in the industry when I've made a suggestion and has someone sigh, get a cup of coffee, and then spend this long telling me why that wouldn't work ... well, I'd have a lot of cups of cold
coffee.

[continuing, and where did that squinty grin come from?]

A set of "maker files" for building a model of a BOP ... now there's an interesting idea. Might be worth breaking out my drawing pens and then learning electronic engineering drawing.

I should introduce myself to the forum I suppose : oilfield geologist, not directly related to well control stuff ; I posted those videos to FB about 8 months ago as a dire warning to a different (not BP) client why we should be careful with the well we were working on then, but they're a convenie
nt warning here too. My experience in 3d printing is zero - I've been interested in it from a distance for a while, and had my interest piqued more by the New Scientist article a few weeks ago. Considering whether the wife will let me acquire even more computing clutter in the house.
TTFN
Oh, a 3000
character posting limit. Pathetic.

Hi guys thanks for the constructive comments especially cyclone's.

I am new to this site so please be patient with me.

I have included a video clip here for the doubtfull to watch.

Can the deadline for the bounty be extended to include my effort?

who would I contact to do this?

http://www.youtube.com/watch?v=FWnHHd2EmSshttp://www.youtube.com/watch?v...
&
amp;feature

Regards
Dave

I like this design better than the other ones we have seen, but I suspect that with the cruddy foundation on the well, plugging it will cause the well itself to break, defeating the point of capping it.

What, just like the "Lusi" blowout which has displaced in the order of 25000 Indonesians from their homes in the last couple of years?
That's certainly not impossible, but with the information in the public domain, it's not clear if that would happen or not.

Anyone like taking risky gambles?

An interesting exercise in engineering theory. Granted none of us have the knowledge and experience needed to design a solution to work in that environment, but that doesn't mean we can't speculate for our own amusement.

The overall idea of a durable plug that is deformable at ludicrously high pressures is interesting.

I wonder if Friction Welding would work in an underwater environment. If you could integrate the needed equipment and compatible materials into the the top of the spike it could provide a way seal the well without relying only on mechanical connections.

  1. Noone who could use this, will find it here.
  2. no kind of plug does anything for unstable, porous and cracked ground in an area of dozens of km^2 around.
  3. this is not shallow water.. Any kind of construction in such a depth has more constraints then you know of.

Dude chill out. It's posted here because http://makerbot.commakerbot.com did a call for submissions.