I’ve been a small part of a discussion on Grist.com regarding solutions for stopping the Deepwater Horizon oil leak.
I’m going to re-post the solution contained in my latest comment regarding a solution to reduce the flow enough to allow a top kill process to work:
First, a few questions… the answers either make the ideas that follow ridiculous or elegantly simple and very effective:
Is is safe to assume the drill head is stuck in rock below the bottom of the casing? Wouldn’t that make an ideal “anchor” for a gradually-introduced mechanical block (explained shortly)?
Does the relief well solution or directional bore that would be used to kill the well require the drill stem be removed?
How is the drill stem assembled? Threaded sections? Pins? What is a typical drill stem diameter compared to the casing over the depth of the well? Would a properly sized pipe be able to fit over the drill stem and make it all the way to the bottom?
The following I like better for the mechanical blockage aspect and it involves a series of simple self-capturing/anchoring devices on pipes put on the drill stem then pushed to the bottom of the casing to GRADUALLY reduce the effective diameter of the well bore, or increase the effective diameter of the drill stem, whichever your perspective.
The self-anchoring device would use properly sized cams not unlike the small ones used in a plumber’s wrench. A steel frame would hold three of these so they could be pushed down the length of the drill stem. Any reverse motion would force them to grip the drill stem via their cam shape. The force of the crude pushing against them would reinforce their self-anchoring action. (steel “chinese handcuffs”)
Keeping the profile small enough to incur forces each assembly can handle is important. They’d have to start small, and be left at the “right” depth, the “pusher pipe” removed for the next one, which would be slightly larger. Reducing the flow rate would allow for gradual buildup via increasingly larger drill stem “sleeves” equipped with similar self-anchoring devices. The larger surface area of the sleeve pipes would add to the forces experienced by the anchoring mechanisms, so flow would have to be reduced first, I think. Then, with flow greatly reduced, a top kill effort through the BOP would be efffective.
Anchoring to the drill stem would help avoid some dangerous forces on a suspect casing.
The shafts through the cams have to be a large enough diameter to resist shearing during self-anchoring action. The drill stem “ring” with these cams could have several more to distribute the load, but this would work against the assembly should it get hit by a rock on the way out of the well. It’s been 25+ years since I did a differential (or closer to 29 years since Nature of Engineering Materials labs), so I’d only have wild-assed guesses at the appropriate sizes.
With the forces being equal to the pressure times the effective surface area, the required load carrying capability of each cam axis be calculated.
The other idea I had may have already been thought of and dismissed: Feed two or three pipes down the casing alongside the drill stem (think of a golf bag with indidual club sleeves to picture this) to the bottom, pump mud straight to the bottom of the well. To not increase pressure at a dangerous rate, this may require oil being able to rise in these pipes as they are built and inserted… messy, but at the surface. Viscosity and diameter are issues as well as being able to pump appreciable volumes over the smaller diameter through the 3-5 mile pipe(s).
I just can’t see how even intercepting the the well a mile below the surface would allow for a “top kill” with mud with the well so open on top.