When drilling like 12 km deep into the ground, how is it possible that a 12 km long pipe (drill string) is able to turn the drill bit AND be pushed down enough to drill??

Question

A 12 km long pipe seems like a ridiculous length for any of that to be possible. Isn’t it like trying to drill a hole with a 258 ft long piece of spaghetti?

In: 1335

Answer 1

Here’s the thing, that 12KM of drill pipe applies a LOT of downward pressure on the cutting head just by its own weight. Second, you’re right, at that length the drill pipe is kind of noodly but that’s fine because the pipe is constrained in the drill hole. It will twist as the drill begins turning and build up torsional tension. Eventually, that tension will either overcome the rock it’s drilling through or you’ll break the drill pipe. A really deep drill can be turned several rotations at the top before the bit begins to turn. Also, no one ever said it was easy or cheap.