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

You actually don’t push down on the bit at all. You suspend the weight of the drill string, except for a few thousand pounds. For example, if your string weighs 500,000 lbs the draw works might be holding 480,000. Every bit/motor/rock type has an ideal “weight on bit”. Otherwise you would become incredibly stuck as the pipe, which you accurately describe as behaving as spaghetti, would be shoved into the sides of the borehole.