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

I worked on underground coring rigs 1000m hole is considered deep. I would run downhole gyro surveys to get an idea of where the hole is headed (deviation) and sometimes the amount of “corkscrewing” the rod string would do amazed me. In that world it’s all about water. Pump water down the line and return it up the hole. The string is fitted with a reaming shell that bores the hole a bit bigger than the bit. Aside from that is grease (to fill small cracks), and mud to reduce torque.