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

The bha mostly the mud motor, I am sure there’s agitators, as well as the drilling mud and of course the drill bit have to appropriate for the job.

Plus, drill pipe standard size is about 30ft or ~9m. So basically after each 30ft section, the drilling is paused so that a new stand can be attached. To save time, 3 drill pipes are usually connected or 1 stand, so about 90ft or 27km of pipe is connected at one time. This has to do with heigh (and weight) limitations of the kelly bushing and the crown block height. There’s no drilling rig that has a 12km or ~39k ft drill string completely pre-assembled (HOLY MOLY if it were). So, attaching new stands when appraching the reaching the 90ft/~9m new connection point. Plus, replacing the mud motor, bit, and adjusting the drilling mud parameters when needed all help optimize the drilling process.

Source: I am a directional drilling engineer