Pressurized fluid is used to keep the hole or well from collapsing. The fluid equalizes the formation pressure and keeps the hole from collapsing. This is calle

Pressurized fluid is used to keep the hole or well from collapsing. The fluid equalizes the formation pressure and keeps the hole from collapsing. This is called "mud engineering," Yes, it's a real thing, look it up! :) Steel is really surprisingly flexible. You can press on a 30 foot length of 6" steel in the middle and it will deflect a lot. Modern drill strings can make 90' turn in as little as 100' to 200' feet and still rotate. Friction is an issue. Friction is combatted with lubricants in the fluid (mud) and devices that are called agitators. Basically big vibrating tools that break the friction with small physical movement. The drilling industry may not be the hot thing but there is literally 175 years of continuous innovation, A/B testing, and incremental improvement at work here.