Directional drilling. It's pretty boring to turn into a story. We drive the drill bit, using measurement while drilling (MWD) instruments to a target zone. The depths vary for each resource and formation. For example, tonight I have two rigs drilling toward a target 5000m(ish) subsurface but yesterday we had one with the zone at 7300m. The target area is usually a column no wider than your kitchen, but that strip will run through the resource for 2000-3000m. The oil or gas will permeate that column for it's entire length, and production from a good target will last decades.