How Oil Rigs Work: Part 3

Heading Out writes: If you remember, we have bought a drilling bit, and over to the side of the site we have some pumps that can deliver a flow of drilling mud to that bit. But where do we go from here?

Well this is where that tall tower known as an oil derrick, so emblematic of the industry, comes into the picture (for which see, for example, the picture here . Because we have to now have something to attach to the drill bit that will turn it, and push it into the rock. (From which it follows that the top guy on the rig is known as the tool pusher). At the same time this connecting device has to be able to allow the mud to get down to the jet nozzles on the bit. The logical way of doing this is to have a tube or pipe, into which the drilling bit can be threaded on the lower end. (Which gives rise to the expression oilfield tubulars). Now, by attaching the mud pumps to the upper end of the pipe, we can also get the mud down into the bit. There is usually a special piece of pipe that fits between the bit itself and the main sections of the pipe, and this is called the drill collar.

Drill pipe comes in various sizes, depending on the hole that is being drilled, but for the sake of an example we might use a pipe that is 5.5 inches diameter on the outside and 3.25 inches wide on the inside. This would weigh around 14 lb a foot, and is normally used in 30 ft lengths.

A whole bunch more about how an oil rig is constructed after the jump at The Oil Drum.