Rotating Equipment

The rotating equipment turns the drilling bit. This equipment consists of the swivel,the kelly, the rotary table, the drill pipe, the drill collars, and the bit. The swivel is attached to the bottom of the traveling block and permits the drill string to rotate. The kelly is a square or hexagonal shaped section of pipe that is attached to the swivel. The kelly fits in a matching slot in the rotary table. As the rotary table turns the kelly is also turned. The movement of the kelly rotates the drill string and the drill bit.

Drilling pipe is round steel tubes about 30 feet long with a diameter of from 4 to 5 inches. The drill collars are used to add weight on the bit. Drill pipe has threaded connections on each end that allow the pipe to be joined together to form longer sections as the hole gets deeper.

The drilling bit is used to create the hole. Drilling bit sizes range from six inches to three feet in diameter. The most common drill bits are roller cone bits and diamond bits. Roller cone bits have three cones containing rows of teeth. The cones rotate on bearings and turn as the drilling bit rotates. 

The teeth cut and crush the rock to create the hole. The bit also contains small nozzles that spraydrilling fluids to remove the rock fragments from the bottom of the hole. 

Diamond bits have a single fixed head that contains many small diamonds. As the bit turns the diamonds cut the rock. Diamond bits also have nozzles to wash away the broken pieces of rock. Different drilling bits are used depending on the type of rock that is encountered.