The gear or chain arrangement by which power is transmitted from the prime mover to the drawworks, mud pump, or rotary table of a drilling rig.

Are related terms for expressing the same basic idea. The difference between input horsepower and output horsepower is transmission loss. It may be stated as so […]

A body of permeable oil-bearing rock surrounded or overlain by an impermeable barrier that prevents oil from escaping. The types of traps are structural, stratigraphic, hydrodynamic, […]

An arrangement of pulleys, or sheaves, through which drilling line is reeved and which moves up and down in the derrick or mast. See block.

A type of bit in which three cone-shaped cutting devices are mounted in such a way that they intermesh and rotate together as the bit drills. […]

The operation of hoisting the drill stem from and returning it to the wellbore. See make a trip.

A trip saver is a device that permits riser hang-off of the disconnected BOP stack to allow drilling operations to continue without retrieval of the BOP […]

A tubular handling machine is a pipe deck tubular handling arm, some of which handle one joint of pipe at a time and some which handle […]

A downhole motor that rotates a bit by the action of the drilling mud on turbine blades built into the tool. When a turbodrill is used, […]

A slang term on a rotary rig referring to the actual drilling operation during which the drill stem is rotated in a clockwise direction.

See Horizontal tubular transfer. A two arm system is the combination of an upper tailing arm and an intermediate hoisting/racking arm. A three arm system is […]