Drill pipe

It is hollow to allow drilling fluid to be pumped down the hole through the bit and back up the annulus.

It comes in a variety of sizes, strengths, and wall thicknesses, but is typically 27 to 32 feet in length (Range 2).

Drill stems must be designed to transfer drilling torque for combined lengths that often exceed several miles down into the Earth's crust, and also must be able to resist pressure differentials between inside and outside (or vice versa), and have sufficient strength to suspend the total weight of deeper components.

Ultrasonic testing and modified instruments similar to the spherometer are used at inspection sites to identify defects from metal fatigue, in order to preclude fracture of the drill stem during future wellboring.

Drill pipe is most often considered premium class, which is 80% remaining body wall (RBW).

Eventually the drill pipe will be graded as scrap and marked with a red band.

Other BHA components can include a mud motor, measurement while drilling (MWD) apparatus, stabilizers, and various specialty downhole tools.

The green tubes are received by the drill pipe manufacturer from the steel mill.

After a quench and temper heat treat, the tool joints are cut into box (female) and pin (male) threads.