• Drill pipes are heavy seamless steel or aluminum alloy pipes that rotates the drill bit.
• Drill pipes are simultaneously subjected to high torque by drilling, axial tension by its dead weight, and internal pressure by purging of drilling fluid. Additionally, alternating bending loads due to non-vertical or deflected drilling may be superimposed on these basic loading patterns.
• Drill pipesare hollow to allow drilling fluid to be pumped through them, down the hole, and back up the annulus.
• Drill pipes are usually between nine and thirteen centimeters in diameter and around 27 to 32 feet in length (Range 2).Longer lengths, up to 45 feet, exist (Range 3).