Drill strings made prior to 1982 were not designed to meet the rigorous demands of today's drilling. Deeper wells and higher angle holes are requiring higher pump pressure, and more tensile and torque capacity. Back-reaming wells, with the use of a power swivel, is agitating these conditions even further.
Recent work has been done to improve the fatigue life of drill pipe by making drill pipe with longer internal taper upsets and stress relief grooves.
Even though improvements have been made, slip damage still takes its toll on drill pipe. This paper addresses the failures caused by slip damage and offers a solution for solving this problem. Finite element work and fatigue testing has been done to prove the effectiveness of this new drill pipe design.