Ultra-deep drilling drill pipe

To reach the upper-most mantle interface, drilling must take place in 4000 m water or deeper and drill to a depth of 7000 m below the seafloor. Therefore, drilling vessels will need to use drill strings with total lengths of 11000 m or longer to reach these depths. Therefore, it is vital that the tension caused by the weight of the drill string and the dynamic tension caused by vessel heave does not exceed the allowable load of drill pipe and tool joints.

Objective:
1. Develop high-tension steel,
2. Develop high-strength drill pipe and tool-joint,
3. Develop methods of fatigue life estimation for high-strength drill pipe and tool joints with respect to the action of large tension load,
4. Develop 12000 m class drill strings that can reach the uppermost mantle.

Trial sections of high-strength drill pipe.

Cross-section of a high-strength drill pipe test section.