To drill into the Mantle, we need to lower drill pipe from the ship to reach the sea floor at about 4,000 m. From there, another 7,000 m of drill pipe is needed to reach below the sea floor down to the Mantle – at least 11,000 m of drill pipe! With this length of drill pipe, the forces that are combining to tear it apart, the weight of the drill pipe itself, dynamic tension owing from the motion of the vessel, bending moment, and additional forces including torque and hoop force during actual drilling operations, should be minimized as much as possible. Added to this is the importance of preventing drill pipe fatigue failure during long duration drilling operations. Taking all these needs into consideration, CDEX is developing 12,000 m-class high-strength and high-performance drill pipe.
- Developing high-strength drilling pipe using materials 10% stronger than conventional drill pipes, and using larger diameter (5-7/8” or 6-5/8”) drill pipe.
- Adding stress relief grooves on the tool joint threads helps mitigate stress, while optimizing drill pipe design with high strength materials, and marking tool joints with stress relief grooves.
- Developing high-performance drill pipe with data transfer capabilities.
- Investigating the use of new materials in drill pipes.