Double-ledge design is better to uniform the stress distribution, with two ends of thread to bear the load. Compared with API joint, it has stronger rigidity, and torsion resistance performance is increased by more than 30% under the same wall thickness;

The junction stress concentration is decreased; fatigue resistance is improved, so as to prolong the service life; compared with API thread, more outer diameter wear loss is allowed prior to the degrade;

Joint outer diameter is appropriately reduced, and annulus space is increased through optimization design, to accordingly lower the circulating pressure loss in annulus space and improve the joint salvageable ability;

Smooth inner surface design improves the joint hydraulic performance, result in more stable flow and smaller turbulence, to reduce the possibility of erosion and cement and solid particles deposition in the joint.

Inner diameter is increased through the optimization design, to reduce the circulating pressure loss within the drill tool, raise the efficiency and capacity of pumping in the drill string, and enhance the capacity of various cables and instruments in the drill string.