Prevents the sudden changes in the drill string section modulus, reduce the fatigue damage of drill rod, Can replace part of the drill collar, can reduce load, increase the drilling ability of rigs, Can drill at high speed under lower torque, improve the ability to change the direction of borehole, Not easy to form differential pressure sticking.Oil well drilling.
1. Size: 3-1/2"HWDP, 4-1/2"HWDP, 5"HWDP;
2. Length: NC31;
3. Type of Connection: 30FT.