Heavy Weight Drill Pipe (HW DP ) is an intermediate weight drill stem component which is used in conjunction with the drill pipes and drill collars. It has smaller wall thickness than drill collar and bigger wall thickness than drill pipe.
We use HWDP between drill pipe and drill collar to prevent sudden change of drill string section and reduce fatigue of drill pipe.
HWDP is also a good way to Reducing torque and increase load when we need to drill much deeper. We can save a lot of time by not using lifting sub and safety clamps when we choose HWDP in the drill stem.
We use HWDP in directional drilling can keep a highly drilling speed under a lower drilling torque. That reduce the wear and rupture of the drill string. Compared with the drill collar HWDP has low rigidity, and wall contact area is small, so differential pressure sticking will not happen easily.