Useful Information on Heavy-weight Drill Pipe

Heavy Weight Drill Pipe (HWDP) looks like an ordinary drill pipe aside from an upset centered along the tube which will help to avoid excessive buckling. And it is produced on the basis of API SPEC7-1 standard. Heavy-weight drill pipes are improved by a gradual transition from heavy drill collars to relatively lightweight drill pipes. And the wall thickness is about one inch, which helps prevent stress concentration at the top of drill collars. Due to utilizing unique centre upset or wear pad, it can increase tube service life and reduce hole drag and differential sticking problems.

Heavy weight drill pipes are proper for directional drilling, because of easy bending, simple directional control and mini connection fatigue problems for high angle or horizontal drilling. For the horizontal wells especially the total vertical depth to total measured depth ration is low, heavy weight drill pipe is the best choice for weight on the bit. Different combinations of HWDP, drill collars and drill string components can be made to meet various challenges of serious drilling conditions.

Directional Drilling
Horizontal and conventional directional well designs;
Improve directional control by reducing torque and drag;
Reduce the risk of differential sticking;

Vertical Drilling
Use as an active weight-on-bit;
Transition zone: the application of heavy weight drill pipe in the transition zone on a vertical drill strings, will reduce the risk of fatigue failure of drill pipes and drill collars.

• Extra-length tool joints provide ample space to re-cut the connections, reduce the wear rate on the OD and extend the service life;
• The center upset protects the tube from OD wear by keeping the tube away from the hole wall, while at the same time reducing the risk of differential sticking;
• The API bore back box stress relief feature is standard for the box connection on heavy weight drill pipe with NC38 and larger connections, helping to extend the service life of the connection;
• Cold rolling the thread roots on all Heavy Weight Drill Pipe connections increases the connection’s ability to resist fatigue cracking;
• Heavy Weight Drill Pipe can be picked up with the drill pipe elevators, for fast efficient handling on the rig floor;
• Stress relief pin groove is also available;