Definition
Heavy-Weight Drill Pipe — Heavy-weight drill pipe (HWDP) is a thick-walled, extra-long-tool-joint pipe run as a transition between drill collars and standard drill pipe, adding weight to the bit while resisting the fatigue that occurs at that stiffness change.
Also known as: HWDP, heavyweight drill pipe, heavy weight drill pipe
What HWDP is
Heavy-weight drill pipe looks like drill pipe but has a much thicker tube wall, extra-long tool joints, and often a wear pad (center upset) on the tube body. Its weight per foot sits between that of standard drill pipe and drill collars, making it the ideal transition member in a drill string.
By placing HWDP between the stiff drill collars and the more flexible drill pipe, the sudden change in cross-sectional stiffness is spread out, which reduces the bending stress and fatigue cracking that otherwise concentrates at the top of the collars.
Common roles
- Transition zone — dampens the stiffness step above the BHA to protect drill pipe from fatigue.
- Weight-on-bit in deviated wells — in directional and horizontal sections, flexible HWDP is run in compression to add WOB without the buckling risk of rigid collars.
- Center upset — the raised mid-body band reduces tube contact with the wellbore wall.
Renting HWDP
HWDP is a workhorse of both vertical and directional strings, and inspection to DS-1 keeps the long tool joints and center upset within tolerance. Browse rentable heavy-weight drill pipe or contact us to size a transition string for your BHA.