Heavy weight drill pipe is a medium-weight drill tool similar to drill pipe, whose wall is thicker than that of drill pipe and thinner than that of drill collar. Its tube is connected with special length-added drill pipe joint (integral heavy weight drill pipe is made up of tube and tool joint). Among assemblies, it is generally added between drill pipe and drill collar to prevent sudden changes in cross-section of drill string, and reduce its fatigue. Using it to replace part of the drill collar can reduce torque, improve load, and increase drilling ability during deep well drilling; meanwhile pick-up sub and safety clamp will not be used drilling operation ,which is easy to operate and can save tripping time. It can drill in in high speed under low torque in directional wells and reduces the abrasion and fracture of string without differential pressure and sticking because of the lower steel grade than drill collar, small touching area with the well wall.

It is made from premium alloyed steel (4145H, or 4145H MOD ). The hard facing welded on the two ends and middle upset are to protect the pipe being weared. Production complies with the provisions under the Standard SY/T 5146-1997. Connector screws comply with the provisions of the Standard API SPEC 7-1.

Manufacturing Process