As a component of the Drilling rig String, Heavy weight Drill pipe has a unit weight between Drill Pipe and Drill Collars. They are run between Drill Collars and Drill Pipes to:

Benefits:

HW Saves Rig Time by Reducing Trip Time

HWs stand back in the rack like regular Drill Pipe

Reducing wall friction In Deviated Well: Reducing wall friction in deviated wells, heavy wall DP gives better direction control in deviated wells.