دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: a short, threaded piece of pipe used to adapt parts of the drilling string that cannot otherwise be screwed together because of differences in thread size or design. A sub (i.e., a substitute) may also perform a special function. Lifting subs are used with drill collars to provide a shoulder to fit the drill pipe elevators;a kelly saver sub is placed between the drill pipe and the kelly to prevent excessive thread wear of the kelly and drill pipe threads;a bent sub is used when drilling a directional hole.

n: A shot section of pipe ,tubing ,or drill pipe run into a hole.

a short section of pipe, used to describe tools or to solve space-out gaps.