A small-diameter, steel pipe that is suspended in a completed (cased) well. It can have either plain or upset ends and can have either threaded or integral joints. It is used on both the Christmas tree and with artificial lift to conduct the produced fluids to the surface.
Tubing is a landing base for pumps, well monitoring, and evaluation equipment and safety valves, chokes, and plugs. Tubing is removable in contrast with casing.