Production String (or Completion String)
The production string consists primarily of production tubing, but also includes additional components such as the surface-controlled subsurface safety valve (SCSSV), gas lift mandrels, chemical injection and instrument ports, landing nipples, and packer or packer seal assemblies. The production string is run inside the production casing and used to conduct production fluids to the surface.
Source: API RP 90, Annular Casing Pressure Management for Offshore Wells, Upstream Segment. First Edition, August 2006. Global Standards