To accommodate downhole wireline toolstrings while rigging up, and during wireline operations, as well as when entering the wellbore and returning to surface.
The lubricator is made up of sections of tubing material threaded on both ends to accept hand unions. Once they are made up with hand unions they are known as lubricator joints, and come in 8 or 10 foot lengths.
Standard lubricator sizes on slickline service units are 2.875 and 3.50 inches OD (outside diameter). Lubricator sizes are also available up to 7” OD. Sour service or NACE spec. lubricator joints are machined from Sour service stock material, where the upper and lower hand unions are machined as part of the lubricator joint or maybe made with sealed premium thread connections.
An optional bleed sub may be incorporated into the lubricator assembly. This involves a ported .50” NPT sub between the lubricator tube and the bottom hand union.
More information available upon request.