Definition - What does Snubbing Unit mean?
A Stubbing Unit is a hydraulically actuated unit that contains slips, hydraulic jack and blowout preventer stack for pulling or inserting bottomhole assembly and tubing from a live or an under-balanced well state. They are one of the most important, efficient and capable well servicing tools used. Slips are the main component of the unit that is operated in a sequence to hold the pipe as it gets snubbed into the well. They have become a chosen resource due to their capability to handle pressure, minimal wall contact and jointed tubing rigidity.
Petropedia explains Snubbing Unit
A Snubbing Unit came into existence in the 1920's when the necessity for rigs to work under pressure was felt. The first unit was designed to work in well control situations to snub casing or drill pipes out of or into the wellbore. The unit was used when conventional methods of well killing did not work. The modern units are powered by hydraulic systems.
The Snubbing Unit is the hydraulic rig that can perform every operation that a rig can perform even under pressure in a live well of under balanced state. By using the hydraulic rotary of the unit, the unit can be used in many functions like milling, drilling, fishing, side tracking and any other task that is needed to remove cement, bridge plugs or deepen wells.