Patent ID: 7117948

Claim:
A snubbing unit for selectively pulling and running a string of tubing in a well under pressure in a stand alone mode and a rig assist mode, comprising: a lower frame for mounting during the stand alone mode on a snubber blowout preventer that is sealable around the tubing; stationary weight supporting slips and stationary snubbing slips carried by the lower frame during the stand alone mode; a plurality of hydraulic cylinder assemblies extending upward from the lower frame during the stand alone mode; a traveling base plate mounted to upper ends of the hydraulic cylinder assembles for upward and downward stroking movement with the upper ends of the hydraulic cylinder assemblies; traveling weight supporting slips and traveling snubbing slips carried by the traveling base plate during the stand along mode for movement therewith; a spacer tube connected to and extending upward from the lower frame in the stand alone mode; a stationary base plate below the traveling base plate, the spacer tube having an upper end connected to the stationary base plate; and wherein in the rig assist mode, the lower frame along with the stationary weight supporting slips and the spacer tube are removed to enable a rig blowout preventer to connect to the stationary base plate, and the stationary snubbing slips are carried by the cylinder assemblies above the stationary base plate.