Slip joint for downhole tubing

Abstract

A movable downhole tubing string for a downhole well. The well has a wellhead and a downhole pump. The movable downhole tubing string has a movable tubing string having a surface end adjacent to the wellhead and a pump end adjacent to the downhole pump. At least one of the surface end and the pump end is telescopically received within a stationary tubing section. The stationary tubing section is stationary relative to the wellhead. There is an actuator for telescopically moving the movable tubing string relative to the stationary tubing section.

What is claimed is: 
     
         1 . A movable downhole tubing string for a downhole well, the well having a wellhead and a downhole pump, the movable downhole tubing string comprising:
 a movable tubing string having a surface end adjacent to the wellhead and a pump end adjacent to the downhole pump, at least one of the surface end and the pump end being telescopically received within a stationary tubing section, the stationary tubing section being stationary relative to the wellhead; and   an actuator for telescopically moving the movable tubing string relative to the stationary tubing section.   
     
     
         2 . The movable downhole tubing string of  claim 1 , further comprising a rotator that rotates the movable tubing string as it moves relative to the stationary tubing section. 
     
     
         3 . The movable downhole tubing string of  claim 2 , wherein the rotator comprises a sleeve having a position that is fixed relative to the stationary tubing section, the sleeve having at least one groove that defines a spiral, each of the at least one groove being engaged by a pin that is carried by the movable tubing string, the pin travelling along the groove as the movable tubing string moves between the retracted position and the extended position. 
     
     
         4 . The movable downhole tubing string of  claim 1 , wherein the actuator comprises a hydraulic actuator or a mechanical actuator. 
     
     
         5 . The movable downhole tubing string of  claim 1 , wherein the actuator comprises a piston actuator formed by the movable tubing string and the stationary tubing section at at least one of the surface end and the pump end. 
     
     
         6 . The movable downhole tubing string of  claim 1 , wherein the stationary tubing section is at the surface end of the movable tubing string. 
     
     
         7 . The movable downhole tubing string of  claim 1 , comprising a stationary tubing section at the surface end and at the downhole end of the movable tubing string. 
     
     
         8 . The movable downhole tubing string of  claim 7 , wherein the stationary tubing section at the downhole end of the movable tubing string comprises flow apertures, the flow apertures being selectively opened by movement of the movable tubing string. 
     
     
         9 . The movable downhole tubing string of  claim 1 , wherein the downhole pump is a progressive cavity pump comprising a rotor and a stator and the downhole end of the movable tubing string is attached to the rotor of the progressive cavity pump. 
     
     
         10 . The movable downhole tubing string of  claim 9 , wherein the movable tubing string moves the stator at least one of up and down relative to the rotor. 
     
     
         11 . In combination:
 a wellhead;   a first stationary tubing section rigidly connected to the wellhead;   a movable tubing string having a surface end and a pump end, the surface end being telescopically received within the first stationary tubing section;   an actuator for telescopically moving the movable tubing string relative to the first stationary tubing section;   a downhole pump adjacent to the pump end of the movable tubing string; and   a pump drive string extending through the movable tubing string between the wellhead and the downhole pump.   
     
     
         12 . The combination of  claim 11 , further comprising a rotator that rotates the movable tubing string as it is moves telescopically relative to the first stationary tubing section. 
     
     
         13 . The combination of  claim 12 , wherein the rotator comprises a sleeve having a position that is fixed relative to the stationary tubing section, the sleeve having at least one groove that defines a spiral, each of the at least one groove being engaged by a pin that is carried by the movable tubing string, the pin travelling along the groove as the movable tubing string moves between the refracted position and the extended position. 
     
     
         14 . The combination of  claim 11 , wherein the actuator comprises a piston actuator formed by the movable tubing string and the first stationary tubing section. 
     
     
         15 . The combination of  claim 11 , further comprising a second stationary tubing section at the downhole end of the movable tubing string, the downhole pump being rigidly connected to the second stationary tubing section. 
     
     
         16 . The combination of  claim 15 , wherein the stationary tubing section at the downhole end of the movable tubing string comprises flow apertures, the flow apertures being selectively opened by movement of the movable tubing string. 
     
     
         17 . The combination of  claim 11 , wherein the downhole pump is a progressive cavity pump comprising a rotor and a stator and the downhole end of the movable tubing string is attached to the rotor of the progressive cavity pump. 
     
     
         18 . The combination of  claim 17 , wherein the movable tubing string moves the stator at least one of down relative to the rotor or up relative to the rotor. 
     
     
         19 . The combination of  claim 11 , wherein the actuator comprises a hydraulic actuator and the tubing string further comprises a piston mounted at an upper end of the movable tubing string. 
     
     
         20 . A method of operating a downhole pump, comprising the steps of:
 providing a tubing string having a stationary tubing section and a movable tubing string telescopically received within the stationary tubing section;   attaching a downhole pump to the stationary tubing section of the tubing string and attaching a pump drive string to the downhole pump;   inserting the tubing string into a producing wellbore;   driving the pump using the pump drive string; and   telescopically moving the movable tubing string of the tubing string relative to the stationary tubing section to distribute the wear on the movable tubing string incurred by the pump drive string along the movable tubing string.   
     
     
         21 . The method of  claim 20 , wherein moving the movable tubing string further comprises rotating the movable tubing string as it moves between the extended position and the refracted position.