Torque Anchor to Prevent Rotation of Well Production Tubing, System for Pumping and Rotation Prevention, and Pumping Installation Equipped with Such a Torque Anchor

Abstract

The invention relates to a torque anchor which prevents rotation of a tubing string with respect to a casing of a well for pumping a fluid. The torque anchor comprises a frame intended to be mounted in the casing, an internal channel formed in the frame; a cavity in fluid communication with the internal channel, said cavity extending along a radial direction, and an anchoring piston capable of sliding relative to the frame along the radial direction and of exerting torque on the casing, when the pumped fluid contained in the internal channel exerts force on said anchoring piston. The invention also relates to a system for pumping and rotation prevention and a pumping device equipped with such a torque anchor.

1 . A torque anchor for preventing rotation of a tubing string relative to a casing of a well for the pumping of a fluid by a progressive cavity pump, said torque anchor comprising:
 a frame intended to be mounted in the casing,   an internal channel formed in the frame, said internal channel extending along an axial direction;   at least one cavity in fluid communication with the internal channel, said cavity extending along a radial direction, and   at least one anchoring piston fitted to said radial cavity,   wherein said torque anchor comprises at least one pre-loading spring adapted to act between said anchoring piston and the frame to bias said anchoring piston in a radial direction against the casing;   and wherein said internal channel is traversed by the pumped fluid, said anchoring piston being capable of sliding relative to the frame along the radial direction; said anchoring piston being capable of exerting torque on the casing, when the pumped fluid contained in the internal channel exerts force on said anchoring piston; said force being a function of the pressure difference between the pressure inside the internal channel and the pressure outside the frame.   
     
     
         2 . The torque anchor according to  claim 1 , wherein the frame comprises a flange facing the periphery of a flat face of the anchoring piston, said flange forming a flat shoulder contained in a plane perpendicular to the radial direction, said at least one pre-loading spring being supported by said shoulder. 
     
     
         3 . The torque anchor according to  claim 2 , wherein said flange forms a wall provided with at least one opening suitable for restraining the flow of pumped fluid; said at least one opening having a surface area of between 0.5% and 5% of the surface area of a cross-section of the radial cavity; said cross-section being perpendicular to the radial direction. 
     
     
         4 . The torque anchor according to  claim 2 , wherein the frame comprises a sleeve interposed between the radial cavity and the anchoring piston; said sleeve comprising said flange and at least a portion of said flange extending into the internal channel. 
     
     
         5 . The torque anchor according to  claim 4 , wherein said sleeve is made of ceramic. 
     
     
         6 . The torque anchor according to  claim 2 , wherein said anchoring piston comprises a head and a skirt extending the periphery of the head, said head and said skirt forming a chamber that opens to the internal channel, said pre-loading spring being housed in said chamber and guided by said skirt. 
     
     
         7 . The torque anchor according to  claim 1 , wherein the anchoring piston and the radial cavity have a cylindrical shape with a circular base, the anchoring piston being prevented from rotating relative to the frame by a rotation prevention device. 
     
     
         8 . The torque anchor according to  claim 7 , wherein the rotation prevention device comprises a groove and a tooth able to slide in the groove in a radial direction, one of the groove and tooth being integral to a free end of the skirt and the other to the frame. 
     
     
         9 . The torque anchor according to  claim 1 , wherein a transverse cross-section of the anchoring piston and of the radial cavity has an oblong shape. 
     
     
         10 . The torque anchor according to  claim 1 , wherein the anchoring piston has an outer face facing the casing, said outer face being provided with a lip that is preferably rectilinear. 
     
     
         11 . The torque anchor according to  claim 1 , wherein, when the at least one anchoring piston is arranged in a single plane, said lip extends for a distance of between 30% and 70%, and preferably between 30% and 48%, of the inside diameter of the casing, and when the at least one anchoring piston comprises a plurality of pistons arranged in a plurality of planes, the distance defined between the ends of the lips of the end anchoring pistons is between 30% and 70%, and preferably between 30% and 48%, of the inside diameter of the casing. 
     
     
         12 . The torque anchor according to  claim 5 , which further comprises a gasket ensuring a fluid-tight seal between the anchoring piston and the frame or sleeve. 
     
     
         13 . The torque anchor according to  claim 1 , which comprises at least one brace adapted to retain the anchoring piston in a retracted position when the torque anchor is being lowered downhole, said brace being attached on the one hand to a face of the anchoring piston and on the other hand to the frame. 
     
     
         14 . A system for pumping and preventing rotation of a tubing string relative to a well casing, said system comprising a progressive cavity pump adapted to intake fluid for pumping through an inlet, compress the pumped fluid, and discharge the compressed fluid through an outlet,
 wherein the system comprises a torque anchor defined according to the features of  claim 1 , said torque anchor being secured downstream of the progressive cavity pump, relative to the direction of flow of the fluid pumped within the internal cavity, said torque being a function of the difference in pressure generated by the progressive cavity pump between its inlet and its outlet.   
     
     
         15 . A pumping installation of a well equipped with a casing, said pumping installation comprising:
 a tubing string arranged in said casing;   a progressive cavity pump adapted to move a fluid to be pumped through an intake inlet, and to discharge the fluid through a discharge outlet,   wherein the installation comprises a torque anchor defined according to the features of  claim 1 ; said torque anchor being secured downstream of the progressive cavity pump, relative to the direction of flow of the fluid pumped within the internal cavity; said force being a function of the difference in pressure generated by the progressive cavity pump between its inlet and its outlet.   
     
     
         16 . A method for preventing rotation of a tubing string relative to a casing of a shaft for pumping fluid by a progressive cavity pump, said method being implemented by a torque anchor comprising a frame intended to be mounted in the casing, an internal channel formed in the frame, said internal channel extending along an axial direction, at least one cavity in fluid communication with the internal channel, said cavity extending along a radial direction, and at least one anchoring piston fitted to said radial cavity, wherein the method comprises the following steps:
 intake of a fluid to be pumped, through an inlet of the progressive cavity pump;   traversal by the pumped fluid of said internal channel;   discharge of said pressurized fluid in the tubing string, through the outlet of said progressive cavity pump;   application of pressure by the pumped fluid on a face of the anchoring piston; and   sliding of said anchoring piston relative to the frame in the radial direction, said application causing torque to be applied by said anchoring piston to the casing, said torque being a function of the pressure difference between the inlet and the outlet of the progressive cavity pump.   
     
     
         17 . A centering device and/or a damper comprising:
 a frame intended to be mounted in the casing;   an internal channel formed in the frame, said internal channel extending along an axial direction, a pumped fluid traveling in said internal channel;   at least one cavity in fluid communication with the internal channel, said cavity extending along a radial direction; and   at least one anchoring piston fitted to said radial cavity, said anchoring piston being capable of sliding relative to the frame along the radial direction and of exerting torque on the casing, when the pumped fluid contained in the internal channel exerts force on said anchoring piston.