Actuated stuffing box for an artificial lift system

Abstract

A stuffing box assembly for an artificial lift system includes a stuffing box including a housing having a passage, in which the housing has a shoulder disposed along the passage. The stuffing box also includes a seal disposed within the passage and engaged with the shoulder. The seal is configured to engage a polish rod while the polish rod extends through the passage, and the seal is configured to expand radially in response to longitudinal compression of the seal. In addition, the stuffing box includes an actuator having an engagement element configured to move along a longitudinal axis to compress the seal. Furthermore, the stuffing box assembly includes a controller configured to determine a flow rate of fluid bypassing the seal based on one or more input signals, and the controller is configured to control the actuator based on the flow rate.

1 . A stuffing box assembly for an artificial lift system, comprising:
 a stuffing box, comprising:
 a stuffing box housing having a passage extending through an entire longitudinal extent of the stuffing box housing, wherein the stuffing box housing has a shoulder disposed along the passage; 
 a seal disposed within the passage of the stuffing box housing and engaged with the shoulder, wherein the seal is configured to engage a polish rod while the polish rod extends through the passage, and the seal is configured to expand radially in response to compression of the seal along a longitudinal axis of the stuffing box; and 
 an actuator having an engagement element configured to move along the longitudinal axis to compress the seal; and 
   a controller comprising a processor and a memory, wherein the controller is communicatively coupled to the actuator, the controller is configured to determine a flow rate of fluid bypassing the seal based on one or more input signals, and the controller is configured to control the actuator based on the flow rate of the fluid bypassing the seal.   
     
     
         2 . The stuffing box assembly of  claim 1 , comprising an actuating line coupled to the actuator and configured to facilitate control of the actuator from a location remote from the stuffing box. 
     
     
         3 . The stuffing box assembly of  claim 2 , wherein the actuator comprises a piston, the actuating line comprises an actuating fluid line, and the actuating fluid line is configured to enable flow of actuating fluid to the actuator to drive the piston to move the engagement element along the longitudinal axis to compress the seal. 
     
     
         4 . The stuffing box assembly of  claim 3 , comprising a valve assembly fluidly coupled to the actuating fluid line and communicatively coupled to the controller, wherein the controller is configured to control the valve assembly to control flow of the actuating fluid to the actuator. 
     
     
         5 . The stuffing box assembly of  claim 2 , wherein the actuator comprises an electric motor, the actuating line comprises an electrical line, the electrical line is configured to provide electrical power to the electric motor, and the electric motor is configured to drive the engagement element along the longitudinal axis to compress the seal in response to receiving the electrical power. 
     
     
         6 . The stuffing box assembly of  claim 5 , wherein the actuator comprises a gear assembly configured to translate rotational motion of a shaft of the electric motor into linear movement of the engagement element along the longitudinal axis. 
     
     
         7 . The stuffing box assembly of  claim 1 , wherein the stuffing box comprises a secondary seal disposed within a circumferential recess of the actuator and engaged with a shoulder of the actuator, the secondary seal is configured to engage the polish rod while the polish rod extends through the passage of the stuffing box housing, and the secondary seal is configured to expand radially in response to compression of the secondary seal along the longitudinal axis of the stuffing box. 
     
     
         8 . The stuffing box assembly of  claim 7 , wherein the stuffing box comprises a packing nut having external threads, the actuator has corresponding internal threads configured to engage the external threads of the packing nut, and the packing nut is configured to compress the secondary seal along the longitudinal axis in response to rotation of the packing nut. 
     
     
         9 . The stuffing box assembly of  claim 7 , wherein the stuffing box comprises:
 a packing driver having a plurality of apertures; and   a plurality of threaded fasteners configured to extend through the plurality of apertures;   wherein the actuator comprises a plurality of threaded recesses, the plurality of threaded fasteners are configured to engage the plurality of threaded recesses, and each threaded fastener of the plurality of threaded fasteners is configured to drive the packing driver to compress the secondary seal along the longitudinal axis in response to rotation of the threaded fastener.   
     
     
         10 . The stuffing box assembly of  claim 1 , comprising a sensor communicatively coupled to the controller, wherein the sensor is fluidly coupled to a cavity configured to receive the fluid bypassing the seal, and the sensor is configured to output the one or more input signals to the controller. 
     
     
         11 . The stuffing box assembly of  claim 1 , wherein the controller is configured to control the actuator to compress the seal in response to determining the flow rate of the fluid bypassing the seal is greater than a threshold flow rate. 
     
     
         12 . The stuffing box assembly of  claim 1 , comprising a user interface communicatively coupled to the controller, wherein the controller is configured to control the user interface to inform an operator in response to determining the flow rate of the fluid bypassing the seal is greater than a threshold flow rate. 
     
     
         13 . A stuffing box for an artificial lift system, comprising:
 a stuffing box housing having a passage extending through an entire longitudinal extent of the stuffing box housing, wherein the stuffing box housing has a shoulder disposed along the passage;   a seal disposed within the passage of the stuffing box housing and engaged with the shoulder, wherein the seal is configured to engage a polish rod while the polish rod extends through the passage, and the seal is configured to expand radially in response to compression of the seal along a longitudinal axis of the stuffing box; and   an actuator assembly comprising an actuator and an actuator housing, wherein the actuator housing is coupled to the stuffing box housing, and the actuator comprises:
 an engagement element configured to move along the longitudinal axis to compress the seal; and 
 a gear assembly disposed within the actuator housing and configured to translate rotational motion of a shaft into linear movement of the engagement element along the longitudinal axis. 
   
     
     
         14 . The stuffing box of  claim 13 , wherein the actuator comprises a rotary actuator, the rotary actuator comprises the shaft, and the rotary actuator is configured to drive the shaft in rotation. 
     
     
         15 . The stuffing box of  claim 13 , wherein the gear assembly comprises:
 a worm gear non-rotatably coupled to the shaft of the rotary actuator, wherein the worm gear has spiral threads; and   a toothed wheel having external teeth and internal threads, wherein the external teeth are configured to engage the spiral threads of the worm gear, the engagement element has external threads, and the internal threads of the toothed wheel are configured to engage the external threads of the engagement element.   
     
     
         16 . The stuffing box of  claim 13 , comprising a first bearing and a second bearing, wherein the first bearing is positioned on a first side of the toothed wheel along the longitudinal axis, the second bearing is positioned on a second side of the toothed wheel along the longitudinal axis, opposite the first side, and the first and second bearings are disposed between the engagement element and the actuator housing along a radial axis of the stuffing box. 
     
     
         17 . The stuffing box of  claim 13 , comprising a secondary seal disposed within a circumferential recess of the engagement element of the actuator, wherein the secondary seal is engaged with a shoulder of the engagement element of the actuator, the secondary seal is configured to engage the polish rod while the polish rod extends through the passage of the stuffing box housing, and the secondary seal is configured to expand radially in response to compression of the secondary seal along the longitudinal axis of the stuffing box. 
     
     
         18 . A stuffing box for an artificial lift system, comprising:
 a stuffing box housing having a passage extending through an entire longitudinal extent of the stuffing box housing, wherein the stuffing box housing has a shoulder disposed along the passage;   a seal disposed within the passage of the stuffing box housing and engaged with the shoulder, wherein the seal is configured to engage a polish rod while the polish rod extends through the passage, and the seal is configured to expand radially in response to compression of the seal along a longitudinal axis of the stuffing box; and   an actuator assembly comprising an actuator and an actuator housing, wherein the actuator housing is coupled to the stuffing box housing, and the actuator comprises:
 an engagement element configured to move along the longitudinal axis to compress the seal; and 
 a piston configured to drive the engagement element to move along the longitudinal axis to compress the seal in response to receiving actuating fluid within a cavity formed by the piston and the actuator housing. 
   
     
     
         19 . The stuffing box of  claim 18 , comprising a cavity seal disposed between the piston and the actuator housing along a radial axis of the stuffing box, wherein the seal is configured to substantially block actuating fluid flow out of the cavity. 
     
     
         20 . The stuffing box of  claim 18 , comprising a secondary seal disposed within a circumferential recess of the actuator and engaged with a shoulder of the actuator, wherein the secondary seal is configured to engage the polish rod while the polish rod extends through the passage of the stuffing box housing, and the secondary seal is configured to expand radially in response to compression of the secondary seal along the longitudinal axis of the stuffing box.