WO2007146931A2 - Appareil et procédé de pompe à tige linéaire - Google Patents

Appareil et procédé de pompe à tige linéaire Download PDF

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Publication number
WO2007146931A2
WO2007146931A2 PCT/US2007/070989 US2007070989W WO2007146931A2 WO 2007146931 A2 WO2007146931 A2 WO 2007146931A2 US 2007070989 W US2007070989 W US 2007070989W WO 2007146931 A2 WO2007146931 A2 WO 2007146931A2
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WO
WIPO (PCT)
Prior art keywords
rod
rack
motor
pump
pumping
Prior art date
Application number
PCT/US2007/070989
Other languages
English (en)
Other versions
WO2007146931A3 (fr
Inventor
Thomas L. Beck
Robb G. Anderson
Ronald G. Peterson
Michael A. Macdonald
Original Assignee
Unico, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Unico, Inc. filed Critical Unico, Inc.
Priority to MX2012012458A priority Critical patent/MX337274B/es
Priority to MX2008015795A priority patent/MX2008015795A/es
Priority to EP07798436.7A priority patent/EP2035702B1/fr
Priority to CA2654908A priority patent/CA2654908C/fr
Publication of WO2007146931A2 publication Critical patent/WO2007146931A2/fr
Publication of WO2007146931A3 publication Critical patent/WO2007146931A3/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B47/00—Pumps or pumping installations specially adapted for raising fluids from great depths, e.g. well pumps
    • F04B47/02—Pumps or pumping installations specially adapted for raising fluids from great depths, e.g. well pumps the driving mechanisms being situated at ground level
    • F04B47/04—Pumps or pumping installations specially adapted for raising fluids from great depths, e.g. well pumps the driving mechanisms being situated at ground level the driving means incorporating fluid means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B47/00—Pumps or pumping installations specially adapted for raising fluids from great depths, e.g. well pumps
    • F04B47/02—Pumps or pumping installations specially adapted for raising fluids from great depths, e.g. well pumps the driving mechanisms being situated at ground level
    • F04B47/022—Pumps or pumping installations specially adapted for raising fluids from great depths, e.g. well pumps the driving mechanisms being situated at ground level driving of the walking beam

Definitions

  • This invention relates to pumping of fluids, such as water and/or hydrocarbons, from subterranean formations or reservoirs, and more particularly to a pumping apparatus and method for use in such pumping applications.
  • walking beam-type mechanism For many years, the familiar "horse head", walking beam-type mechanism has been used for pumping fluids such as water and/or oil from subterranean formations.
  • walking beam-type pumping mechanisms must typically be mounted on a heavy concrete foundation 58, which may be poured in place or pre-cast, located adjacent the well head 54. Construction of a walking beam pumping mechanism, together with its foundation, typically involves the efforts of several construction workers, over a period which may be a week or more, to prepare the site, lay the foundation 58, and allow time for the foundation 58 to cure, in addition to the time required for assembling the various components of the walking beam mechanism 50 onto the foundation 58 and operatively connecting the mechanism to the polished rod 52. In general, because of the costs of transporting the apparatus and the concrete or pre-cast foundation to what may be a remote site and the complexity of the site preparation and assembly process, walking beam-type pumping mechanisms are generally only utilized in long-term pumping installations.
  • walking beam-type pumping apparatuses Another disadvantage of walking beam-type pumping apparatuses is that they cannot typically operate at pumping speeds much below 5 strokes per minute. As a result, it has been necessary in the past, to only pump intermittently or to decommission wells which could not sustain pumping at rates of at least 5 strokes per minute, even though such wells would be capable of continued operation at lower pumping speeds. Intermittent pumping creates problems caused by varying levels of fluid in the well casing and tubing and collection of contaminants into the pump during "off periods. As mentioned above, decommissioning a well equipped for pumping with a walking beam-type mechanism is an arduous and costly task. Further, government regulations frequently require the costly process of sealing the well 56 with cement or other sealing means when a well is decommissioned.
  • U.S. Patent No. 4,114,375, to Saruwatari discloses replacing the conventional walking beam pumping apparatus with a pump jack device including a double acting piston and cylinder motor, with the piston rod of the motor being adapted to be connected to the polished rod projecting upwardly from a well head.
  • a variable displacement hydraulic pump driven by a motor or engine, is included in a closed hydraulic loop wherein conduits are connected to a pair of output ports of the pump.
  • a pump control means controls the direction and volume of flow in the loop so as to establish the stroke of the piston rod.
  • a compressible fluid counter-balance is provided for accumulation of energy during a down stroke of the piston rod so that the energy may be returned to the piston during the upstroke.
  • the counter-balance cylinder may be mounted coaxially above the motor and an additional closed chamber may be provided in fluid communication with a charged chamber of the counter-balance.
  • an above-ground upward stroke of 32 inches, for a well approximately 1300 feet deep may only result in a down-hole stroke in the range of 24 to 26 inches, for example.
  • the difference between the magnitude and direction of movement of the polished rod at the top of the well and the corresponding reaction of the rod string and down-hole stroke of the pump involves other complicating factors, including inherent damping within the rod string, fluid damping which occurs during the pump stroke and longitudinal vibrations and natural frequencies of the rod string.
  • a typical down-hole pump portion of a sucker-rod pump, apparatus is located at the bottom of a length of tubing terminating in a fluid outlet above the surface of the ground and includes a standing valve, located at the lower end of the down-hole pump, and a traveling valve, which is attached to the bottom end of the rod string and is movable by the rod string within the down-hole pump above the standing valve.
  • the standing valve performs a check- valve function which allows fluid to flow into the lower end of the down-hole pump when the pressure within the down-hole pump is lower than the pressure in the well casing outside of the down-hole pump.
  • the traveling valve also includes a check-valve function, which works substantially oppositely to the check- valve function of the standing valve.
  • the traveling valve When the pressure within the down-hole pump below the traveling valve is lower than the pressure within the tubing above the traveling valve, the traveling valve is closed. Conversely, when the pressure within the down-hole pump below the traveling valve is greater than the pressure within the tubing above the traveling valve, the traveling valve opens and allows fluid movement through the traveling valve, so that the traveling valve can descend through the fluid in the down-hole pump.
  • the sucker-rod pump is pumping a fluid with no entrained gas
  • the standing valve closes and the stationary valve opens, to thereby trap fluid within the down-hole pump above the standing valve, and allow the traveling valve to move downward through the trapped fluid within the down-hole pump, toward the standing valve, to the bottom of the pump stroke, where the rod string reverses direction and begins to pull the traveling valve upward at the start of the next pump stroke.
  • Beck et al. having a pumping apparatus driven by an electric motor, instantaneous current and voltage, together with pump parameters estimated through the use of a computer model of the sucker-rod pump, are used in determining rod position and load.
  • the rod position and load are used to control the operation of the rod pump to optimize operation of the pump.
  • Beck et al. also discloses a pump-stroke amplifier that is capable of increasing pump stroke without changing the overall pumping speed, or in the alternative, maintaining the well output with decreased overall pumping speed.
  • the commonly assigned Beck et al. patent also provides a detailed description of the considerable additional complexity involved in operating a sucker-rod pump with a walking beam pumping apparatus, or with prior belt driven pumping units, and further provides a method and apparatus for efficiently and effectively controlling a sucker-rod pumping apparatus having a rod string driven by a walking beam pumping apparatus, or other types of previous Iy -known pumping apparatuses.
  • the invention provides an improved apparatus and method for pumping fluids, such as water and/or hydrocarbons, from a subterranean formation or reservoir, through use of a linear rod pumping apparatus having a linear mechanical actuator arrangement and a reversible motor operatively connected for imparting reciprocating, substantially vertical motion to a rod string of a sucker-rod pump.
  • the linear mechanical actuator arrangement has a substantially vertically movable member attached to the polished rod of the sucker-rod pump for imparting and controlling vertical motion of the rod string of the sucker-rod pump.
  • the reversible motor has a reversibly rotatable element thereof operatively connected to the substantially vertically movable member of the linear mechanical actuator arrangement in a manner establishing a fixed relationship between the rotational position of the motor and the linear position of the vertically movable member.
  • a linear rod pumping apparatus includes a mechanical rack and pinion drive arrangement adapted for attachment to a pumping mechanism, such as the polished rod at the top of a rod string in a hydrocarbon well.
  • the rack gear of the rack and pinion drive arrangement is adapted for connection to, and translating movement with, the polished rod.
  • the pinion gear does not translate with the rack gear, and is driven by a reversible motor for effecting up and down reciprocating motion of the rack gear and pumping mechanism.
  • a compressible gas cylinder is utilized to provide a counter-balancing force which counteracts generally downwardly directed forces which are inherently applied to the reciprocating pumping mechanism by the rod string.
  • a linear rod pump apparatus is utilized without a pressurized gas counter-balance cylinder.
  • the pinion gear is driven by a reversible electric motor.
  • the electric motor may be driven by an electronic drive, having a configuration in accordance with the invention, with the drive being controlled by a controller configured according to the invention.
  • a drive and/or controller may provide energy storage and/or dynamic braking to accommodate energy generation within the drive circuit, resulting from reversals in direction of rotation of the drive motor and/or inherent cyclical fluctuations on the electrical buses of the drive mechanism, particularly during the downward stroke of the pump mechanism, when gravitational force is essentially driving the motor as a generator.
  • energy generated during the pumping process may be stored within a capacitor bank section of the drive and used on a subsequent upstroke of the pump for enhancing overall pumping efficiency of a linear rod pump apparatus and/or method, according to the invention.
  • the drive includes a regenerative control section, which modulates energy generated during the pumping cycle in such a manner that it can be transferred back to the source of electrical power supplying power through the drive to the motor.
  • the drive may include a dynamic braking section, in which electrical energy developed during the pumping process is dissipated across a dynamic braking resistor, of the drive, according to the invention.
  • a given embodiment of a drive and controller may include any one or all of the aforementioned: capacitor bank section; regenerative control section; and/or dynamic braking section.
  • all three sections will be provided within the drive, to allow for adaptation of the drive for operation in various installations.
  • the invention may utilize only one or both of the capacitor bank section or dynamic brake section of the drive. Should circumstances change, such as electrical power from a power grid becoming available at the well site, so that the engine driven generator can be eliminated, the drive can then be simply reconfigured to make use of the regenerative control section.
  • a linear mechanical actuator arrangement may include a rack and pinion gearing arrangement, with the rack being disposed for operation in a substantially vertical direction, for reciprocating motion along a pumping axis.
  • the rack may be operatively connected in gear mesh relationship with the pinion, and the pinion may be operatively connected to the rotating output of the reversible motor, such that rotation of the motor in a first direction is accompanied by a substantially vertically upward motion of the rack along the pumping axis, and such that a substantially vertically downward motion of the rack along the pumping axis is accompanied by rotation of the motor rotatable element in a second direction opposite the first direction.
  • the rack may also be operatively connected to the rod of the sucker-rod pump for imparting vertically upward motion to the rod of the sucker-rod pump along the pumping axis when the rack is moving upward.
  • the rack may be further operatively coupled to the rod of the sucker-rod pump such that the rod exerts a substantially vertically downward directed force on the rack while the rack is moving downward, acting substantially along the pumping axis, during a portion of the pump stroke.
  • the rack of a rack and pinion gearing arrangement has a longitudinally directed opening therein, extending along the pump axis from a bottom end of the rack to the top end of the rack when the linear mechanical actuator is operatively disposed above the sucker-rod pump.
  • the rack may further have an upper end thereof adapted for operative attachment of the rod thereto.
  • the upper end of the rack may define a hole extending therethrough, and an upper load bearing surface.
  • the hole in the upper end may be configured such that the upper end of the rod may slideably extend through the hole.
  • the linear mechanical actuator arrangement may further include a rod securing clamp or collar fixedly attached to the upper end of the rod above the upper end of the rack.
  • a rod securing clamp or collar may have a lower load bearing surface thereof adapted for bearing contact with the upper load bearing surface of the upper end of the rack for transferring force between the rod and the upper end of the rack when the lower load bearing surface of the collar is in contact with the upper load bearing surface of the upper end of the rack.
  • a rack, of a rack and pinion gearing arrangement may be configured to have a substantially U-shaped cross-section, with first and second legs of the U extending from a bight section thereof, in such a manner that the legs and bight define a longitudinally extending opening in the rack having the form of an open channel disposed about the pumping axis, with an outer surface of the bight that faces substantially oppositely from the legs including gear teeth of the rack, configured for engagement with corresponding gear teeth of the pinion.
  • a linear rod pumping apparatus may further include one or more guide rollers, disposed to bear against the longitudinally extending distal edges of the legs of the rack at a point or points substantially opposite the pinion, for urging the rack into gear mesh relationship with the pinion.
  • An apparatus may further include a pair of guide bars bearing against the legs of the rack, substantially opposite from one another, for urging the rack into axial gear mesh relationship with the pinion.
  • An apparatus may also include a pinion housing having a longitudinally extending opening therein, disposed about the pumping axis, for passage therethrough of the rack, and defining a rotational axis of the pinion.
  • the rotational axis of the pinion may be laterally offset from, and extend substantially perpendicularly to, the pumping axis.
  • a first anti-drive end of the pinion may be journaled in a pinion bearing disposed in and mounted to the pinion housing.
  • a second drive-end of the pinion may be adapted for connection to an output element of a drive mechanism such as a motor or gearbox, and for being supported by an output bearing of the drive mechanism.
  • an apparatus may include a gearbox operatively connected between the motor and the linear mechanical actuator apparatus.
  • the gearbox may have an input element thereof operatively attached to the rotatable element of the motor for rotation therewith.
  • the gearbox may also have an output element thereof operatively attached to the pinion for rotation therewith.
  • the input and output elements of the gearbox may be arranged substantially at a right angle to one another, with the output element being oriented for alignment with and rotation substantially about the pinion axis, and with the input element of the gearbox and the rotatable element of the motor being oriented substantially parallel to the pumping axis.
  • Some forms of the invention also include a control arrangement, operatively connected to the motor, for controlling the motor.
  • the control arrangement may operate the motor in a driving mode to urge upward movement of the rack on a lifting portion of the stroke of the pump rod.
  • the control arrangement may also operate the motor in a braking mode, during downward movement of the rack, on a return/fill portion of the stroke of the pump rod.
  • the control arrangement may include an energy storage element for storing energy generated during the braking mode of operation of the motor. In other forms of the invention, the control arrangement may be configured for utilizing the stored energy in the energy storage element to assist in driving the motor during the driving mode. In some forms of the invention, the control arrangement may include an energy dissipation element for dissipating energy generated during the braking mode of operation of the motor. In some forms of the invention, a control arrangement may be selectively configurable for operation of one or the other of the energy storage and energy dissipation modes.
  • a control arrangement may further include sensing arrangements for sensing one or more parameters of the group of parameters consisting of: linear position of the rack along the pumping axis; rotational position of the pinion about the pinion axis; motor torque; motor speed; motor acceleration; and motor input power.
  • a control arrangement may include a pump rod dynamics model, for use in controlling operation of the motor.
  • the sensing arrangement may determine linear position of the rack twice during each pump cycle, once on the upstroke and once on the downstroke.
  • a control arrangement may be configured for detecting fault conditions and applying corrective action to modify operation of the motor.
  • Fault conditions which may be detected, in accordance with the invention, may include, but are not limited to: loss of power to the motor; invalid or missed position reference; non- filling of the pump; and motor overheating.
  • Corrective actions may include, but are not be limited to, applying braking force through the motor, or actuation of brake mechanisms external to the linear rod pumping arrangement; changing stroke length and/or frequency; dwelling for a period of time in an off position; or operating the motor to slowly lower the rack to the lower mechanical limit of travel.
  • the invention may be practiced with a variety of different types of motors, including, electrical, hydraulic, and pneumatic.
  • An apparatus may also include a pneumatic energy storage element operatively connected for storing energy generated during downward movement of the vertically movable element, and utilizing the stored energy for aiding upward vertical movement of the vertically movable element.
  • the pneumatic energy storage element may be operatively connected for storing energy generated during the downward movement of the rack, and releasing the stored energy for aiding upward movement of the rack.
  • a spring member is operatively positioned below the lower end of the rack and configured for engaging and applying an upwardly directed force to the lower end of the rack when the lower end of the rack has moved beyond a normal lower position of the rack during a pump stroke.
  • a spring member operatively positioned below the lower end of the rack may be positioned and configured for engaging and applying an upwardly directed force to the lower end of the rack during a portion of each pump stroke.
  • Some forms of the invention include an oil sump disposed around the lower end of the rack and configured for containing a volume of lubricant therein and for receiving a portion of the rack adjacent the lower end of the rack to thereby apply the lubricant to the rack.
  • the sump and the volume of lubricant therein may be configured and positioned such that the portion of the rack is immersed into the lubricant during at least a portion of each stroke of the pump.
  • the sump may include an inner and outer longitudinally extending, radially spaced tubular wall, sealingly connected at lower ends thereof to define an annular- shaped cavity therebetween, for receipt within the cavity of the volume of lubricant, and terminating in an annular-shaped opening between the upper ends of the inner and outer tubular walls.
  • the inner tubular wall of the sump may have, an inner periphery thereof disposed about the pump rod, and an outer periphery thereof disposed within the opening in the rack.
  • the outer tubular wall of the sump may have an inner periphery thereof disposed about the rack.
  • the apparatus may further include a spring member operatively positioned within the cavity in the sump below the lower end of the rack and configured for engaging and applying an upwardly directed forced to the lower end of the rack when the lower end of the rack has moved beyond a normal position of the rack during a pump stroke.
  • a spring member operatively positioned within the cavity of the sump below the lower end of the rack, may be configured for engaging and applying an upwardly directed force to the lower end of the rack during a portion of each pump stroke.
  • Some forms of the invention include a position sensing arrangement for sensing a position of the rack along the pump axis.
  • the position sensing arrangement may include a stationary position sensor and a sensor flag.
  • the stationary position sensor is disposed adjacent the rack substantially at a mid-stroke position along the pumping axis.
  • the sensor flag is attached to the rack and disposed such that the flag is juxtaposed with, and sensed by, the sensor during each pumping stroke.
  • an upper sensor flag and a lower sensor flag are axially spaced from one another along the rack, to form a gap between the upper and lower flags, with the gap being substantially centrally disposed along the rack.
  • the upper sensor flag extends substantially from the upper end of the rack to a lower edge of the upper sensor flag defining an upper end of the gap between the upper and lower sensor flags
  • the lower sensor flag extends substantially from the lower end of the rack to an upper edge of the lower sensor flag defining the lower end of the gap between the upper and lower sensor flags.
  • the senor may produce an output having a substantially square-wave shape, with a step change from a first state, whereat one or the other of the flags is juxtaposed with the sensor, to a second state whereat the gap is juxtaposed with the sensor.
  • the invention may also be practiced in the form of a method for constructing, operating, maintaining, or replacing a linear rod pumping apparatus according to the invention.
  • a method for operating a linear rod pumping apparatus including a linear mechanical actuator arrangement and a reversible motor, where the linear mechanical actuator has a substantially vertically movable member adapted for attachment thereto of the rod of a sucker-rod pump, for parting and controlling vertical motion of the rod of the sucker-rod pump.
  • the reversible motor has a reversibly rotatable element thereof, operatively connected to the substantially vertical member of the linear mechanical actuator arrangement in a manner establishing a fixed relationship between the rotational position of the rotatable element of the motor and the vertical position of the vertically movable member, with the method including, operating the motor in a manner imparting reciprocating substantially vertical motion to the vertically movable member.
  • the method may further include determining dynamic operation of the pump rod, and controlling the motor in accordance with the dynamic operation of the pump rod.
  • a method may include operating the motor in a driving mode, for applying torque to the rotatable element of the motor in a first direction to urge rotation of the rotatable element in the first direction and upward movement of the vertically movable member on an upward portion of a stroke of the pump rod.
  • a method may further include operating the motor in a braking mode, for applying a net torque to the rotatable element in the first direction, for resisting rotation of the rotatable element in the opposite direction during downward movement of the vertically movable member on a downward portion of the stroke of the pump rod.
  • the motor generates energy during the braking mode
  • a method, according to the invention may further include extracting at least a portion of the generated energy during the braking mode of operation.
  • the extracted energy may be utilized, in some forms of the invention, to assist in driving the motor during at least one of the driving and braking modes.
  • the energy generated during the braking mode of operation of the motor may be dissipated.
  • the invention may also include controlling the motor in accordance with sensed values of one or more parameters selected from the group of parameters consisting of, linear position of the vertically movable member, rotational position of the rotatable element of the motor, motor torque, motor speed, motor acceleration, and motor input power.
  • one or more of the sensed values of parameters used for controlling the motor are sensed above-ground, rather than through the use of down-hole sensors.
  • all sensed values of the parameters used for controlling the motor are sensed above-ground.
  • Some forms of the invention may include detecting a fault condition, and taking corrective action. Some forms of the invention may include detecting a fault condition from the group of faults consisting of, loss of power to the motor, invalid or missed position reference, loss of control of the motor, non-filling of the pump, breakage and/or separation of the pump rod, and overheating of the motor.
  • the corrective action taken may be one of a group of corrective actions from the group consisting of, applying braking, changing pump stroke length, changing pump stroke frequency, dwelling in a non-pumping state, operating the motor to slowly lower the rack to the lower mechanical limit of travel, and entering a start-up mode of operation.
  • a linear rod pumping apparatus includes a position sensing arrangement having a stationary position sensor disposed adjacent the vertically movable member, approximately at a mid-stroke position thereof along the pumping axis, and a sensor flag attached to the vertically movable member and disposed such that the flag is juxtaposed with, and sensed by, the sensor during each pumping stroke
  • a method may include detecting the vertical position of the vertically movable member by detecting juxtaposition of the flag with the sensor during each pump stroke.
  • a sensing arrangement includes an upper sensor flag and a lower sensor flag, axially spaced from one another along the rack, to form a gap between the upper and lower flags, with the gap being substantially centrally longitudinally disposed along the rack.
  • the upper sensor flag may extend substantially from the upper end of the rack to a lower edge of the upper sensor flag, defining an upper end of the gap between the upper and lower flags.
  • the lower sensor flag may extend substantially from the lower end of the rack to an upper edge of the lower sensor flag, to thereby define the lower end of the gap between the upper and lower sensor flags.
  • a method may include detecting the vertical position of the vertically movable member by detecting juxtaposition of the sensor with at least one of the upper and lower sensor flags during each pump stroke.
  • a method may further include detecting an output of the sensor having a substantially square -wave shape, with a step change form a first state while one or the other of the lower flags is juxtapose with the sensor, to a second state when the gap is juxtapose with the sensor.
  • a method for extending the operating life of a hydrocarbon well where the well has a walking beam apparatus operatively connected to the well for imparting reciprocating substantially vertical motion to a rod of a sucker-rod pump stroke.
  • the method may include disconnecting the rod from the walking beam apparatus, and operatively connecting the rod to a linear rod pumping apparatus including a linear mechanical actuator arrangement and a reversible motor, according to the invention.
  • the linear mechanical actuator arrangement may include a substantially vertically movable member configured for attachment to the rod of the sucker-rod pump for imparting and controlling vertical motion of the rod of the sucker-rod pump.
  • the motor may include a reversibly rotatable element thereof, operatively connected to the substantially vertically movable member of the linear mechanical actuator arrangement in a manner establishing a fixed relationship between the rotational position of the motor and the linear position of the vertically movable member.
  • a method for extending the operating life of a hydrocarbon well may further include mounting the linear rod pumping apparatus directly on the well head of the well, to thereby preclude the need for a separate mounting structure for the linear rod pumping apparatus.
  • the walking beam apparatus is left in place adjacent the well.
  • Some forms of a method, according to the invention may include removal of the walking beam pump, while operating the well with the linear rod pumping apparatus.
  • a method for operating a hydrocarbon well may include the steps of: installing a first linear rod pumping apparatus on a well head of the well; operating the well for a period of time with the first linear rod pumping apparatus; removing the first linear rod pumping apparatus from the well head, substantially without disassembly of the first linear rod pumping apparatus; and replacing the first linear rod pumping apparatus with a second substantially assembled linear pumping rod apparatus; and operating the well with the second linear rod pumping apparatus.
  • the method may further include disposing of the first linear rod pumping rod apparatus.
  • a method may include repairing and/or refurbishing of the first linear rod pumping apparatus offline, while the well is being operated with the second linear pumping rod apparatus.
  • FIG. 1 labeled as prior art, is a schematic illustration of a typical walking-beam- type pumping mechanism, mounted on a foundation located adjacent a well head of a hydrocarbon well, and attached to pump fluid from the hydrocarbon well.
  • FIG. 2 is a schematic illustration of a first exemplary embodiment of a linear rod pumping apparatus, according to the invention, mounted on the well head of a hydrocarbon well.
  • FIG. 3 is a schematic illustration of a second exemplary embodiment of a linear rod pumping apparatus, according to the invention, mounted on the well head of the well shown in FIG. 1, and operative Iy connected for pumping fluid from the well, instead of the walking beam apparatus, with the linear rod pumping apparatus and walking beam pumping apparatus being drawn to the same scale, to illustrate the substantial reduction in size and complexity of the linear rod pumping apparatus, according to the invention, as compared to a walking beam apparatus which was providing similar pumping output as the second exemplary embodiment of the linear rod pumping apparatus, according to the invention.
  • FIG. 4 is an external perspective view of the second exemplary embodiment of the linear pumping apparatus, according to the invention, shown in FIG. 3.
  • FIG. 5 is a partially cut-away perspective illustration of the second exemplary embodiment of a linear pumping apparatus, according to the invention, shown in FIG. 4.
  • FIG. 6 is an exterior orthographic illustration of the second exemplary embodiment of the linear pumping apparatus, according to the invention, shown in FIGS. 3-
  • FIG. 7 is a partial cross-sectional illustration of the second exemplary embodiment of the linear rod pumping apparatus, according to the invention, shown in FIG. 6.
  • FIG. 8 is a schematic cross-section view of the second exemplary embodiment of the linear pumping apparatus, according to the invention, shown in FIGS. 3-7.
  • FIG. 9 is an enlarged, partial cross-sectional, schematic illustration of a variation of the second exemplary embodiment having a tubular- shaped spacer disposed between a rod clamp and the upper end of a rack of a rack and pinion arrangement of the second exemplary embodiment of the invention.
  • FIG. 10 is a schematic cross-sectional illustration, taken along line 10-10 in FIG.
  • FIG. 11 is a graphical illustration of an exemplary substantially square-wave output produced by a sensing mechanism, according to the invention, of the second exemplary embodiment of the linear rod pumping apparatus, according to the invention, as shown in FIGS. 8 and 10.
  • FIG. 12 is a schematic cross-section of a third exemplary embodiment of a linear rod pumping apparatus, according to the invention.
  • FIG. 13 is a schematic cross-sectional illustration of a fourth exemplary embodiment of a linear rod pumping apparatus, according to the invention, which includes a pneumatic storage apparatus and regulator, for supply a counter-balance force to elements of the linear rod pumping apparatus.
  • FIG. 14 shows a first exemplary embodiment of a motor drive, for use in a control arrangement in embodiments of the invention having an electric motor.
  • FIG. 15 shows a second exemplary embodiment of a motor drive, for use with an electric motor in practicing the invention.
  • FIG. 2 is a schematic illustration of a first exemplary embodiment of a linear rod pumping apparatus 100 mounted on the well head 54 of a hydrocarbon well 56.
  • the well includes a casing 60 which extends downward into the ground through a subterranean formation 62 to a depth sufficient to reach an oil reservoir 64.
  • the casing 60 includes a series of perforations 66, through which fluid from the hydrocarbon reservoir enter into the casing 60, to thereby provide a source of fluid for a down-hole pumping apparatus 68, installed at the bottom of a length of tubing 70 which terminates in an fluid outlet 72 at a point above the surface 74 of the ground.
  • the casing 60 terminates in a gas outlet 76 above the surface of the ground 74.
  • the down-hole pumping apparatus 68 includes a stationary valve 78, and a traveling valve 80.
  • the traveling valve 80 is attached to a rod string 82 extending upward through the tubing 70 and exiting the well head 54 at the polished rod 52.
  • the down-hole pumping apparatus 68 forms a traditional sucker-rod pump arrangement for lifting fluid from the bottom of the well 56 as the polished rod 52 imparts reciprocal motion to rod string 82 and the rod string 82 in turn causes reciprocal motion of the traveling valve 80 through a pump stroke 84.
  • the rod string 82 may be several thousand feet long and the pump stroke 84 may be several feet long.
  • the first exemplary embodiment of a linear rod pump apparatus 100 includes a linear mechanical actuator arrangement 102, a reversible motor 104, and a control arrangement 106, with the control arrangement 106 including a controller 108 and a motor drive 110.
  • the linear mechanical actuator arrangement 102 includes a substantially vertically movable member attached to the polished rod 52 for imparting and controlling vertical motion of the rod string 82 and the sucker-rod pump 68.
  • the reversible motor of a linear rod pump apparatus includes a reversibly rotatable element thereof, operatively connected to the substantially vertically movable member of the linear mechanical actuator arrangement 102 in a manner establishing a fixed relationship between the rotational position of the motor 104 and the vertical position of the rack 206.
  • a fixed relationship between the rotational position of the motor 104 and the vertical position of the polished rod 52 provides a number of significant advantages in the construction and operation of a sucker-rod pump apparatus, according to the invention.
  • FIG. 3 shows a second exemplary embodiment of a linear rod pumping apparatus 200, according to the invention, mounted on a standoff 202 to the well head 54, and operatively connected for driving the polished rod 52.
  • the second exemplary embodiment of the linear rod pumping apparatus 200 is illustrated to scale, adjacent to the walking beam pumping apparatus 50, to show the substantial reduction in size, weight, and complexity afforded through practice of the invention, as compared to prior approaches utilizing walking beam apparatuses 50.
  • the replacement linear rod pumping apparatus 200 can be installed in a fully assembled form, or in a substantially fully assembled form, with only a minimal number of components, such as the upper section 214 of a housing, for example, being installed after the linear rod pumping apparatus 200 is installed on the well head 54.
  • the second exemplary embodiment of the linear rod pumping apparatus 200 includes a linear mechanical actuator arrangement 204 which, in turn, includes a rack and pinion gearing arrangement having a rack 206 and a pinion 208 operatively connected through a gearbox 210 to be driven by a reversible electric motor 212 in a manner described in more detail below.
  • the linear mechanical actuator arrangement 204 of the second exemplary embodiment of the linear rod pumping apparatus 200 includes a rack and pinion gearing arrangement 206, 208 with the rack 206 being disposed for operation in a substantially vertical direction for reciprocating motion within a three piece housing having an upper, middle and lower section 214, 216, 218 along a substantially vertically oriented pumping axis 220.
  • the rack 206 is operatively connected in gear mesh relationship with pinion 208 and the pinion 208 is operatively connected to a rotating output shaft 222 of the motor 212 (see FIG.
  • the rack 206 is also operatively connected to the polished rod 52 of the sucker-rod pump 68, such that the rack 206 cannot exert a substantially vertically downward directed force on the polished rod 52.
  • the rack 206 of the exemplary embodiment 200 has a substantially U-shaped cross-section, with first and second legs 224, 226 extending from a bight section 228 in such a manner that the legs and bight 224, 226, 228 define a longitudinally extending opening in the rack 206 in the form of an open channel 230 disposed about the pumping axis 220.
  • An outer surface 232 of the bight 228, facing substantially oppositely from the legs 226, 228 of the rack 206, is configured to form gear teeth of the rack 206 for engagement with corresponding gear teeth in the pinion 208.
  • the longitudinally directed channel 230 in the rack 206 extends along the pumping axis 220 from a bottom end 234 of the rack 206 to a top end 236 of the rack 206, with the upper end 236 of the rack 206 being adapted for operative attachment thereto of the polished rod 52.
  • the upper end 236 of the rack 206 includes a top plate 238 having a hole 240 extending therethrough and defining an upper load bearing surface 241 of the upper end 236 of the rack 206.
  • the linear mechanical actuator apparatus 204 of the second exemplary embodiment of the linear rod pumping apparatus 200, also includes an actuator rod 242, having a lower end 244 thereof fixedly attached to the top end of the polished rod 52 by a threaded joint or other appropriate type of coupling.
  • the actuator rod 242 extends upward from the lower end 244, through the channel 230 in the rack 206 and the hole 240 in the top plate 238 of the rack 206, and terminates at and upper end 246 of the actuator rod 242 which is disposed above the bearing surface 241 on the upper surface of the top plate 238 of the rack 236.
  • a rod clamp 248 is fixedly attached below the upper end 246 of the actuator rod 242 and above the upper end 236 of the rack 206.
  • the clamp 248 has a lower load bearing surface thereof adapted for bearing contact with the upper load bearing surface 241 of the upper end 236 of the rack 206, for transferring force between the actuator rod 242 and the upper end 236 of the rack 206 when the lower load bearing surface of the clamp 248 is in contact with the upper load bearing surface 241 on the upper end 236 of the rack 206.
  • the clamp 248, of the exemplary embodiment 200 forms an expanded upper end of the actuator rod 242 having a configuration that is incapable of entry into or passage through the hole 240 in the upper end 236 of the rack 206.
  • the actuator rod 242 may be allowed to extend some distance beyond the collar 248, to thereby provide some measure of adjustment to accommodate variations in the positioning of the upper end of the polished rod 52, with respect to the lower end of the lower section 218 of the housing of the linear mechanical actuator arrangement 204.
  • the upper section 214, of the housing of the linear mechanical actuator arrangement 204 includes sufficient head space to accommodate a portion of the actuator rod 242 extending above the clamp 248.
  • a linear rod pumping apparatus 200 may be formed without the actuator rod 242 such that the polished rod 52, or an extension thereof, may be fed longitudinally entirely through the rack 206 and clamped above the upper end 236 of the rack 206 with a clamp 248. It is contemplated, however, that the addition of the actuator rod 242 will substantially facilitate installation of a linear rod pumping apparatus according to the invention.
  • some forms of the second exemplary embodiment 200 of the invention may also include a tubular-shaped spacer 249 disposed about the actuator 242 between the clamp 248 and the top plate 238 of the rack 206.
  • a spacer 249 may be utilized when practicing the invention with a clamp 248 having a peripheral dimension which is larger than an opening 217 in the center section 216 of the housing.
  • the linear mechanical actuator arrangement 204 of the second exemplary embodiment 200 of the invention includes four guide rollers 250 arranged in two pairs, attached to the center section 216 of the housing substantially opposite the pinion 208, and configured to bear against the longitudinally extending distal edges of the legs 226, 228 of the rack 206 for urging the rack 206 into a gear mesh relationship with the pinion 208.
  • Two guide bars 252, operatively extending from the middle section 216 of the housing and substantially opposite from one another, are provided for urging the rack 206 into alignment with the pinion 208.
  • the middle section 216 of the housing functions as a pinion housing, having a longitudinally extending opening 254 (see FIG.
  • a first, anti-drive end of the pinion 208 is journaled in a pinion bearing 258 disposed in, and mounted to, the pinion housing 216.
  • the second, drive end 260 of the pinion 208 in the linear mechanical actuator 204 of the second exemplary embodiment 200, is adapted for connection to an output element 262 of the gearbox 210 and is supported by an output bearing 264 of the gearbox 210.
  • the output bearing 264 of the gearbox 210 serves two functions and provides a more compact assembly than would be achievable in an embodiment of the invention having an additional bearing attached to the middle housing 216 for supporting the drive end 260 of the pinion 208. In other embodiments of the invention, however, an additional bearing may be provided for supporting the drive end 260 of the pinion 208.
  • the gearbox 210 is a right angle gear box having input and output elements 266, 262 (see FIGS. 7 and 10) arranged substantially at a right angle to one another, with the output element 262 being oriented for alignment with, and rotation substantially about, the pinion axis 256, and the input element 266 of the gearbox 210 and the rotatable shaft 222 of the motor 212 being oriented substantially parallel to the pumping axis 220.
  • a motor 212 may be operatively attached to the pinion 208 by a variety of other means and in other relative orientations.
  • the linear mechanical actuator arrangement 204, of the second exemplary embodiment 200 of the invention also includes an oil sump, formed by the lower section 218 of the housing, and configured for containing a sufficient volume of lubricant therein, such that a lower portion of the rack 206 is immersed into the lubricant during at least a portion of each stroke 84 of the pump 68 (FIG. 2).
  • the sump includes inner and outer longitudinally extending radially spaced tubular walls 270, 272 sealingly connected at lower ends thereof by the bottom end of the lower section 218 of the housing, to thereby define an annular-shaped cavity therebetween, for receipt within the cavity of the volume of the lubricant, and terminating in an annular- shaped opening between upper ends of the inner and outer tubular walls 270, 272.
  • the inner tubular wall 270 of the sump 268 has an inner periphery thereof disposed about the actuator rod 242, and an outer periphery thereof disposed within the channel 230 in the rack 206.
  • the outer tubular wall 272 of the sump 268 has an inner periphery thereof disposed about the rack 206.
  • the inner tubular wall 270 extends substantially above a fluid level 274 of the lubricant within the sump 268, even when the rack 206 is positioned in a maximum downward location thereof, so that the lubricant is precluded from flowing over the top end 275 of the inner tubular wall 270.
  • the cross-sectional area of the sump 268 match the cross-sectional area of the rack 206, or a lower end plate 276 (see FIG. 8) closely enough so that immersion of the rack into the sump 268 generates hydraulic damping of the movement of the rack 206.
  • the linear mechanical actuator arrangement in the second exemplary embodiment of a linear pumping apparatus 200 according to the invention, includes a pair of nested helical compression springs 278, 280, operatively positioned within the annular cavity in the bottom of the sump 268, below the lower end 234 of the rack 206, and configured for engaging and applying an upwardly directed force to the lower plate 276 on the lower end 234 of the rack 206, when the lower end plate 276 comes into contact with a longitudinally movable spring contact plate 282 configured to rest on an upper end of the springs 278, 280 and move longitudinally along the inner tubular wall 270 as the springs 278, 280 act on the lower end 234 of the rack 206.
  • the springs 278, 280 are configured for engaging and applying an upwardly directed force to the lower end 236 of the rack 206 only when the lower end 234 of the rack 206 has moved beyond a normal lower position of the rack 206 during a pump stroke.
  • Such an arrangement provides a safety cushion to safely bring the rack and rod string slowly to a halt in the event that a fault condition should result in the rack 206 moving downward to a longitudinal position lower than would be attained during a normal pump stroke.
  • a potentially damaging impact between components of the linear mechanical actuator arrangement and/or between the stationary and traveling members of the pump 68 is precluded.
  • the springs 278, 280 may be configured in such a manner that they engage and apply an upwardly directed force to the lower end of the rack during a portion of each pump stroke, to thereby recover a portion of the kinetic energy generated by the weight of the rod string and pump during the downward portion of the pump stroke under the force of gravity and utilize that stored energy in the springs 278, 280 for aiding the action of the linear rod pumping apparatus during the upward portion of the stroke, in addition to precluding mechanical damage the rack 206 or other components at the bottom of each pumping stroke.
  • the second exemplary embodiment of a linear rod pumping apparatus 200 also includes a position sensing arrangement for sensing a position of the rack 206 along the pump axis 220.
  • the position sensing arrangement of the second exemplary embodiment 200 includes a stationary position sensor 284 disposed adjacent the rack 206 at a mid-stroke position along the pumping axis 220 in combination with upper and a lower sensor flags 286, 288 attached to the rack 206, respectively, at the upper and lower ends 236, 234 of the rack 206.
  • the first and second sensor flags 286, 288 are positioned along the first leg 244 of the rack 206 in such a manner that the flags 286, 288 are brought into juxtaposition with, and sensed by, the sensor 284 during each complete pumping stroke.
  • the upper sensor flag 286 and lower sensor flag 288 are axially spaced from one another along the rack 286 to form a gap between the upper and lower flags 286, 288 with the gap being substantially centrally longitudinally disposed along the rack 206.
  • the upper sensor flag 286 extends substantially from the upper end 236 of the rack 206 to a lower edge 290 of the upper sensor flag 286, which defines an upper end of the gap between the upper and lower sensor flags 286, 288.
  • the lower sensor flag 288 extends substantially from the lower end of the rack 206 to an upper edge 292 of the lower sensor flag 288, to thereby define the lower end of the gap between the upper and lower sensor flags 286, 288.
  • the senor 284 produces an output, as shown in FIG. 11, having a substantially square wave 294 shape, with a step change from a first state 296, while one or the other of the flags 286, 288 is juxtapose with the sensor 284, to a second state 298, when the gap is juxtapose with the sensor 284.
  • the exemplary embodiment of the sensing arrangement described above can also be utilized to control the motor 212 in such a manner that downward motion of the rack 206 is slowed as the bottom of the pump stroke is approached through braking action of the motor 212, to thereby provide an electrically controlled velocity profile, which may be used in addition to, or in place of, the springs 278, 280 of the second exemplary embodiment of a linear rod pumping apparatus 200.
  • FIG. 12 shows a third exemplary embodiment of a linear rod pumping apparatus, according to the invention, having a linear mechanical actuator apparatus 302, including a rack 304 and pinion 306 gear train arrangement, similar to the rack and pinion arrangement of the second exemplary embodiment 200 described above.
  • the linear mechanical actuator 302, of the third exemplary embodiment 300, as shown in FIG. 11, is mounted directly to the well head 54, through a standoff arrangement 308.
  • the third exemplary embodiment of a linear rod pumping apparatus 300 is similar in many respects to the second exemplary embodiment 200, described above, with several exceptions.
  • the polished rod 52 is shown as extending completely through the rack 304 along the pumping axis 220, and is secured at both the upper and lower ends of the rack 304 by upper and lower end plate and clamp arrangements 310, 312.
  • a stop block 314 is fixedly attached to the middle section 316 of the housing, in such a manner that the end plate and clamping arrangements 310, 312 will contact the stop block 314, and arrest further movement of the rack 304, to preclude having the rack 304 run off of the pinion 306.
  • the third exemplary embodiment of the linear pumping rod apparatus 300 also includes only a single pair of guide rollers 318, disposed for urging the rack 304 into a gear mesh arrangement with the pinion 306.
  • the linear mechanical actuator arrangement 302 of the third exemplary embodiment of the linear rod pumping apparatus 300 further, does not include the oil sump 268 or the springs 278, 280 of the second exemplary embodiment. It will be understood, however, that in alternate embodiments of the invention, various features of the exemplary embodiment shown herein can be used, omitted, or combined together in forms other than the exemplary embodiments of the invention shown in the drawings and specifically described herein.
  • FIG. 13 shows a fourth exemplary embodiment of a linear rod pumping apparatus 400, according to the invention, in which a linear mechanical actuator arrangement 402 that is substantially identical to the linear mechanical actuator arrangement 302 of the third exemplary embodiment 300 of the invention described above, includes a piston plate 404 attached to the lower end of the rack 406 of the rack 406 and pinion 408 arrangement, and the lower end of the lower section 410 of the housing is cooperatively configured with the piston plate 404 in such a manner that a gas tight cylinder is provided, below the piston plate 404.
  • a pneumatic storage apparatus 414 such as an accumulator, is connected to the pneumatic cylinder chamber 412 through a conduit 416, and a regulator 418 is disposed between the accumulator 414 and the cylinder 412 for regulating pressure and volume of the gas stored in the pneumatic cylinder and accumulator 412, 414.
  • a counter-balance force may be applied to the lower end of the rack 406.
  • a singular accumulator 414 and regulating valve 418 are illustrated in FIG. 12, in some embodiments of the invention it may be desirable to have multiple accumulators and/or regulating valves 414, 416, to aid in adjusting the counter-balance force applied to the lower end of the rack.
  • Some embodiments of the invention may also include venting part, or all of the pressure generated in the pneumatic cylinder cavity 412 on the downstroke. In the exemplary embodiment shown in FIG. 13, the interior of the lower section 410 of the housing is vented to atmosphere above the highest level of travel of the piston plate 404.
  • FIG. 14 shows a first exemplary embodiment of a motor drive 500 for use in a control arrangement in embodiments of the invention having an electric motor.
  • the motor drive 500 includes a rectifier bus charging section 502, a capacitor bank section 504, a dynamic braking section 506, and an inverter motor output section 508 connected along common bus rails 510, 512, for connecting a three phase power input R, S, T to a three phase output U, V, W, provided to the motor.
  • diodes in the charging section 502 charge the capacitor bank 504 and an IGBT bridge arrangement in the inverter motor output section 508 modulates capacitor voltage to control current in the motor windings.
  • the motor drive 500 provides two options for dealing with the energy that is transferred to the capacitor bank during braking.
  • the capacitor bank 504 includes sufficient capacitance to store the energy generated during braking action, without exceeding voltage limits on the rails 510, 512.
  • a dynamic braking IGBT 514 in the dynamic braking section 506 may be turned on to allow the energy generated during braking action to be dissipated across a dynamic braking resistor 516 of the dynamic braking section 506.
  • FIG. 15 shows a second exemplary embodiment of a motor drive 600 for use with an electric motor in practicing the invention.
  • the second exemplary embodiment of the motor drive 600 is substantially identical to the first exemplary embodiment of the motor drive 500, as described above, except that an IGBT switching bridge is provided in parallel with the diodes in the rectifier section to provide a regenerative bus charging section 602, a capacitor bank section 604, a dynamic braking section 606 and an inverter motor output section 608 disposed across a pair of common rails 610, 612 for connecting a three phase R, S, T input to the motor drive to a three phase U, V, W connection to the motor.
  • the diodes in the regenerative bus charging section 602 charge capacitors in the capacitor bank 604 and an IGBT bridge in the inverter motor output section 608 modulates capacitor voltage in the capacitor bank section 604 to control current in the motor windings.
  • diodes in the inverter motor output section transfer power to the capacitor bank 604, causing capacitor bank voltage to rise.
  • the second exemplary embodiment of the motor drive 600 provides three options for dealing with the energy being transferred to the capacitor bank.
  • the capacitor bank section 604 has sufficient capacitance to store the energy generated during braking, without exceeding voltage limits.
  • a dynamic braking IGBT 614 of the dynamic braking section 606 is turned on, and all, or a portion of the energy generated during braking, is dissipated across a dynamic braking resistor 616 of the dynamic braking section 606.
  • the IGBTs in the regenerative bus charging section are switched to modulate the capacitor voltage of the capacitor bank section in such a manner as to allow a transfer of the power generated during braking back to the incoming three phase R, S, T source.
  • the surface position of the pump rod, and the current load on the pump rod above the surface of the ground may be readily determined, without the need for down-hole sensors, by virtue of the elegantly simple construction of the linear mechanical actuator arrangement and the direct relationship that exists between the vertical position of the vertically movably member of the linear mechanical actuator arrangement and the rotatable element of the motor.
  • the vertical position of the vertically movable member can be directly determined from the angular rotational position of the motor shaft, and the load on the rod above the surface of the ground can be readily determined from motor current and voltage, in accordance with the apparatuses and methods of a rod pump control system including parameter estimation, as taught by Beck et al., or through the use of other applicable methods and apparatuses in accordance with the teachings with the present invention.
  • a model of dynamic rod performance of the type disclosed in Beck et al., or any other appropriate apparatus or method for modeling the dynamic performance of the pump rod, may be utilized to determine a down-hole pump position and load.
  • the pump dynamic model may then also be utilized to determine pump "fillage" as a percentage of the total capacity of the sucker-rod pump, in real time.
  • Operation of the linear rod pumping apparatus can then be controlled and adjusted to provide a vertical stroke length and speed of the vertically movable member of the linear rod pumping apparatus, according to the invention, to achieve a target desired pump fillage percentage.
  • Practice of the invention also contemplates controlling the linear rod pumping apparatus in a manner consistent with optimizing other performance parameters of a particular well installation, such as minimizing power consumption by the motor for a given volume of pumped fluid, or minimizing variation in the level of input power draw in a manner which might be desirable in hydrocarbon well installations wherein the motor of the linear rod pumping apparatus receives input power from an engine-driven generator.
  • the low inertia of a linear rod pumping apparatus provides particular advantages in affecting real time control of the pumping apparatus, in a manner consistent with achieving a desired performance from the sucker-rod pump.
  • the low inertia of a linear rod pumping apparatus must be taken into account and compensated for, to preclude having the weight of the rod string and fluid load accelerate the vertically movable member of the linear rod pump downward more rapidly than is desirable during the downward portion of the pump stroke under conditions such as a loss of power to the motor, for example, or periods of operation in which the traveling valve of the sucker-rod pump is not immersed in fluid having sufficient viscosity to provide hydraulic damping of the downward movement of the traveling valve and rod string.
  • the controlled stop provisions at the bottom of the motion of the apparatus, as described above, as provided mechanically through spring elements, or electrically through braking of the motor are provided by the present invention, for use in combination with a rod pump control system such as the one described in Beck et al., or another appropriate control system to preclude having the rod string drive the vertically movable member of a linear rod pumping apparatus, according to the invention, at an undesirably high speed and/or acceleration rate, and to preclude damaging of the down-hole pump components by preventing "tagging" of the standing valve by the traveling valve.
  • a method of operating a linear rod pumping apparatus might include the following eight steps. During all eight steps, the instantaneous vertical velocity of the rack 206 is calculated from the instantaneous angular velocity of the motor shaft 222, and the position of the actuator rod 242 is calculated by integration using the instantaneous vertical velocity of the actuator rod 242. [0129] Step 1. Begin with the actuator rod 242, in a fully lowered position, and attached to the upper end of the polished rod 52
  • Step 2 The motor 212 is then energized to accelerate the rod to a predetermined "UP SPEED.”
  • Step 3 As the motor 212 drives the rack 206 upward, to thereby accelerate the actuator rod 242 to UP SPEED, the output signal 294 (see FIG. 10) of the stationary position sensor 284 is monitored to detect the rising edge of the square -wave 294 caused by the upper edge 292 of the lower reference flag 288 coming into juxtaposition with the position sensor 284.
  • the upper edge 292 is detected before the rod 242 reaches a calculated vertical rod position, corresponding to a desired pump stroke, where the upper edge 292 is within a predetermined reference position window, or where the upper edge 292 is not detected within a predetermined period of time or a predetermined angular rotation of the motor shaft 222, a fault condition is identified and the motor 212 is operated in such a manner that the rack 206 and actuator rod 242 are lowered to the fully lowered position at a very slow speed. Once the fully lowered position is achieved, the method may begin again by returning to step 1.
  • the calculated rod position is set to the raised rod reference position value, and the instantaneous vertical position of the actuator rod 242 is calculated by integration using the upward velocity of the actuator rod 242.
  • Step 4 As the actuator rod 242 approaches a desired top of stroke position, the motor 212 is operated in such a manner that the upward speed of the rod 242 decelerates so that the upward velocity is reduced to substantially zero at the desired top of stroke position.
  • Step 5 From the top of stroke position, the motor 212 is operated in such a manner that the actuator rod 242 accelerates to a "DOWN SLOW SPEED.” From the foregoing description of exemplary embodiments, it will be understood that during downward motion of the actuator rod 242, the motor 212 is operated in a braking mode, by commanding the motor 212 to drive the pinion 208 at a slower rotational speed than the pinion 208 would otherwise achieve due to the downward forces on the rack 206 caused by the weight of the rod string and any fluid loads acting on the sucker-pump apparatus, so that a net braking torque is applied to the pinion 208.
  • Step 6 As the rod 242 moves downward, at DOWN SLOW SPEED, the output of the position sensor 282 is monitored to detect a rising edge of the reference signal 294 caused by the lower end 290 of the upper reference flag 286 coming into juxtaposition with the position sensor 282. If this edge 290 is detected before a predetermined calculated rod position whereat the rod 242 is within a lowered rod reference position window, or is not detected, a fault condition is identified and the motor 212 is operated in such a manner that the actuator rod 242 is lowered to the fully lowered position at a very low speed. Once the actuator rod 242 has reached the fully lowered position, the method may then return to step
  • the calculated rod position is reset to the measured lowered rod reference position value, and the rod 242 is allowed to continue downward, while rod position is calculated by integration of the downward velocity of the rod 242.
  • load on the down-hole pump is determined, by monitoring motor torque, for example.
  • the motor 212 is operated such that the actuator rod 242 can accelerate to a "DOWN FAST SPEED.”
  • Step 7 As the actuator rod 242 continues downward at DOWN FAST SPEED, the vertical position of the actuator rod 242 is monitored, and the down-hole position of the traveling valve is calculated. As the actuator rod 242 approaches a predetermined bottom of stroke position, which may be vertically above the fully lowered position of the actuator rod 242, the motor 212 is operated in a braking mode, to provide a velocity profile, such that the actuator rod 242 is decelerated to substantially zero velocity at the desired bottom of stroke position.
  • Step 8 Once the actuator rod 242 has reached the desired bottom of stroke position, operation of the linear rod pumping apparatus 200 is continued by returning to step
  • Step A The controller 108 detects a loss of line power whenever voltage across the common power busses 510, 512 drops below a predetermined minimum threshold value.
  • Step B If the actuator rod 242 is moving upward, at the time that a line power loss is detected, the controller 108 commands the motor 104, 212 to enter a reverse braking mode in which the motor 104, 212 acts as a generator as the rack 206 continues to move upward, due to inertia in the linear rod pumping apparatus, to keep the voltage across the busses 510, 512 at a level which would allow the motor drive 110, 500 to continue to control the motor 104, 212.
  • Step C If the actuator rod 242 is moving downward, at the time that a line power loss is detected or after braking action of Step B has caused the actuator rod 242 to begin downward motion, the controller 108 commands the motor 212 to operate in a braking mode, to limit the lowering speed of the actuator rod 242 in such a manner that impact forces are reduced when the rack 206 contacts the springs 278, 280, and also causing the motor 104, 212 to act as a generator and keep the voltage across the busses 310, 312 at a level which allows the motor drive 110, 500 to continue to control the motor 104, 212.
  • Step D When the actuator rod 242 has reached a fully lowered position, the voltage across the busses 310, 312 will decay and the motor drive 110, 500 is turned off until line power is restored.
  • a linear rod pump apparatus and/or method provides significant advantages, in addition to being physically smaller, in comparison to both a conventional walking beam pumping apparatus, and other prior pumping apparatuses, such as the hydraulic motor driven pump jack device of Saruwatari.
  • All references, including publications, patent applications, and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Reciprocating Pumps (AREA)
  • Transmission Devices (AREA)
  • Compressors, Vaccum Pumps And Other Relevant Systems (AREA)

Abstract

La présente invention concerne un appareil et un procédé pour pomper des fluides, tels que de l'eau et/ou des hydrocarbures, à partir d'une formation souterraine ou d'un réservoir, comprenant une pompe à tige linéaire ayant un agencement de crémaillère mécanique et d'entraînement de pignon, conçue pour être fixée à un mécanisme de pompage, tel que la tige polie située sur la partie supérieure d'une corde de tige dans un puits d'hydrocarbure. L'engrenage de crémaillère de l'agencement de la crémaillère et d'entraînement de pignon est conçu pour être connecté à la tige polie et pour se déplacer avec elle. L'engrenage de pignon ne translate pas avec l'engrenage de crémaillère et est entraîné par un moteur réversible permettant d'effectuer un mouvement de va-et-vient de haut en bas de l'engrenage de crémaillère et du mécanisme de pompage. Certains modes de réalisation de l'invention comprennent un agencement de contre-balancier à gaz compressible. Certains modes de réalisation de l'invention comprennent un entraînement électronique configuré pour utiliser le courant électrique généré par le moteur pendant une partie du cycle de pompage.
PCT/US2007/070989 2006-06-12 2007-06-12 Appareil et procédé de pompe à tige linéaire WO2007146931A2 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
MX2012012458A MX337274B (es) 2006-06-12 2007-06-12 Aparato y metodo para bomba de barra lineal.
MX2008015795A MX2008015795A (es) 2006-06-12 2007-06-12 Aparato y metodo para bomba de barra lineal.
EP07798436.7A EP2035702B1 (fr) 2006-06-12 2007-06-12 Appareil et procédé de pompe à tige linéaire
CA2654908A CA2654908C (fr) 2006-06-12 2007-06-12 Appareil et procede de pompe a tige lineaire

Applications Claiming Priority (2)

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US81279506P 2006-06-12 2006-06-12
US60/812,795 2006-06-12

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WO2007146931A2 true WO2007146931A2 (fr) 2007-12-21
WO2007146931A3 WO2007146931A3 (fr) 2008-11-27

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CA (1) CA2654908C (fr)
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Publication number Priority date Publication date Assignee Title
CN101906953A (zh) * 2010-08-11 2010-12-08 江苏省金峰石油机械制造有限公司 直立式长环齿条抽油机
EP3308022A4 (fr) * 2015-06-10 2018-07-18 Unico, Inc. Pompe à tige linéaire de complétion double

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MX337274B (es) 2016-02-17
CA2654908C (fr) 2014-09-09
EP2035702B1 (fr) 2018-08-22
CA2654908A1 (fr) 2007-12-21
EP2035702A4 (fr) 2017-01-11
EP2035702A2 (fr) 2009-03-18
MX2008015795A (es) 2009-02-11
WO2007146931A3 (fr) 2008-11-27

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