Long stroke pumping unit

Patent metadata

Field	Value
Publication number	US-10962000-B2
Application number	US-201916378085-A
Country	US
Kind code	B2
Filing date	Apr 8, 2019
Priority date	Jan 29, 2015
Publication date	Mar 30, 2021
Grant date	Mar 30, 2021

Abstract

A long stroke pumping unit includes a tower and a counterweight assembly movable along the tower. A belt includes a first end connected to the counterweight assembly and a second end connectable to a rod string. A prime mover is used to reciprocate the counterweight assembly along the tower. A sensor detects the position of the counterweight assembly, and a load cell measures the force exerted on the rod string. A motor is provided to adjust an effective weight of the counterweight assembly during reciprocation thereof along the tower. A controller communicates data with the sensor and the load cell and controls the adjustment force exerted by the adjustment motor.

First claim

The invention claimed is:

1. A long-stroke pumping unit, comprising:
a tower;
a counterweight assembly movable along the tower;
a crown mounted atop the tower;
a belt having a first end connected to the counterweight assembly and having a second end connectable to a rod string;
a prime mover for reciprocating the counterweight assembly along the tower;
a sensor for detecting position of the counterweight assembly;
a load cell for measuring force exerted on the rod string;
a rotary adjustment motor operable to adjust an effective weight of the counterweight assembly during reciprocation thereof along the tower;
a linear actuator connecting the adjustment motor to the counterweight assembly; and
a controller in data communication with the sensor and the load cell and operable to control the adjustment force exerted by the adjustment motor by controlling a torque of the adjustment motor.

2. The unit of claim 1 , wherein the motor is mounted to the crown.

3. The unit of claim 1 , wherein the linear actuator comprises:
a nut mounted to the counterweight assembly; and
a screw shaft extending from a base of the tower to the crown and through the nut,
wherein the motor is torsionally connected to the screw shaft and operable to rotate the screw shaft relative to the nut.

4. The unit of claim 3 , wherein a raceway is formed between a thread of the nut and a thread of the screw shaft.

5. The unit of claim 4 , further comprising balls disposed in the raceway.

6. The unit of claim 4 , further comprising threaded rollers disposed in the raceway.

7. The unit of claim 6 , further comprising:
a tensioner supporting the screw shaft from the crown;
an upper thrust bearing connecting the screw shaft to the tensioner; and
a lower thrust bearing connecting the screw shaft to a base of the tower.

8. The unit of claim 1 , wherein the sensor is a laser rangefinder, ultrasonic rangefinder, string potentiometer, or linear variable differential transformer (LVDT).

9. The unit of claim 1 , further comprising
a drive sprocket torsionally connected to the prime mover;
an idler sprocket connected to the tower;
a chain for orbiting around the sprockets; and
a carriage for longitudinally connecting the counterweight assembly to the chain while allowing relative transverse movement of the chain relative to the counterweight assembly.

10. The unit of claim 1 , further comprising a drum supported by the crown and rotatable relative thereto, wherein the belt extends over the drum.

11. The unit of claim 1 , wherein the controller is a programmable logic controller, application-specific integrated circuit, or field-programmable gate array.

12. A long-stroke pumping unit, comprising:
a tower;
a counterweight assembly movable along the tower;
a crown mounted atop the tower;
a belt having a first end connected to the counterweight assembly and having a second end connectable to a rod string;
a prime mover for reciprocating the counterweight assembly along the tower;
a sensor for detecting position of the counterweight assembly;
a load cell for measuring force exerted on the rod string;
an adjustment motor operable to adjust an effective weight of the counterweight assembly during reciprocation thereof along the tower, wherein the adjustment motor is a linear electromagnetic motor comprising:
a traveler mounted either to an exterior of the counterweight assembly or to a hanger bar for connecting the belt to the rod string; and
a stator extending from a base of the tower to the crown and along a guide rail of the tower; and

a controller in data communication with the sensor and the load cell and operable to control the adjustment force exerted by the adjustment motor.

13. The unit of claim 12 , wherein:
the stator comprises:
a core extending from a base of the tower to the crown and fastened to the guide rail; and
coils spaced along the core, each coil having a length of wire wrapped around the core, and

the traveler comprises:
a core; and
permanent magnets spaced along the core.

14. The unit of claim 13 , wherein:
the stator core is a bar or box,
the traveler core is a C-beam, and
each permanent magnet is part of a row of permanent magnets surrounding three sides of the stator.

15. The unit of claim 14 , wherein:
the stator core is made from electrical steel or a soft magnetic composite, and
the traveler core is made from a ferromagnetic material.

16. A long-stroke pumping unit, comprising:
a tower;
a counterweight assembly movable along the tower;
a crown mounted atop the tower;
a drum supported by the crown and rotatable relative thereto;
a belt having a first end connected to the counterweight assembly, extending over the drum, and having a second end connectable to a rod string;
a first motor operable to lift the counterweight assembly along the tower;
a second motor operable to lift the rod string, wherein the second motor is independently operable from the first motor to lift the rod string; and
a controller for operating the second motor during an upstroke of the rod string and for operating the first motor during a downstroke of the rod string.

17. The unit of claim 16 , further comprising a dual motor driver in electrical communication with each motor and operable to drive the second motor while receiving power from the first motor during the upstroke and operable to drive the first motor while receiving power from the second motor during the downstroke.

18. The unit of claim 16 , wherein the second motor is a linear electromagnetic motor, comprising:
a stator, comprising:
a tubular housing having a flange for connection to a stuffing box;
a spool disposed in the housing;
a coil of wire wrapped around the spool; and
a core sleeve surrounding the coil; and

a traveler, comprising:
a core extendable through a bore of the housing and having a thread formed at a lower end thereof for connection to a sucker rod;
a polished sleeve for engagement with a seal of the stuffing box and connected to the traveler core to form a chamber therebetween; and
permanent magnet rings disposed in and along the chamber, each ring surrounding the traveler core.

19. A long-stroke pumping unit, comprising:
a tower;
a counterweight assembly movable along the tower;
a crown mounted atop the tower;
a belt having a first end connected to the counterweight assembly and having a second end connectable to a rod string;
a prime mover for reciprocating the counterweight assembly along the tower;
a sensor for detecting position of the counterweight assembly;
a load cell for measuring force exerted on the rod string;
a motor operable to adjust an effective weight of the counterweight assembly during reciprocation thereof along the tower, wherein each of the prime mover and the motor is an electric three phase motor;
a controller in data communication with the sensor and the load cell and operable to control the adjustment force exerted by the motor;
a variable torque or a variable force motor driver in electrical communication with the motor; and
a variable speed motor driver in electrical communication with the prime mover,
wherein the controller is in data communication with the motor drivers and is further operable to control speed of the prime mover.

20. The unit of claim 19 , wherein the controller is further operable to monitor the sensor and load cell for failure of the rod string and instruct the motor drivers to control descent of the counterweight asse

Assignees

• Weatherford Tech Holdings Llc

Inventors

• Robison Clark E
• Thomas Benson
• Christian Sean M

Classifications

• F04B47/14

  Counterbalancing · CPC title

• F04B47/02

  the driving mechanisms being situated at ground level (F04B47/12 takes precedence) · CPC title

• F04B49/20 Primary

  by changing the driving speed · CPC title

• F04B47/022 Primary

  driving of the walking beam · CPC title

• F04B47/026

  Pull rods, full rod component parts · CPC title