Long-stroke pumping unit

Patent metadata

Field	Value
Publication number	US-10844852-B2
Application number	US-201816171757-A
Country	US
Kind code	B2
Filing date	Oct 26, 2018
Priority date	Feb 23, 2015
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

Abstract

A long-stroke pumping unit includes a tower, a counterweight assembly movable along the tower, and a crown mounted atop the tower. A sprocket is supported by the crown and rotatable relative thereto. The counterweight is coupled to a belt. The pumping unit further includes a motor having a stator mounted to the crown and a rotor torsionally connected to the sprocket. A sensor is used to detect a position of the counterweight assembly. The pumping unit may include a dynamic control system for controlling a speed of a motor.

First claim

The invention claimed is:

1. A pumping unit, comprising:
a tower;
a counterweight assembly movable along the tower;
a prime mover for reciprocating a rod string;
a belt having a first end connected to the counterweight assembly and having a second end connectable to the rod string;
a downhole pump connected to the rod string;
a load cell for measuring force exerted on the rod string;
a controller in communication with the load cell and operable to determine a load on the rod string,
wherein the load cell includes:
a tubular body disposed around the rod string; and
a strain gauge attached to the tubular body and in communication with the controller, and

wherein the controller is further operable to monitor for failure of the rod string or belt and control descent of the counterweight assembly in response to detection of the failure based on the load on the rod string.

2. The unit of claim 1 , wherein the load cell further comprises an accelerometer in communication with the controller.

3. The unit of claim 2 , wherein the accelerometer is configured to measure vibration of the rod string and is disposed in a chamber defined by a recess on an outer surface of the tubular body and a sleeve disposed around the recess.

4. The unit of claim 3 , wherein the accelerometer is a dual axis microelectromechanical system.

5. The unit of claim 3 , wherein the load cell includes an arm attached to the sleeve and a wire rope.

6. The unit of claim 3 , wherein the load cell is disposed in the chamber.

7. The unit of claim 3 , wherein the chamber further comprises an inert gas.

8. The unit of claim 1 , wherein the load cell is torsionally arrested relative to the rod string.

9. The unit of claim 1 , wherein the load cell includes a pair of washers for coupling the tubular body to the rod string.

10. The unit of claim 1 , further comprising a bar attached to the rod string, and wherein the load cell is disposed between the bar and an upper end of the rod string.

11. The unit of claim 1 , further comprising a sensor configured to detect a position of the rod string by detecting a position of the counterweight assembly.

12. The unit of claim 11 , wherein the sensor is an ultrasonic rangefinder comprising a long range transducer and a short range transducer.

13. The unit of claim 11 , wherein the sensor is a linear variable differential transformer (LVDT) comprising:
a string connected to the counterweight assembly and wound onto a spool;
a screw shaft engaged with a thread of the spool;
an LVDT core mounted to the screw shaft; and
an LVDT body at least partially receiving the LVDT core.

14. 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.

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

16. The unit of claim 1 , wherein the controller is further operable to monitor for failure or imminent failure of the pumping unit and to shut down the pumping unit in response to detection of the failure or imminent failure.

17. The unit of claim 1 , wherein:
the prime mover is an electric three phase motor, and
further comprises a three phase variable speed motor driver.

Assignees

• Weatherford Tech Holdings Llc

Inventors

• Robison Clark E
• Lembcke Jeffrey John
• Pons Victoria M
• Hall William Kevin
• Stachowiak Jr John Edward
• Thomas Benson
• Christian Sean M
• Paulet Bryan A
• Basler Hermann

Classifications

• F04B47/14

  Counterbalancing · CPC title

• F04B49/20 Primary

  by changing the driving speed · CPC title

• E21B47/009

  Monitoring of walking-beam pump systems · CPC title

• E21B43/127

  Adaptations of walking-beam pump systems · CPC title

• E21B43/126

  Adaptations of down-hole pump systems powered by drives outside the borehole, e.g. by a rotary or oscillating drive (powered by fluid E21B43/129) · CPC title