HYDRAULIC PUMPING SYSTEM WITH PISTON DISPLACEMENT SENSING AND CONTROL

• US 20170037714A1
• Filed: 12/02/2015
• Published: 02/09/2017
• Est. Priority Date: 08/05/2015
• Status: Active Grant

• Current Assignee: Amfields, LP, Weatherford Technology Holdings, LLC (Weatherford International PLC)
• Original Assignee: Amfields, LP, Weatherford Technology Holdings, LLC (Weatherford International PLC)
• Inventors: MCDONALD, Robert G., TRAPANI, James S., SCHMITT, Kenneth J., ROBISON, Clark E., THOMAS, Benson
• Granted Patent: US 11,098,708 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: E21B 43/129 Adaptations of down-hole pump systems powered by fluid supplied from outside the borehole gas-lift E21B43/122; jet pumps E21B43/124
• CPC Class Codes: F04B 2201/0802 Vibration
• CPC Class Codes: F04B 47/02 the driving mechanisms being situated at ground level F04B47/12 takes precedence
• CPC Class Codes: F04B 47/04 the driving means incorporating fluid means
• CPC Class Codes: F04B 47/06 having motor-pump units situated at great depth
• CPC Class Codes: F04B 47/08 the motors being actuated by fluid
• CPC Class Codes: F04B 49/12 by varying the length of stroke of the working members
• CPC Class Codes: F04B 51/00 Testing machines, pumps, or pumping installations
• CPC Class Codes: F04B 9/10 the fluid being liquid
• CPC Class Codes: F04B 9/105 reciprocating movement of the pumping member being obtained by a double-acting liquid motor
• CPC Class Codes: F04B 9/107 rectilinear movement of the pumping member in the working direction being obtained by a single-acting liquid motor, e.g. actuated in the other direction by gravity or a spring
• CPC Class Codes: F15B 2201/305 without separating means
• CPC Class Codes: F15B 2201/50 Monitoring, detection and testing means for accumulators
• CPC Class Codes: F15B 2201/505 Testing of accumulators, e.g. for testing tightness
• CPC Class Codes: Y10S 417/904 Well pump driven by fluid motor mounted above ground

Abstract

A hydraulic pumping system can include a hydraulic actuator with a magnet that displaces with a piston, and a sensor that continuously detects a position of the magnet. A ferromagnetic wall of the hydraulic actuator is positioned between the magnet and the sensor. A hydraulic pumping method can include incrementally lowering a lower stroke extent of a rod string reciprocation over multiple reciprocation cycles of the rod string, and automatically varying the lower stroke extent or an upper stroke extent of the rod string reciprocation, in response to a measured vibration. Another hydraulic pumping method can include solving a wave equation in the rod string, and automatically varying a reciprocation speed of the rod string in response to a change in work performed during reciprocation cycles of the hydraulic actuator or a change in detected force versus displacement in different reciprocation cycles of the hydraulic actuator.

Claims

1. A hydraulic pumping system for use with a subterranean well, the system comprising:

a hydraulic actuator including a piston that displaces in response to pressure in the actuator, a magnet that displaces with the piston, and at least one sensor that continuously detects a position of the magnet as the magnet displaces with the piston,

wherein a ferromagnetic wall of the hydraulic actuator is positioned between the magnet and the sensor.

2. The system of claim 1, wherein the sensor comprises a linear transducer.

3. The system of claim 1, wherein the sensor is a Hall effect sensor.

4. The system of claim 1, wherein displacement of the piston is automatically varied in response to solution of a wave equation in a rod string connected to the piston.

5. The system of claim 4, wherein the wave equation solution determines force versus displacement of the rod string at a downhole pump connected to the rod string.

6. The system of claim 1, wherein a lower stroke extent of the piston is incrementally lowered over multiple reciprocation cycles, until a pump-pound condition is detected.

7. The system of claim 6, wherein the lower stroke extent of the piston is raised in response to detection of the pump-pound condition.

8. The system of claim 1, wherein the ferromagnetic wall of the hydraulic actuator has a thickness of at least approximately 1.25 cm.

9. The system of claim 1, further comprising a hydraulic pump connected between the hydraulic actuator and an accumulator, and wherein the accumulator receives nitrogen gas from a nitrogen concentrator assembly while a hydraulic fluid flows between the hydraulic pump and the hydraulic actuator.

10. The system of claim 1, further comprising a hydraulic pump connected between the hydraulic actuator and an accumulator, and wherein a hydraulic fluid is in contact with a pressurized gas in the accumulator.

11. The system of claim 1, further comprising a hydraulic pump connected between the hydraulic actuator and an accumulator, and wherein pressure in the accumulator is automatically regulated in response to measurements of pressure applied to the hydraulic actuator.

12. The system of claim 1, wherein a reciprocation speed of the piston is automatically varied in response to at least one of:

a) a change in work performed during reciprocation cycles of the system and b) a change in detected force versus displacement in different reciprocation cycles of the system.

13. The system of claim 1, wherein an extent of reciprocation displacement of the piston is automatically varied in response to a measured vibration.

14. A hydraulic pumping method for use with a subterranean well having a rod string connected to a downhole pump, the method comprising:

reciprocating the rod string in response to pressure in a hydraulic actuator connected to the rod string;

incrementally lowering a lower stroke extent of the rod string reciprocation over multiple reciprocation cycles of the rod string; and

automatically varying at least one of;

a) the lower stroke extent, and b) an upper stroke extent of the rod string reciprocation, in response to a measured vibration.

15. The method of claim 14, further comprising solving a wave equation in the rod string.

16. The method of claim 15, wherein solving the wave equation in the rod string comprises determining force versus displacement in the rod string at the downhole pump.

17. The method of claim 14, wherein the incrementally lowering is performed until a pump-pound condition is detected.

18. The method of claim 17, wherein the pump-pound condition is indicated by the measured vibration.

19. The method of claim 17, wherein automatically varying comprises raising the lower stroke extent of the rod string reciprocation in response to detection of the pump-pound condition.

20. The method of claim 14, further comprising continuously sensing a position of the rod string as the rod string reciprocates.

21. The method of claim 14, wherein the vibration is sensed by at least one of the group consisting of a pressure sensor, an acoustic sensor, a geophone and a seismometer.

22. The method of claim 14, wherein automatically varying the extent of reciprocation displacement comprises raising the lower stroke extent of the rod string reciprocation.

23. The method of claim 14, further comprising automatically varying a reciprocation speed of the rod string in response to a change in work performed during reciprocation cycles of the hydraulic actuator over time.

24. The method of claim 14, further comprising automatically varying a reciprocation speed of the rod string in response to a change in shapes of force versus displacement graphs for reciprocation cycles of the hydraulic actuator over time.

25. The method of claim 14, further comprising connecting a hydraulic pump between the hydraulic actuator and an accumulator, and the accumulator receiving nitrogen gas from a nitrogen concentrator assembly while a hydraulic fluid flows between the hydraulic pump and the hydraulic actuator.

26. The method of claim 14, further comprising connecting a hydraulic pump between the hydraulic actuator and an accumulator, and wherein a hydraulic fluid is in contact with a pressurized gas in the accumulator.

27. The method of claim 14, wherein a hydraulic pump is connected between the hydraulic actuator and an accumulator, and further comprising automatically regulating pressure in the accumulator in response to measurements of pressure applied to the hydraulic actuator.

28. A hydraulic pumping method for use with a subterranean well having a rod string connected to a downhole pump, the method comprising:

reciprocating the rod string in response to pressure in a hydraulic actuator connected to the rod string;

solving a wave equation in the rod string; and

automatically varying a reciprocation speed of the rod string in response to at least one of the group consisting of;

a) a change in work performed during reciprocation cycles of the hydraulic actuator and b) a change in detected force versus displacement in different reciprocation cycles of the hydraulic actuator.

29. The method of claim 28, wherein the reciprocation speed is decreased in response to a measured decrease in the work performed during the reciprocation cycles.

30. The method of claim 28, further comprising automatically varying an extent of reciprocation displacement of the rod string in response to a measured vibration.

31. The method of claim 30, wherein the vibration is sensed by at least one of a pressure sensor, an acoustic sensor, a geophone and a seismometer.

32. The method of claim 30, wherein automatically varying the extent of reciprocation displacement comprises raising a lower stroke extent of the rod string.

33. The method of claim 28, further comprising connecting a hydraulic pump between the hydraulic actuator and an accumulator, and the accumulator receiving nitrogen gas from a nitrogen concentrator assembly while a hydraulic fluid flows between the hydraulic pump and the hydraulic actuator.

34. The method of claim 28, further comprising connecting a hydraulic pump between the hydraulic actuator and an accumulator, and wherein a hydraulic fluid is in contact with a pressurized gas in the accumulator.

35. The method of claim 28, wherein a hydraulic pump is connected between the hydraulic actuator and an accumulator, and further comprising automatically regulating pressure in the accumulator in response to measurements of pressure applied to the hydraulic actuator.