System and method for operating a pump

Patent metadata

Field	Value
Publication number	US-2016003242-A1
Application number	US-201414776204-A
Country	US
Kind code	A1
Filing date	Mar 14, 2014
Priority date	Mar 15, 2013
Publication date	Jan 7, 2016
Grant date	—

Abstract

A pumping system and method for operating a pumping system including a motor coupled to a variable speed drive to drive a pump. A torque indicator corresponding to the torque presented to the drive is determined. The torque indicator may be used to detect a fault if it exceeds a baseline torque, or to detect a defective transducer, or to detect a system change by perturbing one parameter and comparing another to a predicted value.

First claim

What is claimed is:

1 . A pumping system comprising: a pump and a motor coupled to a variable speed drive to drive the pump, the variable speed drive including a processor and a non-transitory computer readable medium having embedded therein processing instructions configured to perform a method when executed by the processor, the method including:
periodically measuring a fluid parameter with a transducer; controlling the pump based on the fluid parameter; correlating the fluid parameter and a motor torque indicator selected from torque, power and current; predicting a value of the torque indicator or the fluid parameter based on the correlation; comparing the predicted value to an actual value of the torque indicator or the fluid parameter; and if the comparison exceeds a prediction threshold, controlling the pump based on the torque indicator.

2 . A pumping system as in claim 1 , wherein the fluid parameter is based on at least one of pressure and fluid level.

3 . A pumping system as in claim 2 , wherein the fluid parameter is additionally based on a corrected fluid level obtained by subtracting a casing pressure in a well from an actual bottom-hole pressure.

4 . A pumping system as in claim 1 , the method further comprising modeling the motor and predicting toque conditions.

5 . A pumping system as in claim 1 , wherein the variable speed drive comprises a variable frequency drive.

6 . A method for operating a pumping system, the method comprising:
driving a pump with a motor coupled to a variable frequency drive; periodically measuring a fluid parameter with a transducer; controlling the pump based on the fluid parameter; correlating the fluid parameter and a motor torque indicator selected from torque, power and current; predicting a value of the torque indicator or the fluid parameter based on the correlation; comparing the predicted value to an actual value of the torque indicator or the fluid parameter; and if the comparison exceeds a prediction threshold, controlling the pump based on the torque indicator.

7 . A method as in claim 6 , wherein the fluid parameter is based on at least one of pressure and fluid level.

8 . A method as in claim 6 , further comprising calibrating a pump model if the comparison indicates wear.

9 . A method as in claim 6 , wherein controlling includes determining a low level fluid fault when the torque is below a predetermined level.

10 . A method as in claim 6 , wherein controlling includes determining a low level fluid fault when the torque is above a predetermined level.

11 . A method for operating a pumping system, the method comprising:
driving a pump with a motor coupled to a variable speed drive; defining a relationship between head produced in a given pump and a torque indicator selected from torque, current and power; storing the values that define the relationship in non-transitory storage; calculating a fluid parameter based on the values stored in the non-transitory storage; and controlling the pump based on the calculated fluid parameter.

12 . A method as in claim 11 , wherein the fluid parameter is based on at least one of pressure and fluid level.

13 . A method as in claim 11 , wherein controlling includes determining a low level fluid fault when the torque indicator is below a predetermined level.

14 . A pumping system comprising: a pump and a motor coupled to a variable frequency drive to drive the pump, the variable frequency drive including a processor and a non-transitory computer readable medium having embedded therein processing instructions configured to perform a method when executed by the processor, the method including:
correlating a first parameter and a second parameter, the first parameter and the second parameter varying over time; predicting the first parameter based on a perturbation of the second parameter and the correlation; perturbing the second parameter; measuring a value of the first parameter with a transducer; and detecting a system change based on a difference between the predicted value and the measured value of the first parameter.

15 . A pumping system as in claim 14 , wherein the system change includes at least one of fluid level, fluid density and pump wear.

16 . A pumping system as in claim 14 , wherein the first parameter is a fluid parameter, the second parameter is pump speed, and the system change comprises loss of a credible transducer signal.

17 . A method of operating a pumping system, the method comprising:
driving a pump with a motor coupled to a variable frequency drive; correlating a first parameter and a second parameter, the first parameter and the second parameter varying over time; predicting the first parameter based on a perturbation of the second parameter and the correlation; perturbing the second parameter; measuring a value the first parameter with a transducer; and detecting a system change based on a difference between the predicted value and the measured value of the first parameter.

18 . A method as in claim 17 , wherein the system change includes at least one of fluid level, fluid density and pump wear.

19 . A method as in claim 17 , wherein the first parameter is a fluid parameter of a liquid, the second parameter is the pump speed, and the system change comprises loss of a credible transducer signal.

20 . A pumping system comprising: a pump and a motor coupled to a variable frequency drive to drive the pump, the variable frequency drive including a processor and a non-transitory computer readable medium having embedded therein processing instructions configured to perform a method when executed by the processor, the method including:
determining a torque indicator comprising one of torque, motor power and motor current; determining the torque indicator during a fault calibration period to determine a baseline; setting a fault threshold based on the baseline; and after setting the fault threshold, detecting a fault if the torque indicator exceeds the fault threshold.

21 . A pumping system as in claim 20 , wherein the fault threshold is between about 130% and 170% of the baseline.

22 . A pumping system as in claim 20 , wherein the fault threshold is between about 140% and 160% of the baseline.

23 . A pumping system as in claim 20 , wherein the torque indicator comprises a rate of change.

24 . A method for operating a pumping system, the method comprising:
driving a pump with a motor coupled to a variable speed drive; determining a torque indicator comprising one of torque, motor power and motor current; determining the torque indicator during a fault calibration period to determine a baseline; setting a fault threshold based on the baseline; and after setting the fault threshold, detecting a fault if the torque indicator exceeds the fault threshold.

25 . A method as in claim 24 , wherein the fault threshold is between about 130% and 170% of the baseline.

26 . A method as in claim 24 , wherein the fault threshold is between about 140% and 160% of the baseline.

27 . A method as in claim 24 , wherein the torque indicator comprises a rate of change.

28 . A method as in claim 24 , wherein the baseline is determined after a start-up period.

29 . A method as in claim 24 , wherein the baseline is determined after each start-u

Assignees

• Franklin Electric Co Inc

Inventors

• Van Der Merwe Lyon
• Brown Don
• Luarde Paul

Classifications

• E21B43/121

  Lifting well fluids (monitoring of down-hole pump systems E21B47/008) · CPC title

• F04C28/08 Primary

  characterised by varying the rotational speed · CPC title

• F04C2/1071

  the inner and outer member having a different number of threads and one of the two being made of elastic materials, e.g. Moineau type · CPC title

• F04C18/1075

  the inner and outer member having a different number of threads and one of the two being made of elastic material, e.g. Moineau type · CPC title

• G05B13/048

  using a predictor · CPC title