Real time optimization of power in electrical submersible pump variable speed applications

Abstract

A method and apparatus for real-time monitoring of a variable frequency drive (VFD) controlling an electric submersible pump (ESP) and for fine-tuning operation of a VFD-ESP system such that oil production, power, and motor run life are optimized.

1 . A method of adjusting one or more operating parameters of a variable frequency drive (VFD) coupled to an electric submersible pump (ESP) in real time, comprising:
 (a) collecting data associated with the VFD and the ESP while operating the ESP;   (b) analyzing the collected data in real time to determine if the one or more operating parameters can be adjusted to achieve a desired operating state; and   (c) in response to determining that the operating parameters can be adjusted to achieve the desired operating state, adjusting the one or more operating parameters of the VFD.   
   
   
       2 . The method of  claim 1 , wherein the operating parameters comprise at least one of an operating frequency, a carrier frequency, a base frequency, a target operating frequency, a VFD transformer tap setting, and an operating frequency ramp profile. 
   
   
       3 . The method of  claim 1 , wherein collecting data associated with the VFD and the ESP is done without interfering with or impeding operation of the ESP. 
   
   
       4 . The method of  claim 1 , wherein the collected data comprise at least one of current total harmonic distortion (THD), voltage THD, a VFD operating frequency, a VFD carrier frequency, a VFD base frequency. 
   
   
       5 . The method of  claim 1 , wherein the collected data comprises at least one of oil loss, a number of transformer shutdowns, a number of VFD shutdowns, a number of switchboard shutdowns, motor torque, motor vibration, motor current imbalance, motor voltage imbalance, motor temperature, and an apparent power of the VFD. 
   
   
       6 . The method of  claim 1 , further comprising analyzing historical data associated with the VFD and the ESP in conjunction with the collected data to determine if the one or more operating parameters can be adjusted to achieve a desired operating state. 
   
   
       7 . The method of  claim 1 , wherein the desired operating state comprises an equilibrium between a maximum possible hydrocarbon production, a minimum distortion on waveforms to an electrical motor of the ESP, and a minimum level of harmonics on an input side of the VFD. 
   
   
       8 . The method of  claim 1 , wherein the desired operating state does not violate a total harmonic distortion (THD) limit on an input side of the VFD. 
   
   
       9 . An apparatus for monitoring and adjusting one or more operating parameters of a variable frequency drive (VFD) coupled to an electric submersible pump (ESP) in real time, comprising:
 a waveform capture device electrically coupled to the VFD for determining data associated with the VFD and the ESP while operating the ESP, comprising:
 one or more input voltage or current meters coupled to one or more VFD inputs; and 
 one or more output voltage or current meters coupled to one or more VFD outputs; and 
   a computing device coupled to the waveform capture device and configured to analyze the data determined by the waveform capture device in real time to determine if the one or more operating parameters can be adjusted to achieve a desired operating state and to adjust the one or more operating parameters of the VFD if the operating parameters can be adjusted.   
   
   
       10 . The apparatus of  claim 9 , further comprising a remote terminal unit coupled between the waveform capture device and the computing device and configured to adjust the operating parameters of the VFD based on an input from the computing device. 
   
   
       11 . The apparatus of  claim 9 , further comprising a processing unit coupled to the input and output voltage or current meters and configured to sample the meters and provide the data determined by the waveform capture device to the computing device. 
   
   
       12 . The apparatus of  claim 9 , wherein the desired operating state comprises an equilibrium between a maximum possible hydrocarbon production, a minimum distortion on waveforms to an electrical motor of the ESP, and a minimum level of harmonics on an input side of the VFD. 
   
   
       13 . The apparatus of  claim 9 , wherein the desired operating state does not violate a total harmonic distortion (THD) limit on an input side of the VFD. 
   
   
       14 . The apparatus of  claim 9 , wherein the operating parameters comprise at least one of an operating frequency, a carrier frequency, a base frequency, a target operating frequency, a VFD transformer tap setting, and an operating frequency ramp profile. 
   
   
       15 . The apparatus of  claim 9 , wherein the waveform capture device is configured to determine the data associated with the VFD and the ESP without interfering with or impeding operation of the ESP. 
   
   
       16 . A system, comprising:
 a variable frequency drive (VFD);   an electric submersible pump (ESP) coupled to the VFD;   a waveform capture device electrically coupled to the VFD for determining data associated with the VFD and the ESP while operating the ESP, comprising:
 one or more input voltage or current meters coupled to one or more VFD inputs; and 
 one or more output voltage or current meters coupled to one or more VFD outputs; and 
   a computing device coupled to the waveform capture device and configured to analyze the data determined by the waveform capture device in real time to determine if the one or more operating parameters can be adjusted to achieve a desired operating state and to adjust the one or more operating parameters of the VFD if the operating parameters can be adjusted.   
   
   
       17 . The system of  claim 16 , further comprising a remote terminal unit coupled between the waveform capture device and the computing device and configured to adjust the operating parameters of the VFD based on an input from the computing device. 
   
   
       18 . The system of  claim 16 , wherein the operating parameters comprise at least one of an operating frequency, a carrier frequency, a base frequency, a target operating frequency, a VFD transformer tap setting, and an operating frequency ramp profile. 
   
   
       19 . A computer-readable medium containing a program for adjusting one or more operating parameters of a variable frequency drive (VFD) coupled to an electric submersible pump (ESP) in real time, which, when executed by a processor, performs operations comprising:
 (a) collecting data associated with the VFD and the ESP while operating the ESP;   (b) analyzing the collected data in real time to determine if the one or more operating parameters can be adjusted to achieve a desired operating state; and   (c) in response to determining that the operating parameters can be adjusted to achieve the desired operating state, adjusting the one or more operating parameters of the VFD.   
   
   
       20 . The computer-readable medium of  claim 19 , wherein the operating parameters comprise at least one of an operating frequency, a carrier frequency, a base frequency, a target operating frequency, a VFD transformer tap setting, and an operating frequency ramp profile. 
   
   
       21 . The computer-readable medium of  claim 19 , wherein the desired operating state comprises an equilibrium between a maximum possible hydrocarbon production, a minimum distortion on waveforms to an electrical motor of the ESP, and a minimum level of harmonics on an input side of the VFD.