Instrumenting High Reliability Electric Submersible Pumps

Abstract

Instrumentation for high reliability electric submersible pumps (ESPs) is provided. Comprehensive sensors placed throughout ESP components enable monitoring, analysis, and intervention to improve performance of ESP components and provide high reliability and long life for components. Example ESP sensors used to protectively monitor an ESP string may include electrical current leakage detectors, temperature sensors at the pothead, fiber optics used as distributed temperature sensors in the motor stator and windings of the motor, water cut sensors to determine quality of hydrocarbon being produced, tachometer and torque sensors to detect the speed of rotating shafts of the motors and pumps, temperature and vibration sensors for rotor bearings and thrust members, and wye-point imbalance detectors for balancing electrical loads on the three phases in a wye system. Interpretation and control modules analyze the sensor input and apply actions that improve performance and lengthen lifespan of components.

1 . A system, comprising:
 an electric submersible pump (ESP) string, including at least one ESP motor;   a sensor associated with at least a shaft bearing or a rotor bearing of each section of the ESP string;   a monitoring module for dynamically tracking data of each sensor; and   a control module for changing an operating parameter of a component of the ESP string based on the dynamic tracking of the sensor data.   
     
     
         2 . The system of  claim 1 , further comprising a fiber optic strand to perform distributed sensing of temperatures along the ESP string, the control module changing an operating parameter of at least one component of the ESP string based on the distributed sensing of the temperatures. 
     
     
         3 . The system of  claim 2 , wherein the fiber optic strand runs internally in at least one motor stator of the ESP string. 
     
     
         4 . The system of  claim 2 , wherein the distributed sensing of temperature using the fiber optic strand includes sensing a temperature associated with at least a shaft bearing or a rotor bearing of the ESP string. 
     
     
         5 . The system of  claim 4 , further comprising a vibration sensor to dynamically track vibrations generated by the ESP string. 
     
     
         6 . The system of  claim 5 , wherein a vibration module obtains vibration spectral data up to  1  kHz for a select component along the ESP string. 
     
     
         7 . The system of  claim 5 , wherein each vibration sensor dynamically tracks a vibration associated with a pump bearing or a motor bearing of the ESP string. 
     
     
         8 . The system of  claim 7 , wherein the control module changes an operating parameter of at least one component of the ESP string based on analysis of at least one temperature and at least one vibration in the ESP string. 
     
     
         9 . The system of  claim 1 , further comprising a fiber optic strand to measure a distributed temperature profile or a platinum resistive thermocouple device (RTD) to measure a temperature of a power cable of the ESP string or along a motor lead extension (MLE) cable of the ESP string. 
     
     
         10 . The system of  claim 1 , further comprising a tachometer (RPM) sensor or a torque sensor packaged around at least a shaft for monitoring a rotational speed and a torque of the shaft. 
     
     
         11 . The system of  claim 1 , further comprising at least a water cut sensor or at least a chemical sensor located along the ESP string to perform oil purity measurements or chemical measurements. 
     
     
         12 . The system of  claim 1 , further comprising a pressure sensor located in the ESP string to perform a pressure measurement. 
     
     
         13 . The system of  claim 12 , wherein at least one pressure sensor measures a differential pressure inside and outside of a bellows in the ESP string. 
     
     
         14 . The system of  claim 13 , further comprising an electrical relief valve in tandem with a mechanical relief valve for relieving a pressure in the bellows. 
     
     
         15 . The system of  claim 1 , further comprising an electrical current leakage sensor. 
     
     
         16 . The system of  claim 1 , further comprising a wye-point imbalance detector for detecting an unbalanced phase in a wye system. 
     
     
         17 . The system of  claim 1 , further comprising a thrust member sensor to measure one of a temperature, a strain, or a proximity of a thrust member to a thrust member runner in the ESP string. 
     
     
         18 . A system, comprising:
 an electric submersible pump (ESP);   a control module to change an operating parameter of a component of the ESP based on dynamic tracking of data from multiple types of sensors arrayed along the ESP;   a sensor associated with at least a bearing of each component of the ESP; and   a sensor selected from the group of sensors consisting of bearing temperature sensors, bearing vibration sensors, stator temperature sensors, distributed temperature profile sensors, power cable temperature profile sensors, motor lead temperature profile sensors, shaft RPM sensors, shaft torque sensors, water cut sensors, water ingress sensors, chemical sensors, bellows pressure sensors, thrust bearing temperature sensors, thrust bearing strain sensors, thrust bearing proximity sensors, electrical current leakage sensors, and wye-point imbalance sensors.   
     
     
         19 . The system of  claim 18 , wherein the multiple types of sensors arrayed along the ESP are multiplexed along the length of a fiber optic strand by one of:
 assigning different wavelengths of light for each sensor, or   sensing a time delay as light passes along the fiber through each sensor, wherein an optical time-domain reflectometer determines the time delay.   
     
     
         20 . The system of  claim 18 , wherein a control module changes an operating characteristic of at least a segment of the ESP based on monitoring the multiplexed sensors, by varying a power, a voltage, an amperage, a frequency, a pump speed, a motor speed, a valve state, a pressure, a flow, a temperature, or a vibration in a selected spatial plane, of the at least one component of the ESP.