Monitoring a well flow device by fiber optic sensing

Abstract

Monitoring a well flow device by fiber optic sensing. A system includes processing circuitry configured to be disposed downhole in a wellbore. The processing circuitry is configured to receive a downhole parameter signal that represents an operational parameter of a well flow device in the wellbore, and perturb a fiber optic cable, based on the downhole parameter signal, to transmit the downhole parameter signal over the fiber optic cable. A fiber optic sensing system is coupled to the processing circuitry via the fiber optic cable. The fiber optic sensing system is configured to be disposed outside of the wellbore to extract, from the fiber optic cable, the downhole parameter signal.

1 . A system comprising:
 processing circuitry to be disposed downhole in a wellbore, the processing circuitry to:
 receive a downhole parameter signal that represents an operational parameter of a well flow device in the wellbore; and 
 perturb a fiber optic cable, based on the downhole parameter signal, to transmit the downhole parameter signal over the fiber optic cable; 
   a fiber optic sensing system coupled to the processing circuitry via the fiber optic cable, the fiber optic sensing system to be disposed outside of the wellbore, the fiber optic sensing system to:
 extract, from the fiber optic cable, the downhole parameter signal. 
   
     
     
         2 . The system of  claim 1 , wherein the fiber optic sensing system comprises a distributed acoustic sensing system further comprising an interrogator to interrogate the downhole parameter signal extracted from the fiber optic cable, the interrogator configured to be disposed outside the wellbore. 
     
     
         3 . The system of  claim 1 , wherein, to perturb the fiber optic cable based on the downhole parameter signal, the processing circuitry is further configured to:
 convert the downhole parameter signal into a vibration signal that represents the downhole parameter.   
     
     
         4 . The system of  claim 3 , to convert the downhole parameter signal into the vibration signal, the processing circuitry further comprises:
 an analog-to-digital converter to receive the downhole parameter signal;   a floating point calculation unit to encode the downhole parameter signal;   a vibration transducer to convert the encoded downhole parameter signal into the vibration signal; and   a pulse width modulation unit to transmit the vibration signal to the fiber optic cable.   
     
     
         5 . The system of  claim 1 , further comprising a controller configured to be disposed outside the wellbore, the controller connected to the fiber optic sensing system and configured to:
 receive the downhole parameter signal from the fiber optic sensing system; and   determine the operational parameter of the well flow device based on the downhole parameter signal.   
     
     
         6 . The system of  claim 5 , wherein the controller is further configured to:
 identify an operational parameter range for the operational parameter;   compare the determined operational parameter with the operational parameter range; and   transmit control signals to the well flow device to control an operation of the well flow device in response to comparing the determined operational parameter with the operational parameter range.   
     
     
         7 . The system of  claim 6 , wherein the controller is further configured to:
 determine that the determined operational parameter falls outside the operational parameter range in response to comparing the determined operational parameter with the operational parameter range; and   transmit the control signals to the well flow device to modify the operation of the well flow device such that the determined operational parameter falls within the operational parameter range.   
     
     
         8 . The system of  claim 6 , wherein:
 the fiber optic sensing system is further configured to extract a plurality of downhole parameter signals, each downhole parameter signal representing a downhole parameter at or near the well flow device; and   the controller is further configured to determine the operational parameter range based, in part, on the plurality of downhole parameter signals.   
     
     
         9 . The system of  claim 8 , wherein the plurality of downhole parameter signals represent at least one of viscosity of fluid in the wellbore, flow rate of the fluid, wellbore diameter, wellbore temperature, pressure at the well flow device, or pressure drop across the well flow device. 
     
     
         10 . The system of  claim 1 , wherein the well flow device is an electrical submersible pump, and the operational parameter is at least one of power consumed, rotational frequency, or vibration generated by the electrical submersible pump. 
     
     
         11 . A method to monitor a performance of a wellbore pump in a wellbore, the method comprising:
 receiving, downhole, an electrical downhole parameter signal representing an operational parameter of a wellbore pump in a wellbore;   converting, downhole, the electrical downhole parameter signal into a vibration signal that represents the operational parameter of the wellbore pump, the vibration signal to modulate, downhole, a light signal based on the vibration signal, the modulated light signal representing the operational parameter of the wellbore pump; and   transmitting the modulated light signal to outside the wellbore.   
     
     
         12 . The method of  claim 11 , wherein converting, downhole, the electrical downhole parameter signal into the vibration signal comprises:
 converting, downhole, an analog electrical downhole parameter signal into a digital downhole parameter signal; and   encoding, downhole, the digital downhole parameter signal into the vibration signal by implementing floating point calculation.   
     
     
         13 . The method of  claim 11 , wherein modulating, downhole, the light signal based on the vibration signal comprises perturbing a fiber optic cable, based on the downhole parameter signal, the perturbing resulting in the vibration signal. 
     
     
         14 . The method of  claim 11 , further comprising:
 receiving, outside the wellbore, the modulated light signal representing the operational parameter of the wellbore pump;   interrogating the modulated light signal outside the wellbore; and   determining the operational parameter in response to interrogating the modulated light signal outside the wellbore.   
     
     
         15 . The method of  claim 14 , further comprising:
 identifying an operational parameter range for the operational parameter;   comparing the determined operational parameter with the operational parameter range; and   transmitting control signals to the wellbore pump to control an operation of the wellbore pump in response to comparing the determined operational parameter with the operational parameter range.   
     
     
         16 . The method of  claim 15 , further comprising:
 determining that the determined operational parameter falls outside the operational parameter range in response to comparing the determined operational parameter with the operational parameter range; and   transmitting the control signals to the wellbore pump to modify the operation of the wellbore pump such that the determined operational parameter falls within the operational parameter range.   
     
     
         17 . The method of  claim 15 , further comprising:
 receiving one or more downhole parameter signals, each downhole parameter signal representing a downhole parameter at or near the wellbore pump; and   determining the operational parameter range based, in part, on the downhole parameter signals.   
     
     
         18 . A non-transitory computer-readable medium storing instructions executable by data processing apparatus to perform operations comprising:
 receiving, downhole, an electrical downhole parameter signal representing an operational parameter of a wellbore pump in a wellbore;   converting, downhole, the electrical downhole parameter signal into a vibration signal that represents the operational parameter of the wellbore pump, the vibration signal to modulate, downhole a light signal based on the vibration signal, the modulated light signal representing the operational parameter of the wellbore pump; and   transmitting the modulated light signal to outside the wellbore.   
     
     
         19 . The medium of  claim 18 , wherein converting, downhole, the electrical downhole parameter signal into the vibration signal comprises:
 converting, downhole, an analog electrical downhole parameter signal into a digital downhole parameter signal;   encoding, downhole, the digital downhole parameter signal by implementing floating point calculation, and   converting, downhole, the encoded digital downhole parameter signal into the vibration signal,   wherein the operations further comprise transmitting the vibration signal to modulate the light signal by implementing pulse width modulation.   
     
     
         20 . The medium of  claim 18 , wherein the operations further comprise:
 receiving, outside the wellbore, the modulated light signal representing the operational parameter of the wellbore pump;   interrogating the modulated light signal outside the wellbore;   determining the operational parameter in response to interrogating the modulated light signal outside the wellbore;   identifying an operational parameter range for the operational parameter;   comparing the determined operational parameter with the operational parameter range; and   transmitting control signals to the wellbore pump to control an operation of the wellbore pump in response to comparing the determined operational parameter with the operational parameter range.