This typical calibration procedure is just an illustration of how to calibrate a multiphase flow meter for academic purpose only. This typical procedure shall not use as a day to day operation guidance.
The vendor specific maintenance manual shall be used in detail. This procedure is for the meters that operate using gamma densitometer, capacitive, and inductance sensor to determine the fluid composition and speed.
Multiphase Flow Meter Calibration
Gamma densitometer calibration
- Drain all fluid inside the flow meter.
- Fill the flow meter using the atmospheric air.
- By using a laptop, start the calibration (at calibration menu) and enter the known density of the air as reference for the sensor.
- Fill the flow meter using water that the density has been known.
- By using a laptop, start to measure this water density by using the gamma densitometer.
- Make a correction of the measurement constant based on known water density, measured or calculated water density, and the known density of air (see Vendor documentation regarding how to make this constant correction).
- Use the corrected constant as a new constant replacing the old constant.
- Measure the density of the water once again to check whether the densitometer output has been corrected or not.
- If the measurement reading deviate from the known density by less than the densitometer accuracy then the calibration activity is done. Otherwise, repeat the entire step again.
Capacitive sensor calibration
- When the flow meter filled with the atmospheric air in above gamma densitometer calibration, check the permittivity of the air by using a laptop.
- The permittivity should be near the permittivity of air (near 1.00).
- If it differ more than the vendor specified accuracy, then it should be calibrated.
- Calibrate the capacitive sensor by using a laptop as per Vendor guidance (usually by press a single calibration button, the software will calibrate and adjust it automatically).
- Check again if the read has been corrected.
Inductance sensor calibration
- When the flow meter filled with the water in above gamma densitometer calibration, check the water cut reading and the conductivity reading by using a laptop.
- The water cut reading should show a 100% water cut (since it was filled with 100% water) if there are any reading deviation more than the water cut accuracy, then it should be calibrated.
- Calibrate the inductance sensor for water cut reading by using a laptop as per Vendor guidance (usually by press a single calibration button, the software will calibrate and adjust it automatically).
- Now read the conductivity reading, the conductivity reading should be the same with the known conductivity of the water at the actual temperature and pressure. If there is any reading deviation more than the permissible deviation, then it should be calibrated.
- Calibrate the inductance sensor for conductivity reading by using a laptop as per Vendor guidance (usually by press a single calibration button, the software will calibrate and adjust it automatically).
There is also pressure transmitter or temperature transmitter attached to multiphase flow meter. Normally this transmitter calibration will be done by the engineer just like other transmitter so that it’s not part of this procedure.
Typical tools required:
- Maintenance or diagnostic laptop.
- Serial cable for communicating with the flow computer.
- Serial to USB converter to connect the serial cable to the diagnostic laptop.