Three liquids measurement

  • Thread starter Mervyn R. Stewart
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Thread Starter

Mervyn R. Stewart

Hello Folks,

Does anyone know of a way to measure the thickness(depth) of the middle layer of a three phase liquid column. The liquids are: crude oil, a semi-emulsion of oil and water, and water. The SG. of the "emulsion" is approx. 0.91.
regards, Mervyn

David W. Spitzer


One approach is to subtract individual measurements of the top and bottom of the desired "rag" layer. This effectively breaks a more difficult problem into two simpler problems.

David W Spitzer
It depends on the "definition of the middle layer." If it is not a "rag layer" with a continuing gradation of either density, or conductivity, the measurement can be done. Use either a radar or ultrasonic sensor (depending
on whether there is a vapor layer or not) for "top level". Use an RF admittance probe for each of the other interfaces. This should work. If
the middle layer is a "rag layer", the measurement is highly unlikely to be
measureable, unless it can be done optically.

Walt Boyes

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One of these world leaders in petrochemicals, I was consulting, made these measurement with bubbler tubes. Working fine,
pen in the neck for the calibration of the XTR because the algebra involved is not evident.
You could try using servo level transmitter which can travel down or up to measure the exact interface levels and through the difference, computed with a HMI software, you could find the thickness of the middle layer. Proper choice of the servo level system and HMI is a must for solving this problem.
Anand Krishnan Iyer.
You can try Servo level systems. The servo level systems can travel up and down and calculate the interface levels. You can then use a good HMI to
find the thickness.
Best Regards
Anand Krishnan Iyer
We have done this in a live well!

You can detect the nature of the fluid at any point using an complex impedance probe. This will allow you to determine at any probe exactly what sort of fluid you have. If you mount an array of probes you will get a map of what fluid is where. we have done 60 over 30 meters before and it worked OK

If you are interested contact me

Dave Shanks
Axon Instruments Ltd
phone 01467 622332
Fax 01467 625235
e-mail [email protected]