natural gas measurement


Thread Starter

Jorge Diaz

Hi group
Does somebody know if vortex flowmeter technology is accepted to natural gas custody transfer applications?


Jorge Diaz Zamora
GPI Ltda.
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Vortex is not a standard for gas.

First it used to be an orifice, after that turbine, and finally ultrasound (Daniel -part of the Emerson group). All use Flow Computers to calculate the flow and quantity at reference temperature (AGA / API / ISO Standard ). The gas composition can be directly transferred to the Flow Computer from a gas chromatograph (like Daniel ).

H. Zelenka

Do you know a link where I can get more official information about this matter.


Jorge Diaz Z.
You would do best to get some information on multi-path ultrasonic flowmeters. There are only three companies I know who have invested alot
in custody transfer are able to support custody transfer accuracies

FMC Kongsberg

You may also want to find out what approvals or work has been done by the South Western Research Institute if you are in the USA or Nell if
you are in Europe.

The same technology is also used for less expensive (but still accurate) measurement of things like Flare Gas. Roxar from Norway is good in this field as well as Panametrics

Jonathan Treffick

Be careful about the applications when using custody transfer UFMs. These meters do not work well at all in areas where there is higher content of CO2 or wet gas. Good, clean dry gas is ok in pipes with extremely long lengths of pipe. If you are near bends or control valves upstream or downstream (something so common in the gas industry) you are probably looking at errors of more than 20%. It does not matter that you have purchased an meter that states an accuracy of +/- 0.1 or 0.2% or whatever. These are accuracies achieved in test lab situations and are no indication of what goes on at the site with natural gas with different make ups.

You must remember that these types of meters are still inferential meters and they are basing calculations on expected flow profiles in the pipe. When they are calibrated, they are lab calibrated in perfect conditions. In the field, something else is happening. We are pushing the powers that be to address this problem because we are talking about millions of dollars of lost revenue for either the buyer or seller when it comes to small percentage errors. You will find this out when you put two gas custody meters in parallel, the readings are always very different.

We are looking at flow conditioners and changing pipework to accomodate the problems faced by UFMs. Although orifice meeting is now an ancient technique, most of the world is still using orifice measurement. Daniel and Emerson know this, so they still keep making their orifice meters too. Other companies in this area are Instromet and ABB.