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Shale Gas sites normally consist of a multitude of wells. Until now, many site operators rely on the installation of a Separator or Free-Water-Knock-Out at each well line. Given the high costs of a Separator as well as the time and capital consuming efforts in temporarily installing it for a rather short time at the shale gas well, the general aim is to reduce the number of Separators and move towards multipath configurations with several wellhead lines leading into one vessel.

Nevertheless, it is still of crucial importance for the operator to know about the individual gas flows at each wellhead line. Conventionally used Orifice Plates / DP meters, which measure the gas flows after the Separator outlet, cannot cope with the demanding conditions in front of the Separator.

A site operator thus called upon FLEXIM for a trial measurement of the FLUXUS G ultrasonic clamp-on gas flow meters at their Shale Gas sites in Texas and Louisiana. The test was carried out on the gas lines leading to the Separator, being 3'' and 4'' carbon steel pipes with pressures at more than 950 psig / 65 barg and temperatures between 350°F and 390°F / 180°C and 200°C.

The FLUXUS G gas flow meter was able to obtain an accuracy of 0.5% and better in comparison to the gas flow values obtained from the Orifice meter after the Separator - reproducibly and reliably at the two test sites. FLEXIM's ultrasonic clamp-on gas flow meters had no problem in coping with the extreme temperatures, neither with the high amount of liquids / wet gas streams.

Despite their ability to measure accurately and reliably, FLEXIM's clamp-on flow meters have the advantage of not having to enter the pipe. Pipe works or even process stops are not necessary and maintenance efforts are reduced to an absolute minimum.


  • Consistent, repeatable and accurate gas flow measurement in demanding conditions

  • No problem in measuring wet gas with high liquid volume fractions or at high pipe temperatures near 390°F / 200°C

  • Potential cost and time savings in eliminating siginfication numbers of Separator vessels