Multiphase meters were initially developed by several companies during the 1990's and thus far, operators have gained about 10 - 15 years of experience in using them. However, results during this period have been mixed, and many operators, having trialed and tested all technologies began to express concerns in the reliability, accuracy and sensitivity of conventional technologies . A particular concern was the accuracy of multiphase metering in the wetgas regime.
The particular case where the gas fraction (GVF) of a multiphase stream is above 92–95% is denoted wetgas. The vast majority of gas producers contain small volumes of hydrocarbon liquid and water and wetgas metering thus represents a growing interest for operators. Even in cases where the reservoir only produces gases, liquid condensation will usually occur in the flow lines with falling temperature and pressure -causing wetgas conditions at the metering location.
The benefits of accurate and reliable wetgas metering systems are many and varied:
- Allocation in multi-well/multi-operator applications
- Saline water detection and measurement
- Real time reservoir monitoring, and well testing
- Flow assurance and production optimisation
- Installation simplification in challenging developments with multi-well and subsea tie-back configurations
- E-field solutions
A few two-phase wetgas meters are commercially available in the market today, being able to discriminate between gas and liquid or between hydrocarbons and water. The MPM meter is, as far as we know, the only multiphase meter that is capable of independently measuring all three phases in addition to the salt content in a wetgas stream.
This paper gives an overview of the MPM technology, describes the extensive qualification program that was undertaken to prove the technology and provides test data to demonstrate the superior performance of the meter at high GVF conditions - particularly in relation to highly accurate water flowrate measurements.