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The measurement of fluids in the oil and gas industry requires a robust measurement of multiphase flows. Magnetic resonance as a measurement principle has multiple advantages over existing technologies (one single measurement principle, measurement performed from outside the pipe with no intruding sensors, full bore design, suited for producing wells and high sensitivity at high water liquid ratios). A magnetic resonance based multiphase flow meter which is capable of producing an image of the spatial distribution of a multiphase flow has been developed. This article describes the principles of magnetic resonance. Afterwards details of the technical implementation and the method by which the system determines multiphase flow composition are explained.

The flow instruments used in thermal power plants cannot be calibrated directly for the actual process conditions, since no traceable calibration facility with known uncertainty is available. A systematic investigation of the relevant influence parameters is therefore needed. It was found in earlier investigations that the dominant influences on the measurement uncertainty are the flow velocity profile and the temperature. In the present work, we report on our experimental study of the temperature and Reynolds number dependence of a new ten-path ultrasonic flow meter prototype. An improved measuring program is developed that allows for a systematic characterization. Special emphasis was placed on producing and validating well defined velocity profiles on a precision calibration flow rig. It was also for the first time intended and validated to generate fully developed Reynolds-similar velocity profiles for different temperatures so that the two main influence parameters, namely temperature and Reynolds number, can be clearly characterized separately. Since such ideal measurement conditions are not found in practical applications, the approach is also tested for a disturbed flow condition. A well defined disturbance is generated with a new flow disturber.

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