Profiling and Trending of Coriolis Meter Secondary Process Value Drift Due to Ambient Temperature Fluctuations

Abstract: Coriolis mass flow metering technology is widely used within the Oil and Gas industry. There is now an increased focus on utilising the technology's ability to calculate fluid density in areas such as fluid contamination indication and feedback for process control loops. However, it is common for flow meters of this type to be installed within environments that are subject to severe variations in ambient conditions. One such condition, which this paper seeks to address is the effect that air temperature surrounding the meter body can have on the Coriolis meter's ability to correctly calculate fluid density, specifically in scenarios where there is a significant differential between the fluid temperature present within the meter internals and the surrounding ambient air temperature. This paper details an experimental program that was carried out at NEL where the ambient temperature surrounding a Coriolis meter was varied in a controlled manner while diagnostic data output from the meter were logged over time. Analysis of the data has allowed for the identification of repeatable drift in both the calculated fluid density and indicated fluid temperature process values output by the metering technology. Highlights: Ambient air temperature fluctuations within installation environment will cause data output from Coriolis technology to drift. Extent of drift dependant on temperature differentials between ambient air and fluid within meter. Fluid flow rate also shown to be a variable that adds to the drift effect, which is specific to air temperature environments reported within this paper. Specific meter outputs reported on are fluid density and fluid temperature (Secondary Outputs).