UN-118: Liquid Coriolis(water cut meter, Proved as a Volume Meter)


Calculates the uncertainty in gross volume, mass and standard volume flowrate for a liquid flow through a Coriolis meter with an online prover and/or master meter.  The Coriolis meter’s density measurement accuracy is used as an uncertainty term in the calculation of the gross volumetric flowrate uncertainty.  Meter gross volume flowrate uncertainties are determined from proving statistics as per API MPMS 4.2. Pressure, temperature and measured density uncertainties are determined using the technical specification for the transmitters selected from the integrated transmitter selection tool.


The General tab is used to enter information, which is saved along with the uncertainty calculation and included in reports which are generated.

The tabs used for inputting data and calculating the uncertainty in the individual components of the uncertainty can be seen along the top of the module window.

The report tab is only visible once the calculation has been run and will not be visible if any parameters are changed until the calculation has been run once more.



Pressure units

This section gives the option of entering the pressure as either an absolute value or as a gauge value with reference to atmospheric (barometric) pressure. If Absolute is selected inputs are required for Absolute pressure and Atmospheric pressure and if Gauge is selected inputs are required for Gauge pressure and Atmospheric pressure. This ensures that whichever is chosen both the gauge and Absolute pressure value is available to other sections of the module.

For example: the Density calculation tab may require an absolute pressure to perform an AGA 8 calculation and the Gauge pressure may be used for the pressure transmitter calculation.

Absolute pressure – the Atmospheric pressure = Gauge pressure


Volume flow rate

This is the volume flow rate through the Coriolis meter.


This is the measured temperature.


This is the line pressure measured upstream of the Coriolis meter.

Note: As described above, if Absolute is selected inputs are required for Absolute and Atmospheric pressure and if Gauge is selected inputs are required for Gauge and Atmospheric pressure.

The default value for Absolute Pressure is set to 1 standard atmosphere (1.01325 bar)

Densitometer Pressure

This is the pressure measured at the densitometer.

Densitometer Temperature

This is the temperature measured at the densitometer.


The density of the liquid at the densitometer.

Water Cut

Mass Percentage of water in the flow.


The outputs section shows the calculated flow rate and uncertainty taken from the Coriolis as Proved Volume Meter tab and Net Oil Flow Rates tab.

Calculation Blocks

The following blocks are used within this uncertainty module:



Measured Density

Water Cut


Coriolis as a Proved Volume Meter

Net Oil Flow Rates