Coriolis meter flowrate uncertainty is determined using the technical specification for the Coriolis meter selected from the integrated meter selection tool. Water cut is determined from known standard densities of water and oil in addition to line density of the oil-water mixture. Pressure, temperature and measured density uncertainties are determined using the technical specification for the transmitters selected from the integrated transmitter selection tool. The module replicates the “Net Oil” calculations to determine the “Net Oil” and “Water” mass flowrates and determines the associated uncertainties in these outputs. The “Net Oil” calculation require standard density inputs for both the oil and water phases, and uses the relevant standards for Ctl and Cpl to convert these densities to line conditions.
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.
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
This is the line pressure of the gas stream 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)
This is the measured temperature of the gas stream.
the density of the gas flowing through the Coriolis meter.
Mass flow rate
This is the mass flow rate through the Coriolis meter.
The outputs section shows the calculated flow rate and uncertainty taken from the liquid Coriolis meter tab.
The following blocks are used within this uncertainty module: