Wood Group Kenny's Virtuoso®/VMS is used to estimate wellhead flow rates based on the normally measured pressures and temperatures in and around the well and the well choke position. Estimates of the oil, gas, and water production rates are determined by using multiple models to estimate flow rate and then statistically combining their output to determine the best estimated production rates. The use of multiple models leads to more accurate flowrate estimates that are robust in the event of instrumentation failure.
The system is designed for unattended operation so the system automatically collects process data and calculates the flowrate estimates and alarm information. The calculated flowrate information can be transmitted automatically to SCADA, DCS or a process data historian system in real time.
Virtuoso/VMS is made up of four building blocks/models:
It is important to use multiple models to estimate flow rates because model accuracies will vary depending on flow regimes. When using these four models, nine distinct flow rate estimates can be made. Having nine flow rate estimates leads to a more accurate result.
All of the well instrumentation are displayed showing the actual as well as filtered values. Values can be filtered based on a number of criteria. Bad values of replicated instruments can be filtered out instead of just averaging the values to an obvious incorrect value. Instrument quality is displayed by the background color in the value box. Green means it is okay. Magenta means that the value is frozen and has not moved for a user-definable period and cannot be trusted. Red means the communication to the data server is lost and is not updating.
The Well Instrumentation Screen displays these values for bottom measurements, master valve, wing valve, before choke measurements, choke valve and after choke measurements.
The Well Detail Screen provides information about the well flowrate values and accuracies for gas, oil and water. The flow rate and uncertainty calculated by each method and displayed in a box-and-whisker plot so you can easily see if a method is an outlier.
The best estimate of the flow rate is displayed as the vertical red line. The user may selectively add or subtract methods based on current instrument availability..
Status/Overview Screen shows the overview for production for each well, displaying:
The Tuning Screen allows for tuning of certain VMS parameters to maintain accuracy. The Well Tuning Screen displays parameters that affect the calculated flow rate when they are revised.
The flowrate cumulative screen can be configured to provide totalized values based on user-specific criteria. Cumulative values can be displayed in the Cumulative Screen. The Cumulative Screen displays the cumulative production rates by phase for each well Of course, all flowrate data can be passed automatically to a SCADA or data historian system for use by many functions throughout the company.
Other useful functions include: