Split Streams
Streams between facilities can be split in two or more by creating connections from a single output to two or more input connections.
To split streams, select a connection line in the Surface Layout from an output connection that already has a connection, and draw a new connection to a different destination. Split connections are marked by dashed instead of continuous lines.
Split streams and runtime variablesWhen you edit a split connection, the Splits tab presents the list of defined branches.
You can define a separate Max Capacity for each branch by setting the Active switch to Yes. This capacity is independent from the input/output capacity of the facilities it connects (defined in the Capacity Sub-Tab).
The list determines the order of precedence: the branch at the top of the table will first receive all the fluids it can accept (either because of its own capacity limit, or because of constraints downstream) before any fluid is routed to the second one, and so forth. Select a branch and use the and buttons to move it up and down the list.
When working with split streams in complex projects, it is advisable not to define large Max step days in the Preferences Tab.
The reason is that split streams increase the complexity in the calculation of the Fluid Routing in PetroVR. When a project has a complex routing system (with several split streams, constraints based on runtime variables, rerouting jobs etc.), PetroVR applies a logic that keeps the calculation simple and relatively easy to handle, in order to save computational time and resources. In such cases, when a connection is split in two or more branches, only the amount of fluid sent through the first branch is actually included in the calculation corresponding to the current step; the rest is put off until the next step.
This has two important consequences:
- Using large Max step days may cause the calculation of split streams to be suboptimal, since in this case the amount of fluid put off grows proportionally and may yield noticeable differences in the results.
- Conversely, setting a larger Frequency for the Report Periodicity in the General Tab (down to 1 month), minimizes the effect, since the difference is smoothed. Notice that in any case the material balance is always honored at the end of the simulation.
See a full discussion of the implementation under Split Streams and Circularity.