Merge segments

If the flow from two (or more) segments merges into a single segment downstream, the volume exiting each segment must be blended. When a segment is receiving volume from two or more segments, the volume is combined in a single batch before adding it to the fragment or creating a new fragment. If the batch IDs are different, one of the batch IDs is chosen which the new fragment will be assigned to. Choice of batch is according to the following:

• If one of the upstream segments is flagged as the merge pipe, the batch coming from it will be used. Otherwise, the largest capacity pipe will be used as the merge pipe. If capacities are equal, choice of batch at the downstream segment will be random.

• If configured to do so, anomalies will be created, marking the start and end of blended batches.

  Note: If the flow rate of the pipeline is zero (0), and then multiple batches with different batch IDs are simultaneously injected into the line, the first cycle of batch tracking will not perform a merge and will inject one fragment of each batch into the line. Subsequent cycles will merge using the above criteria.

In addition, a merging anomaly will be generated at the node where the merge is taking place. This anomaly will not move with the flow of the pipe, but will stay at the node. It is created to ensure that you can still see that there is a merge in progress, even if the merge start moves off the end of the segment or even the pipeline.

The merging anomaly is removed from the pipeline when the merge stops, being replaced by the merge stop anomaly, which travels with the flow of the pipeline.

Note: There are also a different set of three anomalies (Merge Start, Merge End, and Merging) for the merge of the same product and a bad merge of two different products.

Alarms Issued When Merging

For information about alarms issued during the merging process, see Summary of Batch Tracking messages and alarms.