Threat · Flow Assurance
Slugging
An intermittent multiphase flow pattern: long gas pockets separated by liquid slugs, instead of a steady stream.
What it does
Slugs arrive at the facility as liquid surges, so separators must have enough liquid capacity to handle them and scrubbers trap them ahead of compressors. Pigging multiphase lines limits liquid holdup and the slug volumes the system generates.
Basics
| Pattern | Gas pockets and liquid slugs |
| At the facility | Liquid surges |
| Protection | Separator liquid capacity, scrubbers ahead of compressors |
| Control | Pigging to limit liquid holdup |
Common failures
- A slug larger than the separator liquid capacity floods the vessel
Troubleshooting
- Symptom
- Liquid surges at the inlet grow over time
- Likely cause
- Liquid holdup building in the line
- What to check
- Pig the line more often