Integrity · Pipelines
In-Line Inspection Tool
A smart pig: an instrumented tool that travels inside the pipe with the flow and records the condition of the pipe wall.
What it does
Finds and sizes corrosion, cracks, dents and weld defects over long distances without digging. Magnetic flux tools find metal loss, ultrasonic tools measure wall thickness or find cracks, and geometry tools find dents and ovality.
Basics
| Metal loss | Magnetic flux leakage (MFL) |
| Wall thickness and cracks | Ultrasonic (compression and shear wave) |
| Dents and ovality | Geometry or caliper tool |
| Before a UT run | Clean the line, deposits spoil the reading |
Common failures
- Line not piggable because of tight bends, unbarred tees or valves that are not full open
Troubleshooting
- Symptom
- UT run returns poor quality data
- Likely cause
- Dirty line
- What to check
- Run cleaning pigs before the inspection run