Downhole · Completion
Chemical Injection Line
Small diameter seamless tubing strapped to the outside of the production tubing that carries chemical from surface to an injection point downhole.
What it does
Delivers inhibitors right where the problem forms, such as scale, corrosion or paraffin. The same tubing is also used as the hydraulic control line for safety valves and downhole valves.
Basics
| OD | 1/4, 3/8, 1/2 or 3/4 in |
| Wall | 0.035 or 0.049 in |
| Materials | 316L (ASTM A269, cold drawn), 2205 duplex or Alloy 825 |
| Uses | Chemical injection or hydraulic control line |
Common failures
- Line plugged when the chemical dehydrates, or by solids
- Line crushed while running, for example by the tubing slips
Troubleshooting
- Symptom
- Injection pressure climbs and rate falls
- Likely cause
- Chemical dehydrated and plugging the line
- What to check
- Flush the line; flush it with water or methanol whenever injection stops for a long period
- Symptom
- Pump runs but pressure will not build
- Likely cause
- Line damaged or leaking
- What to check
- Pressure test the line