Downhole · Gas Lift
Casing Annulus
The space between the casing and the production tubing. In gas lift it is the path the injection gas takes down the well.
What it does
Carries high pressure gas from the wellhead down to the gas lift valves, where it crosses into the tubing.
Basics
| Carries | Injection gas, downward |
| Sealed below by | The production packer |
| Pressure | Casing pressure opens the injection pressure operated valves |
Common failures
- Casing pressure too low to reach the deepest valve
- Leaks to surface or between strings
Troubleshooting
- Symptom
- Gas does not reach the operating valve
- Likely cause
- Available injection pressure too low
- What to check
- Check casing pressure against the valve design