Downhole · Abandonment
Well Barriers
The cement plugs, bridge plugs and casing that together keep every zone isolated after the well is abandoned.
What it does
Regulators typically require isolating open hydrocarbon zones, casing shoes, fresh water aquifers and the top of the wellbore. Cement plugs are the main barrier, often set on a bridge plug, and each stage is tested to confirm isolation.
Basics
| Isolate | Hydrocarbon zones, casing shoes, aquifers, top of the well |
| Main barrier | Cement plugs |
| Verified by | Pressure or inflow test at each stage |
| Rules in Alberta | AER Directive 020 |
Common failures
- A plug that fails its test
Troubleshooting
- Symptom
- Leak found during testing
- Likely cause
- Plug or isolation failed
- What to check
- Identify and repair the leak before surface abandonment