Downhole · Completion
Subsurface Safety Valve
A valve in the tubing within a few hundred feet of surface that shuts in the well if the surface controls are lost.
What it does
Closes automatically when surface control is breached and can also be closed on command. It is the last barrier if the wellhead is damaged. It is held open by hydraulic pressure through a control line from surface.
Basics
| Location | Tubing, within a few hundred feet of surface |
| Control | Hydraulic pressure through a control line holds it open; it closes if that pressure is lost |
| Standard | API Spec 14A |
Common failures
- Valve fails its periodic closure test
Troubleshooting
- Symptom
- Valve will not hold or will not reopen
- Likely cause
- Control line leak or worn valve
- What to check
- Pressure test the control line, run the closure test