Surface · Completion
Wellhead & Christmas Tree
The spools and valves at the top of the well. The wellhead holds the casing and tubing strings; the tree above it carries the valves that control the flow.
What it does
Contains well pressure at surface and sends production to the flowline. The master valves shut in the well; the wing valve and choke route and regulate the flow.
Basics
| Main valves | Master and wing valves, plus gauges and chokes |
| Standard | API Spec 6A |
Common failures
- Valve that no longer seals, so the well cannot be shut in safely
Troubleshooting
- Symptom
- Well cannot be shut in with a closed valve
- Likely cause
- Valve no longer seals
- What to check
- Have the valve repaired or replaced before relying on it