Christmas Tree Assemblies
A Christmas tree is the assembly of valves, spools, and fittings mounted on top of the wellhead tubing head. It controls production flow from the well, provides access for well intervention, and enables safe shut-in of the well under normal and emergency conditions. The name comes from the tree-like appearance of the stacked valves and fittings.
What a Christmas Tree Does
The Christmas tree performs three primary functions:
1. Flow control — master valves and wing valves control production flow to the flowline
2. Well shut-in — master valves close the well for maintenance, intervention, or emergency
3. Intervention access — the swab valve at the top provides access for wireline and coiled tubing operations without killing the well
A properly specified and maintained Christmas tree is the last barrier between the wellbore and the production facility.
Christmas Tree Types
Single-Valve Tree
A single-valve tree has one master valve below the flow cross, providing a simpler, lower-cost configuration for lower-pressure wells. Used in applications where the risk profile allows a single barrier on the master valve.
Double-Valve Tree
A double-valve tree has two master valves in series below the flow cross — an upper master valve (UMV) and a lower master valve (LMV). The redundant barrier provides additional well control security and allows one valve to be maintained while the other remains closed. Standard for higher-pressure wells and wells with H₂S.
Rod Lift Christmas Tree
Rod lift Christmas trees are configured to accommodate the polished rod passing through the stuffing box at the top of the tree. The tree includes the casing and tubing valves, flow tee, and the stuffing box mounting arrangement. WNS Lowery supplies rod lift Christmas tree components — stuffing boxes, flow tees, and polished rod lubricators — as part of the surface wellhead assembly.
Key Components
| Component | Function |
|---|---|
| — | — |
| Lower master valve (LMV) | Primary well shut-in valve |
| Upper master valve (UMV) | Secondary well shut-in valve (double-valve tree) |
| Wing valve (production) | Controls flow to production flowline |
| Wing valve (kill) | Provides access for well kill operations |
| Swab valve | Top access for wireline and coiled tubing |
| Flow cross / tee | Connects master valves to wing valves |
| Choke | Regulates wellhead flowing pressure |
Pressure Ratings and Standards
| Rating | Application |
|---|---|
| — | — |
| 2 000 PSI | Low-pressure production wells |
| 3 000 PSI | Standard onshore production |
| 5 000 PSI | Moderate-to-high pressure wells |
| 10 000 PSI | High-pressure wells — on request |
All equipment manufactured to API 6A. Sour service (H₂S) trim available per NACE MR0175.
Suppliers
| Supplier | Products | Notes |
|---|---|---|
| — | — | — |
| Wellhead Systems Inc. (via Power Flow) | Christmas tree assemblies, gate valve trees | API 6A, full documentation |
| WNS Lowery (Marsh Bellofram Group) | Rod lift tree components — stuffing boxes, flow tees | American-made, standard and high-pressure |
Why Source Through Proxima
Proxima supplies Christmas tree assemblies matched to the wellhead configuration — ensuring flange compatibility, pressure rating consistency, and a single documentation package. Power Flow International Sales handles international logistics and export documentation for delivery to any location in the Caspian region and Central Asia.
Frequently Asked Questions
Q: What is the difference between a single-valve and double-valve Christmas tree?
A single-valve tree has one master valve — simpler and lower cost. A double-valve tree has two master valves in series, providing a redundant barrier for higher-pressure or sour service wells. Most operators in Azerbaijan and Kazakhstan specify double-valve trees for producing wells.
Q: Can Proxima supply the Christmas tree matched to an existing wellhead?
Yes. Provide the wellhead make, model, flange size, and pressure rating, and we will specify a compatible Christmas tree. Proxima confirms flange and bore compatibility before supply.
Q: Are sour service Christmas trees available?
Yes. NACE MR0175-compliant trim — valve seats, seals, and trim materials — is available for H₂S service. Specify H₂S concentration and partial pressure when ordering.
Q: What is included in a complete Christmas tree package?
A complete tree includes all valves, the flow cross, flanges, studs, nuts, and ring gaskets. Actuators, chokes, and instrumentation are available as options. Specify your requirements when requesting a quote.
