Wellhead Assemblies
A wellhead assembly is the structural and pressure-containing equipment installed at the top of a wellbore. It supports the weight of the casing and tubing strings, seals the annular spaces between casing strings and between casing and tubing, and provides the mounting point for the Christmas tree and surface flow control equipment.
Every producing oil and gas well requires a wellhead. Its pressure rating, size, and configuration are determined by the well’s maximum anticipated surface pressure, casing programme, and production requirements.
What a Wellhead Assembly Does
The wellhead assembly performs four functions simultaneously:
1. Structural support — carries the weight of casing and tubing strings suspended in the wellbore
2. Pressure containment — seals the annular spaces to prevent uncontrolled flow between casing strings or to surface
3. Suspension — provides the landing point for casing hangers and tubing hangers
4. Interface — provides the flanged connection point for the Christmas tree and surface equipment
A failure in the wellhead assembly is a well control event. All equipment supplied by Proxima meets API 6A requirements.
Wellhead Assembly Components
Casing Head
The casing head is the first component installed on the wellhead. It is welded or threaded to the surface casing and provides the structural base for the entire wellhead stack. It contains the casing hanger that supports the next casing string and seals the annulus between the two casing strings.
Wellhead Systems Inc. casing heads are available in slip-on and threaded connection styles for casing sizes from 4½” through 13⅜”, with operating pressures of 1 500, 2 000, 3 000, and 5 000 PSI. WNS Lowery casing heads cover complementary sizes and pressure ratings.
Tubing Head
The tubing head mounts on top of the casing head stack and provides the landing point for the tubing hanger. It seals the annulus between the production tubing and the production casing, and provides two side outlets for annulus access — used for gas lift, chemical injection, or pressure monitoring.
Available in 7 1/16″ 3M and 5M flange configurations with 4½”, 5½”, or 7″ bottom thread. Manufactured from high-strength forged carbon steel. All API flanges are manufactured to API 6A.
Tubing Head Adapter
The tubing head adapter (THA) connects the tubing head to the Christmas tree. It provides the transition between the tubing head flange and the tree flange, accommodating differences in bore size or pressure rating between the two components.
Pressure Ratings and Standards
| Pressure Rating | Typical Application |
|---|---|
| — | — |
| 1 500 PSI (10 MPa) | Shallow, low-pressure wells |
| 2 000 PSI (14 MPa) | Standard onshore production wells |
| 3 000 PSI (21 MPa) | Moderate-pressure wells |
| 5 000 PSI (34 MPa) | High-pressure wells |
| 10 000+ PSI | HPHT applications — on request |
All equipment manufactured to API 6A. Material class selected to match well fluid composition — standard carbon steel for sweet service; CRA trim for H₂S and CO₂ service.
**H2: Wellhead Seals & Accessories
*This section covers wellhead seals, packing elements, and accessory components. While these items do not carry a dedicated product page, they are an integral part of every wellhead supply and are fully supported by Proxima. Contact us for seal specifications, replacement packing, and accessory components for any wellhead configuration we supply.*
Key accessory items:
- Casing hanger seals and secondary seals
- Tubing hanger seals and packing elements
- Bonnet assemblies and valve stem packing
- Wellhead test plugs
- Lifting subs and installation tools
SEO tags for this section: wellhead seals Azerbaijan, wellhead packing elements, casing hanger seal Caspian, tubing hanger seal Kazakhstan, wellhead accessories Central Asia
Suppliers
| Supplier | Products | Notes |
|---|---|---|
| — | — | — |
| Wellhead Systems Inc. (via Power Flow) | Casing heads, tubing heads, tubing head adapters | API 6A, full documentation for import |
| WNS Lowery (Marsh Bellofram Group) | Wellheads, flanges, complementary sizes | American-made, carbon steel and SS options |
Why Source Through Proxima
Proxima coordinates wellhead supply from Wellhead Systems Inc. through Power Flow International Sales — a logistics partner with over four decades of experience delivering oilfield equipment to Azerbaijan and the wider Caspian region. Full API 6A documentation, material certificates, and pressure test reports are provided with every order. WNS Lowery components are available for complementary sizes and configurations.
Frequently Asked Questions
Q: What pressure rating should I specify for my wellhead?
The wellhead pressure rating must equal or exceed the maximum anticipated surface pressure (MASP) of the well. MASP is calculated from reservoir pressure, fluid density, and wellbore geometry. Proxima engineers confirm the required pressure rating from your well data.
Q: Can Proxima supply a complete wellhead stack — casing head, tubing head, and adapter?
Yes. We supply complete wellhead assemblies as a matched stack from Wellhead Systems Inc., ensuring component compatibility and a single documentation package for import.
Q: What documentation is provided with the wellhead?
API 6A data report, material certificates, pressure test records, and nameplate data are standard. Additional documentation for import into Azerbaijan, Kazakhstan, or other regional markets is provided on request.
Q: Are sour service (H₂S) materials available?
Yes. NACE MR0175-compliant material trim is available for wells producing H₂S. Specify H₂S partial pressure and temperature when requesting a quote.
Q: How long does delivery take to Baku?
Delivery time depends on configuration and current stock levels. Standard configurations are typically available within 8–12 weeks ex-works. Contact Proxima for current lead times.
