Wellhead and production tree equipment illustration

Wellhead Christmas Tree (2,000–20,000 PSI)

API 6A Production Tree Supply

Welong supplies wellhead christmas trees; the responsible designer, manufacturer and applicable API Spec 6A requirements are confirmed in the quotation for use on oil & gas wells and water injection wells on-shore; the casing head, tubing head and valve are designed as a single integral system, rather than three loose components purchased from three different vendors.

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Technical Specifications

2,000–20,000
Working Pressure (PSI)
AA–FF
Material Class
PSL1–PSL3G
Product Spec Level
2-1/16–4-1/16″
Bore Size
-46°C to 121°C
Working Temp (Class LU)
Oilfield Manufacturing

Controlling Well Flow After Drilling — How Welong's Wellhead Christmas Tree Solves It

Once drilling operations finish, a well still needs an assembly of valves that will hold back pressure, control the flow of oil or gas, and give you a shutoff point - that's the job of the wellhead christmas tree. Welong supplies integrated assemblies; the quotation confirms the responsible manufacturer, component scope and applicable API 6A requirements for the selected service.

Which Well Types Need This Assembly

Within the oil and gas industry, tree and wellhead builds are dependent on what the well is actually doing and not what pressure class the build represents. Welong supplies equipment for the range of well types operators currently have in service:

Oil production wells - standard flowing production, metered through the wing valve and choke
A gas well christmas tree handles higher-velocity flow, often paired with a larger choke for gas injection well service.
Water/gas injection wells control gas injection or inject water in the reservoir rather than from it
Test and workover wells - temporary or semi-permanent setups for short-duration well testing

The tree acts as a single control point across all four scenarios - which is exactly why getting the valve count, bore, and material class right at order time matters more than it would on a single-purpose component.

Not Every Well Needs One

But not all producing wells have a christmas tree, and that’s important for your procurement strategy. Most artificial-lifted (pump jack and other rod-pumped) wells don’t need a Christmas tree - there’s no sustained pressure that needs to be contained at the surface. For flowing, gas-lifted, or injected wells, the tree is the pressure boundary that separates your reservoir from your production pipeline, and the quotation should confirm the material class, pressure boundary and responsible manufacturer for the selected surface tree.

No proper flow control means uncontrolled pressure at surface during production, well testing, or workover
Undersizing the material class brings sulfide stress cracking risk in H2S service within months, not years
A mismatched bore or connection means costly re-work at the rig site instead of at the shop

Welong's wellhead christmas tree covers the full pressure range operators actually order - 2,000 to 20,000 PSI - with casing head, tubing spool, and valve configurations matched to your well program before the assembly ever leaves the shop.

Where the Assembly Is Actually Used

In practice, the same christmas tree body handles more than steady-state production. The supplied assemblies can be configured for four distinct scenarios, with the responsible manufacturer and configuration confirmed in the quotation.

Acid fracturing - the tree provides a controlled, pressure-rated path for acid stimulation treatment injected into the well
The water injection duty uses the same valve stack to regulate the injection rate and isolate the annulus for water-flood and pressure maintenance wells
Well testing relies on the swab valve and choke assembly for a controlled, monitored flow path during test service
Emergency shut-in relies on the master valve pair for positive, proven shutoff should a well need to come off-line in an emergency

One operational note from the field: teams that spec a tree purely against expected production flow rate, and skip the acid-fracturing or water-injection duty cycle, sometimes discover mid-life that the valve trim isn't rated for the chemical service they end up running. Confirm every planned use case - not just primary production - before you finalize the order. Tree design itself has evolved considerably since early integrated assemblies like US Patent 4,130,161, but the core control logic specified for the selected order remains the same.

Welong Wellhead Christmas Tree Range — Valves, Bore & Pressure Configurations

A wellhead tree isn't a singular entity - it is a conglomeration of five to six christmas tree valves performing discrete roles. Miss your valve count, or placement on the spec sheet and either you over pay for redundancy you will never need, or underspec a well intervention point you are sure to require come month three.

Installation, Flange Connections & Field Repair

An API 6A wellhead assembly is only as reliable as its weakest connection, and on a christmas tree that's almost always the flanged joint between the tree and the tubing head. For the selected assembly, the responsible manufacturer and applicable API 6A flange and thread requirements are confirmed in the quotation, so installation at the well site is a bolt-up job, not a fitting exercise.

Gate Valves & Pressure Relief

On almost every quote, there are two other pieces of equipment that buyers always want to know more about besides the flange: the gate valve trim and the pressure relief path. Gate valves control the master and wing valve positions on Welong’s standard setup; pressure relief (often via an annulus vent) provides the crew with a controlled way to reduce pressure without opening the master valve.

Position feedback - the valve and choke position indicators provide the crew with positive confirmation of composition and status without needing a look at the top
Field Repair Support - Welong provides the replacement seals, gaskets and gate valve trim to original bill of materials size ensuring that field repairs don't result in a redesign exercise
The thread and connection data goes as full thread specifications in the drawing package, not just the bore diameter.

This is why using wellhead equipment that comes from the same vendor that supplied your casing head and tubing head saves you time and aggravation. Repair parts fit your as-built assembly and not a part number from a catalog that may look similar. The difference becomes important for oil and gas wells, which likely have many years of service in the field.

Surface Tree vs Subsea Tree — Where Welong Fits

Welong supplies only surface (land) christmas trees - those mounted over the wellhead and accessible by the crew - rather than subsea trees installed on the ocean floor for offshore wells. Should your well program be onshore or shallow-water, with the wellhead above sea level, then a surface tree is the right scope; a deepwater subsea tree is another class of equipment that we do not produce.

"We size material class and valve count against the well's actual service—H₂S partial pressure, CO₂, expected working pressure-before we quote. A tree that passes API 6A on paper but is class-mismatched to a sour well is a liability, not a spec sheet win."

— Senior Application Engineer, Welong Wellhead & Well Control Team

Need a standalone choke and kill manifold for well testing or workover instead of an integrated tree? See Welong's choke and kill manifold under the same Wellhead & Well Control product range.

Valve	Position	Function	What It Prevents
Lower Master Valve	Base of tree, above tubing head	Primary well shutoff	Uncontrolled flow if upper valve fails
Upper Master Valve	Above lower master valve	Backup shutoff, often actuated	Single point of failure on the primary valve
Production Wing Valve	Horizontal outlet to flowline	Routes flow to production facilities	Need to close the master valve just to stop production flow
Kill Wing Valve	Opposite side from production wing	Entry point for kill fluid / chemical injection	No safe access point during well-kill operations
Swab Valve	Top of tree	Wireline / slickline / coiled-tubing access	Having to remove the whole tree for intervention
Choke	On the wing valve line	Regulates flow rate	Erosion and pressure spikes from unregulated flow

Parameter	Range
Working Pressure	2,000 / 3,000 / 5,000 / 10,000 / 15,000 / 20,000 PSI
Working Medium	Oil, natural gas, mud — including H₂S, CO₂ service
Working Temperature	-46°C to 121°C (Class LU)
Material Class	AA, BB, CC, DD, EE, FF, HH
Product Specification Level	PSL1, PSL2, PSL3, PSL3G
Performance Requirement	PR1, PR2
Bore Size	2-1/16", 2-9/16", 3-1/16", 3-1/8", 4-1/16"
Governing Standard	API Spec 6A / ISO 10423

Source: Welong product specification cross-checked against API Spec 6A standard pressure/material/PSL designations.

Some operators still source the casing head, tubing head, and tree valves from separate suppliers to chase the lowest line-item price on each component. The honest trade-off is that this approach shifts risk and coordination cost onto your engineering team instead of the manufacturer.

Factor	Welong Integrated Assembly	Multi-Vendor Sourced Components
Connection interface compatibility	Interface dimensions and pressure-test scope confirmed for the selected assembly	Interface tolerances verified only at final site fit-up
Material traceability	Single traceability chain across casing head, tubing head, and tree	Separate MTRs per vendor; buyer must reconcile the paperwork
Lead time coordination	One delivery schedule, one point of contact	Multiple vendor schedules must align independently
Accountability if component fails	Responsible manufacturer identified for each component and full-stack integration	Vendor-to-vendor dispute over which component is at fault
Third-party witness inspection	Inspection plan can cover the full assembly when specified	Separate inspection trips per vendor, or gaps in coverage

Need the full dimensional drawing before you spec a well program?

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Sour-Service Material Class Decision Grid — Matching Class, PSL & PR to Your Well

Ordering "API 6A compliant" isn't enough of a spec by itself. Material class, PSL, and PR each answer a different question-what the metal can chemically tolerate, how much paperwork you get, and how the equipment was performance-tested-and getting one wrong doesn't show up until the well is already sour.

Why Class Selection Fails Silently

Sour-service suitability depends on CO₂ and H₂S exposure, material selection, and hardness limits. Confirm the applicable service conditions and material requirements for the selected tree.

Well Service Condition	Recommended Material Class	PSL	PR	Standard Reference
Sweet, standard onshore	AA / BB / CC	PSL1–PSL2	PR1	API Spec 6A
H₂S present, moderate partial pressure	DD (carbon/low-alloy, sour)	PSL3	PR1–PR2	API 6A + NACE MR0175
H₂S + CO₂, higher severity sour	EE (alloy steel, sour)	PSL3	PR2	API 6A + NACE MR0175
Aggressive sour, high H₂S partial pressure	FF (martensitic stainless, sour)	PSL3G	PR2	API 6A + NACE MR0175
Most severe sour service	HH (nickel-based alloy)	PSL3G	PR2	API 6A + NACE MR0175 / ISO 15156

Class/PSL/PR mapping follows API Spec 6A + NACE MR0175 (ISO 15156) definitions. Confirm exact class against your project's H₂S partial pressure and pH per NACE MR0175 before final order.

Send Welong your H₂S partial pressure, CO₂ content, and expected working pressure up front-not after the quote. A tree ordered as PSL1/Class BB can't be field-upgraded to sour service; it has to be re-manufactured.

It's a common assumption that a higher pressure rating automatically means a more rigorous spec-it doesn't. Sweet service at 20,000 PSI can sit at PSL1 with a basic records package, while a 2,000 PSI tree in an aggressive sour well needs PSL3G with the full sour-service qualification testing.

PSL is a records-and-testing rigor axis; PR is a design-validation axis; material class is a metallurgy axis. Buyers who collapse all three into "give me API 6A" end up under-specified on the axis that actually matters for their well-usually material class, since that's the one that fails silently in service rather than showing up on an inspection checklist.

Wellhead & Christmas Tree Equipment — Inspection & API 6A Order Documentation

API Spec 6A isn't a marketing label-in the U.S., it's incorporated directly into federal regulation. Its wellhead-and-tree equipment scope is referenced in 30 CFR 250.874(g)(2) for offshore operations, and the international parallel standard, ISO 10423:2003, covers the same equipment class for buyers working outside U.S. jurisdiction.

How Inspection Scope for Each Selected Assembly

For the selected wellhead Christmas tree, the quotation identifies the responsible manufacturer, in-process and final inspection points, and the material-traceability records required with the shipment.

In-process inspection at machining and assembly stages
Final inspection before shipment
Optional third-party witness inspection - provider and scope confirmed for the selected order
Material traceability records specified for the selected order

Confirm the required inspection and documentation scope for the selected wellhead Christmas tree at RFQ.

Want to see what a Welong material test report looks like before you order?

Request Material Test Report Sample →

Procurement Guide — Trade Terms, Lead Time & How to Request a Quote

Downtime costs usually exceed whatever operators think they saved on unit price. A single seal failure or a delayed shipment on wellhead components can generate non-productive time (NPT) costs that run into the millions - and in some cases, the cost of an unplanned shutdown alone has exceeded the original equipment purchase price.

15–30 yrs

Service life depends on the operating conditions, material class, and inspection scope selected for the tree.

Industry field-service reporting (qualified, non-Welong-specific) · TCO framing, not a Welong warranty term

What Actually Drives Your Lead Time

A standard-configuration tree in a common bore/pressure/material combination ships faster than a custom sour-service build with a non-standard bore or an unusual valve arrangement. These are the variables that move your delivery date:

Bore size and pressure rating - standard 2-1/16"-4-1/16" combinations are faster than custom bores
Material class - sour-service classes (DD/EE/FF/HH) require additional NACE-compliant processing
PSL level requested - a PSL3G records package takes longer to compile than PSL1
Third-party inspection scheduling for SGS/DNV witness coverage adds coordination time

Welong ships under FOB, CIF, DDP, or DDU terms - your team picks the term that matches how your logistics chain is already structured, not the other way around. Sea, air, and rail freight are all available depending on your delivery window and destination.

Most operators shipping to Europe, the Middle East, or South America run FOB or CIF and manage import clearance with their own customs broker; buyers newer to sourcing from China more often ask for DDP so Welong handles the full door-to-site logistics chain. That's a genuine trade-off, not a right-or-wrong choice - it depends on whether your team already has an established import process at the destination port. The honest answer is that neither term is cheaper in the abstract; each just shifts coordination work to whichever side is better set up to handle it.

Common evaluation criteria (see the industry supplier directory for how buyers screen this equipment class) include API 6A licensing status, in-house manufacturing vs. trading capability, in-process and final inspection records, material traceability practice, and whether third-party inspection (SGS/DNV/Bureau Veritas) is available as an option - not an afterthought you have to negotiate for.

Contact Welong for a project-specific lead time estimate based on your exact bore, pressure, and material class combination - the same ISO 10423:2003 equipment class buyers reference outside U.S. jurisdiction.

Request a Project-Specific Quote →

Information Welong Needs for an Accurate Quote

A quote’s lead time is pretty much directly correlated with the level of detail in your initial request. Send the below information in one go and avoid an unnecessary email ping pong with Welong about details before we can put a number on the job.

Well type and service (oil, gas, water injection, or well testing)
Expected working pressure and bore size
H₂S partial pressure and CO₂ content, if known
Required PSL and PR level, or your governing project specification
Preferred trade term and destination port

Wellhead Christmas Tree Configuration Tools

Sour-Service Material Class & PSL/PR Selector

Trade Term (Incoterm) Selector

RFQ Quick-Spec Builder

Frequently Asked Questions

What is the difference between a wellhead and a Christmas tree?

The wellhead is installed first and provides mechanical support and pressure containment for the well; the christmas tree is a separate valve assembly installed on top of the wellhead afterward to control flow. Drilling crews run a wellhead without any Christmas tree at all - the assembly only goes on once the well moves into production, testing, or injection service, so the reverse relationship doesn't hold.

Does every producing well need a Christmas tree?

No. Wells on artificial lift, such as pump jacks, frequently produce without a christmas tree because there's no surface pressure containment requirement in that configuration. Flowing, gas-lifted, and injection wells are the ones that need one.

What is the difference between API 6A and API 6D?

API 6A covers wellhead and christmas tree equipment - the assembly that sits on top of a well. API 6D covers pipeline valves used in transmission and distribution lines downstream of the wellhead, a different equipment scope entirely.

What do PSL1 through PSL3G actually mean for my order?

PSL (Product Specification Level) sets the records-and-testing rigor, not the pressure rating - PSL1 requires the least paperwork, PSL3G the most, including additional performance and material testing appropriate for the harshest sour-service conditions.

What's the difference between PR1 and PR2?

PR (Performance Requirement) reflects how the design was validated, and it's a separate axis from both pressure rating and material class, which is where a lot of buyers get tripped up on a spec sheet. PR1 relies primarily on design calculations backed by prototype testing to confirm the equipment performs as engineered under its rated conditions. PR2 goes further, requiring more extensive qualification testing - a larger test sample and a broader range of simulated service conditions - before the design is approved for the stated rating, which is why PR2 equipment generally carries a longer manufacturing and documentation lead time than an equivalent PR1 build.

Can a standard-class tree be upgraded to sour service later?

No - material class is fixed by what the base metal and welds were processed and tested to withstand, not a bolt-on option. Spec the sour-service class up front if there's any chance the well turns sour.

What inspection documentation ships with a Welong wellhead Christmas tree?

The quotation confirms the material-traceability and in-process/final inspection records required for the selected order. Third-party inspection by SGS, DNV, or another qualified provider can be arranged when requested.

What trade terms does Welong support?

FOB, CIF, DDP, and DDU, with sea, air, or rail freight depending on your destination and delivery window.

Is a wellhead Christmas tree the same as an "oil Christmas tree" or "X-mas tree"?

Yes - wellhead christmas tree, oil Christmas tree, and X-mas tree all refer to the same equipment class in industry usage. The name comes from the branching arrangement of valves and spools, which resembles a decorated tree, not from any connection to the holiday.

What are the types of wellhead christmas tree available?

Surface trees are installed on top of the wellhead, so that crews have direct, onshore or in-shallow water access to the wells. Subsea trees, on the other hand, are designed to sit underwater on a deep-water offshore rig, a totally different, remote controlled type of equipment. Welong supplies only surface trees.

Which operating conditions affect a wellhead Christmas tree's service life?

Service life depends on operating pressure, fluid corrosivity, and maintenance practices. Confirm the material class and inspection scope for the planned service.

Procurement & Capability

Wellhead Christmas Tree Capability Review

China Welong reviews the buyer drawing, product specification and inspection scope before quotation.

This review is scoped to the Wellhead Christmas Tree configurations set out in the specification table on this page — 6 documented rows covering Parameter and Range.

24 hEngineer-reviewed quotation on business days

2001Founded in 2001

30+30+ engineers on staff

5 yrStamped serial traceability

Quotation Scope and Commercial Terms

Pricing is prepared against the selected product configuration, material route, inspection scope and shipment terms.

Quotes are returned within 24 hours on business days, reviewed by an engineer.
T/T or L/C by wire transfer.
We ship EXW, FOB, CFR or CIF; other Incoterms on request.
We work from 2D drawings and 3D CAD models (AutoCAD, Pro/ENGINEER, SolidWorks; .dwg and .igs).

Production Planning

Production timing is confirmed with the quotation after quantity, process route and finishing scope are reviewed.

We hold agreed items in stock and ship against your release to shorten delivery. Feasibility is confirmed at drawing review.
Manufacturing at Xi'an, Shaanxi and at Jiyuan, Henan.
0.01 mm machining precision.
Material standards to ISO, BS, ASTM, ASME, DIN, JIS and GB.
Orders ship in standard export wooden cases, or the packing you specify.

Order Review and Responsibility

The responsible manufacturer, inspection scope and document package are identified for the selected item.

Every quotation states whether the item is made in our own works or by an approved supplier we developed and supervise.
We develop, audit and supervise the mills and workshops that make your parts: material mills are re-audited every two years and approved by Welong before they run your order.
Forgings from 0.2 to 50 tons.

Specification and Inspection Evidence

The specification table on this page is the technical basis for this review: its numeric rows define what we quote, manufacture and inspect against.

Each piece carries a stamped serial number and stays traceable for five years to its chemical composition, mechanical properties and measurement report, with the test coupon retained.
An EN 10204-3.1B material certificate with chemical composition and mechanical properties, a dimensional measurement report, and UT and MT reports ships with your order.
Inspection is by coordinate measuring machine, ultrasonic, magnetic particle and X-ray.

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Send the drawing, product specification and inspection requirements for a quotation review.

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