How do you choose Wellhead and X-Mas Tree Assembly?

By Application of Wellhead and X-Mas Tree Assembly: Working pressure ratings: 14MPa, 21MPa, 35MPa, 70MPa, 105MPa, 140MPa

① Wellhead Material Selection

Corrosion Resistance: The material must be able to withstand the corrosive effects of the produced fluids, which can include saltwater, hydrocarbons, and other chemicals.

Strength and Durability: The wellhead must be strong enough to handle the pressures and stresses exerted by the well's operations.

Temperature Resistance: The material should be able to operate under the high temperatures that can be present in the wellhead area.

Cost: The material should be cost-effective without compromising on safety and performance.

Compatibility with Other Components: The Wellhead and X-Mas Tree Assembly material should be compatible with the materials used in the rest of the CTA and the wellbore itself.

②Product Specification Level (PSL)

Based on quantitative risk analysis, PSLs define different technical requirements for bodies, bonnets, connectors, hangers, seals, etc.PSL 1, 2, 3, 3G, 4

③ Performance Requirements (PR)

PR 1, and PR 2 define mandatory performance testing like pressure and temperature cycling

PR 2 has more stringent requirements than PR 1

①Unitized vs Conventional Wellhead and X-Mas Tree Assembly

Conventional Christmas trees consist of individual valve components assembled together. The valves like the master valve, wing valves, and swab valves are separate units bolted or flanged into the tree assembly. While offering flexibility for configurations, conventional trees have more potential leak paths due to the numerous connections and require more space on the wellhead.

Unitized Christmas trees integrate the primary valves into a single compact body, combining the functions of the master valve, swab valve, and wing valves. Valve removal is accomplished by unbolting the entire valve block rather than individual valves. Unitized trees reduce the number of connections and minimize potential leak paths. Their highly concentrated and robust design makes them ideal for high-pressure, harsh environment applications like offshore platforms where space is limited. However, unitized trees offer less flexibility for configurations compared to conventional trees.

② Crossover Christmas Trees

These trees feature a crossover side outlet to the main vertical bore in addition to the top outlet. The side outlet can be a single wing valve configuration or a double wing valve configuration with two branch outlets.

The double wing crossover allows well interventions like acidizing or circulating kill weight fluids without killing the well. One wing valve can be opened to displace fluid while the other is closed to maintain pressure on the formation.

Single wing crossover trees are more compact but lack the flexibility of the double wing design for concurrent operations.

③Y-Body Christmas Trees

Y-body or Y-guide Christmas trees have an angled Y-shaped vertical bore as the flow path rather than a straight vertical run. The Y-configuration is machined from a single steel forging for a robust, high strength, and erosion-resistant design particularly well-suited for gas wells.

Like crossover trees, Y-bodies can have single or double wing valve configurations branching off the angled vertical bore run. Double wing valves permit interventions without shutting in the well.

The Y-body design concentrates the entire tree assembly into a very compact footprint ideal when platform space is constrained.

Vigor will provide you with a reliable solution for Wellhead and X-Mas Tree Assembly, Please contact us at info@vigorpetroleum.com.