Wellhead Adapter Flange

Description

Wellhead Adapter Flange

Technical Description and Specifications

The Wellhead Adapter Flange is the critical transition component that connects the Slickline Pressure Control Equipment (PCE) to the wellhead (Christmas Tree). It acts as the “bridge” between the specific flange size/pressure rating of the wellhead and the Quick Union connection of the Slickline Blowout Preventer (BOP).

Key Technical Specifications and Operation

• Function: To provide a safe, pressure-tight connection between the wellhead and the PCE stack. It ensures that the bore of the slickline lubricator is perfectly aligned with the bore of the wellhead for the smooth passage of the BHA.

• Dual-Ended Design: * Bottom Connection: A standard API flange (e.g., 2-1/16″, 3-1/8″, or 4-1/16″) with a specific ring groove (e.g., BX-154 or R-24).

  • Top Connection: A Quick Union (Bowen or Otis style) that matches the base of the Slickline BOP.

• Full Bore Integrity: The internal diameter (ID) of the adapter flange is machined to be consistent with the wellhead and PCE stack, preventing any “shoulders” that could snag the tool string or damage the slickline wire.

• Test Ports: Many adapter flanges feature a side-entry NPT port. This allows the operator to bleed off trapped pressure between the wellhead valve and the BOP or to perform a local pressure test of the flange connection.

• Alignment: Precision machining ensures that even under the weight of a 60ft lubricator stack, the adapter maintains a vertical, concentric path for the wire.

Customization and Materials

• Metallurgy: Typically forged from 4130 Alloy Steel. For operations involving high concentrations of $\text{H}_2\text{S}$ and $\text{CO}_2$, the flange is manufactured to meet NACE MR0175 standards, often featuring a 316 Stainless Steel or Inconel 625 inlay in the ring groove for maximum corrosion resistance.

• Configurations: Available as a single-piece “solid” adapter or a “crossover” assembly depending on the required height and connection type.

• Pressure Ratings: Designed to match or exceed the wellhead pressure rating (e.g., 5k, 10k, or 15k psi).

Critical Parameters