Pressure test plug

Description

Pressure Test Plug

Technical Description and Specifications

The Pressure Test Plug is a vital safety and verification tool used to seal the internal bore of the Pressure Control Equipment (PCE) stack or the wellhead during hydrostatic pressure testing. Unlike a Night Cap (which seals the top of the lubricator), the Test Plug is designed to be inserted into the Quick Union or the Lubricator bore to isolate a specific section for testing.

Key Technical Specifications and Operation

• Function: To provide a temporary, high-pressure internal seal. This allows the operator to pressure test the PCE stack (Lubricators, BOP, Stuffing Box) against the plug to ensure there are no leaks in the connections or seals before the well is opened.

• Sealing Mechanism: Utilizes high-durometer O-rings or T-seals that are compressed against the internal polished bore of a Quick Union or a specialized Test Sub.

• Bypass/Equalization Valve: Most test plugs feature an internal “through-port” with a needle valve or a screw-in plug. This allows the operator to bleed off the test pressure safely before removing the plug, preventing it from becoming a “projectile” under residual pressure.

• Standard Positioning: Typically installed at the very bottom of the PCE stack (at the Wellhead Adapter) to test the entire string, or inside a Quick Test Sub for localized testing.

• Load Bearing: In some configurations, the plug is designed to be “held” by the Tool Trap or the BOP rams to verify their mechanical holding and sealing capability simultaneously.

Customization and Materials

• Material: Manufactured from high-tensile 4140 Alloy Steel or 17-4 PH Stainless Steel. For sour service ($\text{H}_2\text{S}$), the plugs are heat-treated to NACE MR0175 standards.

• Seal Selection: Seals can be customized based on the test medium (water, glycol, or oil) and the expected temperature range of the wellbore environment.

• Connection Profiles: Engineered to match specific Quick Union internal profiles (e.g., Bowen, Otis, or Elmar styles) to ensure a perfect fit.

Critical Parameters