Viper Connectors

Proven performance in deepwater and ultra-deepwater applications.



As the most extensively tested large-diameter connectors on the market, Viper™ weld-on connectors are ideally suited for extreme-service conductor and casing applications. Available in 16- in. to 42-in. diameters, Viper connectors are rated at or greater than 100% of pipe body for internal and external pressure, tension, compression, and bending capacity in most sizes. The patented ViperLock™ anti-rotation device is easy to install and is reversible.

  • A true multipurpose connector suitable for most applications
  • Deepwater subsea well conductors or jet strings
  • Platform conductors or drive pipe
  • Jackup exploratory well conductors
  • Tieback conductors
  • Intermediate and surface casing strings, including deviated wells
  • Deepwater casing strings run in open water

Viper features a weld-on pin and weld-on box design. Viper connectors in sizes up to 34-in. diameter feature a near-flush inside diameter (ID) profile and an upset outside diameter (OD) that serves as an integral lift shoulder.

Viper connectors have a dual-seal design: an elastomeric O-ring as the primary seal and a secondary metal-to-metal seawater exclusion seal. Extensive finite element analysis and physical testing have been used to verify performance capacities across the Viper product line.

Two thread configurations are available. The Viper-1ST connector makes up in approximately 1.75 turns, and the Viper-3ST connector makes up in just over half a turn. Makeup torques range from 50,000 to 70,000 ft-lb depending on size. Viper connectors are suitable for makeup with either power tongs or manual tongs.

The CAL I-E qualification requires the testing of two samples:

  • The first sample (ISO Specimen 1) is machined to an extreme tolerance, worst-case sealing configuration and make-and-break tested. Upon completion, seal performance of this sample is then verified through a series of tests that include two-quadrant combined load with bending (ISO Series B), four-quadrant combined load (ISO Series A), and limit load to failure.
  • The second sample (ISO Specimen 5) is machined to an extreme tolerance, worst-case galling configuration. This sample then undergoes make-and-break testing.


  • Connector ratings meet or exceed full pipe body strength in most sizes
    • Reliable performance under extreme loading conditions
  • Full pedigree of analysis and test data
    • Extensive analysis and full-scale testing data support connector ratings
  • Fatigue rated and tested
    • Designed and fully tested for excellent fatigue performance
  • Dual-sealing design
    • Elastomeric O-ring primary seal and metal-to-metal seawater exclusion seal
  • Three capture features
    • Hooked threadform, OD capture feature, and tapered load shoulder effectively eliminate thread jump-out under extreme loading conditions
  • ViperLock anti-rotation device
    • Patented design is reliable, easy to install, reversible, and fully tested
  • Engineered weld neck
    • Longer connector weld neck moves the weld to a low stress area

Tested Sizes 

  • 20 × 0.625 × 80 in. GP-95 Viper-1ST
  • 22 × 1.000 × 80 in. GP-95 Viper-1ST
  • 22 × 1.250 × 80 in. GP-95 Viper-1ST
  • 22 × 1.500 × 80 in. GP-95 Viper-1ST
  • Viper Connectors Product Summary Flyer

  • Viper High-Performance Weld-On Connector Flyer

  • XL Systems 22×0.625 X80 GP 95 Viper Connector Gas Data Sheet

  • XL Systems 22×1.00 X80 GP 95 Viper Connector Gas Data Sheet

  • XL Systems 22×1.25 X80 GP 95 Viper Connector Gas Data Sheet

  • XL Systems 22×1.50 X80 GP 95 Viper Connector Gas Data Sheet

  • Viper Connector Fatigue Test Summary Technical Summary

  • Viper Connector Physical Testing Program Technical Summary

  • Viper Connector Bolt-On Lift Ring Technical Summary

Closeup of the patented ViperLock™ anti-rotation device
ViperLock anti-rotationx

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Viper connector delivers proven fatigue performance in deepwater and harsh environments

Unprecedented testing verifies the weld-on connector's strength and sealability.

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