Viper connector delivers proven fatigue performance in deepwater and harsh environments

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

Image of two Viper Connectors, one flat on the ground and the other leaning on it
Sep 05, 2023

Connectors play a crucial role in well construction. They often must function as a drilling component—containing pressure and resisting hole collapse—and a structural component—supporting the casing string weight and resisting environmental forces.

Harsh environments and demanding deepwater applications require proven and reliable connectors to withstand extreme conditions and loads. Full pipe body strength, robust sealability, and excellent fatigue performance are essential.

For nearly two decades, the Viper™ weld-on connector from NOV's XL Systems has delivered proven performance and ensured long-term reliability in deepwater and harsh environments worldwide, particularly in the North Sea and offshore West Africa.

XL Systems, part of the NOV Completion & Production Solutions segment, embarked on an unprecedented full-scale physical testing program in Waller, Texas, to verify the Viper connector's strength ratings, define gas and liquid sealability envelopes, and demonstrate connector fatigue performance. As a result, Viper is the most tested large outside diameter connector on the market.

We have more test data than any of our competitors. We embraced testing to validate and prove the fatigue performance because it gives our customers confidence, comfort, and a better understanding of the connector.

Carl Torres

Technical Director, XL Systems

In addition to finite element analysis, the extensive physical testing program included harmonic fatigue, vertical make-and-break, combined load sealability, bending, limit load, anti-rotation, and pile driving.

Among the highlights of the stellar results, the combined loading sealability tests demonstrated the robust performance of the Viper seals over the full pipe body performance envelope. Gas sealability tests to ISO 13679 CAL I-E gas and API 5C5 CAL I (gas protocols) confirmed best-in-class connector pressure integrity to full pipe body envelopes. Also, the ViperLock™ anti-rotation device tests showed robust connector resistance to unintended back-off.

Most Viper connector sizes are rated at or more than 100% pipe body capacity in internal and external pressure, tension, compression, and bending, ensuring the safety and integrity of the well. The dual-seal design includes an elastomeric O-ring primary seal and a secondary metal-to-metal seawater exclusion seal.

Viper is XL Systems' first connector with a hooked threadform, which maintains thread engagement under extreme loading and enables a fast makeup. Unlike wedge thread connectors that do not require an anti-rotation device, all Viper connectors feature the ViperLock anti-rotation device. Quick and easy to install on the rig floor, the patented device provides robust resistance to unplanned connector rotation, reducing the risk of a dropped string.

Since the launch in 2005, the performance of the Viper connector has been fantastic. Our dedication to combining physical testing and finite element analysis has resulted in designing a robust and effective anti-rotation device whereby we have never dropped a string of Viper.

Colin Beaton

Regional Manager – Europe, CIS, and SSA

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Proven performance in deepwater and ultra-deepwater applications.


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