Benefits of UIT on drilling rigs for offshore oil and gas weld repair to extend fatigue life


In the North Seas, an offshore drilling rig takes a constant beating. Welds are exposed to enormous stresses. Applied Ultrasonics' Ultrasonics Division helped the client to extend fatigue life of their aging offshore drilling rig, resetting fatigue life to zero and allowing fifteen additional years of revenue-generating service life.


Aging offshore structures are reaching the end of their design lives. Operators and drilling contractors, in conjunction with government regulatory bodies and class societies, are interested in safely extending the operational lives of these assets. Of paramount concern for ageing offshore infrastructure is maintaining structural integrity and extending the fatigue life. Applied Ultrasonics' Ultrasonics Division offers a state of the art solution for extending the life of aging offshore infrastructure.


In 2007, the client sought a solution to extend the fatigue life of their semi-submersible drilling rig. The rig had seen 28 years of service in harsh North Sea conditions and the client determined that nearly all critical column bracing connections would exceed their design life and likely fail in the next 15 years. The client chose Applied Ultrasonic because our solution for fatigue life extension is the best controlled and most efficient post-weld treatment option available in the industry. During just two weeks in the Rotterdam shipyard, Applied Ultrasonic applied its Ultrasonic Impact Technology to 82 welds on 12 critical column bracing connections of the rig.


Following the shipyard work, the client determined Ultrasonic Impact Technology reset the fatigue life to zero and ABS granted a 15 year extension for the rig. In September 2010, the client executed the required 5-year special survey, performing an underwater inspection (in lieu of drydocking) of all critical connections.  This detailed non-destructive examination found zero defects in welds treated by Applied Ultrasonics' Ultrasonics Technology (UIT) Division. Following this inspection, the rig entered another long-term contract, continuing to generate revenue as a result of Applied Ultrasonics' UIT fatigue life extension technology. 




Applied Ultrasonics' Ultrasonics Division has repeatedly extended the life of ageing infrastructure and assets, from bridges to mining equipment to offshore rigs. Applied Ultrasonics can provide service onsite to maximize cost effectiveness for the customer. To learn how Applied Ultrasonics can help your company, please contact us.

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