Enhancing Weld Fatigue Resistance on FPSO

Challenge: Fatigue Failure in Critical Welds

During a inspection located in offshore Ghana, fatigue failure risks were identified in critical welds within high-stress areas such as the Cargo Oil Tanks. Subjected to severe cyclic loading, these welds were vulnerable to cracking and structural degradation. To safeguard integrity and ensure uninterrupted offshore operations, Ultrasonic Impact Treatment (UIT) was implemented to improve fatigue resistance and extend weld durability.

Solution: Targeted UIT Execution and Quality Assurance

The client and the GRO team jointly identified weld locations requiring UIT, supported by an approved execution work pack. Rope access–certified technicians conducted Magnetic Particle Inspection (MPI) to verify weld integrity prior to treatment. Using high-frequency UIT tools, compressive stresses were introduced at weld toes to reduce stress concentrations and enhance fatigue performance.

A standby team of rope access welders ensured immediate repair of any defects detected, maintaining workflow efficiency and quality standards.

Results: Improved Structural Reliability and Extended Service Life

The application of UIT resulted in a marked improvement in fatigue performance of the FPSO’s welded structures. By enhancing fatigue resistance, the likelihood of premature weld failures was reduced, thereby extending the vessel’s operational life. Additionally, weld repairs where required, were completed seamlessly, ensuring all treated areas met stringent quality standards.

The project was delivered safely, efficiently, and in full compliance with client specifications, contributing to improved structural reliability and long-term asset integrity of the FPSO but also reaffirmed GRO’s standing as a trusted offshore safe and effective solutions provider.