This is a Joint Industry Project (JIP). This study will establish an appropriate level of confidence for using ultrasonic testing for structural assessments and to identify protocols for ultrasonic testing to improve the reliability as a structural assessment tool. Statistical analysis of inspection data will be used. That data will be correlated with actual measurements of thickness and strength properties of tubular parts removed from decommissioned platforms.
The researchers went to McDermott yard in Morgan City, Louisiana, to take measurements from structures that were recently removed from the Gulf of Mexico. They took ultrasonic thickness measurements from several structures. Information was gathered on the life of those structures, including their location in the Gulf of Mexico, the length of time they were used, and the jacket plans. Additional information on APU guidelines for structure reuse was provided.
The researchers established confidence in using ultrasonic thickness (UT) measurements to obtain accurate and reproducible measurements of wall thickness in corroded members. Thousands of thickness measurements were made on the tubular samples from the Testing and Evaluation of Grout Repaired Tubular Members project. Both UT and micrometer measurements were used. Statistical analysis was done on the measurements to determine their accuracy. It was concluded that corrosion has little effect on the accuracy of the UT measurements.