Monitoring Remaining Fatigue Life

NIMA Integrity Management Software

A 500-km-long slurry pipeline in South America suffered two in-service failures only a few years after commissioning. Consequently, the pipeline was shut down for failure investigation inspection and integrity assessment. Field investigation and failure analyses confirmed that the two failures were due to fatigue cracking at seam welds.

Following an internal inspection of the pipeline with a range of technologies, ROSEN performed a study to quantify the remaining fatigue life of the pipeline based on a conservative estimate of the future pressure cycling. Consequently, the operator implemented a range of measures to reduce the severity of the pressure cycling. However, they had no means to regularly and accurately monitor their impact on the remaining fatigue life.