UT-ILI and Fitness-for-Purpose Analysis for Severely Internally Corroded Crude Oil Pipeline

Kuwait Oil Company (KOC) constructed a 36” dia. crude oil pipeline in 2005 to transport its share of crude oil from oil field located at Wafra, south Kuwait. The pipeline receives crude oil from a 20” pipeline. The crude oil velocity is very low due to restricted oil production. Severe internal corrosion was detected during ultrasonic thickness measurement in 2008. Subsequently ultrasonic ILI by NDT Systems and Services detected severe internal corrosion almost through the pipeline length. Initial analysis of anomalies as per ASME B31G code [1] showed that almost half of the pipeline requires repairs. This being uneconomical, KOC decided to carry out Fitness for Purpose assessment and entrusted this work to NDT Systems and Services. The analysis reduced required repair to only 3 km from 12 km. Simultaneous action to control internal corrosion enabled KOC to operate the pipeline safely.