Author(s): Race JM; Dawson SJ; Krishnamurthy R; Peet S
Abstract: In recent years the number of corrosion failures in onshore and offshore pipelines has steadily decreased due to the introduction of corrosion management strategies by pipeline operators. A vital component in effective corrosion management is an accurate determination of corrosion growth rates. In-line inspection using high-resolution pigs to detect and size corrosion can become the basis for defining a future safe operating strategy. A methodology has been developed which includes the direct comparison of magnetic flux leakage or ultrasonic data between two inspection runs. Consequently, any new sites of corrosion or sites at which corrosion growth has occurred can be identified and the extent of the growth quantified. Utilising the variation in corrosion depth, corrosion growth rate and material properties, and reliability methodologies the probability of failure is established as a function of time. This approach has been used for internal corrosion management, and can also be applied for management of excavation for external corrosion. Attention is given to the approaches used to estimate corrosion growth rates and the reliability methodologies which allow the probability of failure to be determined. Case studies are presented of the successful use of the above methods.
Notes: Paper No. 01627
Keywords: Pipelines,Corrosion,Offshore structures, Corrosion rate, Corrosion prevention