Pipeline External Corrosion Model Validation

Abstract Establishing trust in corrosion models requires a robust validation process. This is difficult because large amounts of field data covering a wide range of operating conditions are needed. Relying on a few simple tests is insufficient, as a comprehensive validation demands a thorough comparison between corrosion model predictions and real-world observations. The present study by the Pipeline Research Council International presents the validation of a transmission pipeline external corrosion rate model (EC-01-13, Generic External Corrosion Growth Rate Distributions for Buried Pipelines). The validation was carried out by comparing the external corrosion rate model results with field data gathered by three oil and gas pipeline operators and covering over 400 miles of pipelines. Good agreement was found between modelled corrosion rates and ILI run comparison data. This study has two main benefits to pipeline operators. First, the validation helped identify areas where the corrosion model may need to be adjusted to provide more accurate predictions for specific pipeline locations and operating conditions. Second, a simple set composed of 27 external corrosion rate distributions (as a function of pipeline exposure, mitigation, and time) have been generated by the external corrosion rate model and validated with the ILI data. This publication provides 27 reliable and simple external corrosion rate estimates that can be utilized by pipeline operators without the need for running the external corrosion model or using specialized software. The use of these validated external corrosion rate distributions may provide a more robust basis for decision-making in pipeline integrity management than using the traditional 16 mpy used for worst case scenarios. In addition, this publication provides a simple way to update the external corrosion rate distributions when new field data becomes available.