Abstract
Internal Corrosion Direct Assessment (ICDA) was compared to in-line inspection data from two pipeline segments. The ICDA methodology was previously developed in response to the need to identify locations of internal corrosion, especially for cases where in-line inspection (ILI) is not practical. ICDA predicts where internal corrosion is likely to occur in pipes by integrating flow modeling with an inclination profile of the line. The method is presently applicable to dry gas transmission pipelines. For the first pipeline segment, 85 percent of the internal corrosion indications detected by ILI coincided with ICDA locations. Another five percent of the sites would likely have been identified by ICDA if the pipe elevation profiles had been known more accurately, including the presence of road or stream crossings not shown on elevation maps. For the second pipeline, ICDA was able to identify 78 percent of internal corrosion anomalies indicated by ILI. Improvements in locating, elevation measurements, and data alignment are expected to improve the confidence for selecting excavation locations. In addition, it is recognized that comparison with ILI data reduces the degree of correlation because ILI errors in the detection and identification of internal corrosion are not considered.
