Case Study: Leveraging API 1163 Validation and Verification to Manage SCC Using ILI Ultrasonics Crack Tool

Abstract A pipeline underwent two ultrasonic high-resolution (UTCD) inspection in consecutive years, revealing consistent anomalies but questionable depth accuracy. Despite adequate POD, the POI, especially depth accuracy, was in doubt due to feature underestimation. Subsequent API 1163 Level 2 validation indicated the tool did not meet published specifications. The paper presents a case study demonstrating the application of API 1163 verification and validation to ensure pipeline safety. The authors underwent API 1163 verification for both inspections, followed by Level 1 validation confirming tool repeatability but unable to explain underestimation. Level 2 validation involved categorizing and analyzing features via systematic pattern analysis, identifying feature geometry as the main cause of underestimation. Historical data and simulations were utilized to understand the impact of feature geometry on recorded amplitudes and depth calculation. This study underscores the importance of systematic analysis in maintaining pipeline integrity. Subsequently, ILI analysts developed a non-standard analysis procedure for the pipeline, focusing on features meeting specific criteria identified through pattern analysis. These features were then reevaluated, and depth compensations were applied, ultimately achieving Level 2 validation.