Inline Inspection Internal Measurement Unit (ILI IMU) data analysis is a well understood but often under-utilized technology for detecting, defining, assessing and monitoring soil to pipeline interactions caused by construction/maintenance activities, geohazards and buoyancy.   The technology has been successfully used to detect landslide interactions since 1996 \[1\].  ILI Vendors generally provide the option for Operators to purchase an analysis that includes a strain feature summary and plots of individual features (Vendor Analysis).  The Vendor Analysis is typically based on a preset curvature threshold across a weld or a run to run movement criteria.  Vendor Analysis can identify major soil/pipeline interactions during an initial bending strain and subsequent run to run movement analysis.  Additionally, Operators can request the ILI raw data for either internal or third-party analysis (Raw Data Analysis).  Raw Data Analysis is typically used to define interactions and provide detailed pipe shapes/responses for modelling in known or suspected interaction features within discrete pipeline segments.  Hart \[2\] defines the calculation methods for converting raw data into curvatures/strains and proposes a standard system of presenting Raw Data Analysis. 

An approach for determining if and what type(s) of ILI IMU analysis/data is required for individual ILI run segments is presented that can be applied to any size of pipeline system.  A process for incorporating the data into an integrity management program is defined when Vendor Analysis and/or Raw Data Analysis would be required.  Guidelines are provided for Operators to optimize spend/analysis efforts based on the hazards encountered in individual line segment/systems.  The process includes feature screening, integrity/geotechnical specialist review and risk control/mitigation measures, if required. 

To facilitate the feature screening process, a classification system for ILI IMU features is presented based on type, activity and source modified from the system presented in \[3\].  The screener incorporates orthophoto/LiDAR, construction/maintenance activities, geohazard, interacting anomaly and company record data into the screening process to identify features that require geotechnical/integrity specialist review.  Work flow diagrams are presented for the process.

 

\[1\] Czyz, J and McClarty, E. 2004.  Prevention of Pipeline Failures in Geotechnically Unstable Areas by Monitoring with Internal and Caliper In-Line Inspection.  *Proceedings of IPC2004 5th International Pipeline Conference, Calgary*.

\[2\] Hart, J., 2016.  Utilization of IMU Data for Identifying Strain Locations of Interest.  In *Management of Ground Movement Hazards for Pipelines.* Edited by Wang, YY., West, D., Dewar, D., Hart, J., McKenzie-Johnson, A. and Gray, D.  J.I.P. report prepared by Center for Reliable Energy Systems, Dublin, Ohio.

\[3\] Dewar, D., Elseify, M., Van Boven, G., Bjorn, P, and Bruce, N. 2018. Operational Experiences with Axial Strain Inline Inspection Tools.  Proceedings 11th International Pipeline Conference, Calgary


Incorporating Inline Inspection Internal Measurement Unit Data Analysis Into Integrity Management Programs

Division / Sponsors: 
Pipeline Systems Division

Paper Proceedings: https://asmedigitalcollection.asme.org/IPC/IPC2020/volume/84447

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