White Box Engineering

Predicting future pipeline integrity in landslides using ILI mapping data

Lockey A., Young A.

Pipeline Pigging and Integrity Management Conference; Houston; January 2012.

Pipelines routed through mountainous areas susceptible to landslides are often inspected using inertial mapping tools to determine position and strain. Viewed in isolation, data from a single inspection only gives an indication of the pipeline integrity at a single point in time. Multiple inspections over a period of time can be used to estimate positional change. To extend the capability of these approaches, a method is required to reliably predict the future development of pipeline integrity based on trends in the mapping data from multiple inspections.

This paper presents a novel method developed by Penspen to predict the future integrity of a pipeline subject to landslide loading. The technique takes inertial mapping data from multiple inspections and calculates future strains in the pipeline using finite element analysis. Unlike methods based on interpreting inspection data alone, the finite element model includes the effects of soil-pipe interaction and axial pipeline stress to provide a more complete assessment of pipeline integrity. A case study of a large diameter oil pipeline is described to demonstrate the method.

The paper illustrates how the maximum benefit can be derived from existing data, reducing the need for additional inspections. The method may also be used to optimise future inspection strategy, provide timescales for planning and implementation of remedial works, and make a cost-effective contribution to an integrity management system.