Statistical Soil Characterization of an Underground Corroded Pipeline Using In-Line Inspections

Abstract

Underground pipelines have a space-dependent condition that arises from various soil properties surrounding the pipeline (e.g., moisture content, pH, aeration) and the efficiency of protection measures. Corrosion is one of the main threats for pipelines and is commonly monitored with in-line inspections (ILI) every 2 to 6 years. Preliminary characterizations of the surrounding soil allow pipeline operators to propose adequate protective measures to prevent any loss of containment (LOC) of the fluid being transported. This characterization usually requires detailed soil measurements, which could be unavailable or very costly. This paper implements categorical measurements of soil properties and defect depth measurements obtained from ILI to characterize the soil in the surroundings of a pipeline. This approach implements an independence test, a multiple correspondence analysis, and a clustering method with K-modes. The approach was applied to a real case study, showing that more severe defects are likely located in poorly drained soils with high acidity.

Keywords

• underground pipeline
• soil corrosion
• in-line inspection
• multiple correspondence analysis
• clustering