Using a Degradation Model to Assess Lifetime of a Pipeline

• Activity Number: 291
• Type: Contributed
• Date/Time: Tuesday, July 31, 2012 : 8:30 AM to 10:20 AM
• Sponsor: Section on Physical and Engineering Sciences
• Author(s): Shiyao Liu*+ and William Q. Meeker
• Companies: Iowa State University and Iowa State University
• Keywords: Bayesian ; Longitudinal data ; Pipeline reliability

Abstract

Longitudinal inspections of the pipeline thickness at particular locations along the pipeline provide useful information to assess lifetime of the pipeline. Depending on the mechanism of corrosion processes, various types of general degradation paths have been observed in the practical pipeline applications. In one application, we proposed a degradation model describing the corrosion initiation and growth behavior of the pipeline, and used a Bayesian approach for parameter estimation in the degradation model. We also built a hierarchical model to quantify the pipeline corrosion rate for similar circuits within a single facility, under the assumption that the corrosion rates are constant over time for different locations within a circuit in the facility. The failure-time distribution is derived from the degradation model and we compute Bayesian estimates and credible intervals of the failure-time distribution. In this paper, degradation models are also proposed to evaluate pipeline reliability for other applications.