Rapid Analysis Tool for High-Level Risk Assessment of Pipelines

When the benefits of using risk-based decision making in pipeline integrity management programs have been identified, operators are immediately faced with the challenge of large amounts of risk analysis work. This work frequently has to be done with minimum resources and/or in logistic situations that require a graduated approach extending over several years. In answering this challenge, a starting point must be identified that focuses resources where the risks are greatest. Since these locations are generally unknown in the first instance, the need exists to have a tool available to perform a first or high-level assessment to identify areas requiring further or more detailed study to support the integrity management program. The need also exists to have a robust tool that can be used to direct the assessments of smaller lines that might not require the detailed attention generally given to larger diameter transmission lines. This paper describes the extension of a simple indexing methodology comprising both theoretical and historical components to produce such a tool. It describes the use of so-called “smart” defaults to account for missing data, and a rudimentary decision model that can be used to grade the risk results. Examples are given of applications of the methodology to a gathering system and to the high-level evaluation of a transmission system. The paper also compares the results obtained to other, more detailed methodologies.