Risk-Informed Decision Making to Support the Integrity Management of Lateral Piping

Kulhawy, Amanda (Enbridge Pipelines Inc.) | Woo, Janine (Enbridge Pipelines Inc.) | Nemeth, Alex (Enbridge Pipelines Inc.) | Hassanien, Sherif (Enbridge Pipelines Inc.)

OnePetro 

ABSTRACT

In order to make risk-informed decisions when designing corrosion mitigation and remediation programs for lateral piping, consequence and likelihood of a failure (LoF) are required to estimate the risk. Within industry, lateral piping does not always have In-Line Inspection (ILI) or Direct Assessment (DA) data. As such, the LoF models for corrosion on uninspected lateral piping rely on a semiquantitative historic-based approach. This approach leverages a historic failure rate and modification factors to provide a lateral-specific rate of failure (Rf). However, when lateral piping has been inspected, a quantitative assessment can be applied to evaluate LoF. Based on a sample assessment on laterals with inspection data, the historic-based model showed more conservative LoF results. This conservatism could potentially drive unnecessary mitigation or remediation work on lateral piping where inspection data may not be available. This paper considers the use of calibration of the historic-based model with the inspection data available to provide a less conservative and more accurate assessment of the likelihood of failure for lateral piping without inspection data. Given the limitations and constraints in the data and models, it proposes the use of risk-informed decision making to develop the integrity management plan.

INTRODUCTION

Managing the corrosion threat on lateral piping can be a challenge due to limited inspection capabilities and uncertainties in the available data. Lateral piping does not always have In-Line Inspection (ILI) or Direct Assessment (DA) data, so the data used in probability of failure (PoF) analysis is not always available. Therefore, a likelihood of failure (LoF) is estimated using a semi-quantitative historic-based rate of failure (Rf) approach [5]. This approach leverages a historic failure rate and modification factors to provide a lateral-specific rate of failure (Rf). Within this case study, a sample evaluation of PoF and Rf is completed on 10 laterals. The Rf estimates are generally conservative compared to the PoFs but do not directly align. This conservatism and uncertainty could potentially drive unnecessary inspection and mitigation work on lateral piping.