ABSTRACT
Internal corrosion threat in dry natural gas pipelines is low because of the very low water content controlled under a tariff limit. However, the threat may exist when liquid water is brought into the pipe by condensation, hydrotesting, or intrusion from lateral components. In an earlier project funded by Pipeline Research Council International,* probabilistic models and tools were developed to support guidelines to quantify the internal corrosion threat from condensation for a given dry natural gas pipeline operating conditions. The current work collected and analyzed more field data to enhance the probabilistic model, especially under conditions of higher internal corrosion risk. The enhancement improved the practical tools and guidelines, by attaining a confident prediction of the internal corrosion threat. With these tools, an operator would be able to evaluate whether the current operation of its pipeline has an internal corrosion threat that is unacceptable, or how to adjust the operating parameters to reduce the internal corrosion threat. The framework for predicting internal corrosion threat due to residual hydrotest water and condensate intrusion of liquid water from side branches was also enhanced, and computational tools were developed for field implementation.
