Microbially Influenced Corrosion Assessment in Crude Oil Pipelines

Crude oil pipelines are subject to microbially influenced corrosion (MIC), particularly in water pockets at low-lying sections of the pipeline. Unfortunately, no methods are currently effective to monitor crude oil pipelines for the presence of MIC, and the potential for MIC in individual pipelines remains unknown. An effective MIC assessment and management strategy will greatly improve the control of internal corrosion of pipelines.

This paper discusses the research being conducted in Saudi Aramco in order to develop MIC assessment protocols that will introduce molecular microbiology methods (MMM) to confirm if MIC is the cause of corrosion in a specific case and procedures that will allow reliable field monitoring of MIC.

The MIC assessment protocols include:

1. Assessment of the microbial community in order to determine what types and numbers of MIC-related microorganisms are present in the samples using MMM methods;
2. Determining the chemical nature of the water in the system through detailed geochemical analysis.
3. Investigating the presence of bacteria in solid and filters samples using ESEM/EDS.

Case histories of MIC evaluation of a range of crude oil pipelines will be presented, to show the applicability of the assessment protocols to dry, wet, sweet and sour crude oil pipelines.

Key words: microbially influenced corrosion, molecular microbiology methods, Crude oil pipelines, assessment, monitoring microbial corrosion, corrosion.