Corrosion Assessment Methodology for an Existing Pipeline Network

Ageing of pipeline networks is of major concern to Oil & Gas operators who need to ensure safe operation, avoidance of environmental pollution, and fitness for purpose of major producing assets. In this context, corrosion control is one of the major challenges that they are faced with on existing pipeline networks.
In order to be of any real value, a corrosion evaluation of existing pipelines needs to:
·   Be consistent across the entire network (even worldwide),
·   Deal with past and present corrosive conditions seen by each pipeline,
·   Consider the efficiency of mitigation actions,
·   Take into account available inspection data.
 This paper will describe a semi-quantitative methodology for assessing the corrosion likelihood of existing production pipelines which was developed by the Company and applied over its worldwide operations.
Although apparently less formal than using fully quantitative mechanistic models, this methodology is given a higher degree of confidence as it better covers than any tool can do the wide variety of corrosion and corrosion control events and the variability of service conditions that any pipe experiences over its whole life time. It also places the direct accountability of the evaluation on people in charge, not on models.