PRESSURE CYCLIC FATIGUE OF WRINKLED PIPELINES

The development of a small wrinkle in a buried pipeline can be a challenging issue for pipeline operators to approach. If not dealt with appropriately, these small wrinkle defects can lead to further damage to the pipe wall as a result of fatigue damage caused by operating pressure fluctuations. Presently, in an effort to avoid the uncertainty of failure due to a wrinkle defect, many pipeline operators will conservatively decide to proceed with costly and often avoidable removal or repair actions. Aside from the obvious restoration costs associated with the repair or the removal of the wrinkle, other undesirable outcomes may emerge as a result of the temporary shutdown of the pipeline operations, including but not limited to loss of revenue and interruption of downstream oil and gas service. The purpose of this proposed research study is to develop and provide a defect assessment guideline which pipeline operators will be able to use to assess both the remaining life of a pipe with a small wrinkle defect and the possibility of a small wrinkle defect’s failure. This in hope will allow professionals in the pipeline industry to make more informed decisions about whether or not a restoration action is necessary.