Grant: Collaborative Research and Development Grants

Oil and gas industries in Canada use buried steel pipeline as the primary mode for transporting oil, gas, and various petroleum products. These pipelines are subjected to internal pressure from the oil and gas that they transport. These pipelines sometimes experience impact and contact forces from foreign objects, such as construction and excavating equipment, rocks, etc. As a result, dents form in the pipe wall and the corrosion protection coating gets damaged. Subsequently, the damaged and dented part of the pipeline becomes exposed to a corrosive environment resulting in the formation of cracks in the dent. The pipeline operator becomes concerned about the performance and safety of the pipelines that have developed such dent-crack defect. This is because this defect may lead to a rupture in the pipe wall causing the release of a large quantity of toxic oil or gas into the environment and this in turn could lead to safety issues for the surrounding inhabitants. Currently, very little information on how to assess the burst strength of such pipelines is available. Accordingly, the operating pressure of the entire pipeline is reduced significantly and this causes a huge loss of industry revenue. Therefore, this research project is designed to develop an easy-to-use design tool that the pipeline operators will be able to use for determining the safe operating pressure of pipelines with dent-crack defect. Hence, the operators will be able to make an informed decision on when a necessary remedial action is to be taken for ensuring uninterrupted pipeline operation, therefore, minimizing revenue losses, avoiding environmental damage, and protecting the safety of all inhabitants living around the pipeline zone. This research will be completed using both experimental and numerical studies. Though the primary objective of this study is to determine burst strength of buried pipelines with dent-crack defect, this project will also determine the strain history at various critical locations of a dent, as the dent forms and grows. This information is useful in assessing the safety of field pipelines when only a dent defect has formed.