The aging infrastructure of pipeline systems around the world requires operators to explore novel and innovative methods for rehabilitating pipelines. Conventional repair methods involve the installation of steel sleeves or composite repair systems. While these repair methods are reliable and provide operators with options for pipeline repair, a major drawback is the requirement that pipelines must be excavated. Activities related to excavation have inherent risk in the form of personnel and environment safety along with the applicable cost of excavation activities. If extensive flaws are present in a pipeline system, efforts associated with a comprehensive pipeline repair system can be cost-prohibitive. Additionally, the rehabilitation of pipelines that were installed via horizontal direction drilling, using current repair methods, is near to impossible.
This paper provides an in-depth presentation on a comprehensive study completed to evaluate the use of a spoolable pipeline technology as a means for rehabilitating pipelines. Results are included from an industry survey with responses from 15 pipeline operators on the use of spoolable pipe technologies. One outcome from the survey was the lack of full-scale test data associated with combined loading, which was a central feature in the current study. The combined loads considered in the year-long study included burst testing and cyclic pressure testing utilizing torsion, axial tension, and axial compression loads. More than 30 full-scale test samples were destructively tested in combined loading scenarios, utilizing up to 100,000 pressure cycles to the full operating pressure of the pipeline system. The approach employed in this study, and the associated test results, provides a model for evaluating a spoolable pipeline technology prior to implementation for rehabilitating pipelines. This approach is in addition to the required product qualification standards accepted by industry.