Pipeline infrastructure is the backbone of the energy industry and remains the safest and most cost effective method for transporting oil and gas. For decades corrosion has presented a significant challenge to pipeline operators. According to Alberta Energy Regulator data, internal corrosion is considered to be the root cause for more than 54% of all documented pipeline failures in Alberta . Spoolable composite pipeline technologies have become a mainstream corrosion solution over the last 10 years, however these products are limited to smaller pipelines, typically less than 6 inches in diameter. Traditional slip-lining (field installed plastic lined steel pipe) is used for internal corrosion protection of larger pipelines, however it is costly, requiring labour intensive field construction, often completed in inhospitable environmental conditions. As a result project delays and cost over-runs are commonplace.
Recognizing the need for a cost effective pipeline corrosion solution for larger gathering pipelines, an innovative technology was developed that combines a unique mechanical pipe joining system with an integrated electro-fusion coupler. The new joining system enables insertion of an HDPE liner in a factory environment where costs and quality can be tightly controlled. The new joining system eliminates conventional welding of the pipeline in the field and instead uses a custom field press to quickly energize the mechanical pipe joint. Field scope is significantly reduced, construction completed in less time, and associated costs greatly reduced. This paper discusses the testing completed to qualify the new joining system for use in oilfield gathering pipelines.
The qualification test plan includes all requirements identified in applicable regulatory standards (primarily CSA Z662-11), and prudent engineering requirements based on anticipated field handling and anticipated operating conditions. The test regime was ultimately designed to ensure the suitability of the pipeline system for intended service. Testing included hydrostatic burst, static gas pressure, bend, cyclic pressure and thermal, vacuum, tensile, and compressive tests on the joint.
The test results show that in all cases the jointing system successfully met the established design performance criteria and in most cases exceeded the actual mechanical properties of the parent pipe, thus proving the joining system ready for field installations.