Saudi Aramco needed to protect hundreds of feet of new 24” pipeline during the HDD pull back process. The pipeline would pass through aggressively rocky terrain that could possibly damage the pipe’s coated surface and cause premature coating failure.
The owners turned to NRI’s Scar-Guard to encase and protect the pipeline, not only during the pull back process, but inservice, as well. And the installation process wasn’t the only harsh condition on the job. Although crews began work in May, they had to work mainly at night when temperatures typically only reached 110ºF. They also worked in mobile tents to protect the freshly coated and wrapped pipes from the dust and sand blown by the heavy desert winds.
The pipeline was first surface prepped with a sweep blast to roughen the factory-applied fusion-bonded epoxy coating. The joint welds were power tool cleaned to remove excess rust, dirt or loose scale. Then the pipeline was solvent cleaned. Next the welds were coated and protected with Syntho-Poxy HC, a two-component epoxy filler. The crew also applied the Syntho-Poxy HC as a skim coat over the girth welds to act as corrosion protection. Then the primer-coat application of Thermo-Poxy, a twopart epoxy compound was applied at 100-200 microns around the entire circumference of the pipe. The Thermo-Poxy seals the surface of the pipe and provides a bond for the composite system. While the Thermo-Poxy was still wet, the crew applied the Scar-Guard composite system. Using the patented Resinator to ensure correct fiber-to-resin coverage, the crew ran rolls of Scar-Guard through the resin box to saturate the fibers. The material was then applied to the pipe, in a clockwise manner and quickly covered with compression film. After curing, the film was removed and thickness and hardness tests performed.
Approximately 12 hours after the composite system application, the pipe was ready for pull back. Using drilling mud, they lubricated the pipe and the hole and began the thrust boring process. It was a success. The new pipeline was installed without scarring and is now protected, thanks to NRI’s Scar-Guard.