Case History of Repairing Cracking in the Seam Welds of 1950 Vintage Pipe Using the Steel Compression Reinforcement Technology

Platte Pipeline operates a 1500 km NPS 20” (508 mm) crude oil pipeline connecting Casper, Wyoming to Wood River, Illinois USA. The pipeline was constructed in the early 1950’s with low frequency electric resistance welded (ERW) and flash welded (FW) pipe. The Steel Compression Reinforcement Technology (PetroSleeve) was used to repair active ERW and FW seam cracking detected by an in-line inspection tool. All repairs were performed while the pipeline was in operation. Prior to undertaking the field rehabilitation program, engineering analysis and severe testing was performed to confirm that the steel compression reinforcement technology would arrest fatigue crack extension. Two significant defects were manufactured in the long seam of separate sections of 1950’s vintage line pipe that had been removed from service. The defects included a 50% through-wall manufactured crack and a 70% through-wall electrically discharged machined semi-elliptical slot anomaly. Compression sleeves were installed over both defects, and cycled 36,500 times with internal pressures ranging from 700 kPa to 8000 kPa. Following the cyclic pressuring, the crack and corrosion anomalies were metallurgically inspected. No crack extension or crack development was observed nor detected. At the conclusion of the engineering testing and analysis, it was accepted that the technology permanently restored the serviceability of the pipe by reducing stress levels and preventing crack growth. Platte Pipeline saved significant dollars by using this technology. The time and expenses associated with nitrogen purges and pipe cutouts were avoided. Also, Platte was able to maintain crude oil deliveries at near normal levels throughout the repair program. This paper reviews the engineering analysis, cyclic testing, and field installation practices associated with the Platte rehabilitation program.