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Alyeska Reduces Pipeline Repair Time by 50-66%
- Eight to 12 hour repairs now take four hours
- Consistent, non-fluctuating preheat condition enables completing all welding passes without stopping
- No heat sink to fight means using fewer welders to complete the job
Customer Testimonial
“This area of in-service welding has tremendous ramifications within the oil and gas industry and opens up opportunities for preheating during in-service welding that haven’t been considered before.”
— Alan Beckett, Senior Welding Engineer, Alyeska Pipeline Service Company
Application
Pipeline maintenance activity, including STOPPLE® plugging operations that entail welding special fittings to enable in-service line tapping, and welding full encirclement repair sleeves around the Alaska Pipeline's 48-inch diameter girth to shore up weak spots.
Key Business Issue
Reduce repair welding time.
Challenge
Crude oil flowing at 68 degrees F creates a major heat sink, making it time consuming and difficult to preheat the pipe and to maintain that temperature.
Previous System & Process
Propane turbo torches paired with electrical resistance coils (separately, neither process worked acceptably).
New Solution
- Miller's Intellifire™ 250 (25kW output) induction heating power sources and patented induction heating blankets.
- The Intellifire power supply creates a rapidly alternating (10 to 50 kHz) electromagnetic field inside the blanket. This field excites the molecules of the part (i.e., pipeline, hot tap fitting), raising its energy level and causing the steel material to heat from within.
Results
- Welding time reduced 50 to 66%. “Miller's induction heating technology establishes a minimum preheat temperature and maintains a consistent, non-fluctuating preheat condition. This allows us to [make] one 48-inch repair sleeve girth weld in just four hours.” It used to take eight to 12 hours.
— Alan Beckett, Senior Welding Engineer, Alyeska Pipeline Service Company - Continuous welding. “At a continuous preheat of 125º F, we can complete the rest of the passes without stopping… induction heating helps reduce the heat sink far better than alternative methods.”
— Alan Beckett, Senior Welding Engineer, Alyeska Pipeline Service Company - Less operator stress. “Without induction heating, when we had to fight the heat sink with conventional pre-heating, we were up to a 12- to 18-hour day [to repair] one side of a STOPPLE fitting. [We] had to use five or six welders…the four that were needed, and rotate fresh people in.”
— Alan Beckett, Senior Welding Engineer, Alyeska Pipeline Service Company
