Considering the geographical nature of Alaska’s North Slope, one can only imagine the logistical challenges of operating there. Consumables such as burner plugs and valves, that are found within ConocoPhillips’ 40-year-old original gas turbines at the Kuparuk River Unit, North America’s second-largest oil field, are not manufactured anymore. This, in addition to the geographical challenges associated with Kuparuk, results in lead times anywhere between 30 and 60 weeks to replace such components when they eventually succumb to heat erosion and wear out.
As a solution to the supply chain challenge, the Alaska business unit teams, in collaboration with ConocoPhillips’ Global Production experts, have been testing 3D printed burner plugs and valves in its Ruston gas turbines at Kuparuk.
The burner plugs are printed using Inconel 718, a high-strength superalloy with a nickel-chrome base material resistant to high pressure and extreme temperatures. In the case of these outdated burner plugs (which are no longer covered by intellectual property laws), it’s possible to go from a set of drawings to a printed object in about a week and then have it shipped to the field location.
“So, you’re taking something that would traditionally be a 30-week thing down to a two-to-three-week thing,” said Curt Andersen, an Instrument, Control, and Electrical Engineering Supervisor for ConocoPhillips’ Alaska business unit. “And so far, the printed plugs are working fantastic. They’re performing as good, if not better, than our conventionally made plugs.”
“This was an opportunity for us to try something that had a lot of potential advantages to it, and also use this as data for the rest of the company. For us, this is a new method of manufacturing that comes with a lot of questions, such as what does the part look like when we put it in service? How does it act? Does it act like another piece of metal that was rolled, forged, or cast?”
In another Alaska pilot project, ConocoPhillips teams have partnered with OEM and additive manufacturers to 3D print choke cage valves, which are flow-control devices used in water injection wells.
In this instance, the Alaska team identified numerous choke valves obsoleted by the OEM. The solution was to retrofit the existing valve bodies with 3D printed valve cages, also made of Inconel 718.
“We’ll be able to extend the life of the choke valves using an optimized design,” Andersen said, “replacing parts only when we need them. With additive manufacturing, you don’t have to go out and buy a whole new valve, plug, or whatever the piece.”
These 3D printing trials, such as burner plugs and valves, he said, exemplify the Alaska business unit’s continual search for innovative, cost-effective ways to maintain and optimize its operations.
“Additive manufacturing is an exciting technology with the extreme potential to not only maintain 40-year legacy assets and equipment,” Andersen said, “but also improve the performance of those assets in a cost-competitive way.”
The benefits of additive manufacturing are enticing, he said.
“For an operation like the North Slope of Alaska, because we are so remote, and because it can take such a long time for things to get there, we maintain a fairly large warehouse of parts, especially the ones that we consider critical. That comes with a lot of extra costs. There’s the cost just to simply store them and have the space for them but there’s the ad valorem tax that we have to pay for just having that on the shelf.”
“So, in a utopian future view, if you have these parts in a digital format, if you have the drawings and the design criteria for them, you could simply ship them to a partnered print shop, produce them and have them in a much quicker fashion than worrying about do I need to order this thing 30 weeks out in order to have it on the shelf in time to do this maintenance activity. So, you could create a lot more certainty within the supply chain itself and also potentially significantly reduce costs in terms of warehousing and inventory.”
“We need a good bit of information to execute a successful and legal print. Part information like metallurgy and service conditions, a design drawing/3D model that is either not controlled under intellectual property or can be used with permission, a manufacturer that can meet the need.”