O Christmas Tree, O Christmas tree…
Christmas comes many times a year at the GE Oil & Gas facility at Bridge of Don in Aberdeen, Scotland. It is from there that GE creates so-called “Christmas tree systems” for the subsea oil and gas industry. The manufacturing hub recently produced two particularly significant trees—the first of 22 to be built to control the flow of gas from the huge INPEX-operated Ichthys LNG Project in the Browse Basin, 200 kilometres off the Western Australian coast.
Landing the trees in Australia was cause for celebration—a milestone in the project’s development. The safe arrival of the massive steel structures at GE’s Jandakot technology facility in WA also represented a major logistical feat.
On September 13, 2014, the pair of VXTs, as they’re known in the business (V for their vertical configuration), left Bridge of Don for Aberdeen’s dockside Streamline Facility where cleaning and final preparations were made for shipping on 3 October. GE had commissioned the vessel MV Schokland to carry the trees and associated equipment, such as tubing-head spools.
A key component of the equipment that sits atop any oil or gas well, Christmas trees are flow-control systems, precision engineered, to ensure safe, faultless, reliable channeling and monitoring of the flow of the undersea riches in high-pressure undersea situations. Most such gathering systems are tailor made for their site.
“Depending on the field there will be different conditions, different temperatures, different pressures of gas or oil coming out,” says Graham Atkinson, Engineering, Procurement and Construction project director at GE Oil & Gas’ Bridge of Don facility. “There’ll be different soil conditions on the sea bed. There’s also specific tailoring of the number of valves and ports that a particular client might want. So there’s a lot of tailoring.”
But some things stay the same. A paint job in sunny yellow is mandatory for Christmas trees the world over, because it allows them to be more easily located on the ocean floor where they are secured, often at great depth and in murky conditions. Industry standards also specify that elements such as pad eyes, lifting systems and connectors—the interactive parts when the system is being connected to pipes and injectors—should be identified by an orange colour. The hues of other elements are similarly regulated.
But how does a yellow agglomeration of ports, pipes and valves come to be called a Christmas tree? It takes its name from above-ground well-head structures that can resemble a crudely decorated tree. And there’s certainly something festive, about the procession required to transport each Christmas tree from manufacturing facility to port for shipping, and again from port to its next onshore destination before deployment. Join the parade…
5am on 13 September and there was a burr in the air, a Scottish burr and a shiver of mist… This tree, one of two shipped for pre-Christmas delivery to Australia, and ultimately for the Ichthys Liquified Natural Gas (LNG) project in the Timor Sea’s Browse Basin, is the heaviest ever produced by GE. At 103 tonnes, it is around seven tonnes heavier than the last biggest gift ever dispatched from this near-North Pole facility (well, near enough to lend itself to this Christmas metaphor). A massive machine requires a massive lift, and the Marine Warranty Surveyor is on hand to ensure safe securing of the load for transport.
The Bridge of Don facility, which is the centre of XT manufacture, was originally developed to cater to the North Sea oil industry, and its expertise is now distributed worldwide. “Christmas trees are a common sight on the streets of Aberdeen. But we’ve got to move them at unsociable hours, and only on the weekends, to make sure we don’t have too much traffic being disrupted,” says Atkinson, referring to this image of the XT trees travelling down Market Street in the pre-dawn mist. “We’re restricted in the movements we can make, and it depends on the size of the load how they’ll be escorted. They might not only have a long-load escort, but in some cases a police escort.” Flashing lights—the Christmas theme continues! “Although it’s a well-established route, about three or four miles from our factory down to the harbour, it could take anything from one to a few hours to get there,” says Atkinson. “The thing’s got to go slow. We’ve got to be careful.”
The likeness may not be obvious from these angles, but the two Ichthys-project trees are virtually identical. The 20 other trees in the forest still to come will also likely differ only in slight adjustments made as the trees are deployed to various wells on the ocean floor. Temporary steel lift caps are fixed to the top of each tree, allowing cranes to more easily hook the load, lift and move it. On 3 October, the two XTs left this dock, aboard the MV Schokland bound for Australia. There are a number of choices in shipping substantial cargo such as this, and none of them involves flying. “You can put the equipment at the quayside and wait for the next vessel. You can do a last-on, first-out; so the next vessel going it’s the last cargo on, and then you pay for it to call at your port first and it goes first off. Or you can charter a vessel and pretty much load it with everything you can and that’s what we did with the Schokland,” says Atkinson. This is generally the fastest option.
Forty-three days later, the Schokland arrived in sunny Perth. Having travelled the west coast of Africa, it had endured a bout of bad weather around the notoriously stormy Cape of Good Hope. “You just can’t mitigate for bad weather,” says Atkinson. And if the welcome on Henderson dock was less than tumultuous, it was because the trees arrived in port at 2am. By 5pm, they’d been radiation-tested by port authorities and had their lashings and stoppers removed. That’s not quite yet the sound of corks popping.
It took two days and a total of 31 crane lifts to discharge the vessel of its 461.4 tonnes of cargo. Paul Iredale, Regional Logistics Leader (ANZ) for GE Oil & Gas Australia, had been route planning and negotiating with local authorities for six weeks, to transport the Christmas trees to GE’s Jandakot technology complex where they were due to undergo site-receival testing. First step was to position the Christmas trees precisely on the trucks. “I know it sounds silly, but as little as one degree off on the loading and the trees could have fallen over,” says Iredale. “We’ve got the best people we could use, in Heavy Haulage trucking, doing the job for us, and we’ve got some good marine surveyors as well, and everything’s checked, checked and checked again.”
Primary colours make the Christmas trees’ every move a photo opportunity. Here on 21 November at 9 am, XT #1, still with some protective packing in place, sits atop a vibrant blue Drake 9 axle-line platform trailer ready to roll. “We use trailers that spread out the weight over the road. The configuration of the truck and trailer was probably about 30 metres long. And if you can imagine, you can’t just turn onto a normal street. You’ve got to ensure that the route you take is wide enough, because we’re a wide load,” says Iredale. “There were lots of stakeholders involved in the route planning, from the vessel owners to the trucking companies, to Main Roads, Western Power and marine surveillance,” says Iredale of his logistical challenge. “It’s only about a 10- or 15-kilometre journey, but we did 57 kilometres and it took about two-and-a-half hours.”
“You’d better watch out … Santa Claus is coming ...!” Carolling maybe, but not careering, the tree-toting trucks carefully negotiated a total of 13 roundabouts. “We had five escort vehicles to try to keep the traffic away from us. The convoy had two cars up at the front and one in the middle, and two at the back, making sure that navigating roundabouts and things like that went OK,” says Iredale. He concedes that there were still a few hairy moments: “… members of the public cutting in front of the trucks ... you know, coming out of a side street and not realising the size of them. But that’s why we had the escorts.”
Drivers around Hope Valley, Wandi, Forrestdale, Piara Waters and Canning Vale might have been bemused to see the yellow behemoths on the move, but Iredale was determined that’s all they would feel. “We had to get Western Power involved,” says Iredale of the local utility company, “because they had to lift some of the power lines. We had to get Main Roads involved because we had to go over a number of bridges and we had to make sure the bridges were structurally sound and could take the weight of the trees and the trucks.” Seven bridges and two (“bumpy”) rail crossings later …
After one last roundabout the truck drivers deserve to be decorated. Since their arrival at Jandakot on 21 November, the Christmas trees have been undergoing site-retrieval testing to ensure they are ready to deploy for the expected 20 or more years they will spend at the bottom of the sea.
There was more than a Christmas cheer: “When that second tree got placed on the floor in the workshop, there was a big sense of pride and achievement for everyone who was involved,” says Iredale. INPEX’s Ichthys Project Managing Director, Louis Bon recognised the huge team effort involved in completing, testing and shipping the tree systems from Scotland. He said, “Christmas trees are a vital component of the subsea equipment necessary to complete the project’s development wells.”
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