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SDC drillship returns to Beaufort Sea Steel drilling caisson has been stacked at Port Clarence north of Nome since finishing the Cabot well for ARCO Alaska in the spring of 1992 Kristen Nelson PNA Editor-in-Chief
The SDC — short for steel drilling caisson — is being brought back into the Beaufort Sea by AEC Oil & Gas of Calgary, Alberta, to drill an exploration well at the McCovey prospect north of Prudhoe Bay.
Soren Christiansen, AEC drilling manager, told PNA Nov. 27 that because the SDC is ready to go as soon as the ice is thick enough, it allows AEC to start and finish drilling early. “It’s a unique structure,” he said. “And it is really well suited to this.”
The SDC was built for the Arctic by Canadian Marine Ltd. in 1982 using an old tanker as a shell. “It was built with a very specific purpose in mind,” Christiansen said. The walls were strengthened to more than three feet with concrete and steel. The deck was strengthened. The SDC can store everything needed to drill three to five wells, depending on the well depth, he said.
It drilled in Canadian waters in the winters of 1982-83 and 1983-84. In 1986, a MAT system was constructed in Japan and towed to McKinley Bay, Northwest Territories, where it was installed under the existing box-type skirt on the SDC, extending the water depth range of the SDC and eliminating the need for a dredged berm or site preparation. The vessel can drill in 24 to 80 feet of water.
Tenneco then used it to drill the Phoenix well in Harrison Bay in the winter of 1986-87 and the Aurora well some 25 miles east of Kaktovik in 1987-88.
ARCO Alaska Inc. used the SDC to drill its Fireweed well in 1990-91 some 125 miles east of Barrow; to drill the Cabot in 1991-92 some 50 miles east of Barrow.
The SDC has been stacked at Port Clarence north of Nome since 1992. It was for sale, Christiansen said. There was little activity in the Beaufort and the owners didn’t want the SDC trapped in the Beaufort by ice if it could be sold for work elsewhere in the world.
In 2000, the SDC was sold to Seatankers Management Co. of Oslo, Norway. The unit’s name was changed from SSDC (single steel drilling caisson) to SDC.
This past May, Anchorage-based Fairweather Inc. took over management of the drillship. This fall, Fairweather cut a deal with AEC to do exploratory drilling at McCovey. Work will begin in spring In the spring, Christiansen said, we’ll go out and start generators, get the power on, and get the camp ready. Once the camp is habitable, “then we’d bring people out that would start doing detailed inspections of all the parts and replacing parts” when needed.
“We’d probably start going out in the middle of May, bring the first people out. And then we’d probably have a full contingent of people out there June 1” The vessel would be checked over and so would the rig package. A month and a half of work will probably be required, Christiansen said.
“The rig itself is actually in really good shape and the camp is in good shape,” he said. Some maintenance has already been identified. “What we’ll actually be doing during that month and a half is checking out all the pumps and electric motors” and inspecting the vessel and equipment.
Some crew would remain onboard to continue maintenance, he said, and the vessel would be towed around Barrow and to location.
The SDC can float in 7 meters of water, roughly 22 feet, Christiansen said. The vessel is moved into place by tugs and then water is pumped into the bottom of the vessel, which actually sinks into the seafloor.
The plan is to have the SDC on location Aug. 1. It would then be loaded with supplies and everyone would be off two weeks before the whaling season starts.
Drilling supplies will be loaded from Prudhoe Bay and low-sulfur diesel fuel will come from Canada by barge from Hay River.
There has to be thick ice around the vessel before drilling can begin, he said, so mid-November is probably the earliest drilling would start, Christiansen said.
Ready to go before the ice freezes “We’re ready to go before the ice freezes,” he said, and then you wait until there is a radius of ice around the vessel.
“One of the best advantages with this is the fact that we can start early — because that allows us to finish early. We can actually get a very definite test done on the prospect,” he said.
And, he said, “if you have any problems, you have a lot of time to work with it. In drilling,” he said, “there’s always delays… so if you are delayed at all, you still have a lot of time.”
Christiansen said that depending on the results of the first winter’s drilling, the SDC could remain on site over the following summer if AEC planned more drilling the next winter.
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