ExxonMobil's concrete drilling structure moved from Alaska to Russian Far East

By OGJ editors
HOUSTON, Mar. 27 -- Crowley Marine Services Inc., Seattle, has moved the 312 sq ft concrete island drilling structure Orlan from Prudhoe Bay, Alas., to Sovietskaya Gavan in the Russian Far East for Sakhalin I Project operator, Exxon Neftegas Ltd. (ENL), a subsidiary of ExxonMobil Corp.

The Orlan, formerly the Glomar Beaufort Sea I Concrete Island Drilling System (CIDS), was purchased from Global Marine Drilling Co. and will be used for oil production off Russia.

It was moved from its stack site near Northstar Island off Prudhoe Bay using two Crowley Sea Victory Class 7200 bhp twin screw oceangoing tugs with more than 110 tons bollard pull each. Arctic ice management was handled by Crowley with a third tug contracted for the job, the 23,200 bhp Arctic Kalvik. The certified Ice Class Lloyds +100 A1 Arctic Class 4 tug offered high bollard pull, ice-breaking ability and was outfitted with tow gear for arctic and ocean towing.

"The Orlan has a 34-foot draft and consists of four basic components—a steel mud base, a concrete brick caisson, and two steel deck barges on which the drilling rig, support equipment, and quarters are mounted," said Craig Tornga, general manger of Alaska Services for Crowley Marine Services.

Crowley has been towing barges, ships, and drilling rigs in the North Pacific and Bering Sea since the 1950s, servicing the areas of the Aleutian Islands to Prudhoe Bay. The company has moved the Orlan seven times without incident, including its move into the Arctic from Japan in 1984.

ENL contracted with Glosten Associates Inc. for overall management of the project and with Crowley Alaska for the towing. The Crowley team and tugs arrived at Point Barrow in early August to commence the tow, with Crowley making daily flights in the area to monitor ice melt until suitable passage out of Alaska was possible Aug. 31.

When the tow arrived off Barrow, Alaska on Sept. 4, 2001, the Crowley team set up the Arctic Kalvik with the Sea Victory and Sea Venture for the ocean tow from Barrow to Russia. Because of the large size of the tow, the tugs were refueled along the way by a Russian tanker. On Oct. 14, 2001, Crowley delivered the Orlan to Russia, cleared the structure through customs and began arrangements to put the Orlan down in the Sovetskaya Gavan harbor.

"Our team had to do some dredging at the new site in the harbor to make room for the Orlan, which is about 60 ft deep with its mudskirt," said Anderson. "Then we were able to lower it to its new position on the bottom."

Crowley Marine Services is a subsidiary of Crowley Maritime Corp., Oakland, Calif.