Russia is confronted not only with icebergs and drifting ice floes in its central Barents Sea region, but with towering ice ridges caused by the buckling of frozen seas that can occur anywhere in the Kara Sea and, more importantly these days, the Sea of Okhotsk, where the development of Sakhalin Island's offshore province is underway. There, ice ridges can rise as high as 35 meters. Icebergs on the surface of the seas are a problem only when melting occurs and the sheet ice breaks into bergs. Because the sea can freeze solid, however, scourging of the seafloor to plowed depths of up to 20 meters is possible, essentially preventing any ocean bottom pipeline network such as will be employed in Eastern Canada. Instead, detachable FPSOs with rapidly removable flowlines will likely be the method of transmitting oil from Sakhalin's new fields.
Platforms for the Sakhalin region, however, may eventually go the way of Hibernia, unless ultradeep subsea production systems can be devised that could withstand the scourging of the moving ice. At present, several designs are being considered, including narrow conical structures and ice-strengthened jacket-mounted platforms incorporating layered stainless steel and plate steel to handle the ice loads (up to two meters thickness a year) and the structural stress caused by ice abrasion.
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