NORWAY (Bloomberg) - Seadrill Ltd., owner of the second-largest fleet of deepwater rigs, rose in Oslo trading after agreeing to buy two ultra-deepwater rigs under construction at the Jurong Shipyard Pte Ltd. for $1.2 billion.Seadrill rose as much as 2.1 percent to 201.3 kroner, the most since December 20, and was at 201.1 kroner as of 11.07am, outperforming the one percent gain in the benchmark OBX index. The shares are up 34 percent in the past 12 months, valuing the Bermuda-based company at 89 billion kroner ($15 billion).The Seadragon I and Seadragon II semi-submersible rigs will be delivered in the first and fourth quarter this year, respectively, the company said in a statement. Seadrill has secured bank debt for the investment, it said. Seadragon I has a five-year contract, subject to further discussions between the parties, while Seadragon II has no contract, it said.“We expect the demand for ultra-deepwater units to strengthen over the next years,” Seadrill’s CEO Alf Thorkildsen said in the statement. “This investment increases our exposure to this growing market segment at an acceptable price and a manageable risk.”Seadrill has ordered at least six rigs with options for eight more in the past three months, in addition to buying a jack-up rig from Petrojack IV Pte. Ltd., in anticipation of an improvement in day rates. Seadrill raised its dividend to $0.65 in the fourth quarter from $0.61 in the prior quarter, and said the last three months of 2010 indicated “good growth” and “solid profitability.”