OSLO (Bloomberg) - Seadrill Ltd., the Norwegian oil-rig company set up by billionaire John Fredriksen, got two one-year contract extensions worth about $390 million from Exxon Mobil Corp.

The four-year West Aquarius contract is now worth about $750 million, up from the previous three-year $579 million contract, the Hamilton, Bermuda-based company said yesterday in a stock exchange statement. The now four-year West Polaris contract is worth $815 million.