OSLO (Bloomberg) - Seadrill Ltd., a Norwegian oil- rig company, sold its stake in the drilling-service unit of Indonesia's PT Medco Energi Internasional for $220 million.

Seadrill will book a gain of about $150m in the fourth quarter after selling its 32 percent stake, or 835 million shares, in PT Apexindo Pratama Duta, the company said in a statement to the Oslo stock exchange yesterday.

"The investment in Apexindo was acquired at the time when Seadrill was seeking a strategic partner to build the infrastructure of the company," Seadrill said.

After buying Norwegian rival Semedvig ASA in 2006, the investment in Apexindo "became more of a financial investment," for Seadrill, it said.

Set up in 2005 by Norwegian-born shipping billionaire John Fredriksen, Seadrill is based in Bermuda and run from Stavanger, Norway.

Apexindo owns and operates nine onshore drilling rigs, four swamp barges and two jack-up rigs.