LONDON (Bloomberg) Bermuda-based Seadrill Ltd., the oil rig company controlled by billionaire John Fredriksen, said fourth-quarter net income fell 33 percent on costs for the early conversion of convertible bonds.Net income after minorities fell to $254 million, or 58 cents a share, from $379 million, or 88 cents, the company said. There was an “adverse accounting impact” of $145 million from the early debt conversion. The profit missed the $355 million average estimate in a survey of 11 analysts.Sales gained to $1.2 billion from $879 million a year earlier as higher crude prices boosted rig demand. Seadrill has been expanding its rig fleet to capture demand for more modern rigs as oil producers explore deeper and deeper waters.