Transocean’s stock headed lower in early Tuesday trading, after the oil services company said it expects to book impairment charges of more than $600 million for the sale of assets.

Transocean (RIG) to sell two deepwater drilling rigs for $342M, in an effort to dispose of non-strategic assets, with an expected Q3 charge of $630M-$645M for impairment.

Transocean plans to use "substantially all of the proceeds," which should be $342 million, to pay down debt. The stock dropped 2.6% in morning trading, which put it on track for the lowest close ...