Transocean Ltd. (Transocean) is an international provider of offshore contract drilling services for oil and gas wells. The Company operates in two segments: contract drilling services and drilling management services. Contract drilling services, the Company's primary business, involves contracting its mobile offshore drilling fleet, related equipment and work crews primarily on a dayrate basis to drill oil and gas wells. Its drilling management services segment provides oil and gas drilling management services on either a dayrate basis or a completed-project, fixed-price (or turnkey) basis, as well as drilling engineering and drilling project management services. As of February 14, 2012, it owned or had partial ownership interests in and operated 134 mobile offshore drilling units. On October 4, 2011, the Company acquired Aker Drilling ASA (Aker Drilling). In February 2011, it sold the subsidiary that owns the High-Specification Jackup Trident 20.