Deepwater Horizon was an ultra-deepwater, dynamically positioned, semi-submersible offshore drilling rig owned by Transocean. Built in 2001 in South Korea by Hyundai Heavy Industries, the rig was commissioned by R&B Falcon, registered in Majuro, and leased to BP from 2001 until September 2013. In September 2009, the rig drilled the deepest oil well in history at a vertical depth of 35,050 ft (10,683 m) and measured depth of 35,055 ft (10,685 m) in the Tiber Oil Field at Keathley Canyon block 102, approximately 250 miles (400 km) southeast of Houston, in 4,132 feet (1,259 m) of water.