The Transocean Development Driller III, the rig responsible for drilling the main relief well at the site of the Deepwater Horizon oil wellhead, is seen on the Gulf of Mexico near the coast of Louisiana, in this Aug. 14, 2010 file photo. A relief well drilled nearly 2.5 miles beneath the floor of the Gulf of Mexico has intersected BP's blown-out well, a prelude to plugging it once and for all, the U.S government said late Thursday Sept. 16, 2010. The final seal should happen by Sunday. (AP Photo/Patrick Semansky, File)