The worlds longest drilled oil well is BD-04-A, with a total length of 40,320 ft MDRT. It was completed in May 2008 by Maersk Oil Qatar and Qatar Petroleum, in the Al-Shaheen offshore oil field off the coast of Qatar. The well includes a horizontal section measuring 35,770 ft.
MDRT (measured depth below rotary table).
Comments below may relate to previous holders of this record.