As the world continues its addiction to oil, "ultra-deep" wells -- those drilled 1.5 km (4,500 feet) deep or more -- are now at historic levels with no signs of abating, Reuters reports.

Shell's Perdido platform in the U.S. Gulf. (photo: . Shell / Flickr) The players in the deepwater game include the big oil names of BP, Chevron and Royal Dutch/Shell, which operates the deepest offshore well, nearly three kilometers under the U.S. Gulf.

Using data from rigzone.com, Reuters reports that "more than 80 rigs on contract now have the ability to work in ocean depths of more than 7,500 feet."

Undeterred by the Deepwater Horizon disaster, "BP launched this year a project it calls 20K - aimed at the next generation of even deeper, higher pressure, higher temperature wells at pressures of more than 20,000 psi," referring to the water pressure measured in pounds per square inch (psi).