Oklahoma holds the record for the deepest well ever drilled in the United States. The GHK Co. 1–27 Bertha Rogers located in Washita County, Oklahoma was the former world’s deepest hole. This well reached a depth of 31,441 feet where it encountered molten sulfur that melted the drill pipe and forced the end of drilling.
It took GHK two years to reach 31,441 feet, a depth of almost six miles. During drilling, the well encountered enormous pressure – almost 25,000 psi. No commercial hydrocarbons were found and the well was plugged and abandoned.
The Soviets began drilling a well in Russia in 1970 that is now over 40,000 feet deep. The well is the deepest hole on earth though the Bertha Rogers remains the second deepest.