The technology-driven boom in the production of natural gas trapped in shale rock has dramatically shifted the supply picture in the U.S., reducing the need for imports and driving down prices.

In a speech in Buenos Aires last year, BP Chief Executive Tony Hayward called this "a quiet revolution...in the gas fields of North America."

New techniques like hydraulic fracturing and horizontal drilling are opening up new gas resources that could last the U.S. between 50 and 100 years, he said.

"One field where these techniques were pioneered--the Barnett Shale near Fort Worth in Texas--has almost single-handedly turned around the production of natural gas in the U.S.," Hayward said.

BP made its entry into U.S. shale gas in 2008 when it acquired 90,000 acres of the Arkoma Basin Woodford Shale play and 135,000 acres of the Fayetteville shale from Chesapeake Energy for $2.85 billion in cash.