Based on the industry’s plans, shale and other “tight rock” fields that now produce about half a million barrels of oil a day will produce up to three million barrels daily by 2020, according to IHS CERA, an energy research firm. Oil companies are investing an estimated $25 billion this year to drill 5,000 new oil wells in tight rock fields, according to Raoul LeBlanc, a senior director at PFC Energy, a consulting firm.

“This is very big and it’s coming on very fast,” said Daniel Yergin, the chairman of IHS CERA. “This is like adding another Venezuela or Kuwait by 2020, except these tight oil fields are in the United States.”

In the most developed shale field, the Bakken field in North Dakota, production has leaped to 400,000 barrels a day today from a trickle four years ago. Experts say it could produce as much as a million barrels a day by the end of the decade.

The Eagle Ford, where the first well was drilled only three years ago, is already producing more than 100,000 barrels a day and could reach 420,000 by 2015, almost as much as Ecuador, according to Bentek Energy, a consultancy.