Crude oil production in the US increased by the largest volume for more than 100 years during 2014, helped largely by the shale oil boom in the country that has already changed the energy map of the world.
During 2014, US oil production increased by 1.2 million barrels per day to 8.7 million barrels per day, representing the largest volume increase since record keeping began in 1900, the US Energy Information Administration (EIA) said.
On a percentage basis, output in 2014 increased by 16.2%, the highest growth rate since 1940.
Most of the increase during 2014 came from tight oil plays in North Dakota, Texas, and New Mexico where hydraulic fracturing and horizontal drilling were used to produce oil from shale formations, the EIA noted. The US shale revolution dramatically increased oil production in the US, and has transformed the country into a net exporter.
Crude oil production in the US has increased in each of the previous six years, the agency added.
Nevertheless, production growth is not expected to be strong in 2015 and 2016, given the oversupply in the global oil market that reduced oil prices by half since June 2014.
"Annual increases in crude oil production regularly surpassed 15% in the first half of the 20th century, but those changes were relatively less in absolute terms because production levels were much lower than they are now," the report said.
Hit by lower prices, many oil producers in the US slowed production in marginal drilling areas and focused investment in the more developed areas of tight oil plays
Annual crude oil production is expected to grow at a slower rate, 8.1% in 2015 and 1.5% in 2016, according to EIA's latest Short-Term Energy Outlook.
Between December 2014 and December 2015, oil production is forecast to rise by just 200,000 barrels per day.