The United States is set to be crowned the world’s largest producer of liquid petroleum this week, knocking Saudi Arabia off the top spot for the first time in two decades.

The shale oil and gas boom in America has led to output increasing from about 8 million barrels a day in 2011 to approaching 12 million barrels.

The figures include production of natural gas liquids, such as ethane, that are often used in the chemical industry. As well as redrawing the global energy map, the jump in American production has prevented oil prices soaring over the past few years by replacing lost output from other countries, for example Libya during the Arab Spring.

The surging performance is a big factor behind the slump in