Huge deposit of untapped oil could be largest ever discovered in US

Estimated 20bn barrels of oil found in Texas's Permian Basin, three times larger than the Bakken oilfields of North Dakota, could be worth as much as $900bn

A huge deposit of untapped oil, possibly the largest ever discovered in the US, has been identified by the US Geological Survey (USGS) in west Texas.

The USGS estimated that 20bn barrels of oil was contained within layers of shale in the Permian Basin, a vast geological formation that stretches across western Texas and an area of New Mexico. The discovery is three times larger than the Bakken oilfields of North Dakota and is worth around $900bn.