An assessment by the United States Geological Survey has found that Texas could be sitting atop 20 billion barrels of oil, 1.6 billion barrels of natural gas liquids, and 16 trillion cubic feet of associated natural gas.

If USGS estimates are correct, Texas' continuous oil reserves could be three times larger than those discovered in North Dakota's Bakken Formation, which led to a job boom that peaked in 2012. That means $900 billion worth of recoverable resources are waiting to be tapped in Texas’ Permian Basin province. Bloomberg reports that Pioneer Natural Resources Co. CEO Scott Sheffield believes the Permian Basin's shale endowment could be second only to Saudi Arabia's Ghawar Field.

“The fact that this is the largest assessment of continuous oil we have ever done just goes to show that, even in areas that have produced billions of barrels of oil, there is still the potential to find billions more,” USGS Energy Resources Program coordinator Walter Guidroz said Tuesday. “Changes in technology and industry practices can have significant effects on what resources are technically recoverable, and that’s why we continue to perform resource assessments throughout the United States and the world.”

The USGS' report suggests that the unconventional resources would need to be extracted using horizontal wells that are hydraulically fractured. According to the report, over 3,000 horizontal wells have been drilled and completed in West Texas' Permian Basin.

Click here to read the full USGS report.