Alaska’s onshore and offshore collectively hold about 17.6 billion bbl of oil and more than 50 Tcf of natural gas, according to an updated assessment conducted by Department of Interior (DOI) agencies, which also reported a nearly six-fold increase in onshore oil resources.

The DOI last week said the U.S. Geological Survey (USGS) was the lead agency for the survey of onshore areas, while its Bureau of Ocean Energy Management (BOEM) led the offshore survey, with data contributed by its Bureau of Land Management (BLM).

The USGS estimated that the National Petroleum Reserve in Alaska (NPR-A), as well as adjacent state and native lands, hold an estimated mean of 8.7 billion bbl of oil and 25 Tcf of natural gas, resources which were classified as undiscovered, technically recoverable. The latest survey marked a near six-fold increase in oil from a previous assessment conducted in 2010, which found a mean of 1.5 billion bbl.

In the offshore, BOEM revised the estimated mean of undiscovered, technically recoverable resources in the Beaufort Sea Outer Continental Shelf Planning Area to 8.9 billion bbl of oil and 27.7 Tcf of natural gas. The updated assessment resulted in a net increase of nearly 700 million boe from BOEM’s last survey conducted in 2016. DOI said the offshore areas surveyed included the western Beaufort Sea and state waters.

Interior Secretary Ryan Zinke said the updated assessment was a “big step” toward the Trump administration’s goal of establishing American energy dominance. “Thanks to the incredible work of scientists at the USGS and BOEM, we know what’s available and what our potential is That’s important because with the scientific knowledge, industry partners are more willing to explore the area. New discoveries have changed our geologic knowledge of the area — and these assessments show that the North Slope will remain an important energy hub for decades to come in order to meet the energy needs of our nation.”

The updated assessments were conducted tocomply with a secretarial order (SO) Zinke signed in May. The SO included provisions to jump-start oil and gas production in the NPR-A. DOI said the USGS plans to conduct its next assessment on the area west of the NPR-A, as well as a portion of the coastal plain of the Arctic National Wildlife Refuge, aka the 1002 Area.

Although the 1002 Area has been opened to energy development through a controversial policy rider attached to a comprehensive tax reform bill signed into law last week, such development is still considered to be years away.