Alaska may have “huge” additional reserves of oil and natural gas, federal officials said Friday as the state approved a plan to expand the Point Thomson project, capping a week of advances for energy exploration on the Last Frontier.

The news came hours after President Trump signed into law a sweeping $1.5 billion tax bill, championed by the GOP and hailed by Alaska’s congressional delegation for its opening of drilling in part of the Arctic National Wildlife Refuge.

According to an Interior Department statement, its updated estimates – including 17.6 billion barrels of oil and 50 trillion cubic feet of gas – cover federal, state and Alaska Native lands including the National Petroleum Reserve in Alaska, state waters and the Western Beaufort Sea.

Onshore U.S. Geological Survey and Bureau of Land Management work indicates a mean Alaska estimate of 8.7 billion barrels of oil – a steep rise from a 2010 mean estimate of 1.5 billion barrels – and 25 trillion cubic feet of natural gas.

Offshore, the Bureau of Ocean Energy Management revised its mean estimate of undiscovered, technically recoverable resources in the Outer Continental Shelf Planning Area of the Beaufort Sea to 8.9 billion barrels of oil and 27.7 trillion feet of natural gas.

“BOEM’s updated assessment resulted in a net increase of nearly 700 million barrels of oil equivalent over BOEM’s 2016 Beaufort Sea Planning Area assessment,” Interior officials wrote.

Much of the increase was based on a six-fold increase in earlier USGS assessments for NPR-A and the central North Slope. Parts of the northeastern NPR-A were assessed using three-dimensional seismic reflection data from BOEM, forming the basis for an estimate of seismic amplitude anomalies which Interior said “are considered viable proxies for undrilled prospects.”

In Alaska, Gov. Bill Walker said the state Division of Oil and Gas had approved ExxonMobil’s plan to expand its Point Thomson development. The state had once sued ExxonMobil, accusing it of dragging its heels on developing the area, until Walker dropped the lawsuit in 2015.

Walker said the news was a boon to an agreement with Chinese officials he unveiled last month, in which several firms including Chinese oil company Sinopec will invest in state plans to bring North Slope liquefied natural gas to market.

“Our approval of the Point Thomson to Prudhoe Bay pipeline plan adds to the momentum of the Alaska LNG Project and demonstrates the commitment of the Point Thomson working interest owners to move gas from Point Thomson into Alaska Gasline Development Corp.’s 800-mile pipeline,” Walker said.

Alaska's Department of Natural Resources Commissioner, Andrew Mack, said the approval for ExxonMobil's expansion plans clears the way for the state to have straightforward conversations about gas sales. He also told KTVA 11 Friday, "This is a strong indicator that there's a lot of momentum and a lot of thinking and a lot of effort going on behind scenes to make the joint development agreement reality," referring to the U.S. agreement with China on natural gas.

The Division of Oil and Gas had withheld approval of ExxonMobil’s expansion plan, asking the company on Aug. 29 for more information which the state received in an Oct. 12 letter.

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