Hilcorp Alaska LLC’s relentless march in Alaska carries on as it executed an agreement to purchase XTO Energy Inc.'s Middle Ground Shoal assets in Alaska's Cook Inlet.

If the deal meets regulatory approval, it will represent XTO’s swan song in Alaska, ending a 17-year run in the Inlet and the state, XTO said July 8.

XTO, a subsidiary of ExxonMobil Corp. (XOM), agreed to sell two offshore platforms, a tank facility and offices in Nikiski, Alaska, to Hilcorp, one of the largest private, independent E&Ps in the U.S. Terms of the deal were not disclosed.

“This agreement would sell our interest in Alaska, but we’re still a part of ExxonMobil,” said Suann Guthrie, XTO spokesperson. “It does not impact ExxonMobil’s presence in Alaska” or the supermajor’s Alaskan LNG efforts.

XTO operates platforms A and C in the Middle Ground Shoal with production of about 1,750 barrels of oil per day (bbl/d), said Lori Nelson, spokeswoman, Hilcorp. Nelson said the company anticipates making employment offers to all 31 XTO employees that currently operate the Middle Ground Shoal assets.

“Pending all state and regulatory approval we hope to close the transaction sometime this fall,” she said.

XTO acquired the storied, offshore Middle Ground Shoal field from Royal Dutch Shell Plc (RDS.A) in 1998 and owns 29 wells.

The Middle Ground Shoal field was discovered by Amoco Production Co., which spudded a well there in 1962. Amoco and Shell Oil Co. constructed the first permanent drilling and development platforms in offshore Cook Inlet in 1965.

XTO’s Alaska operations include 1,303 acres and gross production of 2,000 gross bbl/d, Guthrie said. The company does not own any other assets in Alaska, according to the state’s Division of Oil & Gas.

The company has about 1,350 employees, according to its website and operational areas include the Texas and Louisiana Gulf Coast, the northeast U.S. and its Alaska holdings.

XTO remains a huge part of ExxonMobil since it became a part of the company in 2010 in a $41 billion merger. XTO owns interests in about 40,000 oil and gas wells across the U.S.

Exxon has a far larger profile in Alaska. In 2014, it and XTO combined to pay more than $482.9 million in taxes to the state. The companies also contributed more than $800,000 to higher education, medical care, environmental research and other philanthropic causes in Alaska.

Hilcorp, founded by billionaire Jeffery D. Hildebrand, the company’s chairman and CEO, is an independent oil and gas company headquartered in Houston. In recent years, it captured piece after piece from the board in Alaska.

In 2014, Hilcorp bought four of BP Plc’s (BP) operated oilfields on Alaska’s North Slope with production of about 19,700 net barrels of oil equivalent per day. Hilcorp paid roughly $1.5 billion for interests that then had a net asset value estimated at $2.6 billion. The sale was part of BP’s plans to sell about $10 billion in assets by the end of 2015.

As with the XTO deal, Hilcorp reached out to retain field personnel on the North Slope.

“The folks who know the assets best are in the field and are often the driver behind our success,” Nelson said in an October 2014 interview with Hart Energy.

In 2012, Hilcorp Alaska, Anchorage, won control of most of the Cook Inlet’s gas production in a $375 million deal. With waning natural gas production and worries of brownouts in the community, Hilcorp secured regulatory approval of a deal with Marathon Oil Corp. (MRO) to take control of nearly 70% of the natural gas produced in Cook Inlet, according to the Alaska Attorney General’s office. Hilcorp agreed to caps on natural prices for local utilities and industry.

Within two years, production skyrocketed in 2013-14.

“Hilcorp plans to make continued significant investments both in Cook Inlet and on the North Slope. Capital projects, drilling, facility and maintenance projects will all play a role,” Nelson said at the time.

Contact the author, Darren Barbee, at dbarbee@hartenergy.com.