Hong Kong-listed Brightoil Petroleum Holdings Ltd. has agreed to buy Anadarko Petroleum Corp.'s subsidiary in China for $1.075 billion, reflecting efforts by the Chinese company to grow its upstream portfolio, and by the U.S. one to reorganize its foreign holdings and concentrate on domestic oil and gas output.

The Anadarko unit owns minority stakes in two offshore oil fields in northeastern China'sBohai Bay, from which its share of output in 2013 averaged 11,000 barrels a day of crude oil. The fields' operator and majority owner in China's leading offshore producer, Cnooc Ltd.

Under the agreement, Chinese-owned Brightoil, which has oil storage, marine bunker fuel trading and some upstream energy operations, will acquire the entire Anadarko stake, the companies said Tuesday. The deal is still subject to regulatory approvals and is expected to be completed later this year, Brightoil said.

The deal comes as Anadarko continues to divest its overseas projects. It has been raising cash to focus on extracting oil from unconventional formations in the U.S. in states such as Colorado and Texas, as well as the U.S. Gulf of Mexico, where the company has had a string of large oil finds. Other U.S. companies, including Apache Corp. and Devon Energy have also been shedding foreign assets to focus on domestic oil and gas.

Last year, Anadarko sold a stake in a natural gas field off the coast of Mozambique to India's Oil & Natural Gas Corp. for $2.64 billion. Anadarko has also been seeking buyers for some of its Brazil assets.

"This transaction accelerates the recognition of value from a non-operated legacy asset and continues to demonstrate our commitment to active portfolio management," said Anadarko Chairman Al Walker.

As of year-end 2013, Anadarko had approximately 2.79 billion barrels-equivalent of proven reserves, making it one of the world's top independent exploration and production companies, the company said. It reported a fourth quarter loss of $770 million on Feb. 3, compared with year-earlier earnings of $203 million.

"Building on a strong foundation in oil and gas exploration and production, the acquisition will help reinforce the group's overall strategy and facilitate its development as an integrated oil and gas company with sustainable revenue streams," Chairman Sit Kwong Lam said.

Brightoil, which is based in the southern city of Shenzhen, first entered the upstream gas business in 2009 and now has two natural gas field projects in the Xinjiang Tarim Basin in northwestern China. The Hong Kong-listed company has a market value of $2.8 billion.

It made a first-half 2013 loss of $716 millionHong Kong dollars, but said in January it would book a profit in the second half of the year when compared with the same period in 2012--its results are due Feb. 20.

Its share price share soared more than 22% shortly after it restarted trading on Tuesday afternoon, before giving up some of those gains. Trading had been suspended on Feb. 11 pending what it said was a major acquisition.