Sept 15 (Reuters) - U.S energy firm Chord Energy ( CHRD )

said on Monday it would buy assets in the Williston

Basin from Exxon Mobil's ( XOM ) unit XTO Energy for $550

million.

The Williston Basin is located in parts of North Dakota,

Montana and Canada, and is a major U.S. shale oil and gas region

centered by the Bakken formation.

The company said it would acquire 48,000 net acres in the

Williston core and expects near-term production to be around 9

million barrels of oil equivalent per day, mostly oil, with a

low decline rate and strong potential to improve margins on

existing wells.

Chord Energy ( CHRD ) added that the deal is expected to be accretive

to cash flow, free cash flow and net asset value, and will be

funded through a combination of cash and borrowings.

The transaction is expected to close by year-end.