Concho Resources Inc (CXO.N) said it would buy all of the oil and natural gas assets of Three Rivers Operating Company LLC, a portfolio company of private equity firm Riverstone Holdings LLC, for $1 billion in cash.

Three Rivers owns 200,000 net acres in the Permian Basin, an area spanning Texas and New Mexico that is undergoing an exploration boom fueled by crude over $90 a barrel and technology such as horizontal drilling to extract oil.

The company had only acquired its assets in the last two years and the sale to Concho in a relatively short time frame underscores the growth prospects of the U.S. energy sector.

Earlier this year, Riverstone participated in a consortium led by Apollo Global Management LLC (APO.N) that agreed to pay about $7.15 billion for El Paso Corp's (EP.N) oil and gas exploration and production business.

Concho would finance the deal with its $2 billion credit facility, which had about $1.8 billion available as of the end of March, and would sell $200 million to $400 million of non-core assets from the acquisition and its existing assets over the next nine months, the company said in a statement Sunday.

"This acquisition is expected to be immediately accretive to earnings, discretionary cash flow, production and reserves on a per share basis and provides an additional platform to significantly grow our production in the Permian Basin," Timothy Leach, Concho's CEO, said in the statement.

Three Rivers is mostly owned by Riverstone/Carlyle Global Energy and Power Fund IV, a private equity vehicle managed by Riverstone and launched together with Carlyle Group LP (CG.O) in 2007. The two private equity firms have since stopped working together on new funds.

The $1 billion deal is profitable for the buyout fund based on data provided in an IPO registration document filed last January, when Three Rivers said it would sell shares to repay debt under a revolving credit facility that had $286.5 million outstanding as of the end of September.

The parent company of Three Rivers, controlled by the joint venture private equity fund, had injected $270.7 million in capital into the company from inception to the end of September and had already received $60.1 million in distributions.

A Riverstone spokesman declined to comment, while Carlyle representatives were not immediately available for a request for comment.

Three Rivers obtained its assets through acquisitions. In April 2010, it purchased oil and natural gas properties from Chesapeake Energy Corporation (CHK.N) for $202.8 million, and in January 2011, it bought assets of Samson Resources Company for $343.5 million. Together, the two deals represented more than 700 operated and 800 non-operated wells in the Permian Basin.

Concho said the deal with Three Rivers would give it proved reserves of about 58 million barrels of oil equivalent, estimated as of April 1, 2012, and an estimated current net production of 7,000 barrels of oil equivalent per day.

The transaction is expected to close in July 2012, subject to regulatory approval and custom conditions, Concho said. JPMorgan Chase & Co (JPM.N), BMO Capital Markets and Vinson & Elkins LLP advised it on the deal.

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