Oil and gas producer Apache Corp will buy privately held Cordillera Energy Partners III for $2.85 billion in cash and stock, expanding its holdings in one of the most lucrative emerging oil and gas fields in the United States.

It is the largest U.S. deal so far in 2012, according to Thomson Reuters data, and the second-largest deal worldwide.

Cordillera is owned by private equity firm EnCap Investments L.P. and other investors who will receive about $2.25 billion in cash and $600 million of Apache common stock for the assets.

The deal will double Apache's acreage in the energy-rich Anadarko basin, a shale formation in western Oklahoma and the Texas panhandle in which the company has been drilling for more than 50 years.

Apache is particularly interested in Cordillera's acreage in the Granite Wash geological formation within the Anadarko basin, which holds tight gas and natural gas liquids trapped in its sandstone.

Because 80 percent of (Cordillera's) revenue comes from liquid hydrocarbons production, this transaction provides compelling economics at current commodity prices, Apache CEO Steven Farris said in a statement.

As technological advances have made drilling for gas and oil possible in the Granite Wash and other unconventional opportunities like shale formations, energy companies have poured billions of dollars to buy North American acreage with access to those resources.

But with natural gas prices plunging, they have focused on assets that produce more oil and natural gas liquids, which trade at higher prices than so-called dry natural gas.

About 53 percent of Cordillera's current production is liquids, Apache said.


Bernstein analyst Bob Brackett said that the acquired acreage could provide Apache with drilling opportunities for years, if not decades.

He estimated in a research note that Apache was paying around $11,200 an acre for the deal, which he said was reasonable given the number of potential drilling targets.

Apache said there are about 14,000 potential drilling locations in the acreage.

The acquisition, which Apache expects to boost earnings starting this year, will give the company access to proven reserves of 71.5 million barrels of oil equivalent (boe) and current net production of 18,000 boe per day.

Oil and liquids contributed to about 80 percent of Apache's total production in the third quarter of 2011.

Reuters reported last October that Cordillera was exploring a sale and was hoping to bring in more than $3 billion.

But natural gas prices have fallen sharply since then, hitting a 10-year low on Friday.

While unconventional assets like shale gas have attracted firms looking to tap into rich resources, the process used to release the gas -- known as fracking -- has led to a backlash from some local residents and environmentalists who say it contaminates drinking water supplies and fouls streams and rivers.

Apache's advisers on the deal, expected to close in the second quarter, were Goldman Sachs & Co and Tudor, Pickering, Holt & Co. Jefferies & Co and J.P. Morgan advised Cordillera.

Shares of Apache were up 0.3 percent at $97.06 on Monday afternoon on the New York Stock Exchange.

(Reporting by Michael Erman in New York; Additional reporting by Ernest Scheyder in New York, and Kavyanjali Kaushik and Vaishnavi Bala in Bangalore; Editing by Miral Fahmy, Dan Lalor and Matthew Lewis)