May 28 (Bloomberg) -- XTO Energy Inc., the oil and natural- gas producer that has spent more than $2 billion on acquisitions this year, agreed to buy properties in the Bakken Shale in Montana and North Dakota from closely held Headington Oil Co. for $1.85 billion.

The deal includes $1.06 billion in cash and XTO stock worth about $790 million, Fort Worth-based XTO said today in a statement. XTO is acquiring 352,000 net acres with estimated proved reserves of 68 million barrels of oil equivalent, of which 60 million are developed. XTO expects the purchase to add about 10,000 barrels per day to its output.

Chief Executive Officer Bob Simpson is seeking to gain a foothold in the Bakken Shale, an area that may contain as much as 4.3 billion barrels of recoverable oil, according to a survey by the U.S. Geological Survey.

``They come into a basin and they're very aggressive,'' Brian Corales, an analyst at Coker & Palmer in Metairie, Louisiana, who rates XTO shares a buy and doesn't own any, said in a telephone interview. The Bakken Shale ``is a very hot play.''

XTO said drilling and operational activities should increase production in the region by 12 percent to 15 percent annually. The acquisition brings the total of XTO's purchases this year to more than $4 billion.

``With over 3 billion barrels of oil held in place within our acreage position, our team expects to more than double the acquired reserve volumes over time,'' Keith Hutton, XTO's president, said in the statement.

XTO rose 98 cents, or 1.6 percent, to $63.73 in composite trading on the New York Stock Exchange. The stock has gained 19 percent this year.

To contact the reporter on this story: Dan Lonkevich in New York at dlonkevich@bloomberg.net.

Last Updated: May 28, 2008 17:23 EDT