Oct 1 (Reuters) -

U.S. shale producer Diamondback Energy ( FANG ) raised its

third-quarter production forecast on Tuesday to be in the range

of 319,000 to 321,000 barrels of oil per day.

This compares with its previous forecast of 271,000 to

275,000 barrels of oil per day.

Diamondback said it has updated its forecast to reflect its

$26 billion acquisition of Endeavor Energy, which was completed

in September.

The deal, announced earlier this year, makes Diamondback

the third-largest oil and gas producer in the top U.S. shale

patch, the Permian Basin of West Texas and New Mexico, putting

it just behind majors Exxon Mobil ( XOM ) and Chevron ( CVX ).

Diamondback also raised its third-quarter capital

expenditure outlook to $675 million to $700 million, from a

previous forecast of $570 million to $610 million.