UPDATE 1-National Oilwell 4th-qtr profit up 57 pct

(Recasts first paragraph, adds details from results, estimate)

HOUSTON, Feb 6 (Reuters) - National Oilwell Varco Inc (NOV.N) said on Wednesday fourth-quarter profit rose 57 percent as high energy prices lifted demand for its drilling equipment and services.

Net income increased to $376.7 million, or $1.05 per diluted share, from $239.2 million, or 68 cents per diluted share in the same period a year earlier.

Analysts on average had expected a profit of $1.04 a share, according to Reuters Estimates.

Revenue rose to $2.66 billion from $2.08 billion a year earlier.

Fourth-quarter revenue for the Houston company's rig technology unit rose 40 percent from a year ago to $1.59 billion, while operating profit was $410.5 million, up sharply from $225.5 million a year ago.

Backlog for capital equipment orders for the company's rig technology segment at the end of 2007 increased to a $9 billion, compared to $8 billion at the end of the third quarter.

New orders during the fourth- quarter were a record $2.2 billion. (Reporting by Anna Driver in Houston, editing by Dave Zimmerman)