Ensco International Inc warned on Friday that its third-quarter profit would be as much as one-sixth lower than current expectations due to unexpected downtime and repairs for two of its deepwater rigs.

Ensco shares fell to $36.61 after-hours from a close of $37.29, giving up much of their 2.2 percent regular trade gain.

Ensco said its third-quarter profit would be 14 cents to 18 cents lower due to non-routine downtime for Ensco 7500, which is contracted to Chevron Corp in Australia, and Ensco 8500, which is on a four-year Gulf of Mexico contract with Anadarko Petroleum Corp and Eni SpA.

Analysts had been looking for a third-quarter profit, before exceptional items, of $1.14 per share, according to the average on Reuters Estimates.

The revenue and contract drilling expense outlook provided for third quarter and full year 2009 during the July 23, 2009 conference call should be disregarded, the Dallas-based company said in a statement.

But Ensco said its 2010 deepwater outlook was unchanged, with anticipated deepwater revenue of about $600 million.

(Reporting by Braden Reddall; editing by Andre Grenon)