* Q4 EBIT $51.8 mln versus forecast $57.3 mln
* Sees "robust" North Sea demand, stable Mexico
* Rigs off Mexico holding value better than expected (Adds details, background)
OSLO, March 1 (Reuters) - Offshore housing rig provider Prosafe sees strong future demand in the North Sea as oil firms reinvest in mature fields and prepare to develop new ones, it said on Thursday as it posted below-forecast fourth-quarter operating results.
The Oslo-listed company said earnings before interest and taxes (EBIT) rose sharply to $51.8 million in the quarter from $18.4 million a year earlier, missing an average forecast in a Reuters poll of analysts for $57.3 million.
Prosafe said it saw "robust North Sea demand" for three years to come along with stable demand off Mexico, where half of its 12 accommodation rigs are now stationed. It saw rising opportunities elsewhere, including Brazil, Australia and Asia.
"The number of concrete prospects is on a high level and no new supply is scheduled to arrive until 2014," it said of the North Sea, where three of its rigs house workers for the Norwegian and British oil and gas industry.
Prosafe said it would pay a dividend for the fourth quarter of $0.13 per share, and said its policy of paying out up to 75 percent of the previous year's net profit implied dividend growth in 2012.
It also said five of its rigs off Mexico would last longer than originally expected, allowing it to extend the depreciation period to 10 years from an average of four.
"The impact of this change is an estimated annual reduction in depreciation of $5 million," the company said, adding that it has three accommodation rigs under construction. (Reporting by Walter Gibbs; Editing by Mike Nesbit)