* EBIT up 9.4 pct to $431 mln, misses $465 mln forecast
* Seadrill upbeat on demand, sees rig downtime in Q4
* Quarterly dividend raised to $0.65/shr from $0.61 in Q2
* Shares close down 1.4 pct
(Adds more analysts, details, updates share price)
By Wojciech Moskwa and Gwladys Fouche
OSLO, Nov 30 (Reuters) - Seadrill Ltd (SDRL.OL), one of the world's largest deep-water drillers, struck an upbeat tone on rig demand on Tuesday, highlighting its growth prospects after third-quarter earnings missed expectations.
Chief Executive Alf Thorkildsen said he was less concerned about day rates for rigs now than he was a few months ago because demand had kept up with the supply of new vessels coming onto the market.
He said demand for newly built rigs and drillships had surged in expectation of tougher safety regulations following the Macondo blow-out in the Gulf of Mexico, playing to Seadrill's strength in terms of its new fleet of specialised rigs, many made for drilling in deep water.
"The future for us is focused around a very, very modern fleet," Thorkildsen said, adding the company saw more value in building new rigs than buying a rival with an existing fleet.
Operating profit rose 9.4 percent to $431 million in the three months through September, below an average forecast of $465 million given in a Reuters poll of 15 analysts. Revenue rose 25 percent to $10 billion, just missing forecasts.
Seadrill said the weaker margins that surprised investors were caused by higher costs in the quarter compared with the second quarter, due to repairs and other operational issues.
"The margins were somewhat softer than expected," said Janne Kverneland, an analyst at Argo Securities.
Shares in Seadrill, which had risen to a record peak of 196.20 crowns earlier this month, closed down 1.4 percent at 190.5 crowns. A downgrade to "neutral" from "overweight" by brokerage Simmons & Co helped weaken the stock in late trade.
Seadrill said it remained upbeat on demand for its oilfield services amid strong oil prices and raised its quarterly dividend payout to $0.65 from $0.61 the previous quarter.
Oilfield services providers such as Seadrill have seen a surge in demand in recent months, as energy prices rose and the United States lifted a moratorium on deep-water drilling following the plugging of BP's (BP.L) well in the Mexico Gulf.
Seadrill, which this month announced plans to build new drillships in response to fast-growing demand, said its fourth quarter would however be hit by downtime and repairs to some rigs.
"Negative effects will come from the semi-submersible rig West Eminence and the drillship West Navigator that experience two and tree weeks of downtime ... respectively," it said. (Editing by Jon Loades-Carter and David Holmes)