* Raises 2012 capex by a $1 bln to $17 bln
* Maintains output targets, sees upside risk
* 2011 replacement ratio 117 pct vs 87 pct in 2010
* Shares up 1.7 pct, outperforming European oil index (Adds CFO comment on dividend policy in 16th paragraph)
By Gwladys Fouche and Walter Gibbs
OSLO, Feb 8 (Reuters) - Oil firm Statoil is lifting capital spending this year as it bets on the development of shale oil in the United States to help raise its output by a third over the next decade.
The Norwegian firm said it was targeting capex in 2012 at $17 billion, up from $16 billion, following its $4.4-billion acquisition of U.S. independent oil firm Brigham Exploration in October and its shale oil deposits in North Dakota and Montana.
Statoil is echoing a trend across the oil and gas sector, with BP and Shell announcing increased spending this year, prompting fears from investors that the ability to raise dividends will be eroded.
Trapped in deep rock formations, shale oil is extracted using new technologies like hydraulic fracturing - or "fracking" - and directional drilling. A U.S. shale-oil boom is lowering the country's dependency on energy imports.
Statoil is also betting big on unconventional gas resources in the United States, identified as one of its key growth areas.
It has a stake with Chesapeake in the Marcellus shale gas project in the northeastern United States and owns acreage in the Eagle Ford prospect in Texas, together with Canada's Talisman.
The hiked capex figure indicates Statoil may be looking to buy more shale oil acreage around its Brigham property, said Magnus Smistad, an analyst at Oslo-based firm Fondsfinans.
"It could mean they are looking at acquisitions, and if so I would expect it to be in the Williston basin in North Dakota and Montana," said the analyst, who regarded Statoil's move in shale oil as very positive.
Another analyst was more cautious.
"Most people have been quite ambivalent (to the Brigham deal)," said Kim Evjenth at ABG Sundal Collier, adding that shale oil was more expensive to produce.
"There could be some environmental concerns. But so far there doesn't seem to be any problem in North Dakota."
Underlining the potential risk of investing in unconventional resources, Statoil's chief executive told Reuters his company would reduce Marcellus Shale investments in 2012, when U.S. gas prices are expected to stay low amid the shale-gas production bonanza.
"We are taking down the investment level between 2011 and 2012. We live off money, not volumes," said Lund.
Unlike gas, which needs more infrastructure to transport to customers, shale oil is part of the global crude market. The infrastructure to drill for it, moreover, is more flexible than the North Sea platforms Statoil is accustomed to, and can be shut down more easily if prices fall.
Together with hiked output in the Gulf of Mexico, growing shale production will push U.S. oil output to 6.7 million barrels per day in 2020, 11 percent higher than the previous forecast and the highest level of U.S. oil output since 1994, the U.S. Energy Information Administration said in an analysis in January.
Statoil will continue to seek to grow its annual cash dividend after announcing its hike in 2012 capital spending, the firm's chief financial officer told Reuters.
For the first time in years Statoil found more oil and gas than it produced in 2011, with a replacement ratio of 117 percent compared with 87 percent in 2010 and 34 percent in 2008.
"This strengthens our 2020 goal," Statoil's Lund told a news conference. The firm wants to produce 2.5 million barrels of oil equivalent per day (boed) in 2020, compared with 1.89 million boed in 2010.
The firm kept its production targets for 2012, which imply an equity output of some 2 million boed, considered overly optimistic by several analysts ahead of the results. Lund also said he saw an upside risk to the targets.
Statoil has frequently set production targets that were revised downwards months later.
It gives its outlook in terms of equity production, a term used by the firm to reflect volume it would have received if its oil and gas contracts gave the rights to a share of production equivalent to its share of expenditure.
"The main takeaway was that a couple of concerns were addressed positively - reserve replacement, which they did quite nicely on and the other was the production outlook for 2012, which they reiterated," said Evjenth at ABG Sundal Collier.
"That's two factors driving the share up. The third is that they realised gas prices of 2.25 Norwegian crowns per cubic metre in the quarter. That's pretty good."
Shares in Statoil were up 1.7 percent at 1038 GMT, ahead of a European oil and gas index up 0.1 percent.
Fourth-quarter adjusted net income rose to 14.5 billion Norwegian crowns ($2.5 billion) compared with 10.8 billion crowns a year ago and a mean expectation of 13.2 billion crowns in a Reuters poll. The firm benefited from strong oil prices and higher year-on-year oil production.
Oil and gas net entitlement output in the fourth quarter rose year-on-year to 1.78 million barrels of oil equivalent per day (boed). Production was expected to fall to 1.75 million boed, compared with 1.768 million boed last year. (Additional reporting by Henrik Stolen; Editing by David Cowell)