* BG sees output won't grow in 2013; CEO says news ``disappointing''
* Analysts had expected BG to raise output
* BG blames Brazil tie-ins, Egypt, North Sea, U.S. for shortfall
* Agrees $1.93 deal with China's CNOOC
* Q3 earnings just beat forecast
* Shares down 17 pct to lowest level for a year
LONDON, Oct 31 (Reuters) - British oil and gas firm BG Group told investors to expect no output growth in 2013 due to project delays and other factors, prompting a dive in its highly rated share price that wiped out as much as a fifth of its value.
As BG sweats to bring huge new projects in Australia and Brazil onstream, analysts now question its ability to deliver on growth objectives beyond 2013, tarnishing the company's standing as a growth stock in an industry where such a profile is rare.
BG insisted its expectations for production beyond 2013 were unchanged.
``It is disappointing today but I do want to point out that our company has managed to add a huge amount of resources over the years, about a billion barrels of resource a year and that resource now resides inside the company,'' Chief Executive Frank Chapman told a conference call.
Chapman, one of the industry's longest serving CEOs who is due to retire next year, also pointed to a reserve replacement ratio of 200 percent over the period since 2008 in an industry where the average is below 100 percent.
But shares in BG, Europe's sixth-largest oil firm, fell almost 20 percent at one point to their lowest level for over a year. They were 17 percent lower in early afternoon at 1,100 pence, making them the biggest loser on Britain's blue-chip FTSE 100 index.
Surprising investors with quarterly results published a day earlier than scheduled, BG said output in 2013 would be unchanged from this year, versus analyst predictions of production growth of 10 percent and above.
The company said in February it planned to increase production to more than 1 million barrels of oil equivalent (boepd) per day by 2015 from a forecast for a 2012 year-end rate of 720,000 boepd.
Wednesday's announcement means 2013 output will be only about 660,000 barrels, but Chapman said production plans beyond 2013 were unchanged.
``As a long-term investment this remains a solid company with attractive assets,'' Bernstein analyst Oswald Clint said.
``People looking for production growth in 2013 are deeply disappointed, but it doesn't warrant a 15 percent drop in the share price.''
BG blamed the disappointing new production guidance on delays to projects in the North Sea and Brazil, a scaling back of activities in U.S. shale gas where prices have made activities uneconomic, and a project in Egypt where it was unable to slow reservoir decline.
Chapman said the North Sea's Jasmine and Total operated Elgin-Franklin field outages represented about 30,000 barrels a day of lost output.
In Brazil, operator and state oil company Petrobras , wants to perform engineering work that ties some of the fields BG is involved in to others. That will cost about 20,000 barrels a day, Chapman said.
The U.S. shut-ins account for another 15-20,000, while failure to revive Egyptian wells as effectively as hoped will cost 30,000 barrels a day, he said.
BG posted a 16 percent rise in third-quarter earnings to $1.189 billion on production that was 5 percent higher. Results were helped by a robust performance in its liquefied natural gas (LNG) business and topped an analysts' average forecast of $1.1 billion.
BG also said on Wednesday that it agreed to sell a 40 percent stake in part of its Queensland Curtis LNG (QCLNG) project to China's CNOOC.
Analysts have been flagging that BG could sell stakes in its big projects to help fund their development.
The $1.93 billion deal includes a 20-year supply contract which BG said will make it the largest supplier of LNG to China.
Santander analyst Jason Kenney said part of the drop in BG's share price was due to the fact that investors had been expecting BG to achieve a higher price for its QCLNG stake.
``There's a lot of value in the LNG supply contract in addition to the asset sale that maybe the market is just overlooking at the minute,'' he said.