* Big deep water projects vulnerable to low price
* Shale oil adjusts swiftly to price volatility
* Saudi Arabia prepared for long haul on strategy
By Rania El Gamal
DUBAI, Sept 23 (Reuters) - After almost a year of painfully low oil prices, OPEC members are beginning to believe they are winning against upstart U.S. shale producers in a short-term market share contest.
Yet insiders and experts say OPEC is looking for a longer-lasting impact on other high-cost production oil field plans, many in deep oceans, with bigger time scales, even if that means a period of cheap oil prices lasting for years.
Privately, OPEC's core Gulf members say they have resigned themselves to the idea that the U.S. shale industry's high-tech flexibility means it will respond quickly when prices start rising again, making the United States the new swing producer in world oil, the role held for so long by Saudi Arabia.
"The oil surplus is slowly being drawn from the market. U.S. oil production is expected to fall to less than 9 million barrels per day by the end of this year or early next year," said an OPEC delegate from a Gulf oil producer.
"But there is one point that no one is looking at which is the delay in the longer-term oil projects, these are 4-5 year projects. The postponement of these projects will impact the overall supply in the market."
The short investment cycle of U.S. shale, where it takes about few months before returns are seen, make it the most sensitive to oil price fluctuation -- either way.
Thus the spike in oil prices in June where U.S. crude was trading above $60 a barrel drew out more shale output but the price drop in August will reverse that, OPEC sources say.
And even if rising prices pushed supplies up again, in the long run, higher production from shale is expected to be offset by lower production from conventional high-cost offshore projects from countries such as Brazil and Mexico, the sources say.
"Shale will be a new swing producer of sorts," said Yasser Elguindi of economic consultants Medley Global Advisors. "Because of its shorter investment cycle, when prices fall shale producers will be the ones to cut first, but likewise when prices go up, they will also be the first to bring up production.
"This complicates life for those who are looking at investments that have a 2-5 year investment horizon. But again, the idea is to find the price level that slows down the rate of growth considerably to something more sustainable -- and that takes more than 2 to 3 quarters of lower oil prices."
BIG PROJECTS IN DEEP WATER