(Adds comments by CERA analyst, other details, changes dateline from NEW YORK) HOUSTON, Jan 17 (Reuters) - Output from the world's oil fields is declining at 4.5 percent per year -- significantly slower than the 8 percent rate many analysts have assumed, according to a study by Cambridge Energy Research Associates released Thursday. The study of more than 800 oil fields suggests that theories that global oil production may soon hit a peak due to steep declines at maturing fields may not hold water. "Some of the more gloomy, pessimistic 'peak oil' views about the future of oil supplies that are current today result from an assumption of high decline rates," said CERA analyst Peter Jackson. "This new analysis provides the basis for more confidence about the future availability of oil." The 811 fields included in the study account for two-thirds of current global oil production and half the proved and probable conventional oil reserves. Jackson said world production capacity should reach 112 million barrels per day (bpd) by 2017, while demand will be about 100 million bpd. The curve of world production capacity should be like an "undulating plateau" for some time to come, he said. "We don't see any reason for that to change before 2030," Jackson said. CERA Chairman Daniel Yergin said above-ground factors like geopolitical issues or efforts to control prices would more likely limit how much of capacity is actually produced. Current production capacity is about 91 million barrels, according to CERA, while the International Energy Agency sees world production at 85 million barrels. Contributing to the difference are problems like the continuing strife in the Nigeria's oil-rich delta region and the lagging recovery of Iraq's production following the U.S.-led invasion, Yergin said. U.S. oil prices <CLc1> hit a record above $100 a barrel earlier this month on concerns about tight inventories in the world's major consumer nations. Matt Simmons, founder of Houston-based Simmons and Co International and one of the most outspoken proponents of the "peak oil" theory that world oil production is declining irreversibly, said earlier this month that oil at $100 was cheap. Peak oil proponents argue its difficult to decipher whether Saudi Arabian oil production might be declining. Jackson said some Saudi fields were included in the study including the giant Gowar field. "Gowar does not contribute to the decline stats because it's not declining," he said. CERA said peak oil theory overestimates decline rates but also underestimates advances in technology. "The analysis also concludes that decline rates are a function of reservoir physics and investment strategies, and that there is a general historical trend toward lower decline rates in recent years which may be due to better reservoir management practices and the impact of new technology," Jackson said. (Additional reporting by Houston bureau, +1 713 210 8508, editing by Matthew Lewis)
