* Wall St. volatile, after global stock gains aided oil
* China CenBank advisor sees slower growth, weighs on oil
* Coming up: CFTC trader positions on Friday
(Recasts, updates prices, market activity, moves dateline from previous LONDON)
By Robert Gibbons
NEW YORK, June 18 (Reuters) - U.S. crude oil prices edged up in choppy trading on Friday, wavering along with U.S. equity markets while traders considered the danger of slowing Chinese demand versus longer-term deepwater supply risks.
"The 200-day moving average, $76.83 is still acting as a magnet. The market has had nice ride and we're consolidating now before the next big move," said Stephen Schork, president at the Schork Group in Villanova, Pennsylvania.
At 12:37 p.m. EDT (1637 GMT), U.S. crude futures for July <CLc1> rose 8 cents per barrel at $76.87 a barrel, with prices still trading on either side of their 200-day moving average. (For a graphic see: http://link.reuters.com/puq72m)
The front-month North Sea Brent futures <LCOc1> contract, now August, was down 44 cents at $78.24 a barrel, having traded as low as $77.25 earlier.
Front-end U.S. prices held firmer relative to products and longer-dated futures reversing Thursday's trend. On Thursday products surged on refinery glitches and signs of improving demand .
U.S. stocks shed early gains but were still set for back-to-back weekly gains as investors braced for volatility ahead of the expiration of stock options. [
] World stocks rose a ninth straight session. [ ]Oil prices earlier fell as low as $75.56 a barrel after a central bank adviser in China said growth is expected to slow in the second half of 2010 and double-digit growth for the full year is unlikely. [
]That news knocked Shanghai stock markets -- which have often influenced sentiment in China-dependant commodities like oil and metals, although Hong Kong shares ended higher and posted their best week since April. [
]The concerns about China came after U.S. data showing weekly jobless claims increased and factory activity growth in the Mid-Atlantic braked to its slowest pace in 10 months, raising concerns that an anemic economic recovery was faltering. [
]For a graphic see;http://link.reuters.com/fyf82m
LONGER-TERM RISKS
Oil markets remain transfixed on the oil spill in the Gulf of Mexico, which could limit growth in deepwater oil supplies if tougher new regulations that increase costs are imposed.
Other major producers have not shown any inclination to follow the U.S. six-month ban on further drilling in the deep Gulf seas, but analysts still expect some toll on supply, a factor that has helped support far-forward oil prices.
Deutsche Bank analyst Adam Sieminski said the combination of the moratorium, tightened drilling regulations and longer permitting time-frames could defer deepwater Gulf of Mexico oil production by nearly 50,000 bpd in 2010 and 200,000 bpd in 2011.
"In addition we believe it also raises the long-run equilibrium price of oil by as much as $5 per barrel," Sieminski wrote in a note to commodity clients on Friday.
The International Energy Agency's Executive Director, Nobuo Tanaka on Friday said the IEA estimates global offshore oil output could be reduced 800,000 to 900,000 barrels per day by 2015 if there is an extended global moratorium on new drilling similar to that in the U.S. Gulf of Mexico. [
]But Tanaka also cautioned the downside risk to the global economic recovery may prompt IEA to revise lower its demand growth forecast.
Prices of long-dated WTI, including contracts for delivery in December 2018, the farthest out, have remained fairly steady around $95 since BP's Deepwater Horizon explosion on April 20. (Reporting by Robert Gibbons; Editing by Sofina Mirza-Reid)