Oil down 3 pct; tumbling gasoline adds to China, Iran worries

By Barani Krishnan

NEW YORK (Reuters) - Crude oil fell about 3 percent on Monday after a tumble in gasoline futures added pressure to a market already slumping on slower growth in China and signs that Iranian oil will return to market soon because of a nuclear deal likely to be implemented this year.

A stronger dollar and softer equity markets on Wall Street added weight to the petroleum complex, traders said.

"The products markets seem to be taking a hit over concerns the refinery maintenance season has peaked, and there could only be inventory builds from here," said Pete Donovan, broker at New York's Liquidity Energy.

The front-month in Brent, the global crude benchmark, was down $1.44, or 2.9 percent, at $49.02 a barrel by 1:35 p.m. EDT (1735 GMT).

U.S. crude was down $1.15, or 2.4 percent, at $46.11, in lighter volume trades ahead of Tuesday's expiry for the November contract as front-month.

Gasoline tumbled early Monday, falling as much as 5 percent, on worries U.S. refinery utilization could pick up with declining maintenance work. Ultralow sulphur diesel was down nearly 2 percent.

Both gasoline and diesel prices came off their lows on news that Phillips 66's 275,000-barrel-per-day Bayway refinery in Linden, New Jersey -- one of the largest on the U.S. East Coast -- was shut after a transformer malfunction.

The refining profit for gasoline, known as the gasoline crack, was at its lowest since January. The diesel crack traded near a one-week low.

China's economy grew at the slowest pace in six years in the third quarter, according to official data released on Monday.

Data also showed that Chinese oil demand fell slightly in September.

Iran's nuclear negotiator said on Monday he was hopeful for an implementation before year-end of the nuclear deal between Tehran and Western powers. A senior Iranian oil official also said the OPEC member will boost production by 500,000 barrels a day within one week of the sanctions being lifted.

The Buzzard oilfield in the North Sea, the largest contributor to the Forties crude stream that helps to set the global oil price, was, meanwhile, gradually ramping up production after a four-day outage.

Austrian oil producer OMV lowered its forecasts for crude prices, envisioning $55 a barrel for 2016; $70 in 2017; $80 in 2018 and $85 a barrel from 2019 onwards.

(Additional reporting by Karolin Schaps in London and Keith Wallis in Singapore; Editing by W Simon and David Gregorio)