The Organization of Petroleum Exporting Countries Thursday said it expects moderate global oil demand growth next year, in an indication the oil cartel will probably have to keep its big existing supply cuts in place well into a third straight year.

The group, in its monthly oil market report, forecast 2011 world oil demand to grow by 1 million barrels a day, up just 100,000 barrels a day from 2010. The group's 12 members accounts for about 40% of the 86 million barrels consumed globally daily.

The International Energy Agency earlier this week projected world oil consumption to rise by 1.3 million barrels a day next year.

On paper, OPEC announced supply reductions totaling 4.2 million barrels a day in late 2008 during the height of the economic recession, aimed at keeping crude prices supported.

Yet, the group's quota-bound members, which excludes
Iraq , have usually pumped well above their output-quota targets for over the past year. Highlighting that, OPEC said those members pumped on average 26.85 million barrels a day in June--about two million barrels a day above the production target of OPEC's 11 quota-bound members.

However, with oil pumping capacity shut-in due to self-imposed cuts, OPEC's spare output capacity stands at around 5.5 million barrels a day, ample cushion to plug any unexpected supply disruptions and to keep a brake on oil prices.

Most of that capacity is held by
Saudi Arabia , which typically accounts for roughly one-third of OPEC's oil production.

OPEC kept its forecast for global oil demand growth this year unchanged at 900,000 barrels a day.