* Supply falls by 250,000 bpd on Iraq port work, Libya
* Saudi output remains above 10 million bpd
* OPEC pumps just 70,000 bpd above target
By Alex Lawler
LONDON, Sept 30 (Reuters) - OPEC oil output has fallen in September to the lowest in almost two years because of work at Iraq's main export outlet, a Reuters survey found on Monday, although record Saudi Arabian output prevented a larger decline.
Supply from the Organization of the Petroleum Exporting Countries has averaged 30.07 million barrels per day (bpd), down from 30.32 million bpd in August, the survey of shipping data and sources at oil companies, OPEC and consultants found.
Despite signs of recovery, Libyan output is less than half what it was in early 2013 and Nigerian production is far below its potential, underlining the drag that internal strife in OPEC's African members is having on supply.
"This is is a significant reduction and at the same time the Saudis are producing at extremely high levels," said a participant in the survey. "If it was not for U.S. shale oil, prices would be much higher."
Brent crude has fallen to $108 a barrel from a six-month high above $117 in August on signs of recovering supply and as the prospect of a military strike on Syria receded.
In September, work at Iraq's Basra Oil Terminal outweighed small increases in supply from Nigeria and Libya, and a second month of Saudi output at around 10 million bpd.
OPEC's September output is the lowest since October 2011, when the group pumped 29.81 million bpd, according to Reuters surveys, and leaves supply a mere 70,000 bpd above its output target of 30 million bpd.
The biggest fall in supply was in Iraq. Supply declined to 2.7 million bpd from 3.1 million bpd in August because of reduced export capacity due to construction work, as well as a pipeline leak that prompted a cut in output.
Two berths at the Basra Oil Terminal have been closed for part of September, reducing export capacity, Iraqi and industry sources say. Exports remain far below capacity in the north, where Sunni insurgents are targeting Iraq's pipeline to Turkey.
Supply rose in Libya due to a reduced impact of protests at oilfields and terminals. Output averaged 560,000 bpd and had reached 650,000 bpd by the end of September. Libya still has some way to go to bring output back to 1.4 million bpd, the production rate earlier this year.
In Nigeria, where output has been disrupted by spills and theft from pipelines, Eni lifted a force majeure on exports of Brass River crude. Royal Dutch Shell reopened a key oil route, the Trans Niger pipeline, but was forced to close it again.
Saudi Arabia, industry sources say, has kept output at or near August's rate of 10.05 million bpd - the highest since records began in 1980, according to figures from the U.S. Energy Information Administration. Saudi Oil Minister Ali al-Naimi said on Sept. 24 the market had enough oil.
"The market is in good shape, supplies are coming back," said an OPEC source. "Geopolitical fear is easing now, that is why the price is moderating."
Iranian supply to market was estimated at 2.7 million bpd, little changed from August. U.S. and European sanctions on Iran have more than halved its exports since early 2012. (Reporting by Alex Lawler; editing by Keiron Henderson)