UPDATE 1-OPEC Aug oil output falls on Libya, despite Saudi boost-survey
* Supply falls by 180,000 bpd led by Libyan plunge
* Saudi output rises above 10 million bpd, record high
* OPEC pumps just 320,000 bpd above target
(Adds details on Saudi output)
LONDON, Aug 30 (Reuters) - Saudi Arabia, the world's largest oil exporter, has boosted output in August to a record high, a Reuters survey found on Friday, partly offsetting a plunge in Libyan supply that has reduced OPEC output.
Supply from the Organization of the Petroleum Exporting Countries has averaged 30.32 million barrels per day (bpd), down from a revised 30.50 million bpd in July, the survey of shipping data and sources at oil companies, OPEC and consultants found.
The survey shows internal strife is undermining supply from African OPEC producers. The outages plus concern about a military strike against Syria pushed Brent crude to a six-month high above $117 a barrel this week.
"While Saudi Arabia may be stepping up production, the outage of Libyan crude oil alongside multiple declarations of force majeure on exports by fellow OPEC member Nigeria will remain supportive of Brent prices," said Harry Tchilinguirian, head of commodity market strategy at BNP Paribas in London.
"The reason is because the crudes are of very similar quality to Brent and priced off the North Sea benchmark."
In August, involuntary curbs in Libya and no significant recovery in Nigeria have outweighed the extra Saudi crude and a rebound in Iraq's exports. Saudi supply to market in July was revised up by 250,000 bpd.
Saudi Arabia, industry sources say, has produced 10.05 million bpd in August, adding to earlier increases due to higher use in refineries and domestic power plants to meet demand for air conditioning. A Saudi official did not respond to a Reuters request for comment.
"Output in July was up but this was not due to exports, but rather due to increased refinery runs and direct burn," said an industry source who tracks Saudi output. "The increase in August is mainly reflecting higher exports."
Saudi crude output of 10.05 million bpd would be the highest since records began in 1980, according to figures from the U.S. Energy Information Administration.
With the upward revision to July, OPEC's August output is the lowest since March 2013, when the group pumped 30.18 million bpd, according to Reuters surveys, and leaves supply a mere 320,000 bpd above its output target of 30 million bpd.
The most notable drop in OPEC output has come from Libya. Protests at oilfields and terminals have cut supply to a monthly average of 500,000 bpd, according to the survey.
Output, at 1.4 million bpd earlier this year, had slumped to 250,000 bpd or lower by late August.
Supply in Nigeria, increasingly disrupted by oil spills and theft from pipelines, remains far below its potential with exports of crudes including Bonny Light under force majeure, even after a small rise in August.
Output fell slightly in Angola due to reduced production and a force majeure on exports of Saturno crude.
Iraq's exports have rebounded due to increased shipments from southern ports. Iraq allocated extra oil to some customers, trade sources said, before an expected slowdown in September due to maintenance work. Exports remain under pressure in the north, where Sunni insurgents are targeting Iraq's pipeline to Turkey.
An oil revival in Iraq after decades of sanctions and wars has slowed this year due to infrastructure and security problems. Iraq is at risk of its first annual drop in output for three years unless momentum is regained in the autumn.
Iranian supply to market was estimated at 2.68 million bpd, up slightly from July, on indications more crude may be heading to China and India. U.S. and European sanctions on Iran have more than halved its exports since early 2012.
With Brent crude above the $100-mark favoured by Saudi Arabia and most other members, OPEC at its last meeting held in May agreed to keep the output target of 30 million bpd.
The group is not scheduled to meet again until December and has effectively delegated short-term market management to Saudi Arabia, which tweaks supply informally depending on demand.
(Reporting by Alex Lawler; editing by William Hardy and Jason Neely)