* Supply falls by 130,000 bpd led by Iraq, Iran
* Saudi output rises on higher crude burning
* OPEC pumps just 330,000 bpd above target
By Alex Lawler
VIENNA, May 30 (Reuters) - OPEC crude output has fallen in May due to lower exports from Iraq and disruptions in some African producers, a Reuters survey found, improving compliance with an OPEC output ceiling expected to be maintained at a meeting this week.
Supply from the Organization of the Petroleum Exporting Countries is set to average 30.33 million barrels per day (bpd), down from 30.46 million bpd in April, the survey of shipping data and sources at oil firms, OPEC and consultants found.
The survey also showed top OPEC exporter Saudi Arabia, which has been keeping a lid on output, is starting to ramp up supply in response to a seasonally higher requirement for crude in domestic power plants.
OPEC is meeting in Vienna on Friday to review its output ceiling of 30 million barrels per day, in place since January 2012. With oil above Saudi Arabia's preferred level of $100, OPEC is widely expected to make no changes to policy.
"This should be a smooth, quick meeting," said Jamie Webster of PFC Energy, in Vienna to observe the OPEC meeting. "Prices are still in decent shape."
OPEC's May output is the lowest since March 2013, when the group pumped 30.18 million bpd, according to Reuters surveys, and leaves supply a mere 330,000 bpd above the output target.
Iraq and Iran have been the biggest drivers of the fall in OPEC's output this month.
Iraq has shipped about 200,000 bpd less from its southern and northern ports, according to shipping data. Exports of Kirkuk crude remain restrained by a dispute between the central government and the Kurdistan region over payments.
Iran's crude exports fell back in May to around 1.00 million bpd from 1.1 million bpd in April, according to the survey, reflecting the impact of U.S. and European sanctions on sales.
Supply in Nigeria, disrupted lately by oil spills, flooding and theft, remains under downward pressure. A force majeure on exports of Bonny Light crude has delayed some May cargoes, say traders. Unrest is continuing to hold back Libyan output. (Editing by William Hardy)