* Supply rises by 810,000 bpd, led by Libya
* Saudi pumps more, other Gulf members keep supply flat
* OPEC output highest since November 2012 - Reuters
By Alex Lawler
LONDON, Sept 30 OPEC's oil supply jumped to its highest in almost two years in September, a Reuters survey found, due to further recovery in Libya and higher output from Saudi Arabia and other Gulf producers in the face of sub-$100 per barrel oil prices.
The lack of any cutbacks underlines the relaxed view of OPEC's core Gulf members to oil's slide from $115 in June to $97 on Tuesday - a level they can tolerate, but which puts budgets in producers such as Iran and non-member Russia under pressure.
Supply from the Organization of the Petroleum Exporting Countries averaged 30.96 million barrels per day (bpd) in September, up from 30.15 million bpd in August, according to the survey based on shipping data and information from sources at oil companies, OPEC and consultants.
"Libya has increased production massively and if you look forward, OPEC is producing more than the (forecast) demand for OPEC crude in 2015," said Carsten Fritsch, analyst at Commerzbank. "This puts pressure on OPEC ahead of their next meeting."
OPEC pumps a third of the world's oil and meets next in November. This month, the largest increase has come from Libya, where supply is up by 280,000 bpd despite conflict. Iraq, Nigeria, Angola and Saudi Arabia also boosted output.
This month's output is OPEC's highest since November 2012 when it pumped 31.06 million bpd, according to Reuters surveys. Involuntary outages, such as in Libya, kept output below OPEC's nominal 30 million bpd target in earlier months of the year.
Iraq, like Libya, has also managed to increase supplies despite fighting in the country. Oil output rebounded due to higher exports from Iraq's southern terminals and increased output from fields in Kurdistan.
An advance by Islamic State fighters into northern Iraq has not reduced southern exports, but violence has hit supply of Kirkuk crude from the north and shut down the Baiji refinery, keeping crude output below Iraq's potential.
Nigerian output, disrupted in earlier months of the year, has climbed in September, and another increase has come from Angola where CLOV, a new crude stream operated by Total , is ramping up exports.
Top exporter Saudi Arabia, supported by Kuwait and the United Arab Emirates, has boosted output informally to cover for outages elsewhere in the group. So far, there is no sign of any further trimming, according to the survey.
In fact, industry sources in Saudi Arabia have talked of higher demand with the approach of winter and return of refineries from maintenance - factors that would argue against cutting output. Sources in the survey said supply to market had increased this month.
Some OPEC members have voiced concern over the drop in prices and its meeting on Nov. 27 in Vienna is likely see a debate on whether output needs to be cut.
OPEC's own forecasts suggest demand for its crude will fall to 29.20 million bpd in 2015 due to rising supply of U.S. shale oil and supplies from other producers outside the group - almost 1.8 million bpd below current output according to this survey.
Iran on Friday urged OPEC members to make joint efforts to keep the market from falling further, but the Gulf Arab producers remain unruffled according to comments from oil ministers and delegates.
Iranian output was steady in September, the survey found. Western sanctions over Iran's nuclear work are restraining its output, although supply has risen since the start of the year following a softening of the measures.
Iran's budget needs oil prices well above $100, among the highest in OPEC, while the budget of non-member Russia assumes an average of $100. (Editing by Keiron Henderson and Veronica Brown)