ANALYSIS-Angola's excess oil implies OPEC to hold steady

* Angolan output to rise near to record high

* Most analysts see no change in OPEC output at Sept meeting

* Inventories have fallen more slowly than expected

LONDON, Aug 19 - Increased oil output to a year-high from OPEC's president Angola, flouting agreed limits, has helped stack the odds against any formal change when the producer group meets in September.

Without a sharp slide in crude prices the Organization of the Petroleum Exporting Countries is likely to leave its output targets unchanged when it meets on Sept. 9, most OPEC delegates and analysts said.

Within the group, supply has been rising. Angola has raised its exports schedule in October to the highest since December, trade sources said, adding to a breach of output limits by other members such as Iran.

"As long as it does not affect prices, people can still hug each other and smile and say everything is going well. But if it bites into revenues, then people would be making much louder noises," one OPEC delegate said.

OPEC's deal last year to cut output by 4.2 million barrels per day (bpd), or 5 percent of world demand, has helped prices rally, as has a rise in equities, driven by expectations of economic recovery.

Reports this month by three leading forecasters -- the International Energy Agency (IEA), the U.S. government's Energy Information Administration and OPEC -- all hinted at the need for more OPEC discipline.

"We believe that the supply and demand fundamentals suggest that they must get a bit more crude off the market," said Adam Sieminski of Deutsche Bank.

"In the past, it has been easier for the ministers to agree to change the official targets than to improve compliance on existing quotas. So, we may see a modest cut in the OPEC ceilings."

While Sieminski saw a cut in September as possible, other analysts said that would lack credibility as long as Angola and others produced above target. Even a call for more respect of targets could leave the market sceptical.

"Why cut further if the cuts are not implemented in full?" asked Eugen Weinberg of Commerzbank.

"Who is going to implement it, the Saudis again? Well, I think they will not be too glad and the rest would rather like to increase production at the current price levels."

OPEC's adherence to its output curbs reached around 80 percent in March, viewed as an all-time high. But as oil rallied further, compliance has slipped to around 70 percent.

Oil has risen from $32.40 a barrel in December, the weakest in nearly five years, to a high for this year of $73.38 at the end of June. It has since slipped back below $70.

"Sixty dollars a barrel or lower would make it a tougher job for OPEC," the OPEC delegate said. "I think OPEC is satisfied overall and that there will probably be no change. It would have to be a lower trend to worry OPEC."

Many analysts took a similar view.

"Only a dip in prices towards $50 will prompt mutterings about the need to cut output and it may take lower prices to shock the less disciplined members into action," said Lawrence Eagles of JP Morgan.

Among the 11 OPEC members subject to output agreements -- all except Iraq -- Venezuela, Iran and Angola have shown the least discipline, according to industry surveys.

Trade sources this week said Angola would ship 1.9 million bpd in October, near a record. That suggests it will be pumping nearly 400,000 bpd above the level OPEC delegates have said is its target -- a goal Angola has disputed.

NEW OPEC MEMBER

The West African nation only joined OPEC in 2007. Angola is distinct from exporters like Saudi Arabia, which plans to exploit its vast and relatively cheap-to-produce reserves gradually and without international help.

Angola's expensive offshore oil is tapped with foreign partners who want swift returns, and it needs to fund reconstruction after almost three decades of civil war. The result is pressure to pump as much as possible as quickly as possible.

If disciplined producers, such as Saudi Arabia, have allowed for that, they are also supporting the oil price on behalf of Iran and Venezuela, which have big social spending plans.

The gradual rise in OPEC supply means it will take longer for oil inventories to fall without a rebound in demand.

Even so, a firm oil price would probably tip the balance against a supply cut at September's meeting. The group meets to reassess policy again in December, in Angola.

"OPEC will do nothing," said JP Morgan's Eagles. "A cut is more likely in December if there is still no sign of a dent in global inventories by then."