ANALYSIS-Kashagan row to keep Eni outside oil's top league

By Ian Simpson and Tom Bergin

MILAN/LONDON, Jan 23 (Reuters) - Italian oil company Eni's (ENI.MI) loss of its leadership role in the Kashagan oil field may cost it a long-held ambition to join the top tier of the oil industry and leave it reliant on Russia to avoid becoming Big Oil's also-ran.

Eni's founder Enrico Mattei coined the phrase "the seven sisters" to describe the biggest oil companies in the world after World War Two as he sought to snatch production deals from under their noses.

Through mergers, the seven sisters have become five -- Exxon Mobil (XOM.N), Royal Dutch Shell (RDSa.L), BP Plc (BP.L), Chevron (CVX.N) and Total (TOTF.PA), known as the "Supermajors" -- and despite some clever deal-making Eni remains outside their number.

Eni set Kazakhstan's Kashagan field, the largest oil find in 30 years when it was discovered, as a test of its ability to develop the kind of projects which were seen as the preserve of the Supermajors.

However, after months of disputes with the government over cost overruns, delays and environmental concerns, the Eni-led consortium last week agreed to pay the state more money. Eni also was forced to share operating responsibility with Supermajor partners Exxon, Shell and Total.

"The Kashagan story has shown that Eni does not belong to the league of companies that can handle a super task," said Valery Nesterov, an analyst with Troika Dialog brokerage in Moscow.

In the near term, the financial impact on the state-controlled company is seen as limited.

But some analysts questioned whether Italy's largest company would now be able to convince other countries to let it develop big, complex fields, threatening its ability to grow.