UPDATE 1-Nabucco gas scheme woos international energy firms

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LONDON, June 29 (Reuters) - The Nabucco gas pipeline consortium hopes to tap the financial firepower of BP, Statoil and Total to salvage the project, now mired in funding problems, and realise Europe's dream of breaking the stranglehold of Russian supplies.

The three companies lead the giant Shah Deniz II gas field development in Azerbaijan, seen by Europe as a non-Russian source of the fuel that would help diversify its supply and make it more secure.

Nabucco's managing director Reinhard Mitschek on Friday raised the possibility of bringing in new investors by summer or autumn of this year and said the three were candidates, along with German utility Bayerngas.

A scaled down version of the Nabucco pipeline project, Nabucco West, emerged as one of two final contenders to transport Caspian gas into Europe on Thursday, alongside a rival route across Greece and Italy called the Trans-Adriatic Pipeline (TAP). The Shah Deniz partners ruled out another option.

At the same time the developers of Shah Deniz II said they are aiming to pick a winning pipeline six months ahead of schedule at the end of 2012.

Nabucco's only rival TAP, whose partners are Statoil , Swiss EGL and Germany's E.ON Ruhrgas , says it is can meet the European Union's criteria of ensuring reliable supplies.

To boost its chances, Nabucco is looking to add new shareholders, including Shah Deniz II partners with deep pockets like BP and Statoil, Mitschek said on Friday in a conference call with reporters.

"At the moment we are negotiating with Bayerngas for participation in the project...but that does not mean we are excluding any of the Shah Deniz partners from Nabucco West," Mitschek said.

"We will have to see in the near future...until summer or autumn, on new partners in the project," he said.

Nabucco's existing shareholders have voiced doubts this year over the project's uncertain costs.

Hungarian oil and gas group MOL is ready to sell its stake in Nabucco if necessary, it said in April, while RWE is reviewing the strategic requirements of the project.

Azeri gas fields are the most developed new non-Russian sources of natural gas that can be pumped to the European Union through pipelines.

Shah Deniz II is set to add a further 16 billion cubic metres (bcm) a year to the 9 bcm/year from Shah Deniz I. (Reporting by Oleg Vukmanovic; Editing by Keiron Henderson and Anthony Barker)