Exxon Mobil has held talks with state energy company TPAO on exploring for shale gas in Turkey, the head of TPAO said on Monday.

According to analysis released by the U.S. government in early 2011, Turkey has 15 trillion cubic feet of technically recoverable shale gas, reserves that Exxon could help TPAO tap.

We have carried out our studies ... We have big shale gas potential ... This attracts a lot of foreign firms, Exxon Mobil in particular, TPAO Chief Executive Mehmet Uysal told Reuters.

They are currently considering the potential in Trakya (western Turkey) and they're going to make up their mind whether or not to become partners with us.

TPAO signed an accord in November for Europe's largest energy company Shell to look for oil and gas in the Mediterranean and southeastern Turkey and said other major international firms were interested in exploring nearby.

Shell hopes to develop shale gas deposits near the southeastern city of Diyarbakir.

Exxon, the largest oil company in the world by market capitalization, is one of the most active drillers for shale gas in Europe, and is already exploring in Poland and Germany.

A U.S. shale gas production boom over the last few years has turned the U.S. market from shortage to glut, driving down gas prices around the world.

But Exxon sought to cool predictions of a similar European shale gas revolution, saying commercial production was at least five years away.

An April 2011 study by Advanced Resources International (ARI) for the U.S. government of global shale gas prospects identified Turkey - along with France, Poland, Ukraine, South Africa, Morocco and Chile - as countries whose future supply could be significantly boosted by shale.

The ARI study identified the Anatolian Basin in the southeast and Thrace Basin to the west of Istanbul as the main areas of potential shale gas production in the country.

TPAO needs North American companies' expertise in horizontal drilling and fracturing equipment needed to extract gas trapped in Turkish soil and a number of them, including Canada's TransAtlantic Petroleum Ltd , are already looking.

Shale gas has a difficult production process, Uysal said. There aren't a lot of companies with enough infrastructure to drill that many wells at the same time.

(Writing by Daniel Fineren; Editing by William Hardy)