* Joint venture includes Energean ( EERGF ), ExxonMobil ( XOM ), and

Helleniq Energy

* Venture notified Greece of intention to move to next

exploration phase

* U.S. looks to expand footprint in the Mediterranean

ATHENS, March 19 (Reuters) - A joint venture by

Energean ( EERGF ), ExxonMobil ( XOM ) and Helleniq Energy has notified Greece it

would look for gas in a western offshore bloc, the nation's

hydrocarbons management agency said on Thursday, a move that

would involve the first test drilling in the country for

decades.

In a deal announced last year, U.S. oil major ExxonMobil ( XOM )

joined Energean ( EERGF ) and Helleniq Energy, Greece's

biggest oil refiner, to explore for natural gas in Block 2 in

the Ionian Sea.

After assessing the area's potential, the joint venture

notified the agency of its plans to proceed to the second phase,

which also includes the first offshore exploration drilling in

40 years, the state-owned Hellenic Hydrocarbons and Energy

Resources Management Company said in a statement.

The United States, which holds vast reserves of natural gas,

seeks to increase its share in Europe's energy mix via liquefied

natural gas as the European Union seeks to replace Russian gas

in the coming years.

Greece, which produces small volumes of oil and relies on

gas imports for power generation and domestic consumption, has

been keen to explore for gas and bolster its role as a transit

route for Europe.