ANKARA (Reuters) - Iran's Ghadir Investment Holding has signed a $7 billion agreement with Turkey's Unit International and Russia's state-owned Zarubezhneft to drill for oil and natural gas in Iran, the Turkish company announced on Tuesday.

Unit said in a statement that the three companies had invested a total of $7 billion for the drilling, which would take place at three oil fields and one large natural gas field in Iran.

The total reserves at the three oil fields stand at 10 billion barrels, and the fields will produce 100,000 barrels per day, the Turkish company said. It said the natural gas field had a production capacity of 75 billion cubic meters per year.

The consortium will also be able to drill in other parts of Iran, the statement said.

The natural gas extracted from the drilling will be equal to 1.5 times the 50 billion cubic meters of gas Turkey imports annually, Unit said, adding that the reserves in this field would help meet Turkey's gas demands for the next 150 years.

Unit said all three companies had signed the agreement as equal partners, and added that this marked the first trilateral deal an Iranian company signed with foreign partners.