The gas field was found at Eni's Zohr Prospect site, at a depth of 1,450 metres. It covers an area of about 100 square kilometres and could hold a potential 30 trillion cubic feet of gas – the equivalent of 5.5 billion barrels of oil, Eni said.
The site will be able to meet Egypt's natural gas needs for decades, Eni said.
Eni chief executing Claudio Descalzi said: "It’s a very important day for Eni and its people. This outstanding result confirms our expertise and our technological innovation capacity with immediate operational application, and above all shows the strength of the cooperation spirit amongst all the company’s units which are at the foundation of our great successes. Our exploration strategy allows us to persist in the mature areas of countries which we have known for decades and has proved to be winning, reconfirming that Egypt has still great potential."
Eni is the operator of the concession in the Shorouk block, where the well is situated. Eni has been present in Egypt since 1954 through its subsidiary IEOC, it said.
Last week, Norway gave approval to Statoil for the first phase in the largest industrial project in the country, the Johan Sverdrup gas field in the North Sea.
In June Siemens signed a €8 billion deal to provide Egypt with natural-gas-fired power plants and wind power installations. The projects are designed to boost Egypt's power generation by more than 50% compared to the current installed base, adding 16.4GW to the country's national grid.