The discovery, confirmed by Egypt’s oil ministry, could hold a potential 30 trillion cubic feet (850 billion cubic meters) of lean gas in an area of about 100 square kilometers (40 square miles), it said in a statement.

The so-called Zohr project is “the largest gas discovery ever made in Egypt and in the Mediterranean Sea,” it said, adding the find would meet Egypt’s own natural gas demands for decades.

The “supergiant” field — potentially one of the world’s largest natural gas finds — is located at a depth of 4,757 feet (1,450 meters) in the Shorouk Block, Eni said.

It said Eni’s CEO, Claudio Descalzi, has visited Cairo and discuss the discovery with Egyptian President Abdel Fattah El-Sissi and Prime Minister Ibrahim Mahlab.

“This historic discovery will be able to transform the energy scenario of Egypt,” Descalzi said in the statement.

The firm said it will “immediately appraise the field with the aim of accelerating a fast track development of the discovery,” giving a timeframe of four years.

In March, British energy giant BP unveiled plans to invest $12 billion in Egyptian offshore gas fields with Russian partner DEA, despite the slump in world oil prices.

It said the investment in the West Nile Delta fields aims to develop five trillion cubic feet of gas resources and 55 million barrels of condensates, with output expected to begin in 2017.