The Italian energy company Eni knew it was taking a big risk this summer when it spent $60 million on an exploratory rig and began drilling more than 100 miles off the coast of Egypt.

Eni’s gamble worked. The company, using drilling rights from the Egyptian government, found what it called a “supergiant” natural gas field. It may be the largest discovery yet in the Mediterranean and is one of the world’s biggest new gas finds in years.

Eni will need to drill more wells to prove its claim that the field, which it calls Zohr, holds up to 30 trillion cubic feet of gas. That could be worth about $100 billion, even when taking into account current low energy prices. But the promise of Zohr — the Arabic word for noon — is already brightening the prospects of the Egyptian economy, which has been benighted by an energy shortage and years of political turmoil.

As with so many things in the Middle East, however, the discovery of the gas field has geopolitical repercussions. And it has thrust Eni’s chief executive, Claudio Descalzi, into the role of shuttle diplomat.