The partners tapping into one of the largest natural gas fields ever discovered off the coast of Israel said they brokered a power deal worth $2 billion.

Delek Drilling, Texas-based Noble Energy, Israel's Avner Oil and Ratio Oil, a collective working to exploit the Leviathan natural gas field in the Mediterranean Sea, said they reached an agreement with Dalia, the largest private power plant in Israel, to supply fuel for up to 20 years once production begins.

The Leviathan partners said that, in their opinion, cumulative revenues for the sales agreement "is likely to come to $2 billion," assuming Dalia takes on the full amount of gas outlined in the terms of the deal.

Leviathan is expected to start production in 2019 or 2020. Leviathan and the nearby Tamar field combine for an estimated 28 trillion cubic feet of natural gas reserves, with Leviathan accounting for more than half of the aggregate. A good portion of the gas reserves in Leviathan are designated for exports.

In September, a Jordanian power company agreed to a take-or-pay scheme tied to Leviathan field. That agreement was worth an estimated $10 billion and was the first such agreement for the Leviathan field.

Last year, the Israeli partners expressed interest in coordinating gas deliveries from the Mediterranean basin to Egyptian gas and electric companies. The U.S. State Department facilitated talks in 2014 that led to the signing of regional deals for gas deliveries from Israeli fields.