JERUSALEM—Israel Chemicals (ICL) said on Feb. 22 it signed two deals for the supply of natural gas with the partners in the Tamar and Leviathan gas fields off Israel’s coast that could be worth more than $1 billion.

ICL in December signed a 15-year deal of up to $1.9 billion to buy 13 billion cubic meters (Bcm) of gas from Greek energy firm Energean Oil & Gas, which operates Israel’s Karish and Tanin fields that are expected to start production in 2021.

The deals with Tamar and Leviathan are to secure the firm’s gas needs until Tanin and Karish start operating or in case the deal with Energean is terminated, ICL said in a statement to the Tel Aviv Stock Exchange.

It estimated it could buy up to 6 Bcm of gas from Tamar and Leviathan until the end of 2025 for $1.1-$1.2 billion, should the Energean deal be terminated. If Energean starts operating by late 2020, ICL said it would only buy 2.2 bcm from Tamar and Leviathan for $400-$450 million.

ICL is entitled to terminate the agreement as of the fourth quarter of 2020.

The Tamar field is Israel’s main natural gas supplier, while Leviathan is expected to come on line in late 2019.

Tamar and Leviathan are mainly owned by Texas-based Noble Energy and Israeli conglomerate Delek Group.