Sewell & Associates, a Dutch oil and gas consulting company, finds the Oz license area, about 30 miles off the coast of Tel Aviv, may hold more than 1.1 trillion cubic feet of natural gas and 93 million barrels of oil.
Roni Halman, chairman of Oz license partner Israel Opportunity, said Saturday the estimates beat early expectations.
"The Levant basin is rich with gas, and we believe also in oil, which has a huge potential," he said.
Though considerable, Oz holds less than the giant Leviathan and Tamar basins off the Israeli coast.
Production at Tamar began last year. It has an estimated 8.6 trillion cubic feet of natural gas reserves. Leviathan, with an estimated 18 trillion cubic feet of gas, should go onstream in 2016.
No timeline was offered for Oz development.