From the August 31 Financial Times article "Field of dreams: Israel’s natural gas":
For decades a barren energy island, forced to import every drop of fuel, Israel today stands on the cusp of an economic revolution, fueled by the vast riches that lie below its waters.
With reserves of almost 10 trillion cubic feet of natural gas, the Tamar field is a hugely valuable asset for the Israeli economy (see map above). Discovered in January 2009, it was the biggest gas find in the world that year, and by far the biggest ever made in Israeli waters. But the record held for barely two years. In December 2010, Tamar was dwarfed by the discovery of the Leviathan gasfield some 20 miles farther east – the largest deepwater gas reservoir found anywhere in the world over the past decade.
The two fields, together with a string of smaller discoveries, will cover Israel’s domestic demand for gas for at least the next 25 years, and still leave hundreds of billions of cubic feet for sale abroad. The government take from the gasfields alone is forecast to reach at least $140 billion over the next three decades – a staggering sum for a relatively small economy such as Israel’s.
Experts are convinced that Tamar and Leviathan will not be the last big Israeli discoveries. They point to the US Geological Survey, which estimates that the subsea area that runs from Egypt all the way north to Turkey, also known as the Levantine Basin, contains more than 120 trillion cubic feet of natural gas. Israeli waters account for some 40 per cent of the total. Should these estimates be confirmed through discoveries in the years ahead, Israel’s natural gas reserves would count among the 25 largest in the world, on a par with the proven reserves of Libya and ahead of those of India and The Netherlands.
And it's not just natural gas, Israel also might have as much as 250 billion barrels of shale oil in the recently discovered Shfela Basin southwest of Jerusalem (see map below), according to this July 13 article in the Financial Post article titled "Israel's Shale Gale."