At long last, Israel can call itself a gas power, with the confirmation yesterday of a huge deposit of natural gas sitting below its shore in the Leviathan gas field. Production from the field is still years off, though.

Further testing will be necessary to ascertain how much of the gas can be feasibly extracted. A rough estimate shows the find may be worth as much as $90 billion at present market prices.

That said, with the release of the report, Leviathan officially became the biggest deep-water gas discovery in the last 10 years in the whole world. The field, deep in the rock under the Mediterranean Sea, is as big as the biggest hopes for it: 16 trillion cubic feet of gas, the explorers announced yesterday. That's more than double the size of the adjacent Tamar field. Officials were jubilant at the news.

"A day in which we learn about the Leviathan gas field, a day in which we pass a two-year budget, and a day in which we are told that the Israeli economy grew faster than most of the economies of the west and created 100,000 jobs - this is a day to be very optimistic about the Israeli economy," Prime Minister Benjamin Netanyahu said. (For more on those stories, see pages 11 and 12 ).

"Today we received the most important energy news since the country was founded," said National Infrastructure Minister Uzi Landau.

Noble, one of the partners, cautioned that two more wells need to be drilled before the final actual capacity of Leviathan is known.

Even so, the report halts the rumor mill surrounding Leviathan, which is being explored - and will now be developed - by U.S.-based Noble, Delek Group and Ratio.

"We're more than pleased," gushed Yigal Landau, CEO of Ratio Oil Exploration yesterday, heading for a toast at the Herzliya offices of Noble Energy.

Six months ago Noble had ascribed a 50% probability to Leviathan containing at least 16 TCF.

Leviathan lies in an area of seabed called the Levant Basin, which stretches about 32,000 square miles from Cyprus to Syria to the Sinai. The Tamar field, estimated to contain 8.7 TCF, is also in this basin. Delphi says Tamar and Leviathan could supply Israeli gas consumption for 60 years, or alternatively, Israel could become an exporter.

Theoretically the gas could be liquefied and transported by tankers, or it could be transported through pipelines to Europe.

Testing aside, the partners' next step may be to drill even deeper, hoping to find oil below the gas-bearing layers at Leviathan, which is the sixth gas discovery in Israeli territory, and the fifth in which Noble and Delek were involved. The idea is to go 700 meters deeper, to a layer from the Oligocene period, where Noble estimates there is a 17% probability that 3 billion barrels worth of oil will be found.

"We may have become accustomed to discoveries, but we're on the map and intend to stay on the map, as natural gas exporters," said Gideon Tadmor, CEO of Delek Drilling, in conversation with equity analysts yesterday.

The Leviathan-1 exploratory drill began four months ago at a license area called Rachel, 130 kilometers off the Haifa shoreline. A month ago the Sedco Express rig reached the target layer. The water depth at the site is 1,634 meters and the drill went down more than 5 kilometers beneath sea level, ending at 5,170 meters. Having found indications that the gas was there, Noble and the partners began a series of tests - electrical logs and coring, to gauge the characteristics of the rock: thickness, porosity and more. The results of these tests confirmed the partners' fondest hopes. Analysis was held up by technical difficulties but finally came through.

Noble says the quality of the gas is good, but the total thickness of the gas-bearing layers is 67 meters, significantly less than the 140 meters at Tamar. However, Leviathan is vast, says Noble, spanning 325 square kilometers, more than double the size of Tamar.