* Noble consortium raises Tamar reserves to 8.4 Tcf from 7.3
* To start Leviathan well exploration in Q4
* Energy shares jump, push broader market higher
(Recasts, adds Noble CEO comments)
By Steven Scheer
JERUSALEM, June 3 (Reuters) - Israel is poised to become an energy exporter after finding much higher than expected natural gas reserves off its Mediterranean coast, Noble Energy (NBL.N) said on Thursday.
U.S.-based Noble leads a consortium that includes a number of Israeli partners drilling for natural gas. The group raised its reserve estimate at the Tamar field by 15 percent to 8.4 trillion cubic feet (238 billion cubic meters).
Another Noble-led group plans to start gas exploration at the Leviathan prospect in the fourth quarter of 2010. They said Leviathan had estimated deposits of 16 Tcf (453 Bcf), twice that of Tamar, which was the largest global gas find of 2009.
"Today's announcement substantiates the potential of a new and significant energy basin in the eastern Mediterranean," Noble Chief Executive Officer Charles Davidson said in an e-mailed statement.
"In addition to the increase in estimated Tamar resources, we have identified significant additional drilling opportunities nearby which, if successful, could position Israel as a potential energy exporter in future years."
Shares of Israeli energy shares jumped on the news, pushing the broader Tel Aviv market up 2.2 percent.
Noble said the Tamar field's first production remained on schedule for 2010 at a capital investment of $2.8 billion.
"With the Tamar project expected to supply Israel with its natural gas needs for the next three decades, a discovery at Leviathan, should there be one, would be earmarked for export," Deutsche Bank analyst Richard Gussow said.
He said Asia would be a target market due to the high prices there and that the Atlantic market would also be targeted due to Europe's desire to reduce reliance on Russian gas.
"This would likely be through LNG (liquefied natural gas), a long-term process that we believe would take at least six years and would require heavy capex investment," Gussow said.
Noble said Leviathan has gross unrisked mean resources of 16 Tcf of gas and a geologic chance of success of 50 percent.
Israeli media quoted Delek Group controlling shareholder Yitzhak Tshuva as saying there were signs of oil under the natural gas finds.
Noble owns 36 percent of Tamar while Isramco Negev (ISRAp.TA) owns 28.75 percent and Delek Group DELKG.TA has a 31 percent stake through two units that have equal shares -- Avner Oil Exploration AVNRp.TA and Delek Drilling (DEDRp.TA).
Delek and Avner have 22.7 percent each in Leviathan while Ratio Oil Exploration (RATIp.TA) holds 15 percent. Noble owns nearly 40 percent of Leviathan.
Shares of Delek Drilling and Avner jumped some 13 percent, while Isramco shares were up 8.6 percent in late trading and Delek Group was up 10.8 percent. The blue-chip Tel Aviv 25 index .TA25 and broader TA-100 .TA10 were up 2.2 percent.
"Based on its initial interpretation of 2D and 3D seismic data, the company has estimated the gross unrisked resource potential on its Eastern Mediterranean acreage to be in excess of 30 Tcf (850 Bcm)," Noble said.
Israel is also receiving natural gas from Egypt under a 20-year deal signed in 2005. (Editing by Karen Foster and Hans Peters)