Eni has successfully drilled the last appraisal well on its Longhorn discovery, located in the Gulf of Mexico (GoM) US deepwater , 195 km southeast of New Orleans in Mississippi Canyon Block 502.

Eni is the operator with a 75% working interest and Nexen Petroleum Offshore U.S.A. Inc. holds a 25% working interest.

The well, drilled in 740 meters (2,442 ft) of water depth to a total depth of 4,228 metres (13,951 ft), encountered approximately 127 metres (419 ft) of net pay in multiple sands, including a stratigraphically deeper zone than those encountered in the two exploratory wells drilled in 2006. The initial analysis indicates good reservoir quality. While the new data is still under evaluation, an increase in total reserves is expected.

Eni plans to sanction the Longhorn development by December 2007, via a subsea tie-back to a host platform. Production start up is expected in 2009.

Eni holds additional interests in other leases in the ‘Greater Longhorn Area’, which is one of its core areas in the GoM, and has scheduled further exploration activity in 2008.

Eni owns lease interests in 439 GoM blocks, 72% in Deepwater, and was the apparent high bidder in additional 26 leases at the Lease Sale 205 held on October, 3, 2007.

Eni is among the leading GoM producers with a daily equity production in excess of 100,000 barrels of oil equivalent, of which 60% is operated. In addition, Eni owns lease interest in 158 leases in the North Slope of Alaska.