Shell Confirms Presence of Hydrocarbons at Stones Prospect

Shell Exploration & Production Company confirms that hydrocarbons were encountered during the drilling of the Stones prospect located in 9,576 feet of water on Walker Ridge Block 508 in the Gulf of Mexico. Shell has a 26-percent working interest in the prospect while BP Exploration & Production Inc., as operator, and Marathon Oil Company have 59-percent and 15-percent, respectively.

Further drilling is necessary to determine the extent and the commerciality of the discovery. The Deepwater Horizon, owned by Transocean, began drilling operations on December 31, 2004 and reached its final depth on March 10, 2005. The discovery well was drilled to a true vertical depth of 28,560 feet below sea level.

Shell owns a working interest in all Stones prospect blocks, including Walker Ridge 507, 508, 509, 551, 552, 553, 596, and 597.