A Review of the Nigerian Energy Industry

Harvest scores another success offshore Gabon

11 February 2013 – Houston-based Harvest Natural Resources announced Monday that it has made another oil discovery in the pre-salt layer offshore Gabon, West Africa.

Harvest said the Dussafu Tortue Marin-1 (DTM-1) well, drilled in the Dussafu Marin production sharing contract, was initially drilled in 380 feet of water to a vertical depth of 11,260 feet. On January 4, Harvest announced an oil discovery in the pre-salt Gamba and Dentale reservoirs and that it planned to drill a sidetrack to appraise the extent of the Dentale oil discovery.

The Tortue oil discovery was appraised by drilling a sidetrack (DTM-1ST1) to the southwest to test the lateral extent and structural elevation of both the Gamba and Dentale reservoirs. The sidetrack was drilled to a total depth in the Dentale of 11,385 feet, 10,790 feet true vertical depth subsea and approximately 1,800 feet from the original wellbore.

The well found 65 feet of oil pay in the primary Dentale reservoir with better reservoir character and an apparent similar fluid level to that encountered in the vertical well, DTM-1, according to Harvest. The firm added that several other stacked sands with oil shows were encountered, but due to a stuck downhole tool logging operations in the sidetrack were terminated early before pressure data could be collected to confirm connectivity.

The well will be suspended pending future appraisal and development activities and the rig will be released and demobilized.

Harvest said that reservoir and conceptual engineering studies are to start with the aim of evaluating the commerciality of the discovered oil in the Gamba and Dentale reservoirs at Tortue, as well as the firm’s previous Ruche oil discovery and the nearby Walt Whitman and Moubenga oil discoveries to determine the optimum development options for the block.

Harvest commented that the addition of the Tortue oil discovery extends the proven fairway for stacked pre-salt reservoirs and has demonstrated the exploration potential for the outboard part of the Dussafu license.
*Rigzone staff

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