Mariner pegs Gulf discovery at 100 bcfe

Exploration and production independent Mariner Energy scored what appears to be a predominantly gas discovery on its Geauxpher prospect on Garden Banks block 462 in the deepwater Gulf of Mexico, the company said June 17.

The discovery well, which lies in water depths of around 2,700 feet, was drilled to a total depth of 23,156 feet. Mariner estimated the field’s gross proved and probable reserves on the block to be about 100 billion cubic feet of natural gas equivalent. Development already is under way with initial production expected as soon as year-end, Mariner said. It would be produced from an old platform on Garden Banks block 72.

Mariner is the designated operator of the block and holds a 60 percent working interest in the discovery. Fellow E&P independent Apache Corp. holds the remaining 40 percent interest.

In November 2007, Mariner farmed into Geauxpher, providing the rig — Diamond Offshore’s semi-submersible Ocean America — to test the prospect. The drilling rig remains on location and a second well is planned to delineate the extent of the discovery, Mariner said, noting that the company has identified additional potential on the block and expects to test the amplitudes over time.

“Our discovery at Geauxpher provides further evidence of the value potential in Mariner’s deepwater prospect inventory,” said Scott D. Josey, Mariner’s chairman, president and chief executive officer.

British-Borneo Petroleum, Norcen Explorer and Spinnaker Exploration, all of which have since been acquired by other companies, initially won Garden Banks block 462 in an August 1997 federal lease sale for $3.3 million.

—Ray Tyson