Unocal Makes Deepwater Discovery on Tobago Prospect

Unocal said its exploratory well on the Tobago prospect in Alaminos Canyon block 859 is a discovery.

Drilled to a total depth of 18,510 feet, the well found about 50 net feet of oil pay in high quality reservoir sandstones. The discovery was further delineated by a sidetrack that was drilled to 18,425 feet. Gross costs for the original well and the sidetrack totaled approximately $25 million.

The Tobago well was one of several that have been drilled in the Alaminos Canyon area to evaluate the development potential for the Perdido Foldbelt. The company said that the discovery confirms its previous expectations that Tobago could be part of any Alaminos Canyon area development that may be built in the future to produce a number of other existing discoveries, including Unocal's Trident field.

Unocal is the operator at Tobago and holds a 40.01-percent working interest. Unocal's co-venturers are Shell, 30 percent; ChevronTexaco, 16.66 percent, and Nexen, Inc., with 13.33 percent.

The Tobago well has been temporarily plugged and abandoned, and the Discoverer Spirit drillship has moved to Walker Ridge block 678 to conduct appraisal drilling on the St. Malo discovery.