Unocal concludes successful appraisal of St. Malo discovery in Gulf of Mexico

By OGJ editors

HOUSTON, July 13 -- Unocal Corp.'s appraisal well at the St. Malo hydrocarbon discovery on Walker Ridge Block 678 in the deepwater Gulf of Mexico encountered more than 400 net ft of oil pay at depths greater than were encountered in the earlier discovery well in October 2003 (OGJ Online, Oct. 31, 2003).

The appraisal well is located 6,000 ft east of the discovery well in 7,036 ft of water, .

The $31 million St. Malo appraisal well at Dana Point was drilled to 28,903 ft, about 2,000 ft deeper than the original Dana Point well that was completed as a dry hole in early 2001. Redrilling on the Dana Point location saved Unocal and its coventurers $25 million vs. the cost of drilling a new well.

The appraisal well indicates potential hydrocarbon resources greater than previously suggested by the discovery well that encountered more than 450 net ft of oil pay.

Unocal is evaluating its extensive testing results "with the objective of establishing commerciality in 2005."

"Based on the quality of the test data and the increased rock volume, we intend to proceed with work to assess the potential productivity of the field and evaluate development options," said Mike Bell, Unocal's vice president for Gulf of Mexico exploration and appraisal.

Unocal is the operator and holds a 28.75% working interest. Unocal's coventurers in the St. Malo prospect are Petrobras 25%, Devon Energy Corp. 22.5%, ChevronTexaco Corp. 12.5%, EnCana Gulf of Mexico LLC 6.25%, ExxonMobil Corp. 3.75%, and ENI SPA 1.25%.

Upon completion of the St. Malo appraisal well, the Discoverer Spirit drillship will move on to the Sardinia prospect in Keathley Canyon 681.