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Unocal tags choice wildcats Company opts to explore most promising deepwater GOM prospects Petroleum News Houston Staff
For the remainder of the year, Unocal has opted to spend its exploration dollars in the deepwater Gulf of Mexico on prospects near known discoveries, including one of the largest finds in the Gulf region, the ChevronTexaco-operated Tahiti discovery.
Unocal’s drill schedule includes three “high-potential wildcats” — St. Malo, North Brontosaurus and Myrtle Beach — “all following up on industry successes,” Mike Bell, vice president of Unocal Deepwater USA, said July 21.
First on the company’s list is St. Malo, where drilling already has commenced on Walker Ridge Block 678 using the drillship Discoverer Spirit. Unocal said the well would test the deeper Eocene and Paleocene horizons found at neighboring Cascade and Chinook, located within 30 miles of St. Malo.
Chinook operator BHP Billiton announced a discovery on the Chinook prospect in early July, saying the latest well encountered a hydrocarbon column of 620 feet, with 260 feet of net oil pay. The well was drilled in water depths of about 8,830 feet.
After St. Malo, the Discoverer Spirit is scheduled to move to the North Brontosaurus prospect on Alaminos Canyon Block 731, just 10 miles northeast of Unocal’s big Trident discovery. Unocal said the actual structure making up North Brontosaurus is “adjacent to and saddle-separated” from Trident.
“Development scenarios at Trident will be influenced by drilling results in the area,” Unocal said.
Joint development options Operators in the southern reaches of Alaminos Canyon have been studying possible joint development options for discoveries Trident and Great White, as well as prospects waiting to be drilled.
Even with a potential 1 billion barrels or more of oil equivalent in the area, risk-sharing likely would be required because of water depths that approach 10,000 feet and the great distance to existing infrastructure.
Upon completion of the North Brontosaurus well, drilling will begin at Myrtle Beach on Green Canyon Block 943, a prospect six blocks southwest of the ChevronTexaco-operated Tahiti discovery, Unocal said. Tahiti contains an estimated 400 to 500 million barrels of oil equivalent, ranking it among the largest discoveries in the deepwater Gulf of Mexico.
Recent appraisal wells at Tahiti encountered more than 1,000 feet of net pay, raising the hope of other explorers in the area that ChevronTexaco’s good fortune would rub off on them. Appraisal drilling continues at Tahiti with a production test of the 2002 discovery well planned for the first quarter of 2004.
Meanwhile, Unocal said a fourth appraisal well at the deepwater Champlain prospect on Atwater Valley Block 63 encountered more than 200 feet of hydrocarbon pay. Unocal holds a 30 percent interest in the Champlain discovery. ChevronTexaco, the operator, holds a 20 percent stake. Eni Petroleum has a 37.5 percent interest and BHP a 12.5 percent interest.
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