Exploration stands to advance off Gabon with the award of that country's first ultradeepwater permit.
Vanco Gabon Inc., a unit of Vanco Energy Co., Houston, has signed a production-sharing contract (PSC) with the Gabon government for the Astrid Marin block (formerly Block K-97). The 1.2 million-acre block is 90 miles off Gabon in 8,200-9,900 ft of water.
Vanco said it is the first company to sign a PSC for an ultradeepwater prospect off Gabon and the first independent to acquire ultradeepwater rights in West Africa.
The acreage is located along the Gabonese border with the Republic of Congo, south of and adjacent to Vanco's previously awarded 1.6 million-acre Anton Marin block.
Operator Vanco owns 100% interest in Astrid Marin block and a 90% interest in Anton Marin block with partner Reading & Bates Development Co., Houston, 10%. Reading & Bates has an option to increase its ownership to 20%.
Plans
Vanco has reviewed existing 2D seismic data and plans an 870-mile 2D seismic survey on Astrid Marin block within a year.
A seismic program is also planned on Anton Marin block in fourth quarter 1997.
"More than likely, we'll shoot Astrid Marin and Anton Marin at about the same time," said Bob Olson, Vanco exploration manager.
First wells will be drilled as soon as a drillship can be secured and placed under contract.
Olson said there is no existing production infrastructure, and Vanco is eyeing a floating production, storage, and offloading (FPSO) unit with subsea wells tied back to the FPSO to be moored on location.
Houston's Intec Engineering Inc. is preparing a deepwater development plan for Vanco.
"The two blocks are on trend with recent discoveries," Olson said.
Anton Marin block is the northwest extension of the deepwater Cretaceous and Tertiary play being pursued in Congo, Cabinda, and Angola, according to Vanco. Olson said Anton Marin is a post-salt Cretaceous play, and Astrid Marin is Tertiary.
Big area discoveries
Exploration has yielded major discoveries southeast of the Vanco acreage. Elf Aquitaine SA has a 400-600 million bbl discovery, Moho, in 800 m of water on the Haute Mer block off the Congo (OGJ, Sept. 16, 1996, p. 24). Elf's nearby N'Kossa field, the Republic of Congo's largest field to date with estimated reserves of 500 million bbl of liquids, came on stream in June 1996.
Elf's 1996 Girassol discovery off Angola is in more than 1,300 m of water on Block 17, the deepest water in which a West African discovery has been made (OGJ, May 12, 1997, p. 41).
According to Vanco, Chevron Corp. has a discovery off Angola's Cabinda enclave, D-14-2, with reserves pegged at 1 billion bbl. It's located southeast of Elf's Moho and N'Kossa discoveries.
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