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First deepwater oil discovered off East Africa

By OGJ editors
HOUSTON, Aug. 20
-- An exploratory well off Mozambique has penetrated 38 m of net oil and gas saturated sands in the upper of two Cretaceous fan lobes, signaling the first documented occurrence of liquids hydrocarbons in deep water off East Africa.

The Ironclad-1 well, operated by Anadarko Petroleum Corp. in Area 1 off Mozambique, is in the Rovuma basin 110 km south of the Windjammer dry gas discovery, drilled earlier in the same six-well exploratory program to 16,930 ft in 4,800 ft of water 30 miles off the coast (see map, OGJ, May 17, 2010, p. 35).

An Anadarko-led group had planned to drill the Ironclad-1 well to 20,500 ft, but partner Cove Energy PLC said drilling has ceased at 5,304 m after the well penetrated 205 m of targeted Cretaceous-age sediments in two distinct fan lobes. Ironclad’s water depth in the Mozambique Channel wasn’t immediately available.

Cove Energy said Ironclad “was drilled to evaluate the hydrocarbon potential of an areally extensive Cretaceous deepwater fan complex in the southern part of the permit and in particular to determine the presence of oil in an area believed to have the geological parameters necessary for liquid hydrocarbon generation.”

The presence of oil in the upper fan lobe was confirmed by geochemical analysis of rotary sidewall cores taken from the well bore. Significant gas shows were also present throughout the drilling of the Cretaceous section, Cove Energy said. It said future geological analysis of the Ironclad fans “will focus on delineating areas predicted to have good reservoir parameters in terms of porosity and permeability necessary to support commercial exploitation.”

On finishing operations at Ironclad, the Anadarko group will move the Belford Dolphin drillship to the Barquentine well site, east of Windjammer on the northern part of the block, where surface casing is already set at 2,300 m. Barquentine will test multiple stratigraphic traps near Windjammer.

After Barquentine, which is to take 6 weeks to drill, the group plans to drill at least two more exploration wells.

Cove Energy called the Ironclad results “very promising not just for the Cretaceous fan systems, where over 80 sq km of closure have been mapped, but for additional nearby prospects already identified elsewhere in the Offshore Area 1 block. In addition the presence of oil and its associated petroleum system in Ironclad is significant for our extensive deepwater blocks in both Mozambique and Kenya.”

Anadarko operates Area 1 with 43% paying interest. Co-owners are Mitsui E&P Mozambique Area 1 Ltd. 23.5%, BPRL Ventures Mozambique BV 11.75%, Videocon Mozambique Rovuma 1 Ltd. 11.5%, and Cove Energy Mozambique Rovuma Offshore Ltd. 10%. Mozambique’s state Empresa Nacional de Hidrocarbonetos EP has a 15% interest and is being carried through the exploration phase.


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