Chariot Plugs and Abandons First Well in Namibe Basin Campaign
by Jon Mainwaring
Monday, May 14, 2012
Africa-focused Chariot Oil & Gas announced Monday that it will plug and abandon its Tapir South pre-salt exploration well (1811/5-1) in the Namibe Basin, offshore Namibia.
Tapir South was rated by Chariot as having a 25-percent chance of success and was targeting resource potential of some 604 million barrels of oil. But after reaching a total depth of 16,005 feet (4,879 meters), the well was found to contain no commercial hydrocarbons despite the penetration of reservoirs that Chariot described as "excellent".
The well encountered 568 feet (173 meters) of net reservoir sand of Cretaceous age, including two zones in excess of 98 feet (30 meters) with average porosities of 24 percent. Carbonate intervals were also penetrated with porosities up to 18 percent over a net interval of 92 feet (28 meters).
The Tapir South prospect is part of the Tapir Trend, where three prospects have been identified on a large ridge formed by a rotated fault block that contains the potential carbonate target. Tapir South is the southernmost of three culminations on the ridge and forms a focal point for charge migration from an adjacent basin where Chariot believed excellent oil-prone source rocks were present and generating oil.
Chariot said that detailed analyses will be conducted on the data collected during the drilling of Tapir South and that this information will be used to calibrate the firm's existing data set. A resource update of the remaining prospectivity in the block will be provided once this evaluation is complete.
"Whilst the results of the Tapir South well are disappointing, this is the first well of a longer term drilling campaign within a frontier region and only the second well ever to have been drilled in the Namibe basin," said Chariot CEO Paul Welch in a statement. "Our understanding of this basin is rapidly improving and we expect this well to provide more information on the character and maturity of the potential source rocks when we carry out detailed analyses on the recovered samples. These analyses will provide invaluable information for improving the assessment of source risk on other prospects in close proximity whilst also furthering our knowledge of the region."
Welch added that Chariot and its partners (BP and Petrobras) are still on track to begin the drilling of the Kabeljou (2714/6-1) well on the Nimrod prospect in Southern Block 2714A during the third quarter of this year.
Oil analysts at London-based investment bank Peel Hunt said that it understood the main reason for the lack of a discovery was because the source rock is immature. Moreover, the bank said the failure of the Tapir South well could mean that prospectivity towards the Walvis Ridge to the south is diminished.
"However, we understand the area to the north of the license, including the 932MMbbl Zamba prospect, remains attractive from an exploration perspective," added Peel Hunt's analyst.
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