Anadarko has light oil find off Sierra Leone

By OGJ editors
HOUSTON, Nov. 15 – Anadarko Petroleum Corp. has encountered 135 ft of light oil net pay in an exploratory well in the Gulf of Guinea off eastern Sierra Leone.

The Mercury-1 well went to 15,950 ft in 5,250 ft of water on Block SL-07B-10 about 40 miles east-southeast of the 2009 Venus B-1 discovery well. That puts Mercury within 15 miles of Liberian waters. Venus found gas and liquids at 18,500 ft (OGJ Online, Sept. 28, 2009).

Both wells are in the Sierra Leone-Liberian basin. Anadarko holds an interest in more than 4.6 million acres on five deepwater blocks off Sierra Leone and Liberia and has identified more than 17 prospects and leads on 3D seismic on this acreage, said Bob Daniels, Anadarko senior vice-president, worldwide exploration.

"The Mercury well demonstrates that the stratigraphic trapping systems we’ve identified are working, and that the petroleum system is generating high-quality oil,” Daniels said.

Mercury found 114 net ft of light, sweet 34-42° gravity oil in the primary objective with no water contact. A shallower secondary objective has 21 net ft of 24° gravity crude.

Daniels said, “These results continue to build momentum in the basin and enhance our confidence in the team’s seismic interpretation and geologic modeling. We are preserving the wellbore for potential reentry, DST (drillstem testing) or a downdip sidetrack to further delineate the reservoir’s areal extent, quality and deliverability. We also plan to continue working with the government of Sierra Leone and our partnership to accelerate exploration and appraisal activity in the area in 2011.”

Anadarko owns 65% interest in the SL-07B-10 block, Repsol Exploracion Sierra Leone SL has 25%, and Tullow Sierra Leone BV has 10%. The partners are evaluating well results and plan to drill new exploratory wells to determine the area’s commercial viability.

After finalizing Mercury, the drillship will move to Ghana to accelerate the appraisal program at Owo and Tweneboa fields, which Anadarko anticipates sanctioning in 2011.