While not historically promising oil and gas players, change may be in the winds for these impoverished countries, which are trying to recover from years of civil strife. Among the heralds of a potentially more petro-rich future were a string of discoveries in the Sierra Leone-Liberian basin over the last few years by Anadarko and its partners, Repsol and Tullow.

In 2009, the partners’ Venus-1 exploration well in Block SL6-07 hit more than 13.6 net m (45 net ft) of pay. The well was drilled in roughly 1,788 m (5,900 ft) of water to total drilling depth of 5,606 m (18,500 ft). The next year, the companies hit about 41 net m (135 net ft) of light, sweet crude oil pay with its Mercury-1 well, drilled to a total depth (TD) of 4,833 m (15,950 ft) in about 1,621 m (5,350 ft) of water. The partners had another success in 2012 with the Jupiter-1 exploration will in block SL-07B-11, some 40 km (25 miles) west of the Mercury well in the same block. The deepest well yet, Mercury was drilled to a TD of 6,427 m (21,210 ft) in 2,186 m (7,214 ft) of water. However, two more wells drilled last year in same basin weren’t successful.

There’s nevertheless keen interest in the basin with Sierra Leone’s government issuing a license late last year to Minexco, as operator with a 90% interest, and Signet Petroleum with the other 10%, to explore in Block SL-7A-10. This lease is adjacent to the block which brought the Anadarko-led team’s trio of successes. Work will entail licensing all existing seismic data and acquiring more 2D and 3D data. Also off Sierra Leone’s central coastline, African Petroleum Corp. (APC) and Kosmos won provisional licenses in 2012 to explore Block SL-4A-10.

Meanwhile, an exploration license was awarded for two deepwater blocks between 120 and 180 km (75 and 110 miles) off Sierra Leone’s coastline southwest of the capital city of Freetown to Chevron (SL) Ltd. with 55% interest as operator, Noble Energy SL Ltd., 30% interest, and Sierra Leone’s Odye Ltd., 15%. This is before a Sierra Leone National Oil Co. option to back-in 15% at final investment decision.

The two blocks, SL-08A and SL-08B, were combined into one concession and cover an area of about 5,500 sq. km (2,100 sq miles). The average water depths range from about 1,500 to 3,000 m (4,900 to 9,800 ft).

"We have a strong regional interest in the geology and we look forward to applying our technical expertise to this emerging trend," said Ali Moshiri, president, Chevron Africa and Latin America Exploration and Production.

APC is also a player in Liberia, where last February, its Narina-1 exploration well struck 32 m (105 ft) of light crude pay in two separate intervals. The well was drilled to TD of 4,822 m (15,912 ft) in 1,136 m (3,750 ft) of water. The discovery, which the company thinks could be comparable to Ghana’s Jubilee field, touched off fierce nationalistic fervor, prompting the government to suspend further bidding rounds pending legislative reform to increase the chances that local contractors will reap more rewards from increasing petro-development, according to AllAfrica.

Long, brutal civil wars during the 1990s ruined the infrastructures and economies of both Liberia and Sierra Leone. In Liberia’s capital city of Monrovia, for instance, water and electricity shortages are common and the country is “overrun with weapons.” Sierra Leone, by contrast, has seen significant economic growth but still faces tremendous reconstruction needs, according to a BBC profile.

Barbara Saunders

Offshore