Cairn Energy has discovered a hydrocarbon-bearing reservoir and oil at the exploration FAN South-1 well in the South Fan prospect in offshore Senegal. 

The company used Stena DrillMAX drill ship for the probe and the exploration work was completed ahead of schedule and under budget. 

Preliminary analysis shows the oil quality to be 31° API. Additional work is being undertaken to integrate this discovery with FAN-1 well in order to explore the potential commerciality of the deepwater basinal resource in these two wells. 

FAN South-1 is located in water depths of 2,175m, 90km offshore in the Sangomar Deep Offshore block and 30km south-west of FAN-1 exploration well. 

The well reached a total depth of 5,343m targeting dual prospects, which were an upper Cretaceous with multi-layer channelised turbidite fan prospect, and a lower Cretaceous base of slope turbidite fan prospect, similar to the FAN-1 oil discovery in 2014.  

FAN South-1 has since been plugged and abandoned.

"Results of FAN South will be integrated with FAN-1 and SNE to help the joint venture’s ongoing evaluation of the large, deepwater basin potential offshore Senegal."

The rig has now moved to begin operations at the SNE North exploration prospect, 15km north of the SNE-1 discovery well. 

SNE North is targeting a prospective volume of more than 80 million barrels of total resources. This well is located in at water depths of 900m, while the projected total depth of the well 2,800m.

Cairn Energy CEO Simon Thomson said: "FAN South is our tenth well in Senegal in the last three years and our second well to encounter oil in the deep portion of the basin, adjacent to the FAN discovery.

"The results of FAN South will be integrated with FAN-1 and SNE to help the joint venture’s ongoing evaluation of the large, deepwater basin potential offshore Senegal.

"As planning for the phased development of the SNE field moves ahead, we will shortly commence operations on the SNE North prospect, which has the potential to enhance our total resources in Senegal."