Kosmos Energy has announced that the Tortue-1 exploration well offshore Mauritania has encountered additional hydrocarbons while drilling to depths of 5,100m.
The well in Block C8 is located 285km south-west of Nouakchott at depths of 2,700m, with the drilling performed by Atwood Achiever drillship at a cost of $125m.
Kosmos Energy has renamed the Tortue discovery area 'Ahmeyim', which it holds a 90% interest in, along with Société Mauritanienne Des Hydrocarbures (SMHPM) at 10%.
Under production sharing contracts with the Government of Mauritania, the company has held rights to carry out exploration in the C8, C12 and C13 contract areas since 2012.
"We are encouraged by the presence of additional hydrocarbons in the deeper portion of the well."
Chevron's wholly owned subsidiary Chevron Mauritania Exploration acquired a 30% non-operated interest in these contract areas in March 2015.
The company can pay a disproportionate share of their costs related to the Tortue-1 exploration well and can elect to participate at a 30% interest in the discovery.
In water depth of between 1,000 and 3,000m, the contiguous blocks have combined acreage of 27,000km².
Preliminary analysis of drilling results found that the Tortue-1 has intersected 10m of net hydrocarbon pay in the lower Albian section, which is currently expected to be gas.
Kosmos Energy chief exploration officer Brian Maxted said: "We are encouraged by the presence of additional hydrocarbons in the deeper portion of the well.
"While the Albian was not the primary objective of the Tortue-1 well, the presence of additional hydrocarbons in the Albian further de-risks other prospects in the Greater Tortue Complex, which include primary reservoir targets in both the Albian and underlying Aptian."