A WILDCAT well drilled by exploration and production company Kosmos Energy offshore Western Sahara has located hydrocarbons but not enough to make it a commerically viable discovery.

The CB-1 exploration well penetrated about 14 metres of net gas and condensate pay in clastic reservoirs over a gross hydrocarbon bearing interval of roughly 500 metres.

Located in the Cap Boujdour permit area about 170 kilometres offshore Western Sahara in 2,135 metres of water, the CB-1 well was drilled to a total depth of 5,700 metres.

The well, which cost Kosmos about US$85 million, will now be plugged and abandoned.

Kosmos chief executive officer Andrew Inglis said the well was designed to open the frontier Laâyoune basin by testing the Al Khayr prospect.

“While not a commercial find, this first well in the basin has significantly de-risked further exploration by demonstrating a working petroleum system, including the presence of a hydrocarbon charge, as well as effective trap and seal,” he said.

“The well results confirm the substantial exploration potential of our 22,000 square kilometre Cap Boujdour block, which includes a diverse range of independent plays and fairways with multiple prospects.”

“Going forward, the key exploration challenge is finding reservoirs of commercial size and quality,” he said.

“We will analyse the information gathered from CB-1 and integrate it with the additional 3D seismic data we recently acquired to refine our exploration plan, including deciding on the location and timing of a potential second well.”

The Atwood Achiever drillship will now go to Mauritania to test the Tortue Prospect.

Kosmos operates the Cap Boujdour license with 55 per cent equity, joined by partners ONHYM (25%) and Capricorn Exploration and Development Company, a wholly owned subsidiary of Cairn Energy (20%).