Portuguese oil company Galp Energia said on Sunday it had concluded the first phase of exploration in the Mopane field off the coast of Namibia and estimated it could have at least 10 billion barrels of oil.

Galp Energia (OTCPK:GLPEF) (OTCPK:GLPEY) +17.5% in European trading Monday after saying its first phase of exploration in the Mopane field offshore Namibia could contain at least 10B barrels of oil. Galp (OTCPK:GLPEF) (OTCPK:GLPEY) said it conducted testing operations at the Mopane-1X well in January and the Mopane-2X well in March;

The Mopane field is part of the Orange Basin, a region that has recently seen several major oil and gas finds.