ExclusiveShell spuds potential play opening wildcat in West African frontier basinThe Jaca-1 probe lies in Block 6 offshore Sao Tome & PrincipeOn location: drillship Maersk Voyager is drilling ahead on Shell’s Jaca-1 wildcat offshore Sao Tome & PrincipePhoto: MAERSK DRILLINGIain EsauLondon