Oil Search may sell down part of its stake in the P'nyang gas field in Papua New Guinea to Santos in a move that will give the Adelaide-based company a more lucrative role in a planned expansion of the $US19 billion PNG LNG venture. Santos, which already holds a 13.5 per cent stake in PNG LNG, said in May it was working on a potential deal that would give it a stake in the P'nyang gas field alongside existing partners ExxonMobil, Oil Search and JX Nippon, while declining to reveal any specific details.