LNGExpansion of world’s largest gas field progressing impressively, QatarEnergy LNG chief saysTwo-phase project is costing upwards of $50 billionNorth Field expansion: Khalid bin Khalifa Al Thani, the chief executive of QatarEnergy LNG (formerly Qatargas).Photo: REUTERS/SCANPIXNishant UgalMiddle East EditorNew Delhi