The PNG LNG project boasts of a substantial certified reserves base with a high liquids (crude oil and natural gas liquids) content and minimal impurities. Higher liquids content boosts revenues as oil companies earn more revenues per barrel of oil equivalent (BOE) on selling liquids rather than natural gas. Exxon’s consolidated subsidiaries sold liquids at an average price of over $100 per barrel in 2012, while the company realized average price of just over $23 per BOE of natural gas.  Moreover, lower impurities and the existing onshore infrastructure base from oil field development projects in the area also reduce the project’s operating costs. Proximity to the Asian markets, which will drive most of the growth in future energy demand, makes the project even more attractive due to lower transportation costs.
Because of these advantages, Exxon is looking to lock reserves for expansion of the LNG facility in PNG. During the second quarter earnings conference call, the company executives said that they are considering expansion opportunities for the project, including ongoing negotiations with InterOil Corporation and Pacific LNG for the Elk-Antelope resource. If the deal with InterOil goes through, Exxon and its partners can potentially add another LNG train at the PNG facility. 
"Exxon is looking to lock reserves for expansion", first from IOC. Why top priority being from IOC? IOC is the only source they can be certain of getting enough gas from at this point and for quite a while to come. EXXON NEEDS IOC AND HAS COMPETITION. GOOD DEAL COMING FOR IOC!