The major is already looking at expansion opportunities for a third LNG train with first LNG now expected to come onstream mid-year.
An analysts' meeting in the US heard the new project pipeline was expected to give ExxonMobil 300,000 net oil equivalent barrels per day of new capacity.
The two-train, 6.9 million tonne per annum capacity PNG LNG project had been due to start production in late 2014 and back in 2009 was estimated to produce an average of 19,200bpd of condensate.
ExxonMobil senior vice-president Mark Albers said the successful execution of the PNG LNG project had allowed the company to unlock the potential of the high quality 9 trillion cubic foot resource.
"Despite the many challenges, the project is actually progressing a few months ahead of schedule, [expecting] the first cargo delivery in the middle of this year," he said.
"This project is ideally located to supply traditional long-term sales to customers in Japan, China and Taiwan.
"The PNG LNG project provides accretive earnings per barrel yield and we continue to look at expansion opportunities for a third train and there's space for a fourth and fifth.
"We brought all of our execution capability to bear, beginning with the construction of the 434-mile pipeline.
"Installation was accomplished here while overcoming flooding, volcanic soil conditions and steep pinnacle reef slopes.
"Pipes had to be airlifted by helicopter as the soil cannot support heavy machinery or the transportation loads of trucks.
"This was no easy task, as we were talking about enough steel to build 20 Eiffel towers."
Albers said the company built supplemental roads, communication lines and a new airfield "cut into the side of a mountain" due to a lack of pre-existing infrastructure.
"The project required substantial outreach, engagement and effective relationships with the governments and indigenous communities," he added.