The study is about the potential future gas reserves in the Highlands region, the onshore Gulf Province and into the shallow and deep-water offshore plays.
"We want to know what is next after the three-train expansion," said Oil Search chief executive Peter Botten. "We want to know where we should be investing in order to supply more gas for additional LNG trains or backfill the existing trains."
Botten added that results of the study should be out by the end of this year.
"Further LNG expansion can take place," he said. "Identifying where are the gas resources, what are the infrastructure requirements, and cost of delivery will allow us to prioritise our exploration and appraisal investment into the future."
Oil Search has said in the past it believed there was a huge volume of gas and oil volumes still to be discovered in PNG, and that the Gulf of Papua and the Forelands/Fold Belt plays were particularly prospective.