Australia's Oil Search Ltd has cleared the way for ExxonMobil Corp to take over InterOil Corp for $2.2 billion, giving the U.S. giant access to a rich new gas field to expand its exports from Papua New Guinea.

The move could lead ExxonMobil and French giant Total SA to tie together their competing gas interests in the South Pacific nation, cooperating to reduce costs as they battle cheap oil and liquefied natural gas (LNG) prices.

Oil Search, backed by Total, had also bid for InterOil, but said on Thursday it would not raise its offer. The two companies agreed that letting ExxonMobil take over InterOil, which owns a 36.5 percent stake in the Elk-Antelope gas field, would help speed up development of the discovery, it said.

The majors are targeting Papua New Guinea for growth as the quality of its gas, low costs and proximity to Asia's big liquefied natural gas (LNG) consumers make it one of the most attractive places to develop projects following a collapse in oil and gas prices.

Total had envisioned building a new $10 billion LNG project, but said it was now committed to working with ExxonMobil's PNG LNG, which could use Elk-Antelope gas to feed an expansion.

"This scenario would be the lowest cost viable supply in the Pacific Basin," said Saul Kavonic, an analyst at consultants Wood Mackenzie.

Oil Search, a partner in both PNG LNG plant and Papua LNG, estimates that around $2 billion could be saved by tying the two projects together.

"For Oil Search shareholders, the successful takeover of InterOil by ExxonMobil will deliver a major part of our original objectives in the acquisition of InterOil and our agreement with Total SA, without shareholder dilution and any acquisition risk," Oil Search Managing Director Peter Botten said in a statement.

Total, operator of the Elk-Antelope fields, said late on Wednesday it was committed to cooperating with the PNG LNG project to maximize the value of the gas.

"It's going to come down to how you carve up that value pie. Those are the negotiations that will have to take place in order for that joint development to occur," said Kavonic.

Oil Search and Total highlighted a recent certification of the gas field's reserves at less than 6.5 trillion cubic feet, compared to InterOil's dream of 10 tcf, as a factor in their analysis of the best development option for Elk-Antelope.

ExxonMobil declined to comment.

ExxonMobil has offered $45 worth of its shares plus $7.07 per share for each trillion cubic feet equivalent (tcfe) above 6.2 tcfe up to a maximum of 10 tcfe for each InterOil share. InterOil last traded at $48.95.