The increases were driven by an output of 25.21 million barrel of oil equivalent (MMboe) in 2018 and four-year high oil prices, which spiked to $US86 a barrel.

Mr Botten said the PNG LNG project produced an average rate of 8.8 million tonnes of LNG per annum during the second half of 2018, “the highest half-yearly rate ever achieved.”

Oil Search also signed a memorandum of understanding with the PNG government in November to expand operations and begun a work programme in PNG to boost its production rates by around 30 MMboe, slowing the decline in its existing fields.

At its US, Alaska-based projects,  in the Arctic's Nanushuk oil fields, Oil Search will begin drilling its Pikka wells, which could add around 250 MMboe of potential resources.

It will announce a final investment decision for the Alaskan assets in 2020.

Despite the recovery, analysts were disappointed in Oil Search’s performance, noting a slower than expected return to production at its PNG LNG project.

“We attribute weaker production to a softer than anticipated ramp-up in oil from Kutubu and Moran and condensate from PNG LNG post the February earthquake,” RBC Capital Markets analyst Ben Wilson said.

Mr Wilson also expects Oil Search to acquire its partner Armstrong Energy’s interest in its Alaskan joint venture oil assets.

He said Oil Search is then likely to sell-down its share to a third party following after drilling at the project.

Oil Search’s share price slumped 2.8 per cent from a Tuesday high of $7.85 to $7.58 by the close of trading.