InterOil chief executive and chairman Phil Mulacek described the results as encouraging and said he was looking forward to the final completion of the well in about two or three weeks, along with the remaining results from the discovery well.

The preliminary results showed high-pressure gas with more than 3150psi surface pressure, high quality condensate, a highly permeable fractured reservoir, flow rates of 21.7 million cubic feet per day (MMcfd) through a small choke, and potential for a 4000-foot hydrocarbon column and an oil leg.

Elk-1 was drilled to 1983m and at one point had flowed gas to surface at between 30MMcfd and 50MMcfd.

The Elk discovery was announced in May and is InterOil's first commercial success. Mulacek had previously described it as a huge well with the potential to kick-start the company's plans to develop a liquefied natural gas plant in the country.

InterOil owns the only petroleum refinery in the country, the Napa Napa refinery, in Port Moresby.