Assurances by Origin Energy that there was no cause for concern regarding its Amungee Mungee Station well in the Northern Territory hitting a natural fault have been questioned by an agricultural scientist.

The Scientific Inquiry into Hydraulic Fracturing in the NT is holding its final round of community consultations on its draft final report, which will help determine whether or not an NT Government moratorium on fracking is lifted.

During hydraulic fracturing, a mixture of chemicals, water and sand are injected at high pressure into rock to release gas.

On Tuesday, the inquiry heard that drilling at the station, near Daly Waters, hit a natural fault, the well became deformed and a planned twelfth fracking stage had to be cancelled.

Origin Energy chief geologist David Close told the inquiry that there was no need for concern over the well hitting the natural fault.

"All the faults that we encountered in that well were minor, small; the largest was about 15 metres," he said.

"Most of the faults that we encounter are between two and five metres, so they are small faults."

Origin pleased no large faults detected

He said Origin was pleased to see when it drilled the Amungee well that seismic survey results suggesting there were no large faults in the area were correct.

"It was a positive to find that our interpretation was backed up by the drilling results, that we didn't see any faults of a seismic scale, any faults of above 15 metres," he said.

David Close says seismic surveys near the Amungee well found there were no major faults in the area. ( ABC News: Jane Bardon )

In its draft final report published in December the inquiry found the risk of fracking contaminating aquifers with chemicals or gas was low "provided that the hydraulic fracturing does not intersect with a fault".

University of Queensland agricultural scientist Professor Peter Dart has carried out research on the effects of the gas industry on farmers in Queensland.

He said he did not accept Origin's assurances there were no concerns that its well intersected with small fault lines.

"The normal practice for shale wells is that you avoid such faults in siting your well directions," he told the ABC.

"We should be concerned by any deformation in a well casing, caused by a natural fault, that is not picked up by seismic studies. And it's a concern because it can lead to emissions of gas in the drilling processes."

Sorry, this video has expired NT grapples with environment and economy fracking dilemma

'Gas can escape through minor faults'

Professor Dart said his research of gas industry impacts in Queensland had found that even small natural faults could be pathway for gas.

"The natural fault problem in the coal seam gas industry is evidenced by the bubbling in the Condamine River, for example," he said.

"Origin Energy has now drilled wells in which they've tried to depressurise around their own wells, and vent, or burn off, the methane and release carbon dioxide.

"So gas can escape through minor faults."

Origin Energy's capped Amungee NW-1 well now sits alone on a bare pad 50 kilometres east of Daly Waters. ( ABC Rural: Daniel Fitzgerald )

Coal seam gas is typically much closer to the surface than deeper shale gas, and the industry has repeatedly argued it would be more difficult for shale gas to travel 1-2 kilometres to aquifers or the surface.

Origin Energy has responded to Professor Dart's questions by saying there is no risk to aquifers posed by minor natural faults near its Beetaloo Basin wells, including the Amungee well.

"Smaller faults — like the one drilled through at Amungee — are not unusual," Origin Energy told the ABC.

"This is normal practice and does not create a risk to safety, well integrity, or the environment.

"Smaller faults like this are contained within the boundaries of the shale rock formation containing gas. There are no pathways to aquifers associated with these minor faults."

Origin Energy is waiting on the outcome of the NT's independent inquiry into hydraulic fracturing before deciding on the future of Amungee NW-1 well. ( Supplied: Peter Eve )

Well deformation 'goes to heart of economics'

Mr Close told the inquiry that rather than being any threat to the environment, well deformation "goes to the heart of economics".

"If you have events in the horizontal well which prevent you effectively stimulating, then your production could be limited," he said.

An economist from the Institute for Energy Economics and Financial Analysis used those comments to again raise questions about the viability of plans to develop the Beetaloo Basin region between Mataranka and Elliott.

"The results for the Amungee well are not good," Bruce Robertson said.

"If you look at the Marcellus shale in the United States, the [gas] flow rates are about a third.

"We are continually told we have to compete on an international stage, and that's the type of field we are competing with in the US, a field that has three times the flow rates, existing infrastructure in place, and is not remote like the wells in the NT.

"The NT shale province is a very high-cost province."

Map Shale gas resources in NT (Source: NT Department of Mines and Energy)

NT shale gas could be successful: Origin

Origin Energy rejected the assessment that the NT wouldn't be competitive.

"One of the reasons Origin is excited about the Beetaloo and keen to get out and learn more about the resource potential, is because flow rates from Amungee are in a similar range to the early North American shale plays that have proven to be successful, for example Montney, Horn River, Barnett and the Marcellus," Origin Energy said.

"Amungee… is around 600m — a fifth of the size of the wells drilled in the Marcellus. Scale it on per 1,000m basis and it falls within the same range as the US.

"To suggest NT shale gas won't be competitive ignores a decade of evidence from North America that it could be, and if the Beetaloo is successful Australia enjoys strategic location benefits close to Asian buyers relative to North American competitors."