The unanswered question in the rush for Queensland's hidden oil jackpot

Deep beneath Queensland's grassy plains and scrub lies what some believe could be one of Australia's biggest untapped oil prizes.

The Taroom Trough was first drilled more than 60 years ago but abandoned when the technology couldn't unlock it.

Now, advances in drilling and growing concerns over fuel security have sparked a new rush, with governments promising to fast-track development.

But before all those barrels can be brought to the surface from rock buried up to 4.5 kilometres down, one critical question remains: where will the millions of litres of water needed to extract it come from?

Independent hydrogeologist Ned Hamer said unlocking the Taroom Trough's oil reserves would require a water-intensive and controversial extraction method, which could prove one of the project's biggest hurdles.

"It does require fracking,"

he said.

"One of the biggest impacts is the amount of water that is used for the fracking process."

Mr Hamer said the state's enthusiasm for developing the resource had outpaced planning for its water needs.

"We don't really have the water available for that extraction in these water-constrained areas," he said.

The Taroom Trough is a geological formation stretching from the New South Wales border into central Queensland and has become one of the state's hottest oil and gas prospects.

Premier David Crisafulli has called it a "sea of oil", and Resources Minister Dale Last has declared: "I'll sign, you drill."

Companies including Omega Oil and Gas, Shell QGC, Santos and Elixir Energy are exploring the region, and while Shell is already producing about 200 barrels of crude oil a day, full commercial production will require more government approvals.

The companies have invested more than $500 million in exploration, with estimates suggesting the basin could contain more than 30 million barrels of oil.

Fracking controversy

Extracting these reserves requires hydraulic fracturing, or fracking, which involves pumping water underground at high pressure to crack rock between 3.5km and 4.5km below the surface.

Currently in Australia, fracking uses 20 to 30 megalitres of water per well over its lifetime, with some water recycled or treated after use.

That's eight to 12 Olympic swimming pools.

Mr Hamer said Queensland should have a publicly available water plan agreed with landholders before drilling ramps up.

"I've been calling for a plan to forecast that water use, agree on where that water is going to come from, how much is required … before the industry gets up and running," he said.

"I haven't heard any talk at all about the impacts on water resources and landholders."

Mr Hamer said the risk of fracking deep underground contaminating the Great Artesian Basin was low because the target oil formations sat hundreds of metres below groundwater aquifers, and Queensland's well-construction standards were considered strong.

But contamination incidents have happened in Australia.

The lack of detail is also worrying landholders.

Property Rights Australia chair Dale Stiller, who owns grazing properties within the Taroom Trough, said groundwater was critical for many farmers, particularly during drought.

"It's lifeblood,"

he said.

"There needs to be far greater assurance and far more information about where this water is going to come from."

Mr Stiller said most farmers were not opposed to oil and gas development but wanted more transparency.

"The feedback I'm getting is that people aren't deadset against this at all," he said.

"What they want is to say, 'Hang on, we want to know more.'"

The law

Under Queensland law, landowners cannot stop mining or petroleum developments on their properties, only negotiate compensation.

The Crisafulli government has moved to speed up development by creating a Taroom Trough Development Plan, which gives the coordinator-general broader powers to coordinate infrastructure and streamline approvals.

Queensland is also asking the federal government to declare the basin a project of national interest to fast-track federal environmental approvals.

Federal Environment Minister Murray Watt has accused the state of offering "a photo op and a flashy headline" without enough detail to assess the proposal.

His office said no formal referrals for the Taroom Trough had yet been lodged under federal environment laws.

Reassurances given

When asked at a recent press conference where the water would come from, the resources minister punted the question to Omega Oil and Gas chief executive Trevor Brown.

Mr Brown said the company believed the project could be developed safely.

"We're completely removed from any of the aquifers that are used by the ag sector and any of the farmers here," Mr Brown said.

"The water will be an issue that we're working through with the government, and we'll make sure that it's sustainable and done to the highest standards."

Mr Last insists mining and agriculture can work side by side.

"We want the two to co-exist," he said.

"We want that to be a happy marriage."

Despite more than 15 government announcements promoting the Taroom Trough since February, none have explained where the project's water supply will come from.

Taxpayers are backing the project regardless, with at least $11.9 million already allocated.

As Australia races to shore up domestic fuel supplies, communities living above the Taroom Trough say the real debate is no longer just about oil; it's also about water.

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