A natural gas deposit straddling British Columbia, Yukon and the Northwest Territories could be one of the largest in the world, according to a recent assessment.

The first detailed assessment of the Liard Basin, released Wednesday, was a joint effort by the National Energy Board, the B.C. Oil and Gas Commission, the Yukon Geological Survey, the Northwest Territories Geological Survey and the British Columbia Ministry of Natural Gas Development.

The NEB said the Liard Basin is Canada's second-largest known gas resource after the Montney, which straddles B.C. and Alberta, and it ranks ninth in the world.

National Energy Board supply analyst Mike Johnson said the estimated 219 trillion cubic feet of natural gas is enough to meet Canada's natural gas needs at 2014 levels of consumption for nearly 70 years. 

Most of it is located in British Columbia with about 20 per cent in the N.W.T. and four per cent in Yukon.

Hurdles to development

The gas is trapped in layers of shale three to four kilometres deep in the ground in most places. The only way to get it out is by hydraulic fracturing.

Any development involving fracking is guaranteed to provoke opposition due to concern over the extraction method's effects on groundwater. 

"The evidence is mounting of the peril of fracking," said Lois Little with the N.W.T. chapter of the Council of Canadians. "Our water systems are connected. We are part of that landscape."

Another hurdle to developing the Liard Basin is economics. A glut of shale gas has pushed the price of gas down more than 50 per cent in the last few years. 

​Northwest Territories Premier Bob McLeod said that with the downturn in oil and gas prices, pretty much all the exploration companies have "packed up and left" the territory. 

"It's a high-cost environment and it's usually the first place that's affected when prices go down," he said.

But long-term demand forecasts give him hope.

"We see this as an opportunity to get ready," he said.

In B.C., Chevron Canada and Australia's Woodside Petroleum have teamed on a project to develop gas, mostly from the Liard Basin, and liquefy it at a terminal planned for the Kitimat, B.C., area.

The partners expect to have drilled five wells in the Liard by year-end as they continue to appraise their holdings, said Ray Lord, a spokesman for the project.

with files from Canadian Press