Thermal wells point to ‘worst case’ leaks from the deep

Spring water from deep underground carries plenty of heat and chemicals that feed orange microbial mats growing on the rocks at Larsen Spring, one of nine thermal springs in Northern B.C. and the southern Yukon ~ STEVE GRASBY/GSC

Spring water from deep underground carries plenty of heat and chemicals that feed orange microbial mats growing on the rocks at Larsen Spring, one of nine thermal springs in Northern B.C. and the southern Yukon ~ STEVE GRASBY/GSC

VANCOUVER – The water burbles out of the earth carrying evidence of its underground voyage. It has come from depths of up to five kilometres, bringing plenty of heat, gas and chemicals with it.

Bright green and orange mats of micro-organisms grow on rocks where the water tumbles from the thermal springs in the mountains adjacent to areas of active hydraulic fracturing in northeastern B.C. and the southern Yukon.

The water is not from the fracking operations, but the springs show fluids can – and do – naturally make the trip to great depths.

They are like a “worst case scenario” showing that “communication” with the shale gas zone is possible, says Steve Grasby, a federal scientist with the Geological Survey of Canada, who has bushwhacked in to nine thermal springs where natural cracks and faults extend deep underground.

“We can see right next door to where shale gas development is going on that we do have circulation of surface (waters) down to five kilometres depth and back to surface again,” Grasby said in a recent presentation to the Geological Society of America’s annual meeting in Vancouver.

“Not only do we see transmission of water from the crustal levels but we also see transmission of thermogenic gas from the crust up to the surface in these spring systems,” he said.

Thermogenic gas is the variety extracted by fracking. Mixtures of water and sand are injected under immense pressure to shatter rock and release the gas trapped two to three kilometres underground. The fracking process is so intense it can trigger small earthquakes, including 38 in northeast B.C., between 2009 and 2012.

Government regulators and industry say fracking fluids, which is water that can be laced with lead, arsenic, benzene and radioactive compounds, will stay put, locked in geological zones deep underground. But as wells proliferate in Western Canada where thousands of fracking wells have been drilled, so do concerns that fluids and gas will migrate through the growing collection of man-made holes, cracks and fractures beneath the ground.

Enough wastewater and industrial fluids to fill a lake 23 kilometres long, a kilometre deep, and a kilometre wide have been pumped into the Western Canadian Sedimentary Basin underlying the Prairies since oil and gas production began. “And that’s probably an underestimate,” says Grant Ferguson at the University of Saskatchewan, who describes it as a “grand experiment.”

In British Columbia, billions of litres of water is not only injected into active fracking wells that can extend several kilometres underground, but the industry’s wastewater is pumped into old gas wells.

A recent study by the University of Victoria’s Environmental Law Centre found 41 billion litres — enough to fill 16,693 Olympic swimming pools — has been injected into a single well near Fort Nelson, a small town in the midst of northwestern B.C.’s fracking boom.

“Yet because of weak laws, we don’t really know what toxins were in the wastewater, or how much may have leaked into groundwater or surface water,” says the University of Victoria researchers, who are calling for better regulation and monitoring.

The nine thermal springs show that where there are cracks, water can travel.

Grasby says such natural springs are rare, with only nine located in the heavily fractured geological zone where the Rocky Mountains ram into the deep layers of shale containing the gas that energy companies are fracking in lower lying areas.

Grasby says rain and snowmelt percolates down, and then back up, to the springs through the natural cracks and faults.

The water returns carrying heat — the springs range from 30 C to 56 C — and chemicals leached out of rocks. It also carries gas from the shale layer, which is highly deformed and fractured where it runs up against the mountains.

One of the springs is at Liard, along the Alaska Highway, and the other eight are in more remote locations that Grasby says are easy to spot from the air.

“They tend to kill off big chunks of forest due to the high temperatures and mineral precipitation that is going on,” says Grasby.

At the springs calcium carbonate deposits cover the rocks and bright mats of micro-organisms that feast on the gas and chemicals from the deep.

© COPYRIGHT – POSTMEDIA NEWS
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