A nearby fracking operation had been pumping fluids deep underground to blast open a web of cracks to release oil. But 1,850 metres down the fracking fluids, propelled by immense pressure, shot through into the neighbouring well sending 75,000 litres of oily fracking fluids up the well and onto the snowy field in January 2012.
Alberta’s energy regulator later described it as “communication” between the two wells — one of more than 40 such “frack hits” reported in Alberta and British Columbia since 2009.
Regulators have introduced new rules to try to avoid such interactions, but as it gets more crowded underground observers say it is time for serious discussion about the way man-made holes and cracks in the ground are compromising the landscape and resources below.
The impact starts at the surface. Provincial rules require homes and buildings to be set back at least five metres from old wells. In Alberta, home to more than 450,000 wells, that means a lot of land off-limits as development encroaches on old oil and gas fields.
It’s even more complicated underground, where wells can not only “communicate” with each other, but create pathways that can potentially leak into groundwater aquifers and compromise resource development.
“If you have a leaking well and it doesn’t manifest at surface, you don’t know where it is leaking to,” says Theresa Watson, a Calgary-based engineer specializing in wellbores. She is also a former board member of the regulatory agency overseeing Alberta’s energy industry.
“It could be leaking into some other reservoir that you don’t want it to leak into for economic reasons,” says Watson, explaining how wells can “compromise” or “sterilize” areas against future resource development.
She points to the thousands of old or “legacy” wells dotting Alberta and Saskatchewan that may rule out use of steam-driven processes for extracting heavy oil and bitumen.
“Many old wells weren’t abandoned in any way that could handle thermal stress, and now those areas can’t be steamed and therefore the bitumen can’t be recovered,” says Watson.
Old wells can be repaired, but it won’t be cheap.
A report by Chris Diller, a Shell Canada engineer, has predicted it will take “billions of dollars to correct the abandonments” in Alberta alone. And he says “if these wells are not identified and abandoned properly, there is a high risk of negative impact to the environment, operator reputation, and the economics of field operations.”
Diller speaks from experience. Shell Canada wanted to store poisonous sour gas, which smells like rotten eggs, in an underground reservoir near the company’s Peace River operations in northern Alberta in 2010. But then Shell realized the reservoir had been compromised by an old well that was abandoned in 1989, after another company’s drilling gear got stuck 121 metres down the well. Diller says it took two months and cost Shell more than $5 million to repair the abandoned well.
An old well has also been implicated in the leak — one of the worst in Alberta — at the Primrose oilsands project where more than a million litres of a gooey bitumen-water mixture oozed out of the ground last year. (Alberta regulators say a cracked caprock on top of the bitumen layer also played a role in the leak).
And “frack hits,” which have occurred from Texas to northeast British Columbia, show that fracking operators do not always know when they are too close for comfort to other wells.
The “communications” between wells can undermine production and pose a serious safety and environmental hazard by sending fracking fluids into and up other wells. One “incident” in northeast B.C. in 2010 shot fracking fluids and sand into another well 670 metres away. Others have spilled thousands of litres of wastewater, fracking fluids, and oil and gas.
Alberta and B.C. energy regulators say the incidents are rare and have introduced rules and protocols that require fracking operations to stay 200 metres from water wells, and to notify nearby well operators when fracking is taking place.
Abandoned and poorly cemented old wells are also a concern as researchers say they could potentially enable fracking fluids to migrate through cracks in and around the old wells’ casing and into underground aquifers. Decommissioned wells “constitute the seepage pathway of greatest risk for hydraulic fracking fluids,” says a report published in September by University of Waterloo researchers.
Co-author Richard Jackson, a groundwater expert with Geofirma Engineering Ltd. who teaches at Waterloo, is pushing regulators and industry to improve well seals and step up monitoring. He also says the country needs to discuss how it wants to use subsurface.
Energy companies are the big players in the underworld today, but Jackson and his colleagues say there could be plenty of competition in future.
There is talk of desalinating water from deep underground aquifers as the world grows thirstier — aquifers that might be compromised if contaminated wastewater now injected underground migrates through cracks and fissures.
And CO2 sequestration, which entails injecting carbon dioxide deep underground, could become big business. But it could be limited by oil and gas operations drilling holes in zones that might be ideal for carbon capture and storage.
“There is no question that old wells are already a significant impediment to CO2 storage,” says Watson, who agrees it is time for “some serious thought” about the legacy the industry is leaving and how it may be “compromising future resource development.”
“If you’ve created a pathway, presumably that pathway of potential leakage could be there forever,” she says.