A new University of Guelph study proves what many western Canadian landowners have long documented — that methane gas leaking from energy industry wells can travel great distances in groundwater and pose safety risks, contaminate water and contribute to climate change.
The study, published in Nature Geoscience this month, also concluded that current monitoring for gas leakage, usually at ground level and adjacent to wells, is inadequate to detect contamination.
“Current surface and subsurface monitoring efforts of shale gas development are thus insufficient to meaningfully detect or assess methane impacts to atmosphere and groundwater,” the study found.
British Columbia’s floundering shale gas industry has drilled and fracked nearly 10,000 wells in northeastern B.C. over the last decade, causing more than 1,000 earthquakes in the region. Impacts on groundwater are not being systematically monitored.
The study took a novel approach, said Aaron Cahill, lead author and groundwater researcher at the University of British Columbia.
“We asked if leaks occur from an energy well, what happens to the groundwater and where does the methane go, and nobody had looked at that before.”
Cahill and other scientists at Guelph’s Institute for Groundwater Research injected methane over a 72-day period into a shallow sand aquifer at Canadian Forces Base Borden in Ontario at a rate of about a cubic metre a day — a volume much less than actually recorded at many leaking oil and gas wells in Alberta and B.C.
Guelph researchers tracked the injected methane for more than eight months via monitoring wells as the explosive gas travelled through the ground, entered the atmosphere or dissolved into groundwater, causing subtle but important changes to water chemistry.
In an aquifer, bacteria can metabolize methane and generate undesirable byproducts such as hydrogen sulfide. Bacterial reactions can also bring about the release of trace elements, changing water quality and potentially rendering it undrinkable.
“We didn’t see a lot of methane reacting. It degraded at low rates. In other words, if a leak were to occur the methane wouldn’t go away too rapidly from the aquifer,” Cahill said.
Cahill also noted that the study covered only a short time period and used only small amounts of methane.
“For larger leaks over longer times and greater areas, these findings would indicate that the groundwater would likely become unusable,” he said.
Cahill said the distance travelled by the methane in a relatively shallow sand-based aquifer and complex interactions showed the importance of monitoring groundwater around energy developments. He also called for more research in different settings and adjustment in regulations.
Alberta, for example, only classifies a leaking well as “serious” when it leaks 300 cubic metres of methane a day, but the research showed extensive impacts on groundwater with a leak of just one cubic metre per day.
Methane leakage from tens of thousands of shale gas, coalbed methane, inactive and abandoned wells pose a major and costly environmental problem throughout North America where the energy industry has drilled more than 4 million holes since the 1850s.
There are 1,500 inactive and leaking wells in Alberta’s cities (some are in malls and playgrounds) and more than 150,000 abandoned or inactive wells in rural Alberta.
Reports of groundwater contamination are common throughout oil and gas regions in North America. In Pennsylvania alone there have been hundreds of cases of groundwater contamination from energy wells.
Although industry argues that shale gas wells are too deep to affect groundwater, most methane leaks come not from the production source or bottom of the well but from shallower geological formations closer to the surface of the well. Gas flows up then enters groundwater or the atmosphere via corroded, old or faulty seals.
Because all energy wells puncture the earth and caprocks, they often serve as effective pathways for the migration of methane, and other gases such as cancer-causing radon over time.
Phil Rygg, director of communications for the BC Oil and Gas Commission, said there were “some important learnings from the study” but that it only looked at how methane moves through beach sand in Ontario.
He added that “it did not examine how gas could move along a shale gas well and enter groundwater.”
However, the researchers noted in their paper that methane will migrate much farther and faster in fractured sedimentary rock, like that found in northern B.C. and Alberta, compared to a sand aquifer.
Rygg said that a similar groundwater study is now being done by UBC and supported by Geoscience BC with technical input from the B.C. Oil and Gas Commission. Its goal is “to understand methane behaviour in the subsurface in northeast B.C., and includes drone and remote sensing research.”
“The commission will continue to support research in this area, and supports the general recommendation for enhanced monitoring,” he said.
Despite evidence of serious methane leakage into groundwater from energy wells, many regulators and energy companies have denied the scale of the problem, claimed the methane naturally migrated into the groundwater or was caused by bacteria.
But the study challenges those assumptions by showing how a methane leak actually behaves in an aquifer.
Moreover, the study found that methane leakage into groundwater can affect water over a large area and “is an equivalent, if not, more significant process relative to atmospheric emissions.”
Once methane migrates into a pump house or basement it can be explosive in confined spaces.
“There has been no science-based groundwater monitoring using modern methods at fracking sites,” said Beth Parker, director of the G360 Institute for Groundwater Research and a co-author of the paper.
“Our findings are evidence that prospects for insightful information obtained from such groundwater monitoring are good, which goes against the ‘conventional wisdom’ mostly based on speculation or intuition.”
In recent years the chronic problem of methane leakage has been aggravated by hydraulic fracking, which causes more wear and tear on well plumbing and seals with intense pressures, shaking and well-banging seismic activity.
John Cherry, one of Canada’s top hydrogeologists and one of the paper’s authors, said the new study should put to rest any arguments that there is no point monitoring groundwater for methane contamination from energy wells “because it will move like little snakes in channels and you’ll never find it.”
“The study found that very small amounts of injected methane ended up having a large impact on the aquifer — the magnitude was huge, and the methane hung around for a long time.”
No Canadian regulator has set up proper groundwater monitoring near shale gas facilities as recommended by a 2014 Council of Canadian Academies report on fracking.
“No regulator has yet done what we recommended,” confirmed Cherry. Alberta doesn’t have a protocol for investigating methane contamination of groundwater.
The Council of Canadian Academies report found that the fracking industry, the foundation of B.C.’s failing liquefied natural gas strategy, had marched ahead without credible baseline data, scientific knowledge and necessary monitoring and had put groundwater at risk.
Jessica Ernst, a landowner who is suing the Alberta government and Encana alleging negligence in the fracking of shallow coal seams more than a decade ago, welcomed the Guelph study as long overdue.
Ernst said she would include the study in filings to support her lawsuit alleging the government’s “negligent investigation and cover-up of Encana’s fracking practices when the company illegally fractured my community’s drinking water aquifers and put us in explosive risk in our homes.”
Ernst said that the water reservoir in her hamlet of Rosebud blew up in 2005 — an incident the local paper attributed to an “accumulation of gases” that seriously injured a county worker.
In a separate incident a year later, “Alberta rancher Bruce Jack and two industry gas-in-water testers were also seriously injured and hospitalized after industry’s leaking methane and ethane caused his water to explode,” said Ernst. A 2011 Alberta Innovates report on the leak that identified industry contamination was never released to the Alberta public.
The Guelph study adds some cold and hard science to the growing debate about methane migration from oil and gas wells.
Nearly a half a dozen studies done by scientists at Duke and Stanford universities have consistently found elevated levels of methane in water wells near shale fracking operations but couldn’t always identify the source or the mechanism for contamination.
Other studies have found chemistry changes in groundwater near energy wells.
A 2014 University of Texas study, for example, looked at 100 water wells in the heavily fracked Barnett Shale and found that approximately 30 per cent of the wells within 2.9 kilometres of gas drilling sites showed an increased amount of arsenic and other heavy metals.
An earlier 2013 University of Texas study suggested that elevated levels of strontium, barium, selenium and methanol in water wells near gas wells could be due to a variety of factors, including hydro-geochemical changes from lowering of the water table, or industrial accidents such as faulty gas well casings.
For decades, fracking technology patents filed by industry noted that “it is not uncommon during hydraulic fracturing for the fracture to grow out of the zone of productive interest and proceed into a zone of non-productive interest, including zones containing water.”
But industry has repeatedly dealt with abuses of groundwater by offering landowners money and demanding that they sign non-disclosure agreements.
In the absence of any credible groundwater monitoring, governments such as that of British Columbia can also claim, “There has never been a confirmed case of groundwater contamination in B.C. as a result of hydraulic fracturing.”
The Canadian Association of Petroleum Producers still maintains that “more than 215,000 wells have been hydraulically fractured in B.C., Alberta and Saskatchewan without a demonstrated impact on drinking water, according to regulators.”
B.C. Natural Gas Development Minister Rich Coleman denied that energy wells leak methane in 2014. In contrast, the BC Oil and Gas Commission does not deny this reality.
According to a report by three University of Waterloo engineers, more than 10 per cent of B.C.’s existing 20,000 active and abandoned wells leak. In addition, some of the province’s shale gas wells have become “super emitters” of methane.
In recent years one energy company spent $8 million in northern B.C. to repair a badly leaking shale gas well.
Teaser photo credit: Photo of shale gas well by Jeremy Buckingham, Creative Commons licensed.