A two-year investigation has identified the prime suspect behind environmental horror stories that threaten to stunt the growth of infant coalbed methane production in Canada — and the culprit is not the industry. The report squashes a major source of public opposition to developing the province’s estimated 500 Tcf endowment of coalbed methane, in seams the right thickness and depth to be considered candidates for development.
A modern version of the ancient phobia of poisoned wells — natural gas creeping into drinking water — triggered an inquiry by the Alberta Geological Survey, an independent scholarly arm of the Alberta Energy and Utilities Board (AEUB).
High-profile cases before the AEUB have starred residents of the chief gas-producing province’s best farming and ranching regions, protesting that coalbed methane drilling made their water undrinkable and turned their wells into fire hazards. Protests have included televised cases of irate farmers igniting substantial flares by holding matches to faucets opened rapidly after being shut off for a day or two to let pressures build up.
After prolonged study of 20 industry gas and farm water wells in four drainage basins over a 14,750-square-mile area studded with coalbed methane projects, the survey’s scientists confirmed that the country residents have a real problem. But the gas — at times in volumes big enough to cause a distinct pop when taps are turned on after being left off for a while — was not seeping into water wells from nearby gas drilling sites.
Age dating, painstaking biological testing and thorough chemical analyses showed that water in drinking wells and water in gas wells have separate and distinct compositions, the study concluded. The evidence runs completely counter to a widespread popular suspicion, that groundwater sources are all connected and industrial penetration of one is bound eventually to pollute all the rest.
Then what is the source of the gas in the water wells — it is the water wells themselves. Additional testing showed there are naturally occurring bacteria in water wells, in varying volumes depending on local conditions. The bacteria make gas as a byproduct of their digestive process.
The offending micro-organisms, while present in undisturbed aquifers, do not thrive in them. But when the subterranean streams are tapped for drinking water, the pumping action of wells enhances supplies of nutrients for the bacteria, causing them to flourish and multiply, the inquiry found.
The study followed research protocols devised by the United States Geological Survey as well as Canadian federal, provincial and academic agencies, the AEUB said in releasing the results of the investigation. The findings will be incorporated into “the existing knowledge base” used to settle gas-field disputes and reach decisions on development plans, the AEUB said.
In Alberta a provincially-appointed coalbed methane task force of science, industry, government, environmental and public representatives filed a report a year ago warning “the potential for impact on groundwater has been a serious concern.” The group emphasized that “protection of aquifers, water bodies and non-saline water users by the provincial government is critical for the appropriate development of coalbed methane — natural gas from coal.”
The poisoned wells phobia, also known as the theory of “hydraulic connectivity” in polite scientific language, ranked high on the list of technical concerns and at the top or near it on the list of public concerns. Hot-button issues in a province prone to drought also include loss of fresh water supplies and pollution by industrial waste, led by salt water tapped with gas wells into naturally saline wet geological zones.
For the industry, resolving water issues and clearing up public fears is key to tapping Alberta coal seams for gas on a large scale. Coal seams carpet much of the province, prompting industry promoters to call the resource potentially a gas counterpart to oilsands deposits estimated to contain 175 barrels of reserves recoverable with known technology.
Of the coalbed methane endowment, 147 Tcf or 30% is in shallow and mostly dry deposits that yield multiple small-volume gas wells in a band of formations between the two main Alberta cities of Calgary and Edmonton. All the rest occurs in wet formations, including the biggest and best prospect for higher-volume wells, the Mannville layer estimated to contain 320 Tcf of gas.
“Encouraging results” have emerged from early Mannville production trials and pilot projects, the AEUB said in its latest state-of-industry-reserves survey. For the beginning forays to mature into industrial production, the coalbed methane task force urged all concerned to devise standard, publicly accepted methods of assuring development activity neither fouls the province’s water nor stirs up resistance in increasingly sensitive communities.
Â©Copyright 2007Intelligence Press Inc. All rights reserved. The preceding news reportmay not be republished or redistributed, in whole or in part, in anyform, without prior written consent of Intelligence Press, Inc.
© 2023 Natural Gas Intelligence. All rights reserved.
ISSN © 1532-1231 | ISSN © 2577-9877 |