Back in January 2011, a number of stories appeared in Canada’s national media outlets claiming that the Weyburn carbon capture and storage (CCS) project – where high-pressure carbon dioxide (CO2) is injected into the oil reservoir to both help recover more oil and sequester the greenhouse gas – was leaking into the atmosphere and posing a risk to wildlife, and via implication, humans.
The alleged leak was on the Kerr property, near the site where Cenovus injects CO2 into the ground to a depth of well over a kilometre. Dead birds, a rabbit, goat, cat, and duck were reported near the supposed leak, along with “night-time blowouts, which sounded like cannons and left gashes in the side of the pit” on the Kerr’s property.
The troubles began in 2003 after a gravel pit was dug on the property. Following an apparent dispute with the provincial government that continued to 2007, the property owners told the media they received a pledge from the province that the problem would be studied.
The Kerrs claim the promise wasn’t kept, and so they hired an independent consultant to conduct an investigation.
In October 2010, the consultant produced his report, which found CO2 concentrations in the soil at levels 70 times higher than what the consultant considered normal. The consultant’s conclusions were that these concentrations “could be very dangerous” and that the chemical fingerprint of the elevated CO2 levels in the soil matched the signature of the CO2 being injected into the oil reservoir.
These findings caused considerable concern among the scientific community, the oil industry, and the provincial government. A review of the data by some scientists and the industry cast doubt on the claims.
Early soil sampling in the area prior to the start of large-scale CO2 injections found CO2 concentrations much higher than what was reported on the Kerr property in 2010, suggesting the high levels could be naturally occurring.
Similarly, Cenovus argued that it was unlikely that injected CO2 could have travelled underground from their site over to the Kerr property.
Likewise, the provincial government stated that they did indeed keep their promise to the Kerr family, taking air, water and soil samples and producing a 2008 report finding no sign of CO2 leakage.
The lack of evidence to support the allegations of leakage were all consistent with the extensive research done at the carbon injection site by various teams of international researchers prior to the start-up of large-scale injections. This collective body of work had continually shown no significant risk of major CO2 leaks that could endanger nearby wildlife or pose a risk to humans.
Since the allegations surfaced in public in early 2011, a number of subsequent peer-reviewed publications have also appeared in the scientific literature by academic research groups from the United States, Canada, Italy, France and the United Kingdom.
These studies collectively found no evidence of any CO2 leakage at the Kerr property or in the nearby area.
During the past two years, we have also undertaken an extensive monitoring study of near-surface atmospheric CO2 concentrations at dozens of locations both within the Weyburn CCS project and at background locations throughout southeastern Saskatchewan.
We found, in agreement with all the prior studies, no evidence whatsoever of any elevated CO2 levels at, or near, the ground surface, regardless of the time of year, soil temperature, moisture condition, wind speeds, presence or absence of snow cover or other variables.
If there were CO2 leaks of the magnitude alleged in the 2011 media reports, being of an extent that was regularly killing wildlife and posing a potential risk to humans near the CCS site, we would expect there to be reproducible and easily demonstrable evidence for such leaks in the region, possibly even including “domes” of elevated CO2 levels above normal background concentrations near the ground surface within the area.
Our research, along with that of other well-respected groups, has found no such evidence.
As a result, after much controversy since the allegations were made public more than six years ago, we must conclude that there is absolutely no evidence at this time to support concerns that the Weyburn CCS project is leaking into the atmosphere above.
Dr. Sierra Rayne and Kaya Forest
Moose Jaw
Editor’s note: Sierra Rayne, Ph.D., is an independent scientist. Kaya Forest is the program head for environmental engineering technology at Saskatchewan Polytechnic.
