Cenovus Energy says the carbon dioxide gas it uses in its enhanced oil recovery project near Weyburn, Sask., is not leaking to the surface.
The Calgary company held a news conference last week to release the results of a third-party site assessment.
Brad Small, Cenovus’s vice-president of oil and natural gas for Saskatchewan, said the study found no presence of carbon dioxide from the Weyburn project in soil or wetlands on the property of nearby landowners, who earlier this year complained about contamination.
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Small also said detectable hydrocarbons weren’t present in the surface water and no integrity issues were detected with Cenovus-operated wells and infrastructure on the property of Cameron and Jane Kerr.
The Kerrs moved from their land in 2005, alleging that carbon dioxide and hydrocarbons from the project were leaking. In January, the couple released a study by a Saskatoon consultant that showed unusually high carbon dioxide and methane levels in their yard.
Cenovus had promised the provincial government it would ask third-party experts to examine the site.
As well, results of an independent study conducted by the International Performance Assessment Centre for Geologic Storage of Carbon Dioxide in Regina are expected Dec. 12.
“Our findings indicate that there is absolutely no way carbon dioxide in the soil at the property in question originated from Cenovus’s operation in Weyburn,” said Court Sandau of ChemistryMatters, the lead scientist for the Cenovus study.
The study used carbon dating to determine that the carbon dioxide on the Kerr property was more recently formed than the gas Cenovus is injecting from the Dakota Gasification Company in Beulah, North Dakota.
Sandau said carbon dioxide from North Dakota comes from coal deposits formed millions of years ago.
“Our findings assert that the carbon dioxide present at the property was formed recently and is attributed to natural soil respiration processes.”
Sandau said 54 samples were taken in August, followed by 72 more. Elevated carbon dioxide levels were found in only one sample, taken from the first batch. He said that was an anomaly and it was new carbon.
A frog habitat and wetland evaluation conducted after northern leopard frogs were found in the area indicate a healthy ecosystem, he added. Frogs are sensitive to low levels of contamination.
Ecojustice, which is advising the Kerrs, said it was reviewing the Cenovus study, which it called long overdue.
“After years of requesting an in-depth investigation on their property, the Kerrs are glad to see that Cenovus has finally conducted a investigation of the potential impacts carbon capture and storage may have on their property,” said Ecojustice lawyer Barry Robinson in a statement.
Carbon dioxide has been injected underground at the site since 2000.
