Cambrian Carbon-Sequestration Geosystems of Canada

Abstract

Skepticism of carbon capture and storage’s (CCS) potential for curbing anthropogenic global warming continues. That doubt is fed, in part, by the failure of some CCS sites to meet injection targets because of problems with the subsurface geology. This paper argues that more rigorous geoscience characterization is needed to more realistically predict the injectivity, storage, and seal capacity of prospective CCS sites. It illustrates how a holistic, genetic approach to characterizing the geology of those sites, using a carbon-sequestration geosystems approach, can be used to guide property predictions at the screening phase. The case is made by examining Cambrian sandstones at four onshore locations in Canada. At all four sites those sandstones are relatively poorly characterized saline aquifers, making them different from depleted hydrocarbon reservoirs that typically have abundant data. Two of the sites (Quest and Aquistore) are working CCS facilities, and their study illustrates how the tectonic setting, depositional environment and history, and post-depositional structural evolution affected the development of repositories and seals in the Cambrian and overlying strata. CCS facilities have not yet been established in Southern Ontario and Southern Québec, but Cambrian sandstones are the most likely targets for CO2 injection in both areas. Insights from the working CCS locations illuminate geologic opportunities and challenges in these “exploration-stage” areas. However, the Ontario and Québec areas have certain geologic characteristics that are unlike those present at the Quest or Aquistore sites. In such cases, guidance about geologic risks and opportunities needs to be obtained elsewhere, such as from the petroleum industry.