THE IMPORTANCE OF REGIONAL GEOLOGICAL MAPPING IN CO_2 STORAGE SITE CHARACTERIZATION: EXAMPLES FROM THE IEA WEYBURN CO_2 MONITORING AND STORAGE PROJECT

摘要

Assessing geological sites for long-term storage of CO_2 clearly involves not only characterization of the reservoir, but also an understanding of the geological and tectonic framework of the region encompassing the containment unit. To this end, regional geological mapping was conducted as part of the IEA Weyburn CO_2 Storage and Monitoring Project to determine the distribution of relationships between strata comprising the geological container, with particular emphasis on identifying and characterizing primary and secondary seals, mapping the distribution of aquifers and aquitards, and determining whether discontinuities were present in the system. Subsurface processes and features affecting the containment system, such as locations of Devonian salt dissolution, were identified and assessed to determine their impact on storage potential. Mapping was performed over a region large enough (200 x 200 km) to reveal basin and tectonic trends that help define relationships among subsurface features and processes. These regional stratigraphic data are required for hydrogeological and structural investigations into site suitability, and for scaling and building a 3D geological model for numerical risk and performance assessment.