As part of this research, an extensive program of sampling soil gases and shallow water wells across the CO2 injection area has been undertaken for almost 10 years. Baselines for CO2 in the soils and wells were taken in multiple locations starting in July, 2001, prior to any injection, and several surveys have been repeated periodically since injection began.
The soil gas surveys were conducted by independent research organizations including the British Geological Survey, BRGM (French Geological Survey), and INGV (Italian Geological Survey). These tests (some of which are available in the First Phase Report on the PTRC’s website at http://www.ptrc.ca/siteimages/Summary_Report_2000_2004.pdf ) all have indicated that soil gases sampled are in the normal range for these soil types given variations in organic matter content, moisture, temperature and seasonal variations. No evidence of CO2 originating from the 1.5 km deep Midale Reservoir (the geological unit at the Weyburn Field) has been observed in any of these surveys undertaken by these international scientific organizations. Similarly shallow well water samples taken repeatedly throughout this study over 10 years have not indicated any evidence of CO2 from the deep geological reservoir.
The report Geochemical Soil Gas Survey conducted by Paul Lafleur of Petro-Find Geochem, Ltd and submitted to Cameron and Jane Kerr is currently in the process of review by the PTRC. A response to this report will be provided once it has been thoroughly reviewed.
In summary, through its extensive measurement and monitoring program – undertaken in cooperation with researchers from tens of organizations including Canadian and international universities, independent research institutions, consultancies, and government agencies – PTRC has never identified a leak of CO2 into the biosphere or soil in the Weyburn-Midale field area, nor in selected sample locations beyond it.
Many of the results related to the final phase of the IEA GHG Weyburn-Midale CO2 Monitoring and Storage project are a matter of public record in the scientific literature that has been published and presented at conferences and workshops. A Best Practices Manual, which will help guide other projects in the safe storage of CO2 in depleted oil fields, will be released by the end of 2011. For more information on the Weyburn-Midale project visit the PTRC’s website and publications at www.ptrc.ca/publications.php