gAn integrated eophysical, geodetic, geomechanical and geochemical study of CO2 storage in subsurface reservoirs

It is possible to capture emissions of CO2 from coal-fired power plants and store them in deep subsurface reservoirs such as mature oil reservoirs. This Carbon Capture and Storage (CCS) technology has demonstrated the potential to reduce mankind's greenhouse gas emissions while meeting the world's energy needs. Furthermore, if CCS allows the development of the next generation of clean coal power plants, it will be worth an estimated £6.5billion to the U.K. economy, creating 100 000 jobs, as part of the new 'green economy'. However, to guarantee security of storage, monitoring methods must be in place that can track the movements of CO2 through the subsurface, and image the effects of CO2 injection on the subsurface rocks. When CO2 is injected into reservoirs, the pressure changes can lead to expansion of the reservoir, resulting in deformation of both the reservoir and the overlying rocks that provide the seal. Geomechanical deformation can cause problems at CCS sites if faults and fractures open, allowing CO2 to escape from the target reservoir. I propose a study of geomechanical deformation at CCS sites, using geophysical techniques to monitor deformation, and generating computer models to simulate deformation. Fractures in the caprock will generate seismic energy, which can be detected on geophone arrays. By detecting these microseismic emissions, it is possible to determine how the subsurface is responding to CO2 injection. The inflation of the reservoir can push up overlying rocks, causing uplift of the ground surface, which can be monitored with satellites. My project will analyse microseismic events detected at two CCS sites - In Salah, Algeria, and Weyburn, Canada. I will also study high quality surface uplift data at In Salah. By locating the hypocenters of microseismic emissions, it will be possible to identify regions where deformation is occurring, and, if events cluster onto discrete surfaces, to identify actively deforming faults in the...