Monitoring of CO2 sequestration using integrated geophysical and reservoir data

Geophysical techniques provide the most cost-effective approach for obtaining the spatial coverage required for mapping the location and movement Of CO2 in the subsurface. However, the effectiveness of these techniques depends upon many factors, including the contrast between the physical properties Of CO2 and resident formation fluids, the lithology and structure of the reservoir, formation fluid pressures and pressure variations, source and receiver locations, well spacing and injection patterns. An iterative process of reservoir simulation and forward and inverse modeling can be used to access the effectiveness of candidate geophysical methods and to optimize monitoring systems. Results are presented for an example reservoir model of two sandstone reservoirs connected by a fault. Reservoir simulations provide a 3-D time-resolved grid of porosity, permeability, and gas-water-oil saturation, as well as injection and production. Forward calculations where made to predict the seismic, electromagnetic (EM) and gravity response. Through inversion the resolution of the techniques was assessed.