Integrated reservoir, petrophysical, and seismic simulation of CO2 storage in coal beds

In this paper, we present results of an integrated simulation study to assess the effectiveness of seismic imaging for monitoring CO2 sequestration. We considered two scenarios. In the first, injected CO2 remained confined within a shallow coal formation. In the second, the sequestered CO2 gas leaked through a semi-permeable shale layer to an overlying sand unit sealed above. In both scenarios, the CO2 injection process resulted in enhanced production of coal-bed methane. The reservoir and seismic simulations required the construction of 3D geologic and facies models, the estimations of seismic velocities based on rock physics correlations, and the development of geostatistical dual-porosity reservoir descriptions of the coal and overlying shale and sand units. We ran the 3D reservoir simulations with GEM 2008.10, an equation-of-state compositional reservoir simulator from Computer Modeling Group with the capability to model adsorption of injected CO2 in coal, desorption of CH4 , and matrix shrinkage-swel...