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The key issues in CO₂ sequestration involve accurate monitoring, from the injection stage to the prediction and verification of CO₂ movement over time, for environmental considerations. ‘4-D seismics’ is a natural non-intrusive monitoring technique which involves 3-D time-lapse seismic surveys. Successful monitoring of CO₂ movement requires a proper description of the physical properties of a porous reservoir. We investigate the importance of poroelasticity by contrasting poroelastic simulations with elastic and acoustic simulations. Discrepancies highlight a poroelastic signature that cannot be captured using an elastic or acoustic theory and that may play a role in accurately imaging and quantifying injected CO₂. We focus on time-lapse crosswell imaging and model updating based on Fréchet derivatives, or finite-frequency sensitivity kernels, which define the sensitivity of an observable to the model …