Time-lapse, multicomponent seismic data acquired during the CO2 flood at Delhi Field, Louisiana are used to identify zones containing high residual bulk oil volume and to target the location of new injection wells in the field. The data are used to monitor the reservoir and to see if the predicted zones of high residual oil are contacted by the enhanced oil recovery (EOR) process. Because the reservoir is shallow and injection pressures are relatively high, the cap rock is monitored. Stresses associated with injection induce observable shear-wave splitting anomalies in the cap rock. Stresses transmitted into the shale-confining layer by the injection process are not believed indicative of rupturing and CO2 leakage. The ability to monitor geomechanical changes through shear-wave splitting is an important new use of multicomponent seismic data.