Crosswell seismic imaging of reservoir changes caused by CO 2 injection

Monitoring of enhanced‐oil‐recovery processes with crosswell data has been one of the earliest applications of time‐lapse geophysics. Because data with frequencies up to a few kilohertz can often be collected with the crosswell geometry, the method can potentially offer imaging resolution of the order of a few feet. Such resolution is often necessary for time‐lapse investigation to be useful in building reservoir models and for accurately describing fluid flow in heterogeneous reservoirs.