Time-lapse seismology has proven to be a valuable tool in the characterization of reservoir conditions in enhanced oil recovery (EOR). Our collective research experiences with Athabasca, Cold Lake, and Lloydminster oil sands demonstrate the utility of seismic monitoring for mapping steam front zones. Due to seismic velocity decrease with increasing temperature, seismic monitoring of steam zones can be achieved by time-lapse mapping of seismic reflectivity, impedance, and amplitude variation with offset (AVO). The application of seismic monitoring in cold oil production has not been widely applied. With cold production of oil sands, there can be the development of high porosity zones known as "wormholes". These high porosity zones are much smaller than a seismic wavelength so their detection will be extremely difficult unless several wormholes collectively create a larger effective medium with low seismic velocity. Nevertheless, it is interesting to speculate whether time-lapse seismology has a role to play in the reservoir characterization of "cold flow" as well as in "hot flow" heavy oil production.
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