There is a great need for high-quality monitoring data from thermal enhanced oil recovery processes (THEOR; Figure 1) applied to heavy-oil reservoirs. We need to understand the physical mechanisms, to improve our attempts at mathematical simulation of these processes, and to provide information for “real-time” project optimization.
THEOR processes (e.g., steam injection) generate large changes in amplitude and traveltime in the complicated signature of a reservoir's seismic response. Conventionally, pressure, temperature, and saturation changes induced by thermal recovery are examined to study their complex and often counteracting effects on the seismic attributes of the reservoir and bounding rocks. The effects of geomechanical changes in stress and stiffness are less often considered, although they may dominate seismic property changes. Thus, seismic data interpretation to deconvolve in situ rock properties is nonunique and it varies with time as these physical parameters change with the maturity of the THEOR process. A fuller understanding of the effects of these changes will lead to better interpretation of changes of seismic attributes; hence, better project management.