Seismic methods in heavy-oil reservoir monitoring
Duojun (Albert) Zhang, Laurence R. Lines
Laboratory tests show that a significant decrease in acoustic velocity occurs as the result of heating rock samples saturated with heavy hydrocarbons. Therefore, it is possible for us to monitor reservoir characterization during the process of thermal recovery of heavy-oil resources by repeated reflection seismic surveys. To describe the reservoir characterizations, it is imperative that the field data have an extremely good signal-to-noise ratio over a broad frequency band. Specialized acquisition and processing techniques should be used in seismic baseline and monitoring surveys. Some effective seismological methods in monitoring the subsequent subsurface steam movement or injection effect, such as seismic velocity models, isochron analysis, amplitude analysis, frequency attenuation, time-lapse and converted-wave exploration, are summarized from the referenced published papers. All these technologies yield significant new insights about the reservoir parameters, thus leading to a better understanding of the patterns of the heat-front movement. The integration of these into the design and operation of steam injection projects should help in improving their future viability.