Reservoir Monitoring and Characterization for Heavy Oil Thermal Recovery

摘要

Extracted post-stack seismic attributes from time-lapse 3-Drnseismic data have been used extensively to map steam arealrnconformance by using statistical analysis in the developmentrnand monitoring of follow-up processes.rnA quantitative cross-calibration scheme between time-lapsernseismic surveys has been developed using data normalization.rnIt was found that a significant difference results from using arndifferent calibration set; and that time-lapse data cross-calibrationrnprovides better, more stable and consistent results.rnAttributes from principal component decomposition of seismicrndata compensate for the redundancy of conventional seismicrnattributes in statistical analysis and provide better well-to-seismicrnties when a full set of principal component attributesrnare used. Vertical steam conformance can be establishedrnthrough poststack inversion to provide 3-D visualization of thernimpact of lithologic control on steam distribution and steamrnmigration pathway. The vertical conformance reveals thatrnsequence architecture has a significant influence on steamrnmigration. A sequence with high mud content tends to limit orrnslow both vertical and lateral migration of the steamrnchambers.rnIn pre-stack efforts, the functional relation of P- to S-wavernvelocities, called the mud-rock line, plays an important rule inrnextracting S-wave information from pre-stack data. With anrnoptimized mud-rock line and high frequency seismic data, therninverted pseudo S-wave from AVO analysis has much higherrnresolution than the P-S wave data. The reservoir heterogeneityrncan be welldefined by fluid factor alone. The application ofrnthis technique to reservoir monitoring defines steam channelsrnand identifies lithologic barriers within the reservoir.