offshore Louisiana, Gulf of Mexico

Two seismic surveys acquired over South Timbalier Block 295 field (offshore Louisiana) record significant differences in amplitude that are correlated to hydrocar-bon production at multiple reservoir levels. The K8 sand, a solution-gas-drive reservoir, shows increases in seismic amplitude associated with gas exsolution. The K40 sand, a water-drive reservoir, shows decreases in seismic am-plitude associated with increases in water saturation. A methodology is presented to optimize the correlation between two seismic surveys after they have been in-dividually processed (poststack). This methodology in-cludes rebinning, crosscorrelation, band-pass filtering, and cross-equalization. A statistical approach is devel-oped to characterize the correlation between the seis-mic surveys. This statistical analysis is used to discrim-inate seismic amplitude differences that record change in rock and fluid properties from those that could be the result of miscorrelation of the seismic data. Time-lapse seismic analysis provides an important new approach to imaging hydrocarbon production; it may be used to im-prove reservoir characterization and guide production decisions