Using VP/VS to explore for sandstone reservoirs: well log and synthetic seismograms from the Jeanne d'Arc basin, offshore Newfoundland

David J. Emery, Robert R. Stewart

This investigation in the Jeanne d'Arc Basin, offshore Newfoundland, involves a petrophysical analysis to determine the relationship of Vp/Vs to lithology and the evaluation of PP and PS synthetic seismograms for these Vp/Vs values.

The petrophysical analysis indicates that the sediments in the Jeanne d'Arc Basin fit quite well with the Castagna (1985) mud rock line. Our key finding is that for rock in the Jeanne d'Arc Basin, a Vp/Vs of 1.75 should differentiate a clay or calcite-rich bed from a quartz-rich deposit. Analysis of the synthetic seismogram indicates that the Garotta (1987) interval travel-time calculation will successfully determine lithology for formation scale events. Analysis of individual beds indicates that tuning and resolution issues dominate the calculated Vp/Vs. It is recommended that Vp/Vs analysis using interval times should be limited to intervals greater than a wavelength.

Vp/Vs analysis using multi-component seismic in the Jeanne d'Arc Basin shows significant promise.