Petrophysical and seismic signature of a heavy oil sand reservoir: Manitou Lake, Saskatchewan

Maria Fernanda Quijada, Robert R. Stewart

A suite of well logs from the Manitou Lake heavy oil field in Saskatchewan was analyzed to study the effect of lithology and saturating fluid on density and P- and S-wave velocities in the sand reservoirs. The Vp values do not change significantly from shale to sand, but the shear-wave velocity increases significantly from 800 to 1300 m/s. A Vp/Vs value lower than 2.15 indicate sand reservoirs. Within the target zone, densities lower than 2250 kg/m3 indicate sands. Modeling with the log response equation shows improvement in density estimations in comparison to using Gardner's relation. PP and PS synthetics show an opposite seismic signature at the top of the reservoir, seen as a trough on the PP section and as a peak in the PS section, making registration between the two sections more complex. Bright spots are expected on the PS section where sand is present. Post-stack impedance inversion shows promise for delineating the sand channels at the Colony top.