Abstract In this chapter, seismic-attribute spectral decomposition (SD) is used for understanding heavy-oil and bitumen sand reservoir behavior and comprehending their heterogeneities for future reservoir simulation. Spectral decomposition is performed on the migrated stack and on amplitude-versus-offset (AVO) attributes (P- and S-wave impedance reflectivity). Examples provided in this chapter are from reservoirs with cold and thermal production. The observed differences between SD performed on P- and S-wave impedance reflectivity are explained with the solid state of the oil sands at their preproduction reservoir condition. The interpretation of the seismic attributes is based on the poroelastic and viscoelastic behaviors of the heavy oil and/or bitumen. The reservoir characteristics identified on the spectrally decomposed AVO attributes can be summarized as follows: (1) higher energy at the top and base of the reservoir is associated with shale; (2) medium to high energy is an indication of water sand; (3) low energy in the middle of the reservoir is commonly associated with thick bitumen zones that have high absorption; and (4) the bitumen-water interface is identified.

Introduction The oil-sands reservoir related to the Long Lake South (LLS) project is contained within the McMurray formation, which is the basal unit of the Lower Cretaceous Mannville Group. The McMurray formation directly overlies the sub-Cretaceous unconformity, which is developed on Paleozoic carbonates of the Beaver Hill Lake Group and is overlain by the Wabiskaw, Clearwater, and Grand Rapids Formations of the Mannville Group. The study area (Figure 1) is located along the axis of the McMurray Valley system, which was localized by the dissolution of underlying Devonian evaporates, creating the preferred depositional fairway for the Lower Cretaceous McMurray sediments. The most significant bitumen reservoirs within the McMurray formation are found within the multiple channels that represent lowstand system tracts, incised into the regional, prograding parase-quence sets that represent highstand system tracts. During sea level rise, these incised channel systems were filled with a transgressive estuarine complex, consisting of sandy to muddy estuarine point bars. In the Long Lake area, the McMurray formation is dominantly composed of these multiple, sand-rich, fluvial, and estuarine channels, which are incised into each other and stacked along a preferred path of deposition. This preferred path is aligned north-northwest to south-southeast in the Long Lake area (Dumitrescu et al., 2009).