Reservoir Characterization Using Converted-wave Seismic Data - Case Study from Athabasca Oil Sands

The Lower Cretaceous McMurray Formation reservoir used in this study is located in the Athabasca basin, of the Northern Alberta, Canada. High resolution multicomponent 3D seismic data, along with core and well data were processed using the most advanced workflows in order to image the reservoir heterogeneity. These workflows include petrophysical analysis, joint PP-PS inversion and neural network analysis. Three inversions using PP and PS seismic data are analyzed and compared. The joint PP-PS inversion of the prestack seismic data produces the best estimates of P-impedance, S-Impedance and density, allowing for excellent reservoir characterization.

Neural network analysis is used to enhance the resolution of the elastic properties estimated from joint PP-PS prestack inversion, and to estimate petrophysical and engineering properties such as porosity, resistivity and saturation. In all neural network analyses the most significant seismic attributes include converted-wave information.

Some of the results are: 1. converted-wave seismic data have a major role in oil-sands reservoir characterization; 2. estimated density seismic volume shows a good separation of the two bitumen sands; 3. P-wave velocity seismic allows better mapping of the McMurray top; 4. estimated resistivity allows not only to differentiate the reservoir from the non-reservoir but also bitumen sand from water sand.