Interactions between Reservoir Simulations of Heavy Oil and Viscoelastic Seismic Modeling

When seismic waves pass through a porous medium saturated with heavy oil and gas they experience attenuation. This attenuation is related to the coexistence of fluids with significantly different bulk moduli. White’s patchy saturation model was found to be a suitable constitutive model to estimate the velocity dispersion and attenuation of seismic waves in heavy oil reservoirs. The attenuation predicted from the White’s model depends on rock and fluid properties such as saturation, patch size (bubble size), modulus and mobility of liquid phase. A feasibility analysis of viscoelastic forward modeling was performed to illustrate that the propagation of seismic waves was sensitive to the patchy saturation reservoir heterogeneity as predicted by White’s attenuation theory.;Modeling of fluid flow including the process of gas bubbles coming out of solution (patch creation) was completed for a Canadian heavy oil reservoir. The results were then used to estimate White’s attenuation parameters. The accuracy of the flow simulation was ensured through a history matching process. Obtaining a decent history match leads to a high confidence level in the estimation of in situ properties. White’s attenuation model was considered a criterion to indicate the portion of frequency content of repeated seismic data which is affected by saturation heterogeneity. Therefore analysis was focused on this frequency portion which contains information about the depletion in the reservoir. This new processing method developed in this study leads to a better understanding and interpretation of time lapsed data for this type of Canadian heavy oil reservoir. This method helps for mapping the possible bypass reservoir for future infill drilling or possible Enhanced Oil Recovery (EOR) opportunities.