Benjamin Novais Carrasco¹, Ricardo Cunha Mattos Portella², Mauro Roberto Becker²

(1) Petrobras / Cenpes, Rio de Janeiro, RJ, Brazil
(2) Petrobras / Cenpes, Rio de Janeiro, Brazil

ABSTRACT: Studies of Sedimentological Heterogeneities and Their Impact in Fluid Flow Simulation

The aim of our research is to determine the impact of the upscaling method and description level of sedimentological heterogeneities on fluid flow simulation results. Three different models derived from outcrops analog to reservoirs in Brazil  are analized: Deep water, Fluvial and Eolic.

From detailed description of outcrop image, fine cross-section flow simulation models are created. Waterflooding is simulated considering different relative permeabilities and capillary pressures for each lithofacies, and oil properties of fields representative of each sedimentary environment.

The results of the fine-flow simulation are considered the truth to which the progressively more simple models are compared. These simpler models are constructed following two approaches: facies-scaling and upscaling. The facies-scaling approach, the geological description of the outcrop is simplified by replacing the less abundant lithofacies with the locally more dominant lithofacies, while maintaining the same number of grid blocks of the original fine model.

For conventional upscaling, coarse grids are generated based on averaging the properties of the fine grid, where only upscaling of absolute permeability and porosity are made  giving the appearance of going from sharp to unfocused images.

The paper shows the results of facies-scaled, and upscaled models compared with the original fine grid of each outcrop.

Generally, the flow response of the three environments has significant impact on predicted oil recovery as consequence of the simplification process of facies-scaling and upscaling.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado