Integrated Study of a Fractured Middle East Reservoir with Stratiform Super-K Intervals – Part 2: Upscaling and Dual Media Simulation
L. Cosentino, Y. Coury, Jean‐Marc Daniel, Emmanuel Manceau, Christian Ravenne, Paul Peter van Lingen, John C. Cole, M. Sengul · SPE middle east oil show · 2001
Abstract The paper describes the upscaling and reservoir simulation of a giant Middle East oilfield, whose geological modeling is described in a companion paper (1). The main objective of the study was the simulation of the irregular water advance observed in some parts of the field, as a consequence of peripheral water injection. Three scales of heterogeneity were identified in the characterization phase, namely the matrix, the stratiform Super-K intervals and the fractures. To accommodate the different hydraulic properties of each heterogeneity system, a dual-media approach (dual porosity and dual permeability) was used. The assignment of the effective properties to the simulation grids (matrix and fracture grids) was performed independently for the three heterogeneity systems. In particular, the geostatistical facies model was upscaled using algebraic methods, while the stratiform Super-K layers and fractures properties were explicitly reproduced at the simulation gridblock scale, through an original upscaling procedure. The history match was achieved in a short time, by a small variation of the fractal dimension of the fracture distribution and without resorting to any local modification. Simulation results showed that the fracture system was the controlling factor in terms of water advance and breakthrough, while the impact of the stratiform Super-K layers proved to be of second order. In a later stage, the model was utilized to run production forecasts under different exploitation scenarios. Conclusions of this study indicate that for such porous and fractured reservoirs with stratiform Super-K occurrences, a detailed characterization of all the heterogeneity systems, coupled with a dual-media formulation, are necessary requisites for accurate reservoir simulation and effective reservoir management.