Heterogeneity Modeling Used for Production Simulation of a Fluvial Reservoir

Abstract

Summary The application of a stochastic model used for the description of channel sand and overbank flood plain shales of the complicated and heterogeneous Statfjord formation of a field under evaluation for development in the North Sea is presented. The channel sands contain other internal sand facies that have permeabilities different from those of the channels. These internal facies are also modeled. Permeability variations are modeled for each facies type with a Gaussian random field. At the facies and permeability stages of modeling, the stochastic model honors well data, seismic interpretations, and sedimentological knowledge gained by geologists from neighboring fields, outcrop analog studies, and general sedimentological principles. Permeability data, modeled in a fine grid, is upscaled to a coarser corner-point geometry grid used in numerical reservoir simulation. Production profiles resulting from geologic realizations carried forward to the reservoir simulator are compared with profiles obtained from a base-case model with smoothed permeability. The uncertainty originating from the unknown facies architecture and permeability distribution between wells is evident from production-profile analysis.