Geologically Based Fractured Reservoir Simulator

The purpose of this study is to investigate flow of fluids in naturally fractured systems. Fracture networks are simulated using stochastically distributed variables to generate realistic random networks of interconnected planar flow paths. The network model is based on geological observations of actual fracture networks in sedimentary rocks. Network volumes, directional permeabilities, and breakthrough times and curves are generated for various flow geometries through computer simulation. A study is then conducted to relate these various results to variations in network parameters. Another simulator is written to model the behavior of individual matrix blocks during a water flood of the fracture network. Countercurrent imbibition causes oil to be fed into the fractures from the matrix. Specific oil feed functions are derived for rectangular matrix blocks with rock parameters from the Spraberry formation of West Texas. These feed functions are combined with the fracture network simulator and realistic networks with Spraberry network and rock parameters are simulated. Results indicate that while fractures provide the flow paths for the water flood, matrix block imbibition characteristics control breakthrough times and overall recovery.