DefinePK

Abstract

Naturally fractured reservoirs have received considerable attention in the recent decades since more than half of the world oil reserves are found in this type of deposits; then, it is becoming fundamental a good characterization of these reservoirs and their understanding for having a better success in their exploitation and management. Generally, as originally proposed by Warren and Root, naturally-fractured formations are represented by a two scale model: a fracture network and a matrix. This modeling assumes that the fracture network is equivalent to a homogeneous medium fixed into an Euclidean geometry. However, it has been shown that the fracture networks are fractal elements which must be seen as alternative wiews for reservoirs with multiple scales and a network of non-Euclidean fractures. Fractal geometry is a good candidate for representing such systems. Several models and solutions based on the transient-pressure behavior have been presented in the literature with which were found that the change in pressure is a function of a power-law relationship where the exponent is related to the fractal dimension. In this work, direct expressions were developed from observing characteristic features on the pressure derivative log-log plot, so fracture permeability, fractal dimension conductivity index, flow capacity and storativity ratio can be estimated. The equations were successfully tested with synthetic examples.