Pressure transient tests in naturally fractured reservoirs often exhibit non-uniform responses. Various models are available to explain such nonuniformity. However, the relevance of these models is often not justified on a geologic basis. Fractal geometry provides a method to account for a great variety of such transients under the assumption that the network of fractures is fractal. The theoretical basis for this method was presented in  and was verified numerically in . This paper presents an application to real well tests in various fractured reservoirs. The physical meaning of the fractal parameters is presented in the context of well testing. Behaviors similar to the finite conductivity fracture model and to spherical flow are presented and explained by the alternative of fractal networks. A behavior that can be mistakenly interpreted as a double porosity case is also analyzed.
It is well known that pressure transients of wells in naturally fractured reservoirs often lack a similar response. In fact, individual wells at different locations in the same reservoir often exhibit qualitatively different pressure responses. While the traditional double porosity model has been considered as the standard tool for the analysis of such tests, it is also common knowledge that the expected behavior of a parallel line, in a semilog plot of pressure vs. time, is frequently not observed. To reconcile such differences, various explanations are typically advanced, including effects of wellbore storage, short test duration and boundary effects.
While research in pressure transients of fractured systems has considerably advanced in the past decades, it has its underpinnings on the classical notion that naturally fractured systems are characterized by a few (usually two) distinct scales that delineate the fracture network and the embedded matrix. Variations on this approach, including randomly generated fracture networks, triple-porosity systems, etc., although adding complexity, still obey the general premise that the network of fractures is dense and space filling, namely that it is of Euclidean geometry.