Comparison of Pressure Transient Response in Intensely and Sparsely Fractured Reservoirs

Abstract

A comprehensive analytical model is presented to study the pressure transient behavior of a naturally fractured reservoir with a continuous matrix block size distribution. Geologically realistic probability density functions of matrix block size are used to represent reservoim of varying fracture intensity and varying degrees of fracture uniformity. Transient interporosity flow is assumed and interporosity skin is incorporated. Drawdown and interference pressure transient tests are investigated. The results show distinctions in the pressure response from intensely and sparsely fractured reservoirs in the absence of interporosity skin. The pressure response in a nonunifomly fractured reservoir approaches that of a nonfractured (homogeneous) reservoir for the case of large matrix block size variability. Type curves are developed to estimate matrix block size variability and the degree of fracture intensity for drawdown and interference well tests.