Effects of Different Block Size Distributions in Pressure Transient Response of Naturally Fractured Reservoirs

This paper presents a model for pressure transient and derivative analysis for naturally fracture reservoir by a formulation of interporosity flow incorporating variation in matrix block size which is inversely related to fracture intensity. Geologically realistic Probability Density Function (PDF) of matrix block size such as uniform, bimodal, linear and exponential distributions are examined and two model for interporosity flow, Pseudo steady-state and Transient, are assumed. Finally the obtained results have been physically interpreted. Despite results obtained by other authors, it was found that in some ranges of block size variability, interporosity skin, parameters of PDFs and matrix storativity the shape of pressure derivative curves for different PDFs are basically identical. This tool together with other source of information such as Logs and Geological Observations can give an insight into shape of distribution of block sizes.

Keywords:

Block Size , Probability Density Function , Pressure Transient