Estimation of Naturally Fractured Oil Reservoir Properties Using Material Balance Method


1 Science and Research Branch, Islamic Azad University, Tehran, Iran

2 Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, P.O. Box: 11155-‎‎9465, Iran


In fractured reservoirs, large variation of permeability due to the presence of fractures leads to the changes in production mechanism comparing to the conventional reservoirs. Hence, an appropriate model with ability to describe the reservoir properly can provide a more confident prediction of the future performance of the reservoir. One of the features of a representative model is the number and height of matrix blocks. The determination of these two parameters is one of the decisive steps in the calculation of an accurate amount of oil production from these reservoirs. In fact, matrix height shows its effect as a gravity force, which is one of the driving mechanisms. If the matrix height is less than the threshold height, it will have a significant influence on production. The aim of this study is therefore to obtain mathematical relations that are able to estimate the matrix height from material balance analysis. In this study: (a) The Havlena and Odeh’s straight line form of the material balance equation has been extended to analyze the behavior of naturally fractured reservoirs and (b) Equations that can be used to estimate the matrix height are obtained for the Warren-Root and Kazemi models.