The relationship between dry rock bulk modulus and porosity - An empirical study

Brian H. Russell, Tad Smith

There are various approaches to computing dry rock bulk modulus as a function of porosity and, from this, inferring velocity and density changes due to reservoir fluid change as a function of porosity. One such approach is the pore space stiffness method. A second approach is the critical porosity model (Mavko and Mukerji, 1995). Using the clean sandstones at different pressures from a dataset collected by Han (1986), and Han et al. (1986), we will evaluate the accuracy of each method. Based on the observations as a function of reservoir pressure, we will also predict an empirical relationship between pore space stiffness and pressure.