Summary Geophysical methods, especially inversion of the seismic data, have improved considerably in recent years. Methods of determining elastic behavior of rocks are important for oil companies to decrease risk in their operations. Rock Physics functions can help us to predict these behaviors. The first step in this process is to develop a suitable rock physics model. The aim of this paper is to apply well logs and rock physics studies in order to establish models relating elastic parameters and reservoir properties in Asmari reservoir sandstone member. The results show that Krief (1990) and NurDvorkin (1996) models are good for predicting S-wave velocity and porosity respectively. Also Poisson impedance is a good elastic parameter for determining lithology and pore fluid distribution.