Petro physical parameters are important for predicting capacity of reservoir so, many modern oil and gas wells are drilled directly. Based on measuring these parameters, logging operations is done to achieve a complete log of every well. In some cases a complete set of data with minimum error of logs is achieved, but for various reasons such as failure to complete the logging of old wells logs are incomplete or inadequate, so getting complete set of data is too hard or impossible. Density and Neutron porosity are two of the important results of logging. As a result in this study these two parameters have been considered by Possibilistic C-Means clustering to evaluate its range. Gamma ray, Deep resistivity and sonic log are used for inputs.