There has been studied of the rock physics modelling in sand reservoir based on Voigt-Reuss and cement contact theory method case study at FRR field Kutai Basin. The objective of this study to modelling rock physics based on Voigt-Reuss and cement contact theory from geological information. Voigt-Reuss bounds model and cement contact was applied. This method related link between geological information and seismic properties. The data used in FRR field Kutai basin has the sandstone majority marked by 20 % P wave velocity. The results obtained by rock physics modelling shown modulus bulk to porosity has pattern close to lower bounds, that is existence the pore type has soft characterize and decrease bulk modulus with increase clay content and fluid saturation. The results show correlation between bulk modulus estimation and log data have good correlation. This suggests that Voigt-Reuss and cement contact theory model useful for bulk modulus estimation in sand reservoir. © 2021 Journal of Physics: Conference Series.