Sweet spot prediction in tight sandstone reservoir based on well-bore rock physical simulation

Abstract

To establish the relationship among reservoir characteristics and rock physical parameters, we construct the well-bore rock physical models firstly, considering the influence factors, such as mineral composition, shale content, porosity, fluid type and saturation. Then with analyzing the change rules of elastic parameters along with the above influence factors and the cross-plots among elastic parameters, the sensitive elastic parameters of tight sandstone reservoir are determined, and the rock physics template of sweet spot is constructed to guide pre-stack seismic inversion. The results show that velocity ratio and Poisson impedance are the most sensitive elastic parameters to indicate the lithologic and gas-bearing properties of sweet spot in tight sandstone reservoir. The high-quality sweet spot is characterized by the lower velocity ratio and Poisson impedance. Finally, the actual seismic data are selected to predict the sweet spots in tight sandstone gas reservoirs, so as to verify the validity of the rock physical simulation results. The significant consistency between the relative logging curves and inversion results in different wells implies that the utilization of well-bore rock physical simulation can guide the prediction of sweet spot in tight sandstone gas reservoirs.