The Use of Modified Rock Physics Template to Monitor Fluid Saturation in Carbonate Reservoir

Rock physics template (RPT) is a crossplot of acoustic impedance (AI) against the ratio of P- and S-wave velocities that is used for lithology and pore-fluid interpretation of well log data and/or pre-stack seismic inversion results. This study employs an interactive RPT approach, which facilitates calibration using available data and enhances the interpretation and prediction of pore fluids within carbonate reservoir rocks. A previously established RPT model was modified to construct the rock physics template and interpret trends in porosity and fluid saturation within a predictive framework. The modified approach to the RPT formulation demonstrates that the proposed model yields more accurate porosity and fluid saturation trends for the reservoir rocks in the study area than the previous RPT model, as evidenced by the theoretical curves of the Rock Physics Template (RPT) domain. To predict fluid saturation, a workflow was developed to build the modified RPT model that incorporates the Curved Pseudo Elastic Impedance (CPEI) and the Pseudo Elastic Inversion for Lithology (PEIL) attributes. These attributes were used to regulate the fluid saturation and density values in the model space assist for constructing the RPT model. The proposed method can also be used to monitor fluid saturation changes in oil, gas, or CO₂, utilizing the Vp/Vs ratio and acoustic impedance derived from the seismic inversion data and allows calibration with available datasets such as well logs and cores.