Porosity, shale content, and permeability prediction based on prestack multiparameter inversion

Abstract

Permeability, porosity and shale content are important parameters for reservoir characterization, which are of great significance for the prediction of high quality reservoirs. However, in the actual production, the low permeability sandstone reservoirs have large vertical and horizontal variation of lithology, complex pore structure, rapid permeability change and strong heterogeneity. So it is a great challenge for complex reservoirs to obtain physical parameters such as permeability, porosity and shale content directly from seismic data. In order to solve this problem, this paper establishes a set of technical process for predicting reservoir permeability, porosity and pore structure by using prestack seismic multi-parameter inversion results. When the porosity and shale content are weighted, there is a good linear fitting relationship with the P-wave and S-wave velocity. What’s more, when porosity and frame flexibility factor (γ) are coupled, it has a good linear fitting relationship with the P-wave and S-wave impedance. Therefore, the inversion results of shale content, porosity and frame flexibility factor (γ) are obtained based on the relationship between shale content, porosity and pore structure and P-wave velocity, S-wave velocity, P-wave impedance and S-wave impedance, combined with the multiple parameters of pre-stack seismic data inversion. Finally, under the guidance of rock physics experiments, frame flexibility factor (γ) is used to predict the permeability of reservoirs with different pore structures. The prediction method of permeability, porosity and shale content has achieved good application effect in actual production. Note: This paper was accepted into the Technical Program but was not presented at IMAGE 2021 in Denver, Colorado.