An Anisotropic AVO Inversion Method Constrained by Rock Physics for VTI Media

ABSTRACT The amplitude variation with offset (AVO) inversion method is crucial for predicting lithology and identifying fluids in hydrocarbon reservoirs. It is especially useful for evaluating shale oil or shale gas reservoirs. The accuracy of AVO inversion is critical to the quantitative interpretation of lithology and hydrocarbon‐bearing properties in reservoirs with vertical transverse isotropic (VTI) features. This work proposes a rock‐physics‐constrained anisotropic AVO inversion method to achieve stable density estimations in VTI media. This method establishes a new parameter set with density as an independent variable by transforming the conventional elastic parameter domain into a deviation parameter domain through rock‐physics‐constrained equations. Combined with the explicit form of the Rüger approximation, this approach not only eliminates correlations among conventional inversion parameters and mitigates the impact of anisotropy but also significantly improves the accuracy of density inversion. The feasibility and effectiveness of the proposed inversion method are demonstrated through the application of synthetic and field seismic data.