An accurate method of calculating the gradients of seismic wave reflection coefficients to rock properties in transversely isotropic media
Bao, Y., Chen, J. and Liu, X.B., 2020. An accurate method of calculating the gradients of seismic wave reflection coefficients to rock properties in transversely isotropic media. Journal of Seismic Exploration, 29: 275-297. The amplitude versus offset (AVO) inversion technique plays a critical role in exploration geophysics. The key issue of AVO inversion is the computational accuracy of the gradients of seismic wave reflection coefficients (SWRCs) to rock properties. Additionally, the anisotropic medium has the better representation of the earth than the isotropic medium. These issues will lead deviations in AVO process and weak the reliability of the final results. In this paper, we propose to develop a method of accurately calculating the gradients of SWRCs to rock properties (e.g., P- and S-velocities, density and anisotropic parameters) in transversely isotropic (TI) media. We calculate SWRCs in TI media by adding an anisotropic perturbation term on the exact Zoeppritz equations of the isotropic part. We obtain the partial derivatives of SWRCs to rock properties through a series of simple linear equations which not only keep a high accuracy but also offer a low computational cost. Finally, based on numerical tests, we plot the curves of SWRCs and partial derivatives of SWRCs with respect to rock properties and analyze their features.
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