Joint inversion of PP- wave and PSV- wave data for P- wave and S- wave inverse quality factors at different frequencies — Synthetic test

Huaizhen Chen, Kristopher Innanen, Yuxin Ji(SINOPEC), Xiucheng Wei

ABSTRACT

P- wave and S- wave quality factors (Q P and Q S ) can provide valuable information for identifying the type of fluid in reservoir space. The results calculated by rock physics attenuation model suggest that P- wave and S- wave velocities (V P and V S ) and quality factors vary with frequency, which also induce the reflection amplitude variation with frequency. However, the variation of velocities with frequency is small within the seismic frequency range, which can be ignored in the approximation of PP- wave and PSV- wave reflection coefficients. Our research begins with the rock physics numerical modeling to verify the reliability of ignoring the influence of frequency on velocities. The reflection coefficient approximate formulas of PP- wave and PSV- wave are derived using scattering function, and these formulas can be applied in the inversion of seismic data for elastic properties (P-wave and S- wave impedances and density) and quality factors. PP- wave and PSV- wave are employed in our approach to estimate quality factors, which can help to improve the accuracy of the inversion. Singular value decomposition (SVD) algorithm is used to solve the inversion problem, and initial models are utilized to constraint the inversion. Synthetic tests show the P- wave and S- wave impedances, density and inverse quality factors can be estimated reasonably even in the case that signal-to-noise ratio (SNR) is 2.

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