Joint inversion method for interval quality factor based on amplitude and phase information

Estimating the quality factor Q accurately significantly improves the seismic data resolution and reservoir characterization. The commonly used log-spectral ratio method uses least-squares fitting to obtain Q values and involves only the amplitude information of seismic data while neglecting phase information. This paper proposes a joint interval Q inversion method based on the spectral ratio method and employs both amplitude and phase information to improve the accuracy. Based on the assumption that Q is independent of frequency, the nonlinear relation between the Q value and the two types of information is jointly used to construct an objective function, which clarifies the quantitative relation between amplitude spectrum, phase information, and Q value. The interval Q value can be inverted by calculating the minimum value of the objective function. The model test exhibits that the proposed method has higher precision and stability than the spectral ratio method; furthermore, the application to field data demonstrates that accurate Q inversion results are consistent with reservoir characteristics.