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AVO反演是获取地下介质弹性参数的重要手段。反演可在时间域或频率域实现,时间域反演稳定性好但分辨能力受限;频率域反演受益于有利频带的选择,分辨能力提高但反演结果容易受噪音影响。在贝叶斯反演理论框架下,提出了一种时间域和频率域联合的AVO反演方法。该方法在反演目标函数构建中融合了时间域和频率域信息的影响,假设待反演参数先验信息和似然函数分别服从柯西和高斯分布,考虑了待反演参数间的相关性,并采用模型约束提高了反演稳定性。模型测试表明,利用时频域联合反演得到的纵横波速度等弹性参数反射系数的频谱带宽要优于仅用时间域信息得到的结果,且合成地震记录信噪比为2时,仍可以得到较好的反演结果,验证了方法在保持稳定性的同时改善了分辨能力的优势。实际资料试处理进一步验证了方法的可行性及其相对单纯时间域或频率域反演的优势。
AVO inversion is an important means to obtain the elastic parameters of underground media. Inversion can be realized in time domain or frequency domain, and the time domain inversion has good stability but limited resolving power. The frequency domain inversion benefits from the selection of favorable frequency band, and the resolving power is improved but the inversion result is easily affected by noise. In the framework of Bayesian inversion theory, a joint AVO inversion method in time domain and frequency domain is proposed. The proposed method incorporates the influence of time domain and frequency domain information in the construction of inverse objective function. Assuming that the prior information and likelihood function of the parameters to be reversed obey the Cauchy and Gaussian distribution respectively, the correlation between the parameters to be inverted is considered , And using model constraints to improve the stability of inversion. The model tests show that the spectral bandwidth of elastic parameters such as P- and S-wave velocities obtained by joint inversion in time-frequency domain is better than that obtained by using only time-domain information, and the signal-to-noise ratio of synthetic seismogram is 2 The better inversion result verifies the advantage of the method in improving the resolving power while maintaining the stability. The actual data processing further verifies the feasibility of the method and its advantage over the simple time domain or frequency domain inversion.