重构震源振幅谱一致性的吸收参数反演方法

Absorption parameter inversion method based on reconstructed source amplitude spectrum consistency

谱比法和质心频移法是两种工业应用较为广泛的品质因子Q反演方法,它们主要依靠地震振幅谱的某个单一属性(对数谱比斜率或者质心频率)对地层吸收参数进行估算和反演,因而反演结果很容易受到地震噪声和波场干涉等因素的影响。为此,提出一种基于重构震源振幅谱一致性的地层吸收参数反演方法。其核心思想是将地震信号沿射线路径向震源位置反向传播,并进行吸收补偿,然后利用地震信号在震源位置重构的振幅谱一致性进行地层吸收参数反演。该方法既不需要已知震源子波,也不需要提取地震信号振幅谱的某个特定属性,具有提高地层吸收参数反演精度的潜力。模型实验表明:相较于谱比法和质心频移法,该方法具有更高的反演精度和更强的抗噪性。M区块应用结果表明:该方法能够为后续的吸收补偿提供高精度的吸收结构模型,有较好的工业应用前景。

Spectral ratio(SR)method and centroid frequency shif(t CFS)method are two kinds of Q⁃factor inver⁃sion methods widely used in seismic exploration.They mainly rely on a single attribute(e.g.logarithmic spec⁃tral ratio slope or centroid frequency)of the seismic spectral to estimate and invert absorption parameters.Therefore,the inversion results are easily affected by many factors such as seismic noise and wavefield inter⁃ference.To relieve this problem,this paper proposes a novel absorption parameter inversion method based on the consistency of the reconstructed source amplitude spectrum.The core idea of this method is to propagate and compensate the seismic signals back to their source position along the ray paths and then use the amplitude spectrum consistency of seismic signal reconstruction at the source location to invert the formation absorption parameters.Compared with the Q⁃factor estimation methods based on centroid frequency,the source signature can be unknown and it is unnecessary to extract a specified attribute of the signal spectral.Therefore,the pro⁃posed method has great potential to improve the inversion accuracy of absorption parameters.The model experi⁃ments show that the proposed method has better anti⁃noise properties and higher inversion accuracy compared with SR and CFS.The proposed method is applied to Block M.The application example shows that the method can provide a high⁃precision absorption structure model for the subsequent absorption compensation and has a good industrial application prospect.