基于谱反演方法的叠后纵波阻抗反演

Post-stack P-wave impedance inversion based on spectral inversion

提出一种基于谱反演方法的叠后地震数据纵波阻抗反演算法,用于提高地震反演精度。谱反演在地震高分辨率和反射系数反演中应用广泛,其基于反射系数的奇偶分解,能降低薄层之间的调谐效应,使反演数据体的分辨率得以提高,而由反射系数计算纵波阻抗的过程不适定,分步进行纵波阻抗反演会引入较大的累积误差。本研究提出基于谱反演方法的叠后纵波阻抗反演算法,引入TV正则化约束目标方程,通过迭代求解,可直接得到相对阻抗,然后同预先建立的低频模型进行频率域融合得到绝对阻抗。模型和实际数据说明,相比基于稀疏脉冲反褶积的阻抗反演,本文提出的方法反演分辨率较高,更有利于后续储层预测等研究的开展。

Based on spectral inversion,this study proposed a p-wave impedance inversion algorithm for post-stack seismic data to improve inversion accuracy.Spectral inversion is widely used in high-resolution seismic inversion and the reflection coefficient inversion.Based on the odd-even decomposition of reflection coefficients,spectral inversion can reduce the tuning effect between thin layers and enhance the resolution of inverted data volumes.However,the calculation of p-wave impedance using reflection coefficients is ill-posed,and the step-by-step inversion of p-wave impedance tends to introduce a large cumulative error.Therefore,this study proposed a post-stack p-wave impedance inversion method based on spectral inversion.This method introduced the objective equation constrained by TV regularization and calculated the relative p-wave impedance using the iterative method.Then,the absolute p-wave impedance was determined through the frequency-domain fusion of the relative p-wave impedance and the pre-built low-frequency model.As demonstrated by the model and actual data,the method proposed in this study has a higher inversion resolution than the impedance inversion based on sparse-spike deconvolution and is more conducive to subsequent research such as reservoir prediction.