叠后边界保持块约束共轭梯度波阻抗反演

张赛民¹ ，陈灵君²

(1. 成都理工大学 地球物理学院，成都 610059；2. 中国石化勘探南方分公司，成都 610041)

摘 要：为提高地震波阻抗反演的分辨率及运算效率，提出一种边界保持块约束的叠后波阻抗反演方法。首先，根据反射系数的稀疏特性，并利用正则化技术，避免反演过程的平滑效应构造出波阻抗块约束反演的目标函数；其次，推导出用对数波阻抗差值代替反射系数的边界保持的块约束反演系统方程；再次，推导出对应反演系统方程的共轭梯度算法和关键的向量计算公式。结果表明：反演波阻抗呈明显分块特征，上下岩层界线明显，分辨率高，说明反演方法可靠，该方法具有边界保持、分辨率高、收敛速度快、精度高的特点，实现简单、高效。

关键词：边界保持；块约束；波阻抗反演；共轭梯度算法

Post-stack seismic impedance conjugate gradient inversion based edge preserving blocky constrain

ZHANG Sai-min¹, CHEN Lin-jun²

(1. College of Geophysics, Chengdu University of Technology, Chengdu 610059, China;
2. SINOPEC Exploration Southern Company, Chengdu 610041, China)

Abstract:To improve the resolution of seismic impedance inversion and computational efficiency, a post-stack seismic inversion method based edge preserving blocky constrain was developed. First, according to the sparse characteristic of reflection coefficient, and using regularization technique, the objective function of seismic inversion was constructed to avoid smoothing effect; Secondly, equations of inversion system were deduced based on edge preserving blocky constrain and using the difference of logarithmic impedance in stabilizing the reflection coefficient; Additionally, the conjugate gradient algorithm was deduced, and the key vectors formulas were also derived. The results show that inverted seismic impedance has significant block feature, and the rock bottom line is clear, which indicates that the inversion method is reliable. The features of inversion method are edge preserving, high resolution, fast convergence, and high accuracy, simplicity and efficiency.

Key words:edge preserving; blocky constraining; seismic impedance inversion; conjugate gradient algorithm