基于反射振幅傅里叶系数的裂缝弱度反演方法

Fracture weakness inversion based on reflection amplitude Fourier coefficient

首先推导非均匀HTI介质纵波反射系数的傅里叶系数表达式,分析傅里叶系数对各参数的敏感性,提出一种基于反射振幅傅里叶系数的裂缝弱度反演方法,通过傅里叶级数分解分别进行各向同性参数反演和裂缝弱度参数反演。结果表明该方法将不同入射角下的二阶傅里叶系数正、余弦分量作为反演的输入,可有效地减少数据占用存储空间,提高裂缝弱度参数反演的效率;在地震数据含一定噪声的情况下仍可得到稳定合理的裂缝弱度反演结果,可进一步指导裂缝储层的识别;模型测试和实际应用结果证明了该方法的稳定性和有效性。

In this paper,we first derive the formulism of PP-wave reflection in terms of Fourier coefficients in heterogeneous HTI media.Next,we analyze the sensitivity of Fourier coefficients to various parameters,and propose a novel inversion approach for fracture weakness estimates based on the reflection amplitude of the Fourier coefficients.Inversions for isotropic parameters and fracture weakness parameters are performed respectively using Fourier series decomposition.The proposed approach takes the sine and cosine components of the second order Fourier coefficients at different incident angles as the input of the inversion,which improves the inversion efficiency of the fracture weakness parameters.Stable and reliable inversion results of fracture weakness can be obtained in the case of seismic data with moderate noise,which can be further used to guide the identification of fractured reservoirs.Synthetic example and field application illustrate the stability and effectiveness of the proposed approach.