叠前各向异性系数反演及在裂缝预测中的应用

摘要:

宽方位地震资料波场正演响应特征表明:地震纵波在地下地质体中传播时,反射系数在不同的方向具有明显的方位各向异性特征。利用方位各向异性进行裂缝预测已经成为国内外的研究热点之一。本文通过地震纵波随方位变化的正演响应特征分析,结合Bakulin等提出的含流体裂缝各向异性参数之间的相互关系,对Ruger公式进行了近似简化,推导了裂缝型储层含流体情况下,可以用于表征裂缝发育的各向异性参数γ与反射系数之间的表达式,提出了一种基于各向异性参数反演的裂缝预测方法。通过理论模型和实际资料应用证明了方法的有效性和适用性,为应用宽方位叠前地震资料进行裂缝预测提供了一种可行的方法技术。

Abstract:

The forward modeling of wave field response characteristics of wide-azimuth seismic data shows that the reflection coefficient has apparent azimuth anisotropy when the P-waves propagate in underground geologic bodies.It has become a research hotspot at home and abroad to make a fracture prediction using azimuth anisotropy.This study analyzed the response characteristics of the changes in seismic P-waves with azimuth using forward modeling.Based on the analytical results combined with the relationship between the anisotropy parameters of fluid-bearing fractures proposed by Bakulin et al.,this study approximately simplified the Ruger formula,deduced the equation between anisotropic parameter γ that can be used to characterize fracture development and reflection coefficient,and proposed a fracture prediction method based on anisotropic parameter inversion.The validity and applicability of the method have been proven using theoretical models and practical data application.Therefore,this study provides a feasible method and technology for fracture prediction using wide-azimuth prestack seismic data.