各向异性研究的新进展

Advances in seismic anisotropy reflected from the 65^(th) EAGE annual meeting

油气田精细勘探对地震数据分析的精度要求越来越高 ,各向异性已成为不得不考虑的重要因素 ,对地震数据处理的影响 ,特别是对复杂介质成像精度及四维地震属性分析置信度的制约 ,随着资料采集方式的多样化 ,已十分明显。如何在现有处理流程中加上各向异性的校正 ,变得日益迫切。与此同时 ,各向异性介质中散射衰减及速度随频率的变化 ,也为通过地震数据分析预测裂隙大小尺度提供了可能性。裂隙介质分界面上的反射特征是由地震振幅反演裂隙各向异性参数的依据 ,而多孔裂隙介质中地震波传播规律的认识 ,则展示了利用地震资料指导高孔隙度砂岩储层油气开发的前景。第 6 5届EAGE年会所反映出的各向异性研究的新进展包括 :①P波各向异性的表现及其对成像精度的影响 ;②叠前深度偏移后的各向异性校正 ;③衰减与速度的频率依赖关系及其在裂隙尺度预测中的应用 ;④一些理论研究的新进展。

With the increasing need of exploration precision, seismic anisotropy has to be taken as a critical issue that affects data processing quality, especially validity of migration in complex media and reliability of 4-D seismic attribute analysis as the acquisition gets more and more sophisticated. How to tackle anisotropy in routine data processing becomes vital. At the same time, frequency dependence of scattering attenuation and anisotropic velocity variation makes fracture size deduction from seismic data possible. Reflection property analysis on the interfaces between anisotropic media constitutes the background for anisotropic parameters estimation using reflection amplitude, while observations of seismic wave propagation in poroelastic media shows a potential utilization of seismic data in reservoir development where the sand is of high porosity. In this paper advances in seismic anisotropy reflected from the 65 th EAGE annual meeting are summarized as four aspects, behavior of P wave seismic anisotropy and its effects on seismic imaging, anisotropy correction after prestack depth migration, frequency dependence of scattering attenuation and anisotropic velocity and its application in fracture size estimation, as well as some results from theoretic studies.