VTI介质自适应聚焦束偏移

Adaptive focused beam migration in VTI media

自适应聚焦束是高斯束的改进,采用多次聚焦的思想,考虑局部速度场对波束宽度的影响,将地震波束有效能量控制在一个波长的范围内,与常规高斯束的不同点在于动态选择初始波束参数。将自适应聚焦束偏移方法应用到VTI介质,基于经典弹性参数表征下的各向异性射线追踪方程体系,结合自适应聚焦束处理强横向变速成像问题的优势,实现了VTI介质自适应聚焦束偏移。通过与传统高斯束形态的对比,突出了自适应聚焦束形态控制的优势。利用各向异性Sub-Sag模型验证了各向异性介质自适应聚焦束偏移方法的正确性和稳定性,各向异性SEG/Hess模型测试结果证明了该方法对复杂地质模型的适应能力;实际地震资料的处理结果表明,该方法成像效果优于传统各向异性高斯束偏移方法。

Adaptive focused beam is an improvement of Gaussian beam.Considering the affection of local velocity field on beam width,it focuses multiple times to control the effective energy of seismic beam within one wavelength.Different from Gaussian beam,adaptive focused beam selects initial beam parameters dynamically.For adaptive focused beam is advantageous in dealing with the imaging problem in the media with strong horizontal velocity variation,the adaptive focused beam migration method was applied to VTI media in this paper.Based on the anisotropic ray tracing equation system represented by classical elastic parameters,the adaptive focused beam migration in VTI media was realized.The comparison between the beam shape of traditional Gaussian beam and that of adaptive focused beam revealed the advantage of adaptive focused beam in beam shape control.SubSag model test demonstrared the accuracy and stablity of adaptive focused beam migration method in anisotropic media.Anisotropic SEG/Hess model test demonstrated the feasibility of the method proposed in this paper on complex geological model.The application in real data processing demonstrated that the imaging effect of the method proposed in this paper is better than conventional Gaussian beam migration methods in anisotropic media.