各向异性介质弹性多波高斯束正演模拟

Anisotropic Gaussian beam forward modeling for elastic multiple wave

射线类正演方法以其高效性和灵活性的特点,被广泛应用于地震勘探中.然而,普通射线类正演方法存在焦散区、阴影区和多值走时等问题,计算精度不够理想.为此,本文在传统的各向同性介质声波高斯束正演的基础上,推导了各向异性介质运动学和动力学射线追踪方程,发展了各向异性介质弹性多波射线追踪算法;并将该算法应用到高斯束正演模拟中,实现了一种各向异性介质弹性多波高斯束正演模拟方法.各向异性VTI介质断块和VTI介质复杂构造模型试算的结果表明:本文研究的方法能够对各向异性介质构造进行正演模拟,在保证计算精度的前提下,具有较高的计算效率,模型试算的结果说明了方法的有效性和正确性.

Seismic ray forward modeling methods are widely applied to the seismic exploration with its high efficiency and flexibility. The seismic modeling in varying,layered,anisotropic structures plays an important role in the research of seismic wave propagation and imaging. Application of ray method to the seismic modeling has been found valid. But the ray method maybe fails in the caustic area and the the shadow area where the wave field is not regular.Therefore,many scholars propose the Gaussian beam method of forward modeling to overcome this issue.Based on the traditional study of Gaussian beam modeling in isotropic media,we derive the equations and develop an algorithm of anisotropic medium ray tracing of elastic multiple wave.Furthermore our proposed method has also been utilized in the anisotropic Gaussian beam forward modeling for elastic multiple wave. And the numerical results show that this method can well depict the wave fields in anisotropic media. At the same time,it is more efficient and more flexible to obtain synthetic seismogram. The synthetic seismograms for block model and structural model prove its accuracy and efficiency.