Tomography is one of the most important velocity building methods.Travel time tomography in image domain, implemented with migration, is widely used in velocity model building currently. The authors first introduced the method to output the azimuth-reflection angle gathers, and then, under the assumption of the first-order Born and Rytov approximation of wave equation,started with the imaging condition of Gaussian Beam Migration to derive the linear relation between traveltime perturbation and velocity perturbation in the image domain,with which the authors constructed the explicit expression of kernel function for the wave equation traveltime tomography and established the traveltime tomography equation.The key to computing the kernel is how to compute the Green function in the background model.Making use of the Gaussian beam propagation operator to compute the kernel function can be flexible and efficient.Together with the implementation of Gaussian beam propagation operator in migration,the authors truly realized the integrated technological process of velocity building and migration.Numerical tests and field data application demonstrate that the Gaussian-beam-propagator based traveltime tomography in image domain is effective.
① 操作系统:Red Hat Enterpise Linux 4-64 Update 5 ② 并行计算环境:MPICH1.2.6 ③ 编译器:INTEL C++ 、FORTRAN编译器 10.0.023 Linux 版(64位) ④ 配置英特尔 MKL9.1 (Math Kernel Library Cluster Edition)数学库
网络环境
1000 M,4 GB光纤
计算机集群系统软硬件环境
处理名称
处理时间/min
折算单核处理效率
高斯束层析
110.3
0.766 M/h
射线层析
9.99
8.46 M/h
高斯束层析与射线层析计算效率对比
中国南方某山前带工区某单炮实际资料
某实际数据深度域初始建模(a)常规射线层析建模(b)及高斯束层析建模(c)结果对比
实际数据的高斯束偏移结果 a—利用射线层析模型;b—利用高斯束层析模型
实际数据利用高斯束层析模型偏移结果 a—利用Kirchhoff偏移;b—利用高斯束偏移
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