基于波动方程的目标导向观测系统设计方法研究

Target-oriented layout designing method based on wave equations

本文提出了复杂构造地区的目标导向观测系统的设计方法.使用波动方程正演模拟来指导并在二维声波方程的一阶速度-应力方程中应用交错网格有限差分法实现.使用了四阶精度的差分算子和完全匹配层吸收边界条件.通过分析理论模型的模拟结果,展示了如何将地面地震响应与地下目标构造匹配.通过分析桥口地区实际地质模型的模拟结果,指出波动方程正演模拟在小断块、小背斜增生的复杂地区中相对于传统方法更精确,图像更清晰,更利于分析和指导观测系统设计.跟踪目标区的反射同相轴并得到其到达地面的接收范围来约束炮检距的范围,通过比较不同道距的模拟记录并综合考虑成本和任务目标来选取最佳道距.最终获得了实际效果达到设计要求的观测系统参数.

A target-oriented layout designing method guided by wave equation forward modeling in complicated structure areas is proposed in this paper. This method is implemented by using the staggered-mesh finite-difference（FD） method in velocity-stress 2D acoustic wave equations. The fourth-order FD operator on staggered-meshes and perfectly matched layer（PML） absorbing boundary condition are applied. By analyzing numeral results of the synthetic model, we illuminate how to match the surface seismic response with the underground target structure. By analyzing numeral results of the practical model in Qiao Kou area, we indicate that the forward modeling method is based on wave equations better than conventional methods in areas with complicated miniature fault-block and salt anticline for which shows more accurate image, therefore it is more propitious to analyze and guide the design of seismic layout. We set constrains of offset by tracking reflected events of target zone and obtaining the receiving range on the surface. We choose the best trace distance by comparing different simulated records and considering the cost and goals of the project. Finally, Layout parameters which meet the design requirement are obtained.