基于PML边界下的弹性及黏弹性TTI介质波场模拟

摘要

Based on the first-order velocity stress wave equation, the authors use the high order staggered grid finite difference numerical simulation method to simulate the elastic and viscoelastic TTI media. In the simulation, the perfectly matched layer (PML)absorbing boundary condition is used to eliminate the boundary reflection.Meanwhile, layered medium models and fault models are designed. Through the forward calculation of the model, seismic wave field snapshots and synthetic seismograms at different times are obtained, and the kinematic and dynamic characteristics of the wave field are analyzed. The simulation results show that the staggered grid finite difference method can well simulate the wave field of complex medium with high accuracy and reliability.%基于一阶速度-应力波动方程, 采用高阶交错网格有限差分数值模拟方法, 对弹性及黏弹性TTI介质进行正演数值模拟.模拟时采用完全匹配层吸收边界条件 (PML)消除边界反射.同时设计了层状介质模型、断层模型, 通过模型的正演计算, 得到了不同时刻的地震波波场快照及合成地震记录, 分析其波场运动学及动力学特征.模拟结果表明, 交错网格有限差分法可以很好地完成对复杂介质的波场模拟, 具有较高的精度和可靠性.