基于单元交错网格的变坐标系正演模拟方法在声-弹介质中的应用

海上海底电缆(OBC)数据的广泛应用,使得声-弹介质多分量正演模拟技术逐步发展起来。提出了一种基于单元交错网格的变坐标系正演模拟方法,对比模拟试算得到的数值解与解析解的结果可以看出,与常规节点交错网格相比,单元交错网格在处理声-弹界面时结果更准确;同时,将变坐标系技术引入单元交错网格中,可将起伏声-弹界面映射为水平界面,更好地处理声介质中声压与弹性介质中应力之间的转换,可准确地模拟P波和转换S波。复杂起伏声-弹界面模型的试算证明该方法具有较高的准确性和适用性。

We proposed a variable coordinate system forward modeling method using cell-based staggered grids.The contrast of the numerical solutions obtained by forward modeling with the analytical solution proves that the cell-based staggered method is more accurate than the conventional node-based staggered method in treating acoustic-elastic coupled medium.Moreover,the variable coordinate system technique,which is introduced into cell-based staggered grid,can transform the rugged acoustic-elastic interface to horizontal interface,so the pressure in acoustic medium and the stress in elastic medium can be well transformed,and both P-wave & S-wave can be simulated accurately.The simulation results of the complicated rugged acoustic-elastic interface model show the good adaptability of the method.