三维多值走时地震波场重建及格林函数计算

针对三维复杂介质地震波传播数值计算中出现的多值走时情况，阐述了地震波场重建及格林函数计算中的困难，提出一种在相空间拉格朗日流形上的波场重建及格林函数计算方法．本文算法应用于三维叠前深度偏移处理流程时，可高效地获得均匀网格点上地震波多值走时及振幅的数值计算结果．文中还阐明两类数值计算过程判据，以在多值走时区域及计算的全区域中，控制射线追踪过程中的射线密度及格林函数计算精度．算例验证了本文方法的有效性．

3-D MULTI-VALUED SEISMIC WAVEFIELD RECONSTRUCTION AND GREEN' S FUNCTION COMPUTATION

Based on wavefield construction, an efficient algorithm for multivalued traveltime wavefield is presented. This method overcomes the difflculties in ray series method in conventional configuration space due to complicated velocity structure by implementing the calculation in phase space instead. It solves out the required multi-valued traveltime and amplitude at the uniform dispersed grids efficiently when applied to 3-D prestack depth migration. Two criterions for controlling and balancing the global computational accuracy and efficiency are also discussed in this paper. The numerical examples show that our method is applicable to complicated geological models.