准规则网格高阶有限差分法非均质弹性波波场模拟

为精确描述弹性波在非均匀介质中的传播,本文提出一种准规则网格高阶有限差分地震正演模拟方法。该法是将位移分量交错排列,做中心差分运算,在数学上等价于交错网格法,并给出了震源加载方法、边界条件和稳定性条件。与传统交错网格法和规则网格法相比,该方法在模拟精度和稳定性方面与交错网格法相同且优于传统规则网格法;而从内存占用上,相较于交错网格,二维时内存占用减少了60%,三维时减少了66.7%。利用层状模型验证了方法的模拟精度;利用复杂的Marmousi-2模型说明了方法的适用性和稳定性。

Elastic wavefield forward modeling in heterogeneous media based on the quasi-regular grid high-order finite difference

In this paper, we propose a quasi-regular grid high-order finite-difference seismic forward mo-deling to accurately describe elastic wave propagation in heterogeneous media.The quasi-regular grid strategy is to stagger the displacement component of the elastic wave equation and make a new center difference operator for displacement, while the si-mulation accuracy and stability are the same as those of the staggered grid.But the memory usage of the quasi-regular grid is reduced by 60% in 2D and 66.7% in 3D compared to the staggered grid.Then the equivalence between the quasi-regular grid and staggered grid is mathematically demonstrated, and the source loading, boundary conditions and stability are analyzed.A numerical test is carried out on a layered model to validate the accuracy of the quasi-regular grid method by comparing with staggered grid and regular grid methods.Finally, a test on Marmousi-2 model proves the applicability and stability of the proposed method.