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TTI(Tilted Transversely Isotropic)各向异性是对地下岩石中广泛存在的规则发育的裂缝和层理的一种有效的弹性近似,基于TTI介质的地震波数值模拟技术是分析地震波在复杂各向异性介质中的传播机理的有效工具.同时,高精度的数值模拟算法也能为后续的逆时偏移技术提供重要的技术支撑.由于TTI介质中地震波方程的弹性参数众多且变化复杂,常规有限差分技术在解决TTI介质正演模拟问题时往往会产生严重的数值频散现象,降低了数值模拟精度.通量校正传输(FluxCorrected Transport,FCT)技术能够有效地压制由空间离散产生的数值频散.本文将FCT技术用于TTI介质中弹性波方程的交错网格高阶精度差分正演,在数值模拟过程中通过对波场进行漫射和反漫射校正实现了空间网格频散的压制.模型模拟结果表明,与常规有限差分算法相比,本文算法能够有效的压制大网格条件下的数值频散,提高模拟精度.
TTI (Tilted Transversely Isotropic) Anisotropy is an effective elastic approximation of the regularly occurring fractures and bedding in underground rocks. The seismic wave numerical simulation technique based on TTI is to analyze seismic wave propagation in complex anisotropic media Of the transmission mechanism of effective tools.At the same time, high-precision numerical simulation algorithm can also provide important technical support for the subsequent reverse-time migration technology.Because the elastic parameters of seismic wave equation in TTI media are numerous and complicated, the conventional finite-difference technique To solve the problem of forward modeling of TTI media, serious numerical dispersion often occurs and the numerical simulation accuracy is reduced.Flux Corrected Transport (FCT) can effectively suppress the numerical dispersion caused by spatial discretization.In this paper, The FCT technique is applied to the staggered-grid high-order differential forward modeling of the elastic wave equation in TTI media, and the dispersion of space grid is suppressed by diffusing and anti-diffusing the wavefield in the numerical simulation. The results show that, compared with the conventional finite difference algorithm, the proposed algorithm can effectively suppress the value under the condition of large grid Powder, improve the simulation accuracy.