波动方程非规则网格任意阶精度差分法正演

Differential forward modeling of wave equation having irregular grid and any-order precision

在波动方程正演中通常采用有限差分算法,而有限差分的计算精度又取决于所用离散网格类型及差分阶数。采用规则网格进行离散,对于倾斜界面无法避免绕射噪声,若加密网格又过度增加工作量。为此,本文提出一种非规则网格任意阶精度差分正演方法,在不增加太多计算量的前提下,达到了基本消除离散绕射噪声,提高正演精度的目的。通过两个模型试算,特别是在有倾角的反射界面处,较好地克服了由于数值离散带来的离散绕射噪声问题。

The finite differencl algorithm is usually used in forward modeling of wave equation,and its calculating precision depends on used discrete grid and differential order.Using regular grid for discretization results in diffraction noise for dip interface,and infilling grid may increase the computing efforts.For that reason,the paper presented a differential forward modeling method by using irregular grid and having any order precision,which can basically eliminate discrete diffraction noise and improve forward modeling precision in a precondition of slightly increasing computing efforts.The tests of two models showed that the method can better overcome discrete diffraction noise resulted from numeric discretization on dip interface and is an effective and practical method for increasing forward modeling precision in complicated geological model.