矢量Kirchhoff叠前深度偏移

Vector prestack depth migration based on Kirchhoff integral equation

由于传统的Kirchhoff积分法偏移基于标量声学波动方程,没有考虑地震波场的矢量特性,偏移成像的精度较低、保幅性较差。因此,本文从多分量地震波矢量场的特征出发,基于均匀各向同性弹性波波动方程,推导了Kirchhoff积分法矢量偏移公式;利用弹性波波动方程的矢量特性,在偏移过程中将泄漏的地震波信息还原到PP波与PS波分量中,实现了偏移过程中的波场分离。二维理论模型与实际数据的应用结果表明,基于矢量数据的深度偏移方法能够有效消除多分量地震数据的波型泄漏现象,提高偏移成像的精度。

Conventional Kirchhoff integral migrations lead inaccurate multi-component seismic imaging and cannot preserve true amplitude due to the scalar acoustic wave equation basis.In this paper,we put forward a vector prestack depth migration based on Kirchhoff integral equation.First we deduce Kirchhoff integral vector migration formula based on multi-component seismic vector field and homogeneous isotropic elastic wave equation.Then we apply it to the prestack depth migration of multi-component seismic data.Using wave equation vector characteristics we recover leaked seismic information PP-and PS-wave components in the migration,and achieve PP-and PS-wave separation.Tests on 2 Dnumerical model and real data prove that the proposed method can eliminate the mode leak and increase the imaging accuracy.