基于PML井间地震纵横波分离的弹性波数值模拟

BASED ON THE PERFECT MATCHED LAYER CROSSWELL SIMULATION OF ELASTIC WAVE WITH SEPARATED P-WAVES AND S-WAVES

井间地震方法观测到的波场信息丰富且复杂,其难点是如何识别和分离这些波场信息。这里从纵波波场为无旋场,横波波场为无散场出发,利用一阶速度～应力方程的交错网格高阶有限差分法,对井间弹性波纵、横波场分离问题进行了数值模拟。经数值模拟试验表明,同二阶的位移方程相比,使用等价的波场分离交错网格的一阶速度应力方程,无论是模拟精度还是模拟的稳定性方面都有了较大的提高,同时该横波资料的获取方法为井间地震资料的解释应用,提供了一种新的技术思路。

Crosswell seismic method observed rich and complex wave-field information.The difficulty is how to identify and separate the wave-field information.Starting from the idea of P-wave wave-field being rotation-free field and S-wave being divergence-free field,using staggered-grid high-order finite difference method,we have numerically simulated the problem of crosswell separated P-waves and S-waves.The numerical results show that it is obviously improved the accuracy and stability of numerical results compared with two-order displacement equation through the application of staggered-grid first order velocity-stress wave-field separation equation.This kind of acquisitive method about S-wave data provides a new thought for the applications and interpretation of crosswell seismic.