弹性波逆时偏移及其成像条件

从弹性波动方程出发,推导了二维各向同性介质情况下弹性波逆时传播的高阶差分格式,实现了弹性波在数值空间中的逆时延拓。从程函方程出发,采用逆时差分格式求取网格空间中各点的直达波旅行时,以此作为弹性波逆时偏移的成像条件(激发时间成像条件),实现多波多分量资料的逆时偏移。文中给出了几个典型模型的理论记录的偏移结果,数值试验表明,逆时偏移能够使地表接收到的波场准确归位,提高资料处理的精度。

Reverse Time Migration of Elastic Wave and Its Imaging Conditions

Start from elastic wave equation,it has deduced higher difference forma t of elastic wave reverse time transm ission under the condition of two -dimensional isotr opic medium,and realized reverse time continuation of elastic wave in th e numerical space.Start from eikonal equation,used reverse time difference format to derive direct w ave travel -time of each point in the n et space,take it as imaging condition of reverse time migration of elastic wave(exciting time imaging condition),thus realized reverse time migrati on of multiwave and multicomponent informations.T he paper has provided the theoretic r ecord migration results of several t ypical models,and numerical testing showing that reverse time mi gration can be make wave field receiv ed on the surface return position acc urately,and heighten processing precision of informatio ns.