波动方程模拟PML吸收影响因素分析  

Analyzing PML absorbing impact factors with wave equation simulation

作　　者：刘瑞合 印兴耀[1] 浦义涛 

机构地区：[1]中国石油大学(华东)地球科学与技术学院,山东青岛266580 [2]中国石油东方地球物理公司塔里木物探处,新疆库尔勒841001

出　　处：《物探与化探》2016年第4期757-762,共6页Geophysical and Geochemical Exploration

基　　金：国家重点基础研究发展计划("973")(2013CB228604);山东省自然基金项目(ZR2014DM009)联合资助

摘　　要：地震数值模拟中,完全匹配层(PML)边界能有效地吸收衰减地震波,得到无边界反射干扰的波场快照和地震记录。在前人研究的基础上,进一步分析了分裂完全匹配层(SPML)的衰减机制,通过波动方程模拟,分析了震源主频、空间网格间距、介质速度等参数对SPML边界吸收衰减特征的影响。得到了不同条件下,PML边界对地震波的吸收效果。通过分析对比,得出了震源主频对PML吸收效果无直接影响,空间网格间距与PML吸收效果成反比,高速层PML吸收效果缓慢等结论。并通过Marmousi2模型测算,对结论进行了验证。最后给出了复杂模型、不同尺度数值模拟中SPML参数的选取方法,为地震数值模拟中SPML边界参数的定量选取奠定了基础。In seismic numerical simulation,the perfectly matched layer（ PML） boundary can attenuate the seismic wave effectively,and the snapshots and record have no boundary reflection interferes. The authors further analyzed the attenuation mechanism of split perfectly matched layer（ SPML）. By wave equation simulation,the authors analyzed the problem as to how the parameters affect absorption and attenuation characteristics of SPML boundary,such as source dominant frequency,spatial grid spacing and medium speed. As a result,the authors obtained the results of PML attenuation based on different conditions. Through analyzing and comparing the results,the conclusions have been reached that source dominant frequency has no direct influence on PML attenuation,spatial grid spacing is in inverse proportion to the PML attenuation,and high-speed medium slows down PML attenuation effect. By Marmousi2 test,the authors confirmed the validity of the conclusions. The selection method of SPML parameter in complex model or different scales of numerical simulation was given,which lays a foundation for quantitative selection of SPML boundary parameters in numerical simulation.

关 键 词：地震数值模拟 波动方程 完全匹配层 吸收衰减特征 小尺度 

分 类 号：P631.4[天文地球—地质矿产勘探]