多频组合胖射线旅行时层析成像方法  

Fat ray traveltime tomographic imaging based on multiple frequencies' combination

作　　者：杨雪霖 李振春[1] 尹正 张凯[1] 桑运云 

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]东方地球物理公司物探技术研究中心,河北涿州072751 [3]东方地球物理公司油藏地球物理研究中心,河北涿州072751 [4]东方地球物理公司研究院华北分院,河北任丘062552

出　　处：《石油地球物理勘探》2014年第5期911-915,924,共6页Oil Geophysical Prospecting

基　　金：国家自然基金项目(41204086);国家"863"计划项目(2011AA060301);国家科技重大专项(2011ZX05006-002)联合资助

摘　　要：基于射线理论的地震波旅行时层析成像是重建地下速度分布的有效工具,然而传统的射线层析建立在无限高频近似的基础上,导致反演问题产生严重的不适定性,从而影响层析成像的效果。针对传统射线层析存在的问题,本文提出了基于第一菲涅尔带的多频率组合的胖射线层析方法。该方法通过第一菲涅尔带拓宽射线,并利用权重影响因子修改层析核函数,有效降低了反演矩阵的稀疏性,解决了射线层析的不适定性问题。同时由于多个频率的引入,在迭代反演过程中,有效地提高了层析的分辨率与精度。同时该方法不需计算射线路经,因而提高了计算效率。模型试算结果证明了本方法的有效性与稳定性。In conventional seismic imaging experiments,traveltime tomography based on ray theory plays an important role in gaining the velocity construction.However,the traveltime tomography relies on infinite frequency assumption which results in serious ill-conditioned matrix and has negative inference on the result.We propose the fat ray traveltime tomography based on first Fresnel zone and multiple frequencies' combination. We broaden the ray by first Fresnel zone and modify the Frechet function by weighting influence factors to resolve the instability caused by ill-conditioned matrix.Meanwhile,we enhance the resolution and precision by combining multiple frequencies.Our method improves the efficiency by avoiding the calculation of ray path.The inverted result proves that our method has a higher resolution and accuracy than the ray theory tomography.

关 键 词：胖射线层析 菲涅耳带 多频组合 影响因子 层析核函数 

分 类 号：P631[天文地球—地质矿产勘探]