基于染色算法的VTI介质地震波数值模拟及偏移成像  

Numerical modeling and migration imaging for VTI seismic wave based on the staining algorithm

作　　者：高彬 呼少平 陈忠杰 张池 庞少东 GAO Bin;HU Shaoping;CHEN Zhongjie;ZHANG Chi;PANG Shaodong(Shenmu Zhangjiamao Mining Co.,Ltd.of Shaanxi coal group,Yulin 719099,China;China Coal Technology&Engineering Group Xi’an Research Institute(group)Co.,Ltd.Xi’an 710077,China)

机构地区：[1]陕煤集团神木张家峁矿业有限公司,榆林719099 [2]中煤科工西安研究院(集团)有限公司,西安710077

出　　处：《物探化探计算技术》2024年第6期656-664,共9页Computing Techniques For Geophysical and Geochemical Exploration

基　　金：中煤科工西安研究院(集团)有限公司科技创新基金项目(2022XAYJS06);陕西省自然科学基金重点研发计划项目(2022SF-046)。

摘　　要：各向异性偏移成像技术在高精度地球物理勘探中扮演着重要角色。为了提高声学VTI(垂直对称轴横向各向同性)介质的成像精度,笔者在波场外推中采用了一种改进的纯P波方程,相速度分析验证了改进方程的精度优势;采用混合法(有限差分+伪谱法)对改进方程进行了求解。相比于传统拟声波方程,改进的纯P波方程在产生高精度P波响应的同时能够有效消除干扰,进一步地考虑到逆时偏移剖面中深部成像能量较弱的问题,将染色算法推广到VTI纯P波逆时偏移。在模型深部选取用于参考的目标区域,基于染色算法的地震波传播仅在该区域产生响应,由此获得更丰富的波场信息。模型算例表明,基于染色算法的VTI纯P波偏移成像技术能够在保证原始成像精度的前提下,对深部介质结构产生更高精度的成像结果。Anisotropic migration imaging technique plays an essential role in high-accuracy geophysics exploration.To improve imaging accuracy in acoustic VTI(Vertical Transversely Isotropy)media,this paper first uses a modified pure P-wave equation for wavefield extrapolation,and phase velocity analysis to validate the accuracy advantage of the modified equation.Then,a hybrid solution(finite-difference method+pseudo-spectral method)is used to compute the modified equation.Compared with the traditional pseudo-acoustic wave equation,the modified pure P-wave equation can generate a high-precision P-wave response while eliminating the pseudo-shear wave interference.Further,considering the weak imaging energy in the deep region of the reverse-time migration(RTM)profile,the staining algorithm is extended to VTI pure P-wave RTM.Selecting the appropriate target region in the deep section of the model and the seismic wave propagation based on the staining algorithm can only produce a response in this region,thus more abundant wavefield information can be obtained.Several modeling examples verify that the VTI pure P-wave RTM technique based on the staining algorithm can result in higher precision imaging results for deep structures while ensuring the original imaging accuracy and can be regarded as an effective supplement for the traditional anisotropic imaging methods.

关 键 词：各向异性 纯P波 逆时偏移 染色算法 

分 类 号：P631.4[天文地球—地质矿产勘探]