高级检索

    基于点扩散函数的成像域矢量弹性最小二乘逆时偏移方法

    • 摘要: 与传统弹性逆时偏移(ERTM)相比,弹性最小二乘逆时偏移(ELSRTM)具有更高分辨率、更好的振幅平衡、更少的串扰噪声和更宽的频带等优势。然而,目前大多数ELSRTM方法在数据域实现,通常需要多次迭代,每次迭代涉及大量计算。此外,传统ELSRTM获得的扰动反射系数模型与ERTM的成像结果存在显著差异。因此,我们提出了一种基于点扩散函数的成像域矢量弹性最小二乘逆时偏移方法(ID-VELSRTM)。该方法旨在获得与ERTM地质构造一致的成像结果,同时提高成像质量和分辨率。反演在成像域的模型空间中进行,与数据域方法相比具有显著的计算效率优势。利用光学中的点扩散函数(PSF)作为Hessian矩阵的局部近似,我们为ID-VELSRTM方法构建了成像域目标函数。在最小二乘反演框架中,将空变反卷积与快速迭代收缩阈值算法(FISTA)相结合,应用于ERTM成像结果,获得最终的PP和PS成像结果。地堑模型和SEG/EAGE盐丘模型的数值实验证明了ID-VELSRTM方法的有效性。与ERTM相比,ID-VELSRTM实现了更少的旁瓣、更宽的波数范围和更高的成像分辨率。

       

      Abstract: Elastic least-squares reverse time migration (ELSRTM) offers higher resolution, better amplitude balancing, fewer crosstalk noises, and broader bandwidth compared to traditional elastic reverse time migration (ERTM). However, most current ELSRTM methods are implemented in the data domain, typically requiring multiple iterations, each iteration involving significant computational cost. Additionally, the perturbation model of the reflection coefficients obtained from conventional ELSRTM differs apparently from the imaging results of ERTM. Therefore, we propose an image-domain vector elastic least-squares reverse time migration (ID-VELSRTM) method based on the point spread function (PSF). This method aims to achieve imaging results that are consistent with the geological structures obtained via ERTM while improving image quality and resolution. The inversion is performed in the model space of the image domain, offering significant computational efficiency advantages over data-domain methods. Using the PSF from optics as a localized approximation of the Hessian matrix, we construct an image-domain objective function for the ID-VELSRTM method. In the least-squares inversion framework, space-variant deconvolution combined with the fast iterative shrinkage-thresholding algorithm (FISTA) is applied to the ERTM imaging results to obtain the final PP and PS images. Numerical experiments with layered, graben, and SEG/EAGE salt models demonstrate the effectiveness of the ID-VELSRTM method. Compared to ERTM, ID-VELSRTM achieves better amplitude balancing, fewer crosstalk noises, a broader wavenumber range, and higher imaging resolution.

       

    /

    返回文章
    返回