ABSTRACT A novel traveltime tomographic approach is applied to anisotropic media, limited to 2D geometry at present. A general anisotropic Eikonal solver based on a discontinuous Galerkin method is combined with an efficient adjoint formulation for multiparameter least‐squares inversion. This new approach is tested considering synthetic crosshole ground‐penetrating radar data. The configuration of the ground‐penetrating radar survey is inspired by a real experiment done on layered carbonate media disturbed by the presence of a deep gallery, which induces a localized high‐electromagnetic contrast. This made it possible to define a well‐adapted general workflow in this context. We notably show that, under the elliptical anisotropic assumption, the parametrization based on vertical and horizontal velocities provides less biased results than those obtained by considering the vertical velocity and the relevant Thomsen parameter e. The initial vertical and horizontal velocity models are identical and built from an isotropic inversion. The presence of the high‐contrast gallery generates a weak diffraction pattern, which is taken into account in our tomography approach. It also creates potential artefacts due to the model discretization, which are mitigated by a model regularization term within the definition of the misfit function. This general workflow is then applied to the real experiment dataset. The vertical and horizontal velocity images provide similar structures as those previously obtained by isotropic full waveform inversion, complemented by an image of a rather weak elliptical anisotropy.

中文翻译：

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无基质井间椭圆各向异性断层扫描：参数化分析和探地雷达在碳酸盐岩中的应用

摘要 一种新颖的走时层析成像方法应用于各向异性介质，目前仅限于二维几何。基于不连续伽辽金方法的通用各向异性 Eikonal 求解器与多参数最小二乘反演的高效伴随公式相结合。考虑到合成的井间探地雷达数据，对这种新方法进行了测试。探地雷达勘测的配置受到在层状碳酸盐介质上进行的真实实验的启发，该实验受到深画廊的干扰，从而导致局部高电磁对比度。这使得在这种情况下定义一个适应性强的通用工作流成为可能。我们特别表明，在椭圆各向异性假设下，与通过考虑垂直速度和相关 Thomsen 参数 e 获得的结果相比，基于垂直和水平速度的参数化提供的结果偏差更小。初始的垂直和水平速度模型是相同的，并且是根据各向同性反演建立的。高对比度画廊的存在会产生弱衍射图案，这在我们的断层扫描方法中被考虑在内。由于模型离散化，它还产生了潜在的伪影，这些伪影可以通过失配函数定义中的模型正则化项来减轻。然后将此通用工作流程应用于真实的实验数据集。垂直和水平速度图像提供了与以前通过各向同性全波形反演获得的结构相似的结构，