起伏地形的2.5维主轴各向异性海洋CSEM反演研究

Research on 2.5-dimensional axially anisotropy marine CSEM inversion of undulating topography

笔者利用OCCAM方法实现了MPI并行的2.5维海洋CSEM反演算法。正演采用基于非结构网格的有限元方法,在精确模拟海底起伏地形和构造模型的同时,对核心区域和扩展区域进行不同尺度的剖分以减少反演参数。水平海床和起伏海床的理论模型算例表明,沿测线发射的2.5维剖面数据对垂直各向异性模型的恢复效果优于水平各向异性模型。复杂海底地形模型的试算结果表明,带地形沉积层的存在会对反演结果产生较大影响,在实际资料解释中应该引起重视。

An MPI parallel 2.5-dimensional marine CSEM inversion algorithm was implemented using the OCCAM method.The forward modeling adopts a finite element method based on unstructured grids,which accurately simulates the seabed's undulating topography and structural model while meshing the core and extended regions at different scales to reduce inversion parameters.The examples of horizontal and undulating seabed models indicate that the recovery effect of the vertical anisotropic model is better than that of the horizontal anisotropic model using 2.5-dimensional profile data emitted along the survey line.The trial results of complex seabed topography models indicate that the presence of sedimentary layers with topography can significantly impact the inversion results,which should be taken seriously in actual data interpretation.