超高密度电法有限单元法正演与广义最小二乘反演

Finite element forward simulation and least square generalized inversion of ultra-high density resistivity method

针对超高密度电法的全四极装置,采用三角形网格剖分和线性插值的有限单元法进行正演模拟,然后对该模拟结果开展广义最小二乘正则化反演,反演过程中对模型参数同时施加光滑模型和背景模型约束以提高反演稳定性。以一个低阻双层结构模型为例,与5种常规电法进行对比,发现超高密度电法具有数据信息量大、反演精度高的优点。对一个山谷地形下正方体低阻模型的超高密度电法数据进行正演和反演模拟,反演结果表明:该方法在较复杂地形条件下也能较好地刻画出异常体的形态及地下电性的分布,提高物探解释精度。

According to the full-four-pole array of ultra-high density resistivity method, the triangle mesh subdivision and the finite element method of linear interpolation were used for forward simulation, and then generalized least square regularization for inversion was used for the simulation results. At the same time, the smooth model and background model constraints were imposed in model parameters to improve the stability of inversion. Taking a low resistivity double-layer structure model as an example, ultra-high density resistivity method possesses the advantages of large volume data and high inversion accuracy compared with 5 kinds of conventional resistivity methods. The forward and inversion simulations were carried out on data of low resistance cube under valley terrain model using ultra-high density electrical method. The inversion results show that even under complex terrain conditions this method can portray the shape of abnormal body and underground electrical distribution well, thus, effectively improving the precision of geophysical interpretation.