摘要:
设计了一个简单的三维模型:三维低阻异常体和高阻异常体位于一维层状介质模型中,以“十”字型和“米”字型观测剖面方式作为模拟方式,开展模型一维、二维、三维反演技术有效性对比试验,其中一维反演计算采用自适应正则化( ARIA)反演,二维反演计算采用非线性共轭梯度( NLCG)反演,三维反演计算采用REBOCC三维反演,将剖面下方不同的反演结果与原始模型进行对比分析,发现:在该模型条件下,一维和二维反演都能得到反映模型真实信息的结果,REBOCC三维反演更偏向重建原始模型的宏观电性特征;在一维反演结果中,对于深部的电性结构特征,通常TE极化模式的反演结果好于TM极化模式,TE/TM几何平均值反演结果介于前两者之间;在二维反演结果中,通常TM极化模式的反演结果好于TE极化模式,TE/TM联合模式反演结果与TM极化模型相当,甚至更好;模型REBOCC三维反演相比一维、二维反演更易受反演结果多解性影响,REBOCC三维反演结果偏向重建原始模型的宏观电性特征。
Abstract:
A simple three?dimensional model, a low?resistivity abnormal body and a high resistance abnormal body located in one?di?mensional layered medium were designed in this paper. The authors used the"+" and"?" type observation profiles as the analog form to carry out the comparative experimental study of the effectiveness of MT 1D, 2D, 3D inversion. The authors employed adaptive regu?larization ( ARIA) to perform 1D inversion, and adopted nonlinear conjugate gradient ( NLCG) to conduct 2D inversion and REBOCC to carry out 3D inversion. The comparison of the different inversion results below the profile with the original model shows that 1D and 2D inversion can be reflected in the results of real model information, while 3D inversion of REBOCC tends to build a three?dimension?al model of macroscopic electrical characteristics. In the 1D inversion results, as for the deep electrical structure, the inversion result shows that the TE polarization mode is better than TM polarization mode, and the combination mode of TE and TM has a medium result between the TE and TM. In the 2D inversion results, usually the TM polarization mode is better than TE polarization mode, and the in?version results of combination mode of TE with TM are almost equal with the TM polarization mode inversion results, or even better. In the 3D REBOCC inversion results, due to the influence of multiple solutions on inversion results, the 3D inversion of REBOCC tends to build a three?dimensional model of macroscopic electrical characteristics.
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