| 基于模型空间压缩的大地电磁三维反演研究 |
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| 引用本文： | 王青,刘云鹤,殷长春,李金峰,张洁.基于模型空间压缩的大地电磁三维反演研究[J].地球物理学报,2019,62(2):752-762. |
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| 作者姓名： | 王青 刘云鹤 殷长春 李金峰 张洁 |
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| 作者单位： | 吉林大学地球探测科学与技术学院, 长春 130026 |
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| 基金项目： | 国家自然科学基金项目（41530320，41774125），国家重点研发计划（2017YFC0601900，2016YFC0303100）和中国科学院先导专项（XDA14020102）联合资助. |
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| 摘 要： | 本文提出了一种基于模型空间压缩技术的大地电磁三维反演方法.该方法在传统大地电磁三维反演理论的基础上,通过小波变换将待反演的空间域模型参数映射到小波域进行反演,获得小波域更新模型后再通过小波逆变换得到空间域反演模型.由于小波变换具有压缩特性和多尺度分辨能力,本文反演方法可在一定程度上提高反演分辨率.为了提高反演效率,我们针对基于L_1范数的模型约束求解不易收敛的反演问题,提出了一种基于模型粗糙度的简单有效的预条件处理技术.为验证本文算法的有效性,本文首先对经典的"棋盘"模型进行三维反演测试.反演结果表明本文算法的反演效率与传统方法相当,但对于深部异常体具有更好的分辨能力.最后,我们通过对实测数据反演进一步验证本文算法的有效性.
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| 关 键 词： | 大地电磁 三维反演 小波变换 压缩 多尺度 |
| 收稿时间： | 2018-04-06 |
3D MT inversion based on model space compression |
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| WANG Qing,LIU YunHe,YIN ChangChun,LI JinFeng,ZHANG Jie.3D MT inversion based on model space compression[J].Chinese Journal of Geophysics,2019,62(2):752-762. |
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| Authors: | WANG Qing LIU YunHe YIN ChangChun LI JinFeng ZHANG Jie |
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| Institution: | College of Geo-exploration Science and Technology, Jilin University, Changchun 130026, China |
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| Abstract: | As an effective geophysical tool,the Magnetotelluric (MT) method is widely used in geological surveys, exploration of minerals, oil and gas and research of electrical structures of the earth crust and upper mantle. As the MT exploration model becomes more and more complex, the requirements for inversion speed and accuracy are increasing.
Since the 1970s, with the continual improvement of computational equipment, new Three-Dimensional (3D) MT inversion techniques have been rapidly developed. They include the steepest descent, Gaussian Newton, conjugate gradient, nonlinear conjugate gradient, and fast relaxation inversion method. In this paper, we propose a new 3D MT inversion method based on model space compression. We develop this new method by adopting wavelet transform into the traditional inversion algorithm. A simple model of a piecewise constant structure in the space domain has a very sparse representation in the wavelet domain, which means that if the sparse representation of the model can be recovered in the wavelet domain, then the corresponding model in the space domain can also be recovered. Taking into account that the wavelet spectrum can describe the spectral characteristics of signals at different scales, the wavelet transform is applied to geophysical signal processing.
To accelerate the inversion, we further propose a simple but useful preconditioned technology. After that, we test our new inversion algorithm on both synthetic and field survey data. The inversion results show that our method can improve the model resolution from the inversion, while the feasibility of our method is comparable to the traditional one. This new method has potential to become a feasible inversion method. |
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| Keywords: | Magnetotelluric (MT) 3D inversion Wavelet domain Compression Multiscale |
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