含激电效应的航空瞬变电磁数据横向约束反演  

Laterally constrained inversion of airborne transient electromagnetic data with induced-polarization effects

作　　者：路俊涛 雷达[1,2,3,4] 任浩[1,2,3,4] LU JunTao;LEI Da;REN Hao(CAS Engineering Laboratory for Deep Resources Equipment and Technology,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Key Laboratory of Shale Gas and Geoengineering,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Innovation Academy for Earth Science,CAS,Beijing 100029,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院深地资源装备技术工程实验室,中国科学院地质与地球物理研究所,北京100029 [2]中国科学院页岩气与地质工程重点实验室,中国科学院地质与地球物理研究所,北京100029 [3]中国科学院地球科学研究院,北京100029 [4]中国科学院大学,北京100049

出　　处：《地球物理学进展》2022年第1期220-229,共10页Progress in Geophysics

基　　金：北京市科技计划“地球深部探测技术攻关”专项(Z81100005718001);国家重点研究开发项目(2016YFC0601104);国家重大项目(2017ZX0500800-7)联合资助。

摘　　要：受激电效应影响,航空瞬变电磁响应曲线经常出现异常快速衰减和符号反转现象,使用Cole-Cole模型的等效电阻率代替原模型实电阻率能很好的解释该现象,但由于激电多个参数的引入,使得反演多解性问题更加严重.本文基于Cole-Cole模型实现了航空瞬变电磁一维正演,采用横向约束反演同时计算激电参数及层厚,增加约束条件改善多解性问题.基于链式法则推导了求取雅可比矩阵的解析公式,结果表明与传统差分法相比,得到相同精度结果的情况下,解析法可大幅减少计算时间,同时在反演过程中采用令满足迭代误差的测点不再参与后面迭代的策略,以此减少不必要的正演和雅可比计算,进一步提高反演效率.通过对简单模型和复杂模型进行激电横向约束反演,并与传统一维反演方法对比,验证了横向约束反演能有效提取激电信息,得到与理论模型吻合的反演结果.The response abnormal attenuation and sign reversal in the Airborne Transient Electromagnetic(ATEM) are frequently observed in the field measurement, due to Induced-Polarization(IP) effects. This phenomenon can well be explained by introducing the Cole-Cole complex resistivity model, however, the introduction of four IP parameters makes the non-uniqueness of inversion more serious. Based on the Cole-Cole model, this paper realizes the 1 D ATEM IP forward, to improve the non-uniqueness and stability, we utilized laterally constrained inversion to calculate four IP parameters and thickness by adding constraint conditions. We derived the analytical formula of the Jacobian matrix based on the chain rule, compared with the conventional finite-difference method, the analytical method can greatly improve the inversion efficiency and reduce the calculation time. In the inversion processing, we propose a strategy that makes the measuring points that satisfy the iteration error no longer participate in the later iterations, to avoid the unnecessary forward and Jacobian calculation, improve the inversion efficiency and stability. We employ laterally constrained inversion on two synthetic models and compare them with the results produced by conventional 1 D inversion. It is verified that laterally constrained inversion can extract IP information effectively, and the results are highly consistent with the theoretical models.

关 键 词：航空瞬变电磁 激电效应 COLE-COLE模型 解析法 横向约束反演 

分 类 号：P631[天文地球—地质矿产勘探]