煤矿倾斜地层瞬变电磁加权横向约束反演  

Transient Electromagnetic Weighted Laterally-Constrained Inversion of Inclined Strata in Coal Mine

作　　者：高小伟 苏超[2] 庞少东 Gao Xiaowei;Su Chao;Pang Shaodong(Xi’an Research Institute Co.,Ltd.,China Coal Technology and Engineering Group Corp.,Xi’an 710077,China;College of GeoExploration Science and Technology,Jilin University,Changchun 130026,China)

机构地区：[1]中煤科工西安研究院(集团)有限公司,西安710077 [2]吉林大学地球探测科学与技术学院,长春130026

出　　处：《吉林大学学报（地球科学版）》2024年第1期310-322,共13页Journal of Jilin University：Earth Science Edition

基　　金：陕西省自然科学基础研究计划重点项目(2022JZ-16)。

摘　　要：传统的单点一维反演是煤矿瞬变电磁数据处理与解释应用最广泛的技术方法,然而,实际地层往往存在一定倾角,当地层倾角较大时,基于单点水平层状模型的一维反演方法将不再适用,无法准确还原倾斜地层的电性分布特征。为此,针对煤矿瞬变电磁探测点距小、沉积地层地下电性结构相对连续的特点,本文采用加权横向约束反演(weighted laterally-constrained inversion,WLCI)方法,将相邻测点地电参数的差异作为约束项加入目标函数,对层界面的深度进行约束,同时引入加权因子控制约束强度,反演过程尽可能使相邻测点反演剖面具有横向的连续性以及纵向的光滑性。首先,阐述了瞬变电磁一维正、反演原理,并对WLCI计算过程进行了详细介绍。然后,建立了2组不同倾斜角度的H型与K型模型进行测试,分析加权因子对反演结果的影响。与传统的一维反演结果相比,WLCI通过建立层参数和深度加权约束方程并合成总的反演方程,是一种拟二维的反演方法,反演的电阻率剖面横向及纵向连续性好,与实际模型的吻合度较高,验证了反演方法的有效性。最后,实测数据的反演结果显示,WLCI可以准确还原倾斜地层的电性分布,反演结果与实际地质资料吻合。The traditional single-set one-dimensional(1D)inversion is the most widely used technique for the processing and interpretation of transient electromagnetic data in coal mines.However,this approach becomes inadequate when the stratum exhibits a significant dip,as the single-set horizontal layered model fails to accurately represent the electrical distribution characteristics.To address this limitation,we employ the weighted laterally-constrained inversion method to constrain the layer interface depth and incorporate the difference in geoelectric parameters between adjacent measurement points into the objective function as a constraint term.We describe the transient electromagnetic 1D forward and inversion theory,and detail the inversion method with weighted lateral constraints.The influence of the weighting factor on inversion results is analyzed using the H-type and K-type models with varying inclinations.Compared with the traditional 1D inversion,the weighted laterally-constrained inversion is a pseudo-2D inversion method by establishing layer parameters and depth-weighted constraint equations and synthesizing total inversion equations.The obtained resistivity profiles exhibit strong agreement with actual models and demonstrate good longitudinal and transverse continuity.The employed method effectively restores the electrical distribution of inclined strata,and the inversion results match the actual geological data.

关 键 词：倾斜地层 瞬变电磁 一维反演 加权横向约束反演 拟二维反演 

分 类 号：P631[天文地球—地质矿产勘探]