回线源瞬变电磁法的一维Occam反演

doi:10.11720/wtyht.2021.0103

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Abstract

A 1D inversion code is developed for the loop-source transient electromagnetic method (TEM) based on the open-source code Dipole1D and Occam's algorithm. This code is tested by a four-layer stratified model. Then, the model with a tilted earth-air interface is considered, for which the synthetic data are calculated by 3D finite-element method. The inversion results show that 1D inversion can be directly used for the scenario with tilted interface. Finally, this 1D inversion code is used for a field case, in which TEM is employed to delineate the 3D distributed domains of a basalt which intruded into shale and sandstone. The inversion result shows that the thickness of the basalt coincides with the drilling data, and the shape of the basalt like a pot bottom.

Key words： loop source TEM Occam's method 1D inversion

Received: 26 February 2021 Published: 15 December 2021

ZTFLH:

P631

Corresponding Authors: LI Jian-Hui E-mail: 156663062@qq.com;ljhiiicumt@126.com

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	Articles by authors
	Tao XING
	Wei YUAN
	Jian-Hui LI

Cite this article:

Tao XING,Wei YUAN,Jian-Hui LI. One-dimensional Occam's inversion for transient electromagnetic data excited by a loop source[J]. Geophysical and Geochemical Exploration, 2021, 45(5): 1320-1328.

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https://www.wutanyuhuatan.com/EN/10.11720/wtyht.2021.0103 OR https://www.wutanyuhuatan.com/EN/Y2021/V45/I5/1320

The framework of 1D forward modeling for loop-source transient electromagnetic methods

The inversion geo-electric model for the loop-center point and for 4-layer model

The data computed from the inversion model

The sketch map for the tilted-surface model

Geoelectric model obtained by inversion of data at the center of the loop( inversion schemes 1)

The inversion geo-electric models obtained from different inversion schemes

Under the influence of random noise, the inversion geoelectric model of the actual model (Tx2 loop)
The black line denotes the realistic model, the color lines denote the inversion models

The inversion geo-electric models for five survey points

The data computed from the inversion model for x=1 000 m and 2 000 m
a、c—EMF curves at different measuring points; b、d—Misfit curver and the standard deviation curves of measured data

The section view stitched from the single-point 1D inversion models for survey line 1

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