用TEM反演法进行MT静位移的识别和校正

杨长福; 林长佑

用TEM反演法进行MT静位移的识别和校正

杨长福¹,
林长佑²

1.
南京大学地球科学系, 江苏南京 210093
2.
中国地震局兰州地震研究所, 甘肃兰州 730000

基金项目: 原煤炭工业部国家Ⅱ类科研项目; 甘肃省科委资助项目

详细信息

作者简介:
杨长福(1964-), 男, 副研究员, 2000年在青岛海洋大学获应用地球物理专业博士学位, 主要从事电磁测深理论、方法和应用等方面的研究工作

中图分类号: P631.3⁺25
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出版历程
- 收稿日期: 2001-01-05
- 刊出日期: 2001-11-25

JUDGMENT AND CORRECTION FOR MT STATIC SHIFT BY TEM INVERSION METHOD

Yang Changfu¹,
Lin Changyou²

1.
Department ofEarth Science, Nanjing University, Nanjing 210093, China
2.
Lanzhou Institute ofSeismology, China Seismological Bureau, Lanzhou 730000, China

摘要

摘要: 对瞬变电磁(TEM)资料进行反演时, 采用观测磁场而不用视电阻率, 避免了由于TEM视电阻率定义而引起的误差, 并且由源象磁场和观测磁场之间的拟合进行反演使反演结果受非均匀性影响较小; 将反演结果构置出地电模型, 计算出它的MT曲线作为静位移校正的参考曲线, 使它用于MT静位移校正更为可靠, 同时也解决了两种电磁资料从时间域到频率域的转换问题.由此实现用TEM反演的方法进行MT静位移的识别和校正.实例表明, 这种方法对MT静位移的识别和校正十分有效.
- 瞬变电磁 /
- 反演 /
- 大地电磁 /
- 静位移校正
Abstract: The inversion for TEMdata using the observed magnetic fields instead of using the apparent resistivities avoids the errors caused by the definition of the TEMapparent resistivity. In addition, the inversed results by fitting the magnetic fields of the transmitter source's image to those of the observed magnetic fields are relatively less affected by the conductivity inhomogeneity. The MTapparent curves calculated from the geo-electric model constructed with the TEMinversion results, serve as reference curves for the more reliable correction of MTstatic shift, and also actualize the transformation from time domain to frequency domain between these two kinds of electromagnetic data. Therefore, TEMinversion can be applied to the correction of the MT static shift. Many field studies show that this method is very effective for the judgment and correction of the MTstatic shift.
- TEM /
- inversion /
- telluric electromagnetism /
- correction ofMTstatic shift

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图 1 电阻率结构模型

a. 模型1.层状地球中存在一个50 m×150 m×5 m的导电表面非均匀体, 平面图标出了方形发射源中心环TEM接受器所在位置; b.模型2.层状地球存在一导电表面非均匀体和一较大埋深3D体同(a), 平面图阴影区表示埋深100Ω·m层顶面的10Ω·m体, TEM接受器位于表面体中央(引自Pellerin等^[12])

Fig. 1. Model of resistance structure

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图 2 静位移校正示意

矩形和圆圈表示的曲线分别为XY和YX极化方式的畸变响应, 虚线表示畸变曲线将要平移到的所计算校正曲线.a.对模型1(实线表示未畸变的1D响应); b.对模型2(实线表示未畸变的两种极化响应)(引自Pellerin等^[12])

Fig. 2. Diagram for static shift correction

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图 3 由TEM反演结果所计算的MT视电阻率曲线(实线)及观测MT曲线

Fig. 3. MT apparent resistivity(solid line) calculated by TEM inversion result and the observed MTcurves

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图 4 榆中峡口测点TEM反演结果

实线为本文方法反演结果, 虚线为广义逆反演结果

Fig. 4. TEM inversion results at Yuzhong Xiakou

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参考文献(19)

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