摘要
针对层状介质模型,在忽略井眼影响的条件下,利用边界条件推导出垂直磁偶极子源在全空间中的电磁场。选用Anderson提出的汉克尔滤波系数,采用自适应的线性滤波算法编制了计算程序,对几种典型地电模型在井中的电磁场及视电阻率进行了计算。计算结果显示,当高阻基底之上存在低阻层时,在井下一定深度范围内观测会出现电磁场的假极小值异常,假极小值出现的深度与低阻层的电阻率以及厚度有关;与地面观测相比,地-井电磁场观测方式可削弱浅部高阻覆盖层影响,从而提高深部探测的精度,更好地反映下部低阻层的特性。
Based on layered medium, vertical magnetic dipole source electromagnetic field in full space was deduced from 3D boundary conditions on ignoring the influence of the borehole itself. The computation program of electromagnetic field was compiled by an adaptive linear filtering algorithm and Hankel filter coefficients proposed by Anderson. Electromagnetic field and the apparent resistivity in borehole survey for some typical layered mediums were calculated in this program. The calculated results show that when a high resistivity layer above a low resistivity one, a spurious minimum anomaly appeared on the electromagnetic field surveyed in borehole and the position of the anomaly was related to both thickness and depth of the covering low resistivity layer. Moreover, compared with the ground surface survey, the surface-borehole electromagnetic field survey can decrease the interference of the shallow covering high resistivity layer, so as to improve the accuracy of detecting in deep and better reflect the characteristics of low resistivity layer in the lower part.
出处
《桂林理工大学学报》
CAS
北大核心
2016年第3期458-463,共6页
Journal of Guilin University of Technology
基金
国家重大科学仪器设备开发专项(2012YQ030126)
广西自然科学基金项目(2013GXNSFBA019212)
广西高校科学技术研究重点项目(2013ZD029)
广西隐伏金属矿产勘查重点实验室系统研究课题(15-140-27-04)
有色及贵金属隐伏矿床勘查教育部工程研究中心项目(2015GCZX002)
关键词
垂直磁偶极子
层状介质
电磁场响应
地-井
滤波算法
vertical magnetic dipole
layered media
electromagnetic response
surface- borehole
filtering al-gorithm
