摘要
基于矿井瞬变电磁法全空间效应会增加低阻体空间定位的难度,易误判地质异常发育的位置,为提高解释精度,准确得出地质异常发育的位置,基于电磁场扩散理论,建立井下瞬变电磁场正演模型,采用9点扇形探测法,研究了矿井低阻体对电磁场全空间分布的影响规律,提出了全空间地质体校正系数,并在祁东煤矿进行了试验。结果表明:当顶底板均有低阻体时最大感应电位的数量级达107,比底板单有低阻体时高1个数量级,此时单支曲线尾支衰减更平缓,可得到校正系数0.2～0.6;底板探测低阻区域视电阻率为10Ω.m,经校正后升至25Ω.m,呈高阻反映,钻孔验证无水,证明该区域不存在低阻异常发育。
The full space effect of the minetransient electromagnetic method would increase the space positioning difficulty of the low re- sistance geological mass and would misjudge the location of the geological abnormal development. In order to improve the explanation ac- curacy and accurately obtain the location of the geological abnormal development, based on the diffusion theory of the electromagnetic field, a forward model of the mine transient electromagnetic field was established. A nine sector detection method was applied to study the influence law of the mine low resistance mass to the full space distribution of the electromagnetic field. The correction coefficient of the full space geological mass was provided and the test was conducted in Qidong Mine. The results showed that when the roof and floor both had the low resistance mass, the magnitude order of the max induced potential was 10^7 and would be one magnitude order higher than the floor with the low resistance mass only. At this moment, the decay of the single curve tailrace would be more gently and the correction coeffi- cient would be 0. 2 - 0. 6. The apparent resistivity of the low resistance region detected in the floor was 10 Ω.m and could increase to 25 Ω.m after the correction. The apparent resistivity would be high resistance in reflection. The borehole was no water as confirmed and there was no low resistance abnormal development in the region.
出处
《煤炭科学技术》
CAS
北大核心
2012年第8期107-110,共4页
Coal Science and Technology
基金
国家重大科学仪器设备开发专项资助项目(2011YQ03013307)
关键词
矿井瞬变电磁法
低阻地质体
全空间效应
校正系数
数值分析
视电阻率
mine transient electromagnetic method
low resistance geological mass
full space effect
correction coefficient
numerical a-nalysis
apparent resistivity
