分布式电磁探测系统在深部地下水资源勘查中的应用

Application of Distributed Electromagnetic System in Deep Groundwater Prospecting

可控源音频大地电磁法(CSAMT)是一种有效的地下深部资源勘探方法,但现有仪器分段分时的工作方式使得其观测精度受不同排列观测条件差异的影响。为了提高测量精度和效率,研制了一种实现整条测线多点同步观测的分布式电磁探测系统。系统由级联式大功率发射系统和分布式多通道接收系统组成,通过移动发射源位置实现CSAMT和激发极化法2种测量功能;仪器采集的多道原始数据经过干扰噪声抑制后提取出反演参数。利用该系统在吉林松江河地区开展了深部地下水资源勘查,并与同类仪器GDP32II的勘探结果进行了对比。结果表明:分布式电磁探测系统多点同步观测方式不但提高了工作效率,而且有效地克服了时变性、区域性外界噪声产生的横向异常影响。根据勘查结果在该地区成功预测了深部地下水的有利赋存位置并得到了钻井验证。

Controlled sourse audio frequency magnetolelluric （CSAMT） is an effective geophysical method for deep resouree prospecting. The accuracy of most current instruments functioning in time- sharing measurement mode is easily affected by differences of various arrangement observation condition. In order to improve the efficiency and accuracy, a distributed electromagnetic system was developed which achieves multi-point observation simultaneously in a survey line. The system consists of an electromagnetic receiver array and a high power transmitter base on series technology and it can be used for the CSAMT and induced polarization method by moving emission source location. Inversion parameters are extracted from the original multi-channel data after interference suppression. The system was applied to deep groundwater prospecting in Songjianghe area, Jilin Province. The results which were compared with GDP32II shows that multi-point simultaneous measurement not only improve efficiency, but also overcome the horizontal abnormal impact generated by time-varying and regional noise. The potential location of deep groundwater was successfully predicted according to the explorationresults and it had been verified by drilling.