电磁法勘探中梯度场测量方法研究

发布时间：2018-04-24 11:07

本文选题：电磁法 + 梯度测量　；参考：《仪器仪表学报》2017年04期

【摘要】：梯度测量对提高电磁法勘探的分辨能力和压制环境噪声干扰具有重要意义。通过硬件差分直接测量梯度场和先测量绝对场后经软件差分计算求取梯度场是实现电磁梯度数据获取的两种典型方式。给出了这两种测量方式的具体实现方案,并对测量效果进行了对比分析,探究了误差来源和压制方法。研究表明,测量通道的不一致性,尤其是相位差是影响电磁梯度测量准确性的关键因素。对于硬件差分直接测量梯度场而言,这种通道不一致引起的误差难以通过事后校准的方法消除,且误差大小随梯度值减小而急剧增加,最终不可用。先测量绝对场后进行软件差分的方法,可以得到更小的测量误差,而且通过通道校准后,测量精度得到进一步提高。在不能确保采集通道高度一致的情况下,先测量绝对场再求取梯度场的方式是实现电磁梯度测量的最优途径,该方法还可以同时获取绝对场以辅助梯度数据解释。该研究成果为电磁梯度系统开发提供了有益参考。依据该方法所研制的频率域电磁场梯度采集系统在江苏滩涂获得的实验结果也证明了该测量方法的优越性。
[Abstract]:Gradient measurement is of great significance to improve the resolution of electromagnetic exploration and to suppress noise interference in the environment. It is two typical ways to obtain the electromagnetic gradient data by measuring the gradient field directly by the hardware differential and measuring the absolute field first after the measurement of the absolute field. This gives the concrete realization of the two kinds of measurement methods. The result of the measurement is compared and analyzed, and the error source and the suppression method are explored. The research shows that the inconsistency of the measurement channel, especially the phase difference is the key factor affecting the accuracy of the electromagnetic gradient measurement. For the gradient field of the hardware differential direct measurement, the error caused by this channel inconsistency is difficult to be calibrated afterwards. The method is eliminated, and the size of the error increases sharply with the decrease of the gradient value, and it is not available at last. The method of software difference after measuring the absolute field can get smaller measurement error, and the measurement accuracy is further improved after the channel calibration. The absolute field is measured first when the height of the collection channel can not be ensured. The method of obtaining the gradient field is the best way to realize the measurement of the electromagnetic gradient. The method can also obtain the absolute field at the same time to assist the interpretation of the gradient data. The results provide useful reference for the development of the electromagnetic gradient system. The experimental results obtained by the frequency domain electromagnetic gradient recovery system developed in this method are obtained in the Jiangsu beach. The superiority of the method is also proved.

【作者单位】：吉林大学地球信息探测仪器教育部重点实验室;吉林大学仪器科学与电气工程学院;
【基金】：吉林省重点科技攻关项目(20150204021G X) 国家重大科学仪器设备开发专项(2011YQ030133)资助
【分类号】：P631.325

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