海底电磁接收机新进展

New progress of ocean bottom electromagnetic receiver

海洋电磁法广泛用于物理海洋学、地球物理学、水下目标检测等领域,以上研究及应用均建立在对海洋环境下的电磁场信号高精度观测基础上。用于海底电磁场高精度观测的海底电磁接收机,需要解决仪器的高可靠性投放回收、高稳定性水下作业、低噪声、大动态范围、低时漂等一系列技术难题。文中介绍了中国地质大学(北京)近些年来在海底电磁接收机研制方面为达到以上目标所取得的一些经验、成果以及最新进展。新海底电磁接收机的典型电场本底噪声为槡0.1 n V/m/Hz@0.5 Hz,动态范围大于110 d B,时漂小于5 ms/day,与国外同类先进产品技术指标平齐。截止到2016年初,累计完成了约60站位的海底电磁数据采集作业,2012年以来接收机回收率达到100%,获取了多批次高质量的海底MT及CSEM资料,研制的接收机成功应用于水合物勘查及油气勘探领域。

The marine electromagnetic method has been widely used in physical oceanography, geophysics and underwater target detection. These applications should be based on high precision electromagnetic signal observation in the marine environment. The ocean bottom electromagnetic receiver designed for high precise ocean bottom electromagnetic observation should overcome some technical problems such as high reliable release and recovery, high stable underwater operation, low noise level, high dynamic range, and low time drift. The research experience and results as well as the latest developments of ocean bottom electromagnetic receiver from China University of Geoseiences （Beijing） were reported in this paper. The new ocean bottom electromagnetic receiver＇s indicators are as follows ： typical E-field noise： 0.1 nV/m/√Hz @ 0.5 Hz; dynamic range： higher than 110 dB; clock drift： lower than 5 ms/day, in line with advanced receivers of other countries. By early 2016, ocean bottom electromagnetic data acquisitions on about 60 sites had been completed. Since 2012, the receiver＇s recovery rate has reached 100%. A lot of high-quality ocean bottom magnetotelluric data as well as controlled-source electromagnetic data were obtained by these receivers, which have been successfully used in oil-gas and hydrate explorations.