基于MEMS的槽波地震仪采集效果试验研究

Experimental Study on the Effect of Data Acquisition with In-seam Wave Seismograph Based on MEMS

目前槽波探测中的采集工作通常是通过数字地震仪配合动圈检波器来实现的,动圈检波器在频带宽度、抗干扰能力及自身重量方面仍有一定提升空间。同时,煤矿井下干扰严重、运输条件差、槽波震源频带宽度大,常规的数据采集系统有一定的局限性。地面MEMS(Micro-Electro-Mechanical System)全数字检波器相对于动圈检波器具有动态范围大、频带宽、设备轻、受电磁干扰影响小的特点。为了减少井下环境对槽波探测技术的影响,本文将MEMS加速度计引入到煤矿井下地震勘探,利用自主研发的基于MEMS的槽波地震仪开展了与传统的动圈检波器采集系统对比试验,进行了透射槽波和反射槽波的波场分析,并对对比数据分别进行了偏移成像。实验证明,基于MEMS的槽波地震仪除了在仪器重量有一定优势外(100道设备总重量大约相当于集中式地震仪的25%),采集的数据波形连续性更好,频带宽度大约高于动圈检波器200 Hz,偏移成像结果中巷道及断层反应更明显。

At present,the acquisition system commonly used in in-seam wave detection is realized by the digital seismometer in cooperation with the dynamic coil detector.The dynamic coil detector still has some room for improvement in the bandwidth,anti-interference ability and its own weight.At the same time,the conventional data acquisition system has certain limitations due to the serious interference,poor transportation conditions and large frequency bandwidth of the channel wave source in the coal mines.Compared with the dynamic coil detector,all digital detector based on MEMS(micro-electro-mechanical system)has the characteristics of large dynamic range,wide frequency band,light equipment and little electromagnetic interference.In order to reduce the impact of the underground environment on the in-seam wave detection technology,this paper introduces the MEMS accelerometer into the underground seismic exploration of the coal mines.The self-developed in-seam wave seismograph based on MEMS is used to carry out the comparative test with the traditional dynamic coil geophone acquisition system,followed by the wave field analysis of the transmission groove wave and the reflection groove wave and the migration imaging of the comparative data respectively.Experiments show that MEMS based on in-seam wave seismometers have certain advantages in terms of instrument weight(the total weight of 100 channels of equipment is approximately 25%that of a centralized seismometer),and the collected data waveform has better continuity.The frequency band width is about 200 Hz higher than that of the moving coil detector,and the migration imaging results show more obvious reflection on tunnels and faults.