| 基于重构激发信号的电磁式可控震源相关检测参考信号方法研究 |
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| 引用本文： | 杨志超,姜弢,徐学纯,林君,贾海青,马瑞琪,陈振振.基于重构激发信号的电磁式可控震源相关检测参考信号方法研究[J].地球物理学报,2016,59(1):318-329. |
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| 作者姓名： | 杨志超 姜弢 徐学纯 林君 贾海青 马瑞琪 陈振振 |
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| 作者单位： | 1. 吉林大学仪器科学与电气工程学院, 长春 130061;2. 地球信息探测仪器教育部重点实验室(吉林大学), 长春 130061;3. 吉林大学地球科学学院, 长春 130061 |
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| 基金项目： | 深部探测技术与实验研究专项SinoProbe-09-06(201311197;201011083),SinoProbe-09-04(201011081)和高等学校博士学科点专项科研基金(20110061110053)联合资助. |
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| 摘 要： | 针对电磁式可控震源地震数据的相关检测,研究发现,在地下结构复杂、基板-大地耦合不佳时,常规方法——基于震源控制信号或基板附近信号作为参考信号检测得到的地震记录中,存在子波到时误差和虚假多次波问题.本文分析了上述问题的理论原因,并提出基于重构激发信号的相关检测参考信号方法(Correlation Detection Reference Signal Based on the Reconstructed Excitation Signal,CDRSBRES).首先,利用直达波与其他地震波到时不一致的特点,从震源基板附近信号中分离、提取直达波.然后,利用直达波重构震源激发信号并作为参考信号对地震数据进行相关检测.最后,应用谱白化技术提高检测结果质量.数值模拟研究表明,重构激发信号与理想激发信号的相关系数为0.9869,达到高度线性相关,CDRSBRES方法检测的地震记录在子波到时和波形特征上均与模型相符.随后,在某金属矿区开展了可控震源对比实验.与液压式可控震源MiniVib T15000检测结果相比,电磁式可控震源PHVS 500的检测结果中:基于震源控制信号的检测结果存在子波到时误差约0.012s,对应垂向精度误差约11.16m;基于基板附近信号的检测结果部分区域出现虚假多次波,信噪比降低;而CDRSBRES方法的检测结果子波到时误差约0.001s,对应垂向精度误差约0.93m,波形特征一致,相同区域无虚假多次波.综上,本方法适用于电磁式可控震源地震数据的高精度检测,尤其对于地下结构复杂区域的高分辨率地震勘探具有重要意义.
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| 关 键 词： | 电磁式可控震源 相关检测 参考信号 激发信号 重构 |
| 收稿时间： | 2014-12-09 |
Research on correlation detection reference signal based on the reconstructed excitation signal for electromagnetic seismic vibrator |
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| YANG Zhi-Chao,JIANG Tao,XU Xue-Chun,LIN Jun,JIA Hai-Qing,MA Rui-Qi,CHEN Zhen-Zhen.Research on correlation detection reference signal based on the reconstructed excitation signal for electromagnetic seismic vibrator[J].Chinese Journal of Geophysics,2016,59(1):318-329. |
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| Authors: | YANG Zhi-Chao JIANG Tao XU Xue-Chun LIN Jun JIA Hai-Qing MA Rui-Qi CHEN Zhen-Zhen |
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| Institution: | 1. College of Instrument Science and Electrical Engineering, Jilin University, Changchun 130061, China;2. Key Laboratory of Geo-exploration Instruments, Ministry of Education of China(Jilin University), Changchun 130061, China;3. College of Earth Science, Jilin University, Changchun 130061, China |
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| Abstract: | The electromagnetic seismic vibrator has wide application prospect in high resolution seismic exploration. However, in searching of correlation detection reference signal for electromagnetic seismic vibrator, two conventional methods both have problems compared to hydraulic seismic vibrator in the condition that the subsurface media is complex or the base-plate is poorly coupled with ground. One method that based on the control-signal will cause error of wavelet arrival time. The other one that based on the near base-plate signal will cause error of waveform characters, called false multiple waves in this paper. This paper analyzes the errors above systematically and then proposes a method called correlation detection reference signal based on the reconstructed excitation signal(CDRSBRES). Firstly, the direct wave is separated and extracted from the near base-plate signal according to different arrival time among the direct wave and other seismic waves. Secondly, applying the extracted direct wave to reconstruct the vibrator excitation signal as the reference signal to detect the seismic data. Finally, the spectral whitening is used to improve the quality of detected result, such as the SNR and resolution. This paper designs a horizontal layer model to confirm the CDRSBRES method. The simulation data demonstrates that the correlation coefficient between the reconstructed excitation signal and the ideal excitation signal is 0.9869, up to high linear correlation. The correlation detected record by CDRSBRES method is consistent with the designed model not only on wavelet arrival time but also on waveform characters. Then a comparison experiment is carried out at one metal deposit in West China. It uses the correlation detected record of the hydraulic seismic vibrator MiniVib T15000 as a standard. Compared to MiniVib T15000, there are different results for the electromagnetic seismic vibrator PHVS 500. The 0.012 s error of wavelet arrival time is detected based on the control-signal method, corresponding error of vertical position is about 11.16 m. The false multiple waves are detected based on the near base-plate signal method and it drops the SNR of detected record. But the error of wavelet arrival time is only 0.001 s, corresponding error on vertical position is down to 0.93 m. The waveform characteristic is consistent, no false multiple waves detected at the same zone using CDRSBRES method. In summary, the CDRSBRES method can be used for high precision detection of electromagnetic seismic vibrator data, especially for the region where the subsurface media is complex. It is of great significance for high resolution seismic exploration. |
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| Keywords: | Electromagnetic seismic vibrator Correlation detection Reference signal Excitation signal Reconstruction |
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