Adaptive Elimination Of Low Frequency Noise In Fiber Ocean Bottom Seismic Systeme

Fiber Ocean Bottom Seismic System has the characteristics of strong electromagnetic interference resistance,easy to large-scale array,and so on.It is an important development direction of offshore oil and gas exploration.However,the background noise of the Fiber Ocean Bottom Seismic System is greatly affected by the factors of the system itself and the external interference,especially for the low-frequency part for seismic exploration,which is more seriously disturbed by the environment.In this paper,the low-frequency noise of o Fiber Ocean Bottom Seismic System is studied,which is of great significance to promote the application of the system in oil and gas exploration.Based on the analysis of seismic detection system noise,this paper studies the application of adaptive noise suppression method in seismic detection system,and the main conclusions and innovation points are:1.The source and characteristics of low frequency noise in Fiber Ocean Bottom Seismic System are analyzed.Low frequency noise of the laser noise,transmission noise generated by optical fiber temperature and stress change,the Rayleigh scattering noise and amplifier noise on of each geophone are strongly similarity,suitable for the use of adaptive eliminating noise suppression;2.The strengths and weaknesses of minimum mean square error(LMS),normalized least mean square error(NLMS)and recursive least squares(RLS)are deeply contrasted.The simulation results show that both single frequency noise and broadband noise can be suppressed by adaptive elimination.The noise reduction effect of adaptive elimination better than that of DS under the condition of the phase of noise in the reference channel and sensing channel are difference.3.Carry out a systematic experimental study of adaptive noise suppression simulation in Fiber Ocean Bottom Seismic System.In practical system,the noise suppression ability of adaptive elimination is better than that of DS,and the performance of NLMS is higher than that of LMS and RLS when considering the noise suppression ability and calculation amount.At the low frequency of 100 Hz,NLMS can be used to suppress laser noise by 10 dB,100km remote transmission system by 9dB,and the 100 km transmission system with EDFA by 6dB.