Because of the different excitation conditions of the airgun source,there will be subtle differences in airgun signals.Travel time variation of airgun signals often mix into source information which can’t fully refle...Because of the different excitation conditions of the airgun source,there will be subtle differences in airgun signals.Travel time variation of airgun signals often mix into source information which can’t fully reflect the evolution of the medium.This article uses the airgun signals from the Binchuan Transmitting Seismic Station to analyze the airgun signal′s characteristics of phase and correlation.We conducted a comparative analysis of the effects of the pair difference method and the deconvolution method on eliminating the influence of the excitation conditions in travel time variation.The results show that:(1)The pressure pulse and its subsequent wave of airgun source wavelet are less affected by excitation conditions that we can use it to obtain high-precision excitation moments.(2)Deconvolution can improve the correlation of the airgun signal.(3)The pair difference method can’t eliminate the influence of excitation conditions in travel time variation.Deconvolution can reduce excitation condition interference and the influence of the excitation condition in the travel time variation after deconvolution of the vertical signal is significantly reduced.展开更多
Seismic signal denoising is a key step in seismic data processing.Airgun signals are easy to be interfered with by noise when it travels a long distance due to the weak energy of active source signal of the airgun.Aim...Seismic signal denoising is a key step in seismic data processing.Airgun signals are easy to be interfered with by noise when it travels a long distance due to the weak energy of active source signal of the airgun.Aiming to solve this problem,and considering that the conventional Curvelet transform threshold processing method does not use the seismic spectrum information,we independently process the Curvelet scale layer corresponding to valid data based on the characteristics of the Curvelet transform of multi-scale,multi-direction and capable of expressing the sparse seismic signals in order to fully excavate the information features.Combined with the Curvelet adaptive threshold denoising the algorithm,we apply the Curvelet transform to denoising seismic signals while retaining the weak information in the signal as much as possible.The simulation experiments show that the improved threshold denoising method based on Curvelet transform is superior to the frequency domain filtering,wavelet denoising and traditional Curvelet denoising method in detailed information extraction and signal denoising of low SNR signals.The calculation accuracy of the relative wave velocity variation of underground medium is improved.展开更多
This paper summarizes the basic situation of the Binchuan Transmitting Seismic Station and the geophysical observations of the area where it is located,with a focus on the constitution of the observation system of the...This paper summarizes the basic situation of the Binchuan Transmitting Seismic Station and the geophysical observations of the area where it is located,with a focus on the constitution of the observation system of the transmitting seismic station,the excitation characteristics and propagation distance of signals excited by the airgun source in the reservoir and well. The paper also summarizes and discusses on the results of the observations and problems encountered since the Transmitting Seismic Station was built.Finally,this paper proposes the main research to be carried out on the basis of the project aims.展开更多
基金jointly sponsored by the National Natural Science Foundation of China(41574059,41474048)Seismological Science and Technology Spark Program of China Earthquake Administration(XH16028)Scientific Research Fund of Institute of Seismology and Institute of Crustal Dynamics,China Earthquake Administration(IS201726164)
文摘Because of the different excitation conditions of the airgun source,there will be subtle differences in airgun signals.Travel time variation of airgun signals often mix into source information which can’t fully reflect the evolution of the medium.This article uses the airgun signals from the Binchuan Transmitting Seismic Station to analyze the airgun signal′s characteristics of phase and correlation.We conducted a comparative analysis of the effects of the pair difference method and the deconvolution method on eliminating the influence of the excitation conditions in travel time variation.The results show that:(1)The pressure pulse and its subsequent wave of airgun source wavelet are less affected by excitation conditions that we can use it to obtain high-precision excitation moments.(2)Deconvolution can improve the correlation of the airgun signal.(3)The pair difference method can’t eliminate the influence of excitation conditions in travel time variation.Deconvolution can reduce excitation condition interference and the influence of the excitation condition in the travel time variation after deconvolution of the vertical signal is significantly reduced.
基金sponsored by the National Natural Science Foundation of China(41574059,41474048)sponsored by the State Key Laboratory of Earthquake Dynamics,CEA(LED2016B06)
文摘Seismic signal denoising is a key step in seismic data processing.Airgun signals are easy to be interfered with by noise when it travels a long distance due to the weak energy of active source signal of the airgun.Aiming to solve this problem,and considering that the conventional Curvelet transform threshold processing method does not use the seismic spectrum information,we independently process the Curvelet scale layer corresponding to valid data based on the characteristics of the Curvelet transform of multi-scale,multi-direction and capable of expressing the sparse seismic signals in order to fully excavate the information features.Combined with the Curvelet adaptive threshold denoising the algorithm,we apply the Curvelet transform to denoising seismic signals while retaining the weak information in the signal as much as possible.The simulation experiments show that the improved threshold denoising method based on Curvelet transform is superior to the frequency domain filtering,wavelet denoising and traditional Curvelet denoising method in detailed information extraction and signal denoising of low SNR signals.The calculation accuracy of the relative wave velocity variation of underground medium is improved.
基金jointly sponsored by the National Natural Foundation of China(41474048)the Special Fund of Academician Chen Yong Workstation Project of Yunnan Province(2014IC007)
文摘This paper summarizes the basic situation of the Binchuan Transmitting Seismic Station and the geophysical observations of the area where it is located,with a focus on the constitution of the observation system of the transmitting seismic station,the excitation characteristics and propagation distance of signals excited by the airgun source in the reservoir and well. The paper also summarizes and discusses on the results of the observations and problems encountered since the Transmitting Seismic Station was built.Finally,this paper proposes the main research to be carried out on the basis of the project aims.
