The Research On Key Summing Processing Techniques Of Ocean Bottom Cable Dual-sensor Seismic Data

The ocean bottom cable(OBC)dual-sensor seismic data acquisition technology overcomes the shortcomings of conventional towed cable acquisition technology.In obstacle or shallow water areas,it is easy to implement wide azimuth acquisition by using geometry consistent with onshore 3D seismic exploration.The dual-sensor seismic data combination process can effectively suppress the reverberation and ghost wave.Compared with conventional processing,dual-sensor seismic data processing has its own characteristics and requires specific processing techniques and processing flows.The scopes of the study include the influence of the dual-sensor different response mechanism on the seismic data and their correction methods,the noise suppressing method of the dual-sensor seismic data,the OBC data combination technique and migration method.The hydrophone and geophone have different response mechanisms to the upand down-going wave fields.This is the basis to eliminate the ghost wave and reverberation of the water layer by dual-sensor data combining processing.Based on the working principle of the two sensors,the differences in amplitude and phase were analyzed and corrected.Noise suppression is the precondition of dealing with dual-sensor seismic data.The reflection coefficient in dual-sensor combined processing is calculated by hydrophone and geophone corresponding amplitude,which requires more care for noise attenuation.According to the noise characteristics of the dual-sensor seismic data,this dissertation proposes a noise treatment process for the hydrophone data and the geophone data,and maintains the consistency of the relative amplitude of the dual-sensor seismic data to the greatest extent.This dissertation analyzed the factors which affect the effect of the suppressing of ghost wave and reverberation.The cross-ghost wave method is used to correct the geophone data,and a new dual-sensor data-mixing autocorrelation function method is proposed to obtain the reflection coefficient,which improves the combination effect of the dual-sensor seismic data.In the case of OBC dual-sensor seismic data imaging processing,The up-and-down wave field joint least squares reverse time migration(LSRTM)processing is realized,which makes full use of the advantage that the dual-sensor data is easy to be separated.Compared with the up-going wave reverse time migration,the new method is more advantageous in terms of migration,eliminating acquisition footprints,and improving signal-to-noise ratio.Based on these studies,a new treatment concept for the OBC dual-sensor seismic data combination has been proposed and a new processing flow has been constructed,which effectively improved the processing quality of OBC dual-sensor seismic data.