Research On Low-frequency Seismic Processing Techniques Constrained By Stationary Broadband Signals

With the deepening of seismic exploration,Shengli Oilfield has entered the lithology exploration stage.Facing the exploration problems of complex fault blocks and thin interbeds,we put forward higher requirements for the resolution of seismic data.The improvement of resolution is not only the improvement of high frequency signal,but also the improvement of low frequency signal.And the low frequency signal plays an important role in speed inversion,improving resolution and hydrocarbon detection.So low frequency acquisition and processing are necessary.In terms of low-frequency acquisition,one of the current practical methods is to use the wide-band seismograph and 20 DX detector jointly to collect wide frequency band and high S/N seismic data.And the method achieves low frequency acquisition under existing reception conditions.Based on the low-frequency data and conventional three-dimensional data acquired simultaneously,the paper analyzes the signal characteristics of the wide-band seismograph and the conventional detector in detail.Through the comparison of the differences between the two detectors,we analyze the factors effecting reliability of least effective frequency,propose the method obtaining least effective frequency,and construct the inverse filter operator.The related research work of using wide-band seismograph to collect signals to extend the low-frequency end of conventional acquisition data was carried out.The embedded link of low-frequency correction in the whole process flow was tested and analyzed,and corresponding conclusions were obtained.Finally,the low-frequency processing technology was optimized and formed,and a method and process for processing low frequency recovery of conventional detector data is constructed.Through the processing of the actual data in the target area,the seismic data of the conventional detector after low frequency recovery is obtained,and the correctness and reliability of the method are tested,.Based on this,the optimization and improvement of the processing technology for low frequency seismic data is carried out.The low frequency processing results have been applied in geological interpretation.The actual processing of the target area data shows that the technology can effectively recover the low-frequency information of the conventional detector data,achieve the purpose of broadening the low-frequency end signal and effective octave of the seismic data,and improve the ability of seismic data to solve lithological problems.It has broad vision of application.