Research And Application On Prestack Time Migration Of Complex Fault Block Group

As the difficulty of modern seismic exploration is increasing,the faced geological conditions are more and more difficult,the regional structures are more and more complicated,and the demand for imaging precision is higher and higher.As the dominant technology of seismic migration imaging,prestack time migration(PSTM)has always been the primary choice to deal with the image problem of seismic data in complex geological areas.Therefore,the research on high-precision imaging of PSTM has its practice significanceIn this paper,two kinds of prestack time migration methods are compared firstly,and further we discuss their characteristics.According to the unique advantages of Kirchhoff integral method,the Kirchhoff integral method is selected as the research method in high precision imaging of prestack time migration,secondly,high quality CMP path is set as the base data to carry out the optimization analysis of the velocity parameters of the prestack time migration,and we combines the actual conditions of the BM area to analyze the other parameters.Then the influence of imaging accuracy is analyzed.Finally,the processing effect is analyzed and compared with the previous data.Through the research of high precision imaging of PSTM in BM area,We find that the accuracy of seismic data is closely related to signal-to-noise ratio,especially in the research area with complex fault block characteristics.Therefore,in the research process of this thesis,some key prestack noise attenuation technologies to improve the signal-to-noise ratio of seismic data.On the premise of high signal to noise ratio of seismic data,the imaging problem of complex block group can be effectively solved by using fine speed analysis technique and prestack time migration technique.After the study on the selection of prestack time migration parameters and the establishment of the velocity field,this paper takes the BM area as an example to carry out practical application and analyses the effect of the new and old seismic processing sections.Finally,a set of processing methods suitable for complex block group with low signal-to-noise ratio is summarized,and it has better imaging results compared with the previous data.