Vertical Cable Seismic Data Multiple Wave Imaging Technology

High-precision natural gas hydrate seismic exploration requires a variety of detection methods to cooperate with each other.Vertical cable seismic exploration technology has become an indispensable part of marine three-dimensional seismic exploration due to its wide-angle,wide-band,easy-to-identify large-angle layer.The biggest feature of the Vertical cable seismic observation system is that its shots are excited on the sea surface,and the detectors are arranged perpendicular to the sea floor in seawater.This special observation method causes the received wave field propagation path to be asymmetric,resulting in subsequent data processing,which technology is also different from conventional seismic data processing techniques.At present,vertical cable seismic is still in its infancy in China,and its seismic data processing technology is not mature enough to form a recognized and feasible industrialization process;Moreover,due to the high cost of the vertical cable,the number of placements during the collection is small,resulting in a narrow range of underground illumination.Based on the above two problems,I have used the multiwave image migration technique to broaden the illumination range of the effective wave field of the vertical cable seismic method;At the same time,a variety of unconventional seismic processing techniques were studied.Through a combination of tests,a set of processing procedures for vertical cable data was finally established.This series of processing methods together constitute a multi-wave imaging technology for marine vertical cable data.Based on the characteristics of vertical cables and multiple waves,this study specifically addresses the following issues: The real position of the vertical cable detector in water is determined by time slicing secondary positioning;the ghost reflection and bubble effect are suppressed by the vertical cable far-field wavelet deconvolution method;thorough the Kirchhoff wave field continuation technique,the shot is downward extended to the plane of the detection point,which solves the problem of asymmetric propagation of the wave field in the vertical cable seismic method;the shallow velocity field in the exploration area is obtained by the first arrival wave travel time tomography inversion technique;The multiple waves are imaged as effective waves,which solves the problem of insufficient underground illumination range;combining the above special processing techniques with conventional seismic processing techniques to establish a reliable vertical cable multiple wave imaging technology flow.