| In the central block of Junggar basin,especially in blocks 2 and 4,the surface dunes fluctuate greatly,and the low deceleration belt is very thick,which makes the problems of static correction and absorption attenuation particularly prominent.At the same time,the noise types are various.All of that bring great difficulties to the accurate seismic imaging in this area.At present,there is no standard processing flow for desert area,the existing geophysical exploration technology and methods are not mature enough,lack of systematic theoretical guidance,there are many blindness in the selection of processing methods,and the pertinence of test work is not strong enough.Through the fine investigation of near surface structure in the central of Junggar basin,the accurate near surface model is established,the near surface seismic response and absorption attenuation characteristics of the area are clarified,and the main factors affecting the quality of original seismic data are determined.The relationship between the near surface Q value and the near surface velocity is studied,forming the near surface Q-body establishment technology;the viscoelastic wave equation extension algorithm is studied,forming the near surface absorption compensation technology based on the viscoelastic wave equation wave field extension,obviously improving the effective wave reflection energy and frequency.The cross array coherent noise suppression technology,quasi four-dimensional random noise suppression technology and other complex multi domain interference suppression technology are researched and developed,which significantly improves the signal-to-noise ratio of seismic data.The influence analysis of the floating datum in the great desert area is completed,and the best floating datum is determined;the Fresnel tomographic inversion static correction technology with low measurement data constraint is completed,which improves the static correction processing precision in the great desert area;the static correction technology research of the dune curve in the great desert area is completed,and the better application effect is obtained in the actual data processing.The actual data are migrated in common offset and OVT domain by Kirchhoff prestack time,and the appropriate migration method in the current exploration process is defined.Through this research,we have formed a processing method and efficient processing flow for the seismic data in the desert area,and tested it in the old data repeated processing,the new processing effect is better to reflect the characteristics of the geological body,the processing flow is tested in the current mainstream high-density data,and the efficiency can not meet the actual production needs,with the development of software and hardware,it is believed that the further optimization algorithm can be realized,so that these methods can be better applied to the actual data processing in the large desert area. |
