The influence of wavelet delay on the migration imaging accuracy
The imaging problems of common shot data with prestack reverse time migration method are solved with the seismic source wave field forward continuation and the observed wave field backward continuation in depth direction at the same time. In order to obtain imaging value, the conventional method is that the two wave field carry out cross correlation at the same time and stack the cross correlation value at all the same time. This method is fit for the case where the seismic wavelet is a pulse or minimum phase. However, in generally speaking, the event picked from seismic data is the peak of seismic wavelet which has a short time delay relative to the wavelet initial time. It subsequently results in some imaging position errors in cross correlation method. In this paper, theoretical seismic data are simulated and migrated by wave equation finite element prestack reverse time migration program with cross correlation imaging conditions. The influence of the wavelet delay both in seismic source wave field and observed wave field on the imaging accuracy is discussed. Numerical experiments demonstrate that the influence of wavelet delay on the position error is related to the relative delay length of the peak of wavelet in the two wave fields and the medium velocity around the reflection point. Our results provide a theoretical reference for the selection of seismic wavelet, which is important to the application of the cross correlation imaging conditions in prestack reverse time migration method. Some advice is given at last.
cross correlation imaging conditions wavelet delay finite element method reverse time migration
Wen Tang
Key Laboratory of Geophysical Exploration, CNPC, China University of Petroleum, Beijing 102249 China School of Petroleum Resources, Xi an Shiyou University, Xi an 710054, China
国际会议
成都
英文
275-279
2010-06-14（万方平台首次上网日期，不代表论文的发表时间）