Research and Application of Uphole Constrained Tomographic Static Correction Technology

Summary In Western China, the surface structure is very complex and the terrain fluctuates severely. There are high-speed rock formation exposed and thick loess covered, at the same time, the thickness and velocity of the low-velocity zone vary drastically, the seismic energy is absorbed and attenuated seriously, so there is a serious static problem. Tomographic inversion static technology has obvious advantages in solving the static problem. However,the velocity models obtained from first break information inversion of different offsets are quite different under complex surface conditions. Therefore, uphole constraint tomographic static method is proposed, that is, the initial velocity model is constrained by uphole information to perform tomographic inversion. This method not only avoids the impact of high-velocity rays on the shallow layer during the inversion process, but also makes full use of the first break of the mid-to-far offsets, which can effectively improve the inversion accuracy of near surface velocity. The method solves the static problem with complex surface conditions in Western China, and significantly improves the quality of stacking sections.