Refraction First-Break Automatic Residual Static Corrections By Using Difference Method For The Seismic Wave Signals

Residual static corrections play an important role in general seismic data processing flow. And that it is resolved well or not directly determine the effect and accuracy of the seismic exploration. So it has become a key problem that constricts seismic exploration.Nowadays the techniques of reflection waves based residual static corrections always choose well-continual and high S/N ratio reflection layer as reference layer and make piloted trace on CMP stacked section. Then the residual static corrections of source and receiver are calculated by using cross-correlation. But when the S/N ratio of reflection wave is low on stacked section, the reflection residual static corrections are invalid because we can't build a right piloted trace.. Base on this instance, we put forward the residual static corrections technique by using refraction first breaks. Otherwise, the most techniques of residual static corrections are based on first-break pick up time. The effect and accuracy of the first-break picking up become an important thing for the processing well or not to the residual static corrections. The technique of first-break picking up is not work well for the low S/N ratio data of the complex areas, and bring a few error for the the statics caculating.To solve serious static corrections problems in complex near-surface areas of western China, different refraction first-break statics methods are studied in this thesis. The paper presented a new method of refraction first-break automatically residual-static correction in the face of the problems that the residual-static corrections techniques have today. The method doesn't need first-break times of refraction waves. Firstly, it carries out the LMO (linear moveout) to the seismic data, and then calculate the time difference of each adjacent trace by using cross-correlation method in the common shot gathers. Secondly, the linear equations are constructed according to the different feature of 2D and 3D surveillance system. Finally, the residual statics have been obtained by using recursion and sum method to solve 2D equations and Gauss-Seidel iterative to solve 3D equations. Theoretical modeling and practical data processing show that the residual static corrections by using refraction first-break waves given in this paper is practical and feasible to the high frequency residual statics.