Topography Pre-stack Time Migration And Parallel Implementation

We know that the current oil exploration, as exploration areas in the western deflection, but the western region of the surface complex, dramatic changes in surface elevation, old rock Chula, causing the surface low with a relatively high rate, some even close to the next stratum speed, complex underground geological conditions, over-thrust faults and more, resulting in velocity modeling very difficult, thereby affecting the accuracy of seismic migration imaging.Present in practical applications bending ray Kirchhoff pre-stack time migration to its advantages in a wide range of applications, but regular applications such as CGG, GEODEPTH are all base-level or application level of the ultimate base level for partial pre-stack time shift. In these relatively flat surface offset for the surface and underground geology is relatively simple situation. But in the western region, the complex surface'and subsurface geological conditions in the application of conventional pre-stack time migration has been difficult to obtain high-quality imaging.Therefore, in this paper proposed the application of non-symmetrical walking Kirchhoff pre-stack time migration algorithm, a smooth surface in the aperture offset pre-stack time migration to solve the complex surface seismic migration problem of poor accuracy. Asymmetric walking Kirchhoff pre-stack time migration in the travel time from the theoretical formula was introduced in odd, while the average travel time bending Kirchhoff formula, there is only the even entries. The introduction of the odd items into account lateral variation of seismic ground wave velocity. This can improve the accuracy of seismic imaging. And proposed to offset the elevation aperture on the surface to smooth, then the smooth surface after the calculation of pre-stack time migration, to achieve a total pore surface offset pre-stack time migration, which can improve the surface in the complex circumstances, migration accuracy,In addition to these two aspects, the effect of topography pre-stack time migration velocity model was discussed. In the current practical applications, pre-stack time migration a lot of calculation, the time spent in the conventional processing of seismic data is also the longest. This paper present new technologies and discuss the use of CPU and graphics processor, combined with parallel computing.Finally, through a large number of theoretical and practical data on the topography of the method is validated.