The Research Of Kirchhoff Pre-Stack Depth Migration In TTI Media

With the deepening development of oil and gas,the requirement on seismic exploration techniques have become more and more sophisticated,such as: it demands processed stack section to characterize the structure formation,thin features,changes in lithology and fluid properties,etc.more accurately and finely.The seismic migration imaging is one of the key parts in seismic data processing,and the presence of anisotropy will cause inaccurate seismic wave energy home position,low image resolution,and poor signal to noise ratio.So during the migration process,we need to fully consider the effect of anisotropy.In addition,as Kirchhoff integral pre-stack depth migration method has the advantage of strong adaptability,flexible handling,and high efficiency,it has always been occupied an important position in actual production.In this paper,we first analyzed research status of the Kirchhoff integral pre-stack depth migration imaging method and of anisotropic media,and described the research background and significance of this main research contents.Then we studied the theory of isotropic pre-stack depth migration Kirchhoff integral method,and carried out tests on classical model;Afterwards,considered the poor effects of the methods metioned above,we performed preserved amplitude Kirchhoff integral method pre-stack depth migration imaging,and tested it on both simple and complex model.After added some security measures amplitude,the image of the two models has improved significantly.But the test results on Hess model showed that in anisotropic media,even if we use the pre-stack depth migration amplitude preserving Kirchhoff integral method,we still cannot get efficient and clear imaging section,and the convergence effect of diffraction wave is very poor.Therefore,this article continues to study the migration imaging in anisotropic media,especially for TTI media..In order to carry out the accurate Kirchhoff integral pre-stack depth migration imaging in TTI media,based on the basic theory of anisotropic media,combing the Kelvin-Christoffel equations and phase velocity and group velocity in anisotropic media,we summarized and analyzed tracing methods in TI medium.Then,by deriving the equation of the TTI medium based on the matrix transformation,and used the three-dimensional dynamic programming travel time calculation method to calculate the travel time of TTI medium,we realized the Kirchhoff integral pre stack migrating method in TTI medium.Next we applied this method on simple VTI media,TTI media model and complex model.The results on multiple anisotropic media model data show that the proposed method can accurately carry out the imaging of the TTI medium,and the imaging profile and the horizon information are clear.